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Preview: The International Journal of Medical Robotics and Computer Assisted Surgery

The International Journal of Medical Robotics and Computer Assisted Surgery

Wiley Online Library : The International Journal of Medical Robotics and Computer Assisted Surgery

Published: 2017-09-01T00:00:00-05:00


A comparative analysis and guide to virtual reality robotic surgical simulators


Background Since the US Food and Drug Administration approved robotically assisted surgical devices for human surgery in 2000, the number of surgeries utilizing this innovative technology has risen. In 2015, approximately 650 000 robot-assisted procedures were performed worldwide. Surgeons must be properly trained to safely transition to using such innovative technology. Multiple virtual reality robotic simulators are now commercially available for educational and training purposes. There is a need for comparative evaluations of these simulators to aid users in selecting an appropriate device for their purposes. Methods We conducted a comparison of the design and capabilities of all dedicated simulators of the da Vinci robot – the da Vinci Skills Simulator (dVSS), dV-Trainer (dVT), Robotic Skills Simulators (RoSS) and the RobotiX Mentor. This paper provides the base specifications of the hardware and software, with an emphasis on the training capabilities of each system. Results Each simulator contains a large number of training exercises for skills development: dVSS n = 40, dVT n = 65, RoSS n = 52, RobotiX Mentor n = 31. All four offer 3D visual images but use different display technologies. The dVSS leverages the real robotic surgical console to provide visualization, hand controls and foot pedals. The dVT, RoSS and RobotiX Mentor created simulated versions of all of these control systems. Each includes systems management services that allow instructors to collect, export and analyze the scores of students using the simulators. Conclusions This study provides comparative information on the four simulators' functional capabilities. Each device offers unique advantages and capabilities for training robotic surgeons. Each has been the subject of validation experiments, which have been published in the literature. But those do not provide specific details on the capabilities of the simulators, which are necessary for an understanding sufficient to select the one best suited for an organization's needs. This article provides comparative information to assist with that type of selection.

Trends in the diffusion of robotic surgery: A retrospective observational study


Background Recent studies have suggested that the use of robotic surgery for prostatectomy has been increasing, but characterization of the diffusion of robotic surgery in other procedures has not been available. Methods Data were analysed for the years 2006–2014 using hospital episode statistics (HES), a database of all admissions to National Health Service (NHS) hospitals in England. OPCS codes were used to determine the annual number of prostatectomy, partial nephrectomy, and total abdominal hysterectomy procedures. Concurrent OPCS codes were then used to identify whether these procedures were robotic, conventional laparoscopic or open surgery. Results The proportion of robotic cases varied depending on the surgical procedure. Diffusion of robotic surgery was relatively rapid in prostatectomy, moderate in partial nephrectomy, and slow in total abdominal hysterectomy. Conclusions Although high institutional cost might explain the earliest delays in diffusion, this barrier does not fully account for the different rates of diffusion among surgical procedures.

Semi-autonomous image-guided brain tumour resection using an integrated robotic system: A bench-top study


Background Complete brain tumour resection is an extremely critical factor for patients' survival rate and long-term quality of life. This paper introduces a prototype medical robotic system that aims to automatically detect and clean up brain tumour residues after the removal of tumour bulk through conventional surgery. Methods We focus on the development of an integrated surgical robotic system for image-guided robotic brain surgery. The Behavior Tree framework is explored to coordinate cross-platform medical subtasks. Results The integrated system was tested on a simulated laboratory platform. Results and performance indicate the feasibility of supervised semi-automation for residual brain tumour ablation in a simulated surgical cavity with sub-millimetre accuracy. The modularity in the control architecture allows straightforward integration of further medical devices. Conclusions This work presents a semi-automated laboratory setup, simulating an intraoperative robotic neurosurgical procedure with real-time endoscopic image guidance and provides a foundation for the future transition from engineering approaches to clinical application.

Feasibility of infrared tracking of beating heart motion for robotic assisted beating heart surgery


Background Accurate tracking of the heart surface motion is a major requirement for robot assisted beating heart surgery. Method The feasibility of a stereo infrared tracking system for measuring the free beating heart motion was investigated by experiments on a heart motion simulator, as well as model surgery on a dog. Results Simulator experiments revealed a high tracking accuracy (81 μm root mean square error) when the capturing times were synchronized and the tracker pointed at the target from a 100 cm distance. The animal experiment revealed the applicability of the infrared tracker with passive markers in practical heart surgery conditions. Conclusion With the current technology, infrared tracking with passive markers might be the optimal solution for accurate, fast, and reliable tracking of heart motion during robot assisted beating heart surgery.

Development of a physical shoulder simulator for the training of basic arthroscopic skills


Background Orthopaedic training programs are incorporating arthroscopic simulations into their residency curricula. There is a need for a physical shoulder simulator that accommodates lateral decubitus and beach chair positions, has realistic anatomy, allows for an objective measure of performance and provides feedback to trainees. Methods A physical shoulder simulator was developed for training basic arthroscopic skills. Sensors were embedded in the simulator to provide a means to assess performance. Subjects of varying skill level were invited to use the simulator and their performance was objectively assessed. Results Novice subjects improved their performance after practice with the simulator. A survey completed by experts recognized the simulator as a valuable tool for training basic arthroscopic skills. Conclusions The physical shoulder simulator helps train novices in basic arthroscopic skills and provides objective measures of performance. By using the physical shoulder simulator, residents could improve their basic arthroscopic skills, resulting in improved patient safety.

Modeling the convergence accommodation of stereo vision for binocular endoscopy


Background The stereo laparoscope is an important tool for achieving depth perception in robot-assisted minimally invasive surgery (MIS). Methods A dynamic convergence accommodation algorithm is proposed to improve the viewing experience and achieve accurate depth perception. Based on the principle of the human vision system, a positional kinematic model of the binocular view system is established. The imaging plane pair is rectified to ensure that the two rectified virtual optical axes intersect at the fixation target to provide immersive depth perception. Results Stereo disparity was simulated with the roll and pitch movements of the binocular system. The chessboard test and the endoscopic peg transfer task were performed, and the results demonstrated the improved disparity distribution and robustness of the proposed convergence accommodation method with respect to the position of the fixation target. Conclusions This method offers a new solution for effective depth perception with the stereo laparoscopes used in robot-assisted MIS.

A master manipulator with a remote-center-of-motion kinematic structure for a minimally invasive robotic surgical system


Background In robotic surgical systems, commercial master devices have limitations owing to insufficient workspace and lack of intuitiveness. To overcome these limitations, a remote-center-of-motion (RCM) master manipulator was proposed. Methods The feasibility of the proposed RCM structure was evaluated through kinematic analysis using a conventional serial structure. Two performance comparison experiments (peg transfer task and objective transfer task) were conducted for the developed master and Phantom Omni. Results The kinematic analysis results showed that compared with the serial structure, the proposed RCM structure has better performance in terms of design efficiency (19%) and workspace quality (59.08%). Further, in comparison with Phantom Omni, the developed master significantly increased task efficiency and significantly decreased workload in both experiments. Conclusions The comparatively better performance in terms of intuitiveness, design efficiency, and operability of the proposed master for a robotic system for minimally invasive surgery was confirmed through kinematic and experimental analysis.

Robotic-assisted versus open radical cystectomy in bladder cancer: A meta-analysis of four randomized controlled trails


Background Robot-assisted radical cystectomy (RARC) is increasing annually for treatment of bladder cancer. The objective of this meta-analysis was to compare the safety and efficacy of RARC and open radical cystectomy (ORC) for bladder cancer. Methods Our meta-analysis searches were conducted using PubMed, Web of Science, and Cochrane Library databases to identify randomized controlled trials (RCT) assessing the two techniques. Results Four RCT studies were identified, including 239 cases. Our studies indicated that RARC was associated with longer operative time (WMD: 69.69, 95% CI:17.25 to122.12; P= 0.009), lower estimated blood loss (WMD: –299.83, 95% CI:–414.66to −184.99; P<0.00001). The two groups had no significant difference in overall perioperative complications, length of hospital stay, lymph node yield and positive surgical margins. Conclusions RARC is mini-invasive alternative to ORC for bladder cancer. The advantage of RARC was reduced estimated blood loss. More studies are needed to compare the two techniques.

Improving the human–robot interface for telemanipulated robotic long bone fracture reduction: Joystick device vs. haptic manipulator


Objectives Intramedullary nailing is the treatment of choice for femoral shaft fractures. However, there are several problems associated with the technique, e.g. high radiation exposure and rotational malalignment. Experimental robotic assistance has been introduced to improve the quality of the reduction and to reduce the incidence of rotational malalignment. In the current study, we compare two devices for control of the fracture fragments during telemanipulated reduction. Methods Ten male and ten female subjects were asked to participate as examiners in this experiment. A computer program was developed to render and manipulate CT-based renderings of femur fracture bone fragments. The user could manipulate the fragments using either a simple joystick device or a haptic manipulator. Each examiner performed telemanipulated reduction of 10 virtual fracture models of varying difficulty with each device (five in a ‘training phase’ and five in a ‘testing phase’). Mixed models were used to test whether using the haptic device improved alignment accuracy and improved reduction times compared to using a joystick. Results Reduction accuracy was not significantly different between devices in either the training phase or the testing phase (P > 0.05). Reduction time was significantly higher for the Phantom device than for the Joystick in the training phase (P < 0.0001), but it was no different in the testing phase (P = 0.865). High spatial ability with electronics had a significant effect on the alignment of fracture reduction and time to reduction. Conclusions The Joystick and the Phantom devices resulted in similarly accurate reductions, with the Joystick having an easier learning curve. The Phantom device offered no advantage over the Joystick for fracture telemanipulation. Considering the high cost of the Phantom device and the lack of a demonstrable advantage over the Joystick, its use is not justified for implementation in a fracture telemanipulation workflow. The Joystick remains as a low-cost and effective device for developing 3D fracture telemanipulation techniques.

Comparison of algorithms for automated femur fracture reduction


Purpose We designed an experiment to determine the comparative effectiveness of computer algorithms for performing automated long bone fracture reduction. Methods Automated reduction of 10 3D fracture models was performed using two computer algorithms, random sample matching (RANSAM) and Z-buffering (Z-Buffer), and one of five options of post-processing: none; iterative closest point algorithm (ICP); ICP-X1; ICP-X2; and ICP-X3. We measured the final alignment between the two fragments for each algorithm and post-processing option. Results The RANSAM algorithm combined with postprocessing algorithm ICP-X1 or ICP-X3 resulted in the most accurate fracture reduction in the translational plane. No discernible difference was observed in the rotational plane. Automated reduction had more accurate translational displacement than telemanipulated manual reductions. Conclusion This study supports the use of the RANSAM algorithm for automated fracture reduction procedures. The use of ICP algorithms provides further optimization of the initial reduction.

A novel approach for intra-operative shape acquisition of the tibio-femoral joints using 3D laser scanning in computer assisted orthopaedic surgery


Background Image registration (IR) is an important process of developing a spatial relationship between pre-operative data and the physical patient in the operation theatre. Current IR techniques for Computer Assisted Orthopaedic Surgery (CAOS) are time consuming and costly. There is a need to automate and accelerate this process. Methods Bespoke quick, cost effective, contactless and automated 3D laser scanning techniques based on the DAVID Laserscanner method were designed. 10 cadaveric knee joints were intra-operatively laser scanned and were registered with the pre-operative MRI scans. The results are supported with a concurrent validity study. Results The average absolute errors between scan models were systematically less than 1 mm. Errors on femoral surfaces were higher than tibial surfaces (P<0.05). Additionally, scans acquired through the large exposure produced higher errors than the smaller exposure (P<0.05). Conclusion This study has provided proof of concept for a novel automated shape acquisition and registration technique for CAOS.

Single-incision robotic cholecystectomy is associated with a high rate of trocar-site infection


Background Single-incision robotic cholecystectomy has been developed to decrease post-operative pain and improve cosmetic results. Methods Thirty-seven patients underwent single-site robotic cholecystectomy between 2014 and 2015. Postoperative outcomes and costs were compared to reported outcomes for laparoscopic cholecystectomy using the configuration of suprapubic trocars. Results The median age was comparable between the two groups (46 years in the robotic group vs. 47 years in the laparoscopic group). The operative time was longer in the robotic group (132 minutes) than in the laparoscopic group (53 minutes). The average length of stay was 1 day in the robotic group and 1.7 days in the laparoscopic group. Costs were higher in the robotic group (2229.46 €) than in the laparoscopic group (1141 €). In the robotic group, the trocar-site infection rate was 13.5%. Conclusion The robotic approach does not seem to offer additional benefit in terms of surgical outcomes.

Finite element analysis of customized implant in mandibular reconstruction after tumor resection with and without using customized surgical osteotomy guide


Objectives The aim of this work was to compare different 12 cases (3 patients * 4 cases = 12 cases) with varying gaps between implant and bone by analyzing the effect of these gaps on implant and screws using FEM. Methods In each patient's case 1 using CSOG and in case 2, 3, and 4 without using CSOG tumor cutting was done. Hence in each patient zero gaps at case 1 and overcutting at case 2, 3, and 4 have obtained at different locations. Results FEM results reveal that in each patient's case 4 (maximum gap) was more susceptible to loosening of the screws due to higher strains (37%) and implant failure due to higher stress (28%) concentration under the same loading conditions when compared with case 1 (zero gap). Conclusions The study reveals that mandibular reconstruction with implant placement using CSOG can significantly enhance the stability and safety of the implant.

An automated skills assessment framework for laparoscopic training tasks


Background Various sensors and methods are used for evaluating trainees' skills in laparoscopic procedures. These methods are usually task-specific and involve high costs or advanced setups. Methods In this paper, we propose a novel manoeuver representation feature space (MRFS) constructed by tracking the vanishing points of the edges of the graspers on the video sequence frames, acquired by the standard box trainer camera. This study aims to provide task-agnostic classification of trainees in experts and novices using a single MRFS over two basic laparoscopic tasks. Results The system achieves an average of 96% correct classification ratio (CCR) when no information on the performed task is available and >98% CCR when the task is known, outperforming a recently proposed video-based technique by >13%. Conclusions Robustness, extensibility and accurate task-agnostic classification between novices and experts is achieved by utilizing advanced computer vision techniques and derived features from a novel MRFS.

Influence of surgical gloves on haptic perception thresholds


Background Impairment of haptic perception by surgical gloves could reduce requirements on haptic systems for surgery. While grip forces and manipulation capabilities were not impaired in previous studies, no data is available for perception thresholds. Methods Absolute and differential thresholds (20 dB above threshold) of 24 subjects were measured for frequencies of 25 and 250 Hz with a Ψ-method. Effects of wearing a surgical glove, moisture on the contact surface and subject's experience with gloves were incorporated in a full-factorial experimental design. Results Absolute thresholds of 12.8 dB and −29.6 dB (means for 25 and 250 Hz, respectively) and differential thresholds of −12.6 dB and −9.5 dB agree with previous studies. A relevant effect of the frequency on absolute thresholds was found. Comparisons of glove- and no-glove-conditions did not reveal a significant mean difference. Conclusions Wearing a single surgical glove does not affect absolute and differential haptic perception thresholds.

Development of a novel robotic platform with controllable stiffness manipulation arms for laparoendoscopic single-site surgery (LESS)


Background For current LESS robotic systems, the trade-off between dexterity and payload capability is always present. This paper presents a novel LESS robotic platform equipped with controllable stiffness manipulation arms. Methods Each manipulation arm with an articulated section and a controllable stiffness continuum section (CSCS) can be switched between a 7-DoF compliant status and 5-DoF rigid status according to the operation requirement. Screw theory and product exponential formula are used to quantify the kinematic performance. Results The stiffness of the manipulation arm promotes 3.03 to 4.12 times from compliant to rigid CSCS with maximum payload of 10 N in rigid status. The shortest rigid/compliant switching time is 5 s. The precision of a tracking test and an ex vivo procedure verified the accuracy and effectiveness of the controllable stiffness manipulation arms. Conclusions This robot could potentially improve the surgical performance and further expand robotic LESS procedures.

A comparison of operative outcomes between standard and robotic laparoscopic surgery for endometrial cancer: A systematic review and meta-analysis


Background Evidence has been systematically assessed comparing robotic with standard laparoscopy for treatment of endometrial cancer. Methods A search of Medline, Embase and Cochrane databases was performed until 30th October 2016. Results Thirty-six papers including 33 retrospective studies, two matched case–control studies and one randomized controlled study were used in a meta-analysis. Information from a further seven registry/database studies were assessed descriptively. There were no differences in the duration of surgery but days stay in hospital were shorter in the robotic arm (0.46 days, 95%CI 0.26 to 0.66). A robotic approach had less blood loss (57.74 mL, 95%CI 38.29 to 77.20), less conversions to laparotomy (RR = 0.41, 95%CI 0.29 to 0.59), and less overall complications (RR = 0.82, 95%CI 0.72 to 0.93). A robotic approach had higher costs ($1746.20, 95%CI $63.37 to $3429.03). Conclusion A robotic approach has favourable clinical outcomes but is more expensive.

Intraocular robotic interventional surgical system (IRISS): Mechanical design, evaluation, and master–slave manipulation


Background: Since the advent of robotic-assisted surgery, the value of using robotic systems to assist in surgical procedures has been repeatedly demonstrated. However, existing technologies are unable to perform complete, multi-step procedures from start to finish. Many intraocular surgical steps continue to be manually performed. Methods: An intraocular robotic interventional surgical system (IRISS) capable of performing various intraocular surgical procedures was designed, fabricated, and evaluated. Methods were developed to evaluate the performance of the remote centers of motion (RCMs) using a stereo-camera setup and to assess the accuracy and precision of positioning the tool tip using an optical coherence tomography (OCT) system. Results: The IRISS can simultaneously manipulate multiple surgical instruments, change between mounted tools using an onboard tool-change mechanism, and visualize the otherwise invisible RCMs to facilitate alignment of the RCM to the surgical incision. The accuracy of positioning the tool tip was measured to be 0.205±0.003 mm. The IRISS was evaluated by trained surgeons in a remote surgical theatre using post-mortem pig eyes and shown to be effective in completing many key steps in a variety of intraocular surgical procedures as well as being capable of performing an entire cataract extraction from start to finish. Conclusions: The IRISS represents a necessary step towards fully automated intraocular surgery and demonstrated accurate and precise master-slave manipulation for cataract removal and—through visual feedback—retinal vein cannulation.

EyeSLAM: Real-time simultaneous localization and mapping of retinal vessels during intraocular microsurgery


Background Fast and accurate mapping and localization of the retinal vasculature is critical to increasing the effectiveness and clinical utility of robot-assisted intraocular microsurgery such as laser photocoagulation and retinal vessel cannulation. Methods The proposed EyeSLAM algorithm delivers 30 Hz real-time simultaneous localization and mapping of the human retina and vasculature during intraocular surgery, combining fast vessel detection with 2D scan-matching techniques to build and localize a probabilistic map of the vasculature. Results In the harsh imaging environment of retinal surgery with high magnification, quick shaky motions, textureless retina background, variable lighting and tool occlusion, EyeSLAM can map 75% of the vessels within two seconds of initialization and localize the retina in real time with a root mean squared (RMS) error of under 5.0 pixels (translation) and 1° (rotation). Conclusions EyeSLAM robustly provides retinal maps and registration that enable intelligent surgical micromanipulators to aid surgeons in simulated retinal vessel tracing and photocoagulation tasks.

MRI-compatible breast/rib phantom for evaluating ultrasonic thermal exposures


Introduction The target of this study was the development of a magnetic resonance imaging (MRI) compatible breast phantom for focused ultrasound which includes plastic (ABS) ribs. The objective of the current study was the evaluation of a focused ultrasound procedure using the proposed phantom that eliminates rib heating. Material and Methods The proposed phantom was evaluated using two different focused ultrasound exposures. The surrounding breast tissue was mimicked using an agar–silica–evaporation milk gel (2% w/v – 2% w/v – 40% v/v). Results The attenuation of the ABS was similar to that of ribs. MR thermometry of focused ultrasound exposures were acquired using the breast/rib phantom. In one exposure focused ultrasound was applied with far-field targeting of the ribs. In the other exposure, the transducer was positioned laterally, thus avoiding exposure of the rib to focused ultrasound. Conclusions Due to growing interest in using MRI guided focused ultrasound (MRgFUS) for patients with breast cancer, the proposed breast/rib phantom can be utilized as a very useful tool for evaluating ultrasonic protocols.

Manipulator-driven selection of semi-active MR-visible markers


Background A method for the identification of semi-active fiducial magnetic resonance (MR) markers is presented based on selectively optically tuning and detuning them. Methods Four inductively coupled solenoid coils with photoresistors were connected to light sources. A microcontroller timed the optical tuning/detuning of coils and image collection. The markers were tested on an MR manipulator linking the microcontroller to the manipulator control to visibly select the marker subset according to the actuated joint. Results In closed-loop control, the average and maximum were 0.76° ± 0.41° and 1.18° errors for a rotational joint, and 0.87 mm ± 0.26 mm and 1.13 mm for the prismatic joint. Conclusions This technique is suitable for MR-compatible actuated devices that use semi-active MR-compatible markers.

Robotic versus thoracoscopic thymectomy: The current evidence


Background The purpose of this study was to analyze all relevant comparative studies comparing robot-assisted minimally invasive thymectomy (RATS) and video-assisted thoracic surgery thymectomy (VATS) in terms of surgical and short-term outcomes. Methods A systematic search for articles describing robot-assisted and video-assisted thymectomy and addressing surgical outcomes, operation time, length of hospitalization, intra-operative blood loss, conversion to sternotomy and post-operative complications was performed using the medical databases. Results Of the 478 studies from preliminary screening, five articles were included. By pooling these studies, we found no significant differences between the RATS and VATS (odds ratio 1.24 (95% CI 0.51, 3.03; p = 0.63)).There were no significant differences in comparison of conversion rates, operation time (26.29 min (95% CI –2.57, 55.35; p = 0.07)) and length of hospitalization (–1.58 days (95% CI –4.78, 1.62; p = 0.33)). There was a slightly higher blood loss in the RATS group. Conclusion Our meta-analysis did not detect any statistically significant differences in surgery outcomes between the two groups.

Motion control skill assessment based on kinematic analysis of robotic end-effector movements


Background The performance of robotic end-effector movements can reflect the user's operation skill difference in robot-assisted minimally invasive surgery. This study quantified the trade-off of speed–accuracy–stability by kinematic analysis of robotic end-effector movements to assess the motion control skill of users with different levels of experience. Methods Using ‘MicroHand S’ system, 10 experts, 10 residents and 10 novices performed single-hand test and bimanual coordination test. Eight metrics based on the movements of robotic end-effectors were applied to evaluate the users' performance. Results In the single-hand test, experts outperformed other groups except for movement speed; in the bimanual coordination test, experts also performed better except for movement time and movement speed. No statistically significant difference in performance was found between residents and novices. Conclusions The kinematic differences obtained from the movements of robotic end-effectors can be applied to assess the motion control skill of users with different skill levels.

Automated robot-assisted surgical skill evaluation: Predictive analytics approach


Background Surgical skill assessment has predominantly been a subjective task. Recently, technological advances such as robot-assisted surgery have created great opportunities for objective surgical evaluation. In this paper, we introduce a predictive framework for objective skill assessment based on movement trajectory data. Our aim is to build a classification framework to automatically evaluate the performance of surgeons with different levels of expertise. Methods Eight global movement features are extracted from movement trajectory data captured by a da Vinci robot for surgeons with two levels of expertise – novice and expert. Three classification methods – k-nearest neighbours, logistic regression and support vector machines – are applied. Results The result shows that the proposed framework can classify surgeons' expertise as novice or expert with an accuracy of 82.3% for knot tying and 89.9% for a suturing task. Conclusion This study demonstrates and evaluates the ability of machine learning methods to automatically classify expert and novice surgeons using global movement features.

Accuracy of navigated cam resection in femoroacetabular impingement: A randomised controlled trial


Background The main cause for revision hip arthroscopy surgery is incomplete bony resection of femoroacetabular impingement (FAI). This study aimed to compare the cam resection accuracy via the conventional hip arthroscopy technique with the navigation technique. Methods Two prospectively randomized groups were recruited: navigated (n = 15) and conventional (n = 14). A pre-operative CT and post-operative MRI scan were obtained in all cases to compare alpha angle, range of motion simulation and determine a pre-operative 3D surgical resection plan. Results Post-operatively, the mean maximal alpha angle improved significantly in the navigated group compared with the conventional group (55°vs.66°; P = 0.023), especially in the 12 o’ clock position (45°vs.60°; P = 0.041). However, positioning time and radiation exposure were significantly longer in the navigated group. Conclusion Navigated surgery is effective for patients with cam type FAI in helping restore normal anatomy, however, not without drawbacks. Larger studies will be required to validate our results.

Robotic proctectomy for rectal cancer: analysis of 71 patients from a single institution


Background Despite increasing use of robotic surgery for rectal cancer, few series have been published from the practice of generalizable US surgeons. Methods A retrospective chart review was performed for 71 consecutive patients who underwent robotic low anterior resection (LAR) or abdominoperineal resection (APR) for rectal adenocarcinoma between 2010 and 2014. Results 46 LARs (65%) and 25 APRs (35%) were identified. Median procedure time was 219 minutes (IQR 184–275) and mean blood loss 164.9 cc (SD 155.9 cc). Radial margin was negative in 70/71 (99%) patients. Total mesorectal excision integrity was complete/near complete in 38/39 (97%) of graded specimens. A mean of 16.8 (SD+/− 8.9) lymph nodes were retrieved. At median follow-up of 21.9 months, there were no local recurrences. Conclusions Robotic proctectomy for rectal cancer was introduced into typical colorectal surgery practice by a single surgeon, with a low conversion rate, low complication rate, and satisfactory oncologic outcomes.

The biomechanical effect of tunnel placement on ACL graft forces in double-bundle ACL reconstruction – A 3D computational simulation


Background The posterolateral (PL) graft experiences a high failure rate in anterior cruciate ligament double-bundle (DB) reconstruction. It is hypothesized that tunnel positions could dramatically affect the graft forces. Methods A validated computational model was used to simulate DB reconstruction with various femoral PL tunnel locations (8–11 mm center–center tunnel spacing). Graft fixation was simulated at both 0° and 30°. Knee biomechanics were examined with the knee under a 134 N anterior load and 400 N quadriceps load at 0°, 30°, 60°, and 90° of flexion. Graft forces, tibial translation, and tibial rotation were calculated. Results PL graft forces at full extension increased with increasing tunnel spacing under both fixation settings, but the knee kinematics was not dramatically affected. Conclusion Small changes in the femoral PL tunnel position could result in large changes in graft forces, implying that precise PL tunnel position is an important factor in a successful DB reconstruction.

Precision and accuracy of imageless navigation versus freehand implantation of total hip arthroplasty: A systematic review and meta-analysis


Background Total hip arthroplasty (THA) is named the most successful surgical procedure of the twentieth century. To remain a success in the twenty-first century THA should meet the higher demands of patients and society with regard to technical and functional outcome, costs and implant survival. To meet these demands optimal acetabular cup positioning is necessary. An imageless navigation system (NAV) might prevent malpositioning of the acetabular cup in THA. The aim of this study has been to compare the precision and accuracy of the anteversion and inclination of the acetabular cup position after NAV implantation and after freehand implantation of THA. Methods A systematic review and meta-analysis was conducted to assess the precision (variance) and accuracy (deviation from the target) from all available high-quality randomised control trials to date. Results Six out of seven studies concluded a statistically significant difference in precision in anteversion between the NAV group and the freehand group. Five out of seven studies concluded a statistically significant difference in precision in inclination. There is a significantly better accuracy for the NAV group than for the freehand group for anteversion (p = 0.002) and for inclination (p = 0.01). Conclusion This study showed that NAV placement is more precise and has an improved accuracy for anteversion and inclination than freehand placement of the acetabular cup. However, there is a lack of evidence to support an improved functional outcome and a reduction of complications and revisions.

Robotic bariatric surgery: A general review of the current status


Background While conventional laparoscopy is the gold standard for almost all bariatric procedures, robotic assistance holds promise for facilitating complex surgeries and improving clinical outcomes. Since the report of the first robotic-assisted bariatric procedure in 1999, numerous publications, including those reporting comparative trials and meta-analyses across bariatric procedures with a focus on robotic assistance, can be found. Purpose This article reviews the current literature and portrays the perspectives of robotic bariatric surgery. Conclusions While there are substantial reports on robotic bariatric surgery currently in publication, most studies suffer from low levels of evidence. As such, although robotics technology is without a doubt superior to conventional laparoscopy, the precise role of robotics in bariatric surgery is not yet clear.

A prospective randomized controlled trial for assessment of perineal hydrodissection technique for nervesparing robot assisted radical prostatectomy


Background This study prospectively evaluated the safety and efficacy of perineal hydrodissection in robot assisted nervesparing prostatectomy. Methods Patients were randomized for perineal, ultrasound guided hydrodissection (HD) before radical prostatectomy and compared with standard treatment (ST). Follow-up was done every 3 months, including erectile function (IIEF5-score), reported grade of erection, ability for sexual intercourse, continence, PSA. Results 21 patients were enrolled to this prospective study, 10 for ST and 11 for HD. No significant differences in demographic and preoperative oncological data between both groups were identified. Blood loss and time for surgery did not differ significantly. HD resulted in 66% (4/6) rate of positive surgical margins (PSM) in pT3 tumors vs 50% in ST (1/2; P = 0.67). Follow-up revealed higher IIEF scores, better ability for sexual intercourse and early continence in HD. Conclusions Erectile function after radical prostatectomy was improved by perineal hydrodissection in this proof of principal study. However, careful patient selection and further studies are needed as perineal hydrodissection could result in increased positive surgical margins in pT3a tumors.

Robotic distal locking of intramedullary nailing: Technical description and cadaveric testing


Interlocked intramedullary nailing is the treatment of choice for femoral shaft fractures. However, distal locking is a technically challenging part of the procedure that can result in distal femoral malrotation and high radiation exposure. We have tested a robotic procedure for robotic distal locking based on the computation of a drilling trajectory on two calibrated fluoroscopic images. Twenty distal holes were attempted in ten cadaveric femur specimens. Successful screw hole drilling was achieved at the first attempt in each of the ten specimens (20 drill holes in total). No failures were recorded. The average total number of images needed was 6.5 +/− 3.6. The average computation time was 16.5+/− 16.0 seconds. Robotic distal locking was feasible in this test and can be integrated into a fully robotic intramedullary nailing procedure.

Negating the fulcrum effect in manual laparoscopic surgery: Investigating skill acquisition with a haptic simulator


Background Manual laparoscopic surgery requires extensive training and familiarization. It has been suggested that motion inversion caused by the ‘fulcrum effect’ is key to motor challenges. We investigate the potential of a conceptual semi-robotic handheld tool that negates natural inversion. Methods A custom laparoscopic simulator with haptic feedback was developed to allow interactive evaluation of the conceptual tool via virtual prototyping, prior to fabricating a physical prototype. Two groups of eight participants each used either the conceptual or a regular virtual tool over a ten week study to complete two abstract tasks of motor control and force regulation. Results Statistically significant higher rates of skill improvement were demonstrated with the conceptual tool for motion efficiency, task completion time and error reduction. Force regulation increased for both groups but without significant differences. Conclusions The results indicate potential for fulcrum-negating hand tools in reducing the time needed to acquire motor skills.

Technical feasibility and safety of image-guided parieto-occipital ventricular catheter placement with the assistance of a wearable head-up display


Background Wearable technology is growing in popularity as a result of its ability to interface with normal human movement and function. Methods Using proprietary hardware and software, neuronavigation images were captured and transferred wirelessly via a password-encrypted network to the head-up display. The operating surgeon wore a loupe-mounted wearable head-up display during image-guided parieto-occipital ventriculoperitoneal shunt placement in two patients. Results The shunt placement was completed successfully without complications. The tip of the catheter ended well within the ventricles away from the ventricular wall. The wearable device allowed for continuous monitoring of neuronavigation images in the right upper corner of the surgeon's visual field without the need for the surgeon to turn his head to view the monitors. Conclusions The adaptable nature of this proposed system permits the display of video data to the operating surgeon without diverting attention away from the operative task. This technology has the potential to enhance image-guided procedures.

Research of the master–slave robot surgical system with the function of force feedback


Background Surgical robots lack force feedback, which may lead to operation errors. In order to improve surgical outcomes, this research developed a new master–slave surgical robot, which was designed with an integrated force sensor. Methods The new structure designed for the master–slave robot employs a force feedback mechanism. A six-dimensional force sensor was mounted on the tip of the slave robot's actuator. Sliding model control was adopted to control the slave robot. According to the movement of the master system manipulated by the surgeon, the slave's movement and the force feedback function were validated. Results The motion was completed, the standard deviation was calculated, and the force data were detected. Hence, force feedback was realized in the experiment. Conclusions The surgical robot can help surgeons to complete trajectory motions with haptic sensation.

Mastery Learning – does the method of learning make a difference in skills acquisition for robotic surgery?


Background Few studies compare the effectiveness of blocked vs random practice conditions in minimally invasive surgery training, and none have evaluated these in robotic surgery training. Methods The dV-Trainer® and the da Vinci® Surgical System (dVSS) were used to compare practice conditions. Forty-two participants were randomized into blocked and random practice groups. Each participant performed five tasks: Ring Walk, Thread the Rings, Needle Targeting, Suture Sponge and Tubes Level 2. Transfer to the dVSS was also assessed. Results No significant differences were observed between the two groups, except for a few instances. For example, during Ring Walk, the random group performed significantly faster than the blocked group (100.78 ± 5.26 s vs 121.59 ± 5.26 s, p < 0.01). Conclusions The study results do not follow the current evidence presented in the education literature. This is the first time that blocked versus random practice was tested for robotic surgery training.

Modeling and evaluation of hand–eye coordination of surgical robotic system on task performance


Background Robotic-assisted minimally invasive surgery changes the direct hand and eye coordination in traditional surgery to indirect instrument and camera coordination, which affects the ergonomics, operation performance, and safety. Methods A camera, two instruments, and a target, as the descriptors, are used to construct the workspace correspondence and geometrical relationships in a surgical operation. A parametric model with a set of parameters is proposed to describe the hand–eye coordination of the surgical robot. Results From the results, optimal values and acceptable ranges of these parameters are identified from two tasks. A 90° viewing angle had the longest completion time; 60° instrument elevation angle and 0° deflection angle had better performance; there is no significant difference among manipulation angles and observing distances on task performance. Conclusion This hand–eye coordination model provides evidence for robotic design, surgeon training, and robotic initialization to achieve dexterous and safe manipulation in surgery.

Real-time simulation of soft tissue deformation and electrocautery procedures in laparoscopic rectal cancer radical surgery


Background Laparoscopic surgery (LS), also referred to as minimally invasive surgery, is a modern surgical technique which is widely applied. The fulcrum effect makes LS a non-intuitive motor skill with a steep learning curve. Methods A hybrid model of tetrahedrons and a multi-layer triangular mesh are constructed to simulate the deformable behavior of the rectum and surrounding tissues in the Position-Based Dynamics (PBD) framework. A heat-conduction based electric-burn technique is employed to simulate the electrocautery procedure. Results The simulator has been applied for laparoscopic rectum cancer surgery training. From the experimental results, trainees can operate in real time with high degrees of stability and fidelity. A preliminary study was performed to evaluate the realism and usefulness. Conclusions This prototype simulator has been tested and verified by colorectal surgeons through a pilot study. They believed both the visual and the haptic performance of the simulation are realistic and helpful to enhance laparoscopic skills.

An adaptive and fully automatic method for estimating the 3D position of bendable instruments using endoscopic images


Background Flexible bendable instruments are key tools for performing surgical endoscopy. Being able to measure the 3D position of such instruments can be useful for various tasks, such as controlling automatically robotized instruments and analyzing motions. Methods An automatic method is proposed to infer the 3D pose of a single bending section instrument, using only the images provided by a monocular camera embedded at the tip of the endoscope. The proposed method relies on colored markers attached onto the bending section. The image of the instrument is segmented using a graph-based method and the corners of the markers are extracted by detecting the color transitions along Bézier curves fitted on edge points. These features are accurately located and then used to estimate the 3D pose of the instrument using an adaptive model that takes into account the mechanical play between the instrument and its housing channel. Results The feature extraction method provides good localization of marker corners with images of the in vivo environment despite sensor saturation due to strong lighting. The RMS error on estimation of the tip position of the instrument for laboratory experiments was 2.1, 1.96, and 3.18 mm in the x, y and z directions, respectively. Qualitative analysis in the case of in vivo images shows the ability to correctly estimate the 3D position of the instrument tip during real motions. Conclusions The proposed method provides an automatic and accurate estimation of the 3D position of the tip of a bendable instrument in realistic conditions, where standard approaches fail.

2D/3D reconstruction of the distal femur using statistical shape models addressing personalized surgical instruments in knee arthroplasty: A feasibility analysis


Background Personalized surgical instruments (PSI) have gained success in the domain of total knee replacement, demonstrating clinical outcomes similar or even superior to both traditional and navigated surgeries. The key requirement for prototyping PSI is the availability of the digital bony surface. In this paper, we aim at verifying whether the 2D/3D reconstruction of the distal femur, based on statistical shape models (SSM), grants sufficient accuracy, especially in the condylar regions, to support a PSI technique. Methods Computed tomographic knee datasets acquired on 100 patients with severe cartilage damage were retrospectively considered in this work. All the patients underwent total knee replacement using the PSI-based surgical technique. Eighty out of 100 reconstructed distal femur surfaces were used to build the statistical model. The remaining 20 surfaces were used for testing. The 2D/3D reconstruction process was based on digital reconstructed radiographies (DRRs) obtained with a simulated X-ray projection process. An iterative optimization procedure, based on an evolutionary algorithm, systematically morphed the statistical model to decrease the difference between the DRR, obtained by the original CT dataset, and the DRR obtained from the morphed surface. Results Over the 80 variations, the first ten modes were found sufficient to reconstruct the distal femur surface with accuracy. Using three DRR, the maximum Hausdorff and RMS distance errors were lower than 1.50 and 0.75 mm, respectively. As expected, the reconstruction quality improved by increasing the number of DRRs. Statistical difference (P < 0.001) was found in the 2 vs 3, 2 vs 4 and 2 vs 5 DRR, thus proving that adding just a single displaced projection to the two traditional sagittal and coronal X-ray images improved significantly the reconstruction quality. The effect of the PSI contact area errors on the distal cut direction featured a maximum median error lower than 2° and 0.5° on the sagittal and frontal plane, respectively. Statistical difference was found (P < 0.0001) in the reconstruction accuracy when comparing SSM built using pathologic with respect to non-pathologic shapes (cadavers), meaning that, to improve the patient-specific reconstruction, the morphologic anomalies, specific to the pathology, must be embedded into the SSM. Conclusions We showed that the X-ray based reconstruction of the distal femur is reasonable also in presence of pathologic bony conditions, featuring accuracy results similar to earlier reports in the literature that reconstructed normal femurs. This finding discloses the chance of applying the proposed methodology to the reconstruction of bony surfaces used in the PSI surgical approach.

A single port surgical robot system with novel elbow joint mechanism for high force transmission


Background Despite its evident clinical benefits, single-incision laparoscopic surgery (SILS) imposes inherent limitations of collision between external arms and inadequate triangulation because multiple instruments are inserted through a single port at the same time. Methods A robot platform appropriate for SILS was developed wherein an elbowed instrument can be equipped to easily create surgical triangulation without the interference of robot arms. A novel joint mechanism for a surgical instrument actuated by a rigid link was designed for high torque transmission capability. Results The feasibility and effectiveness of the robot was checked through three kinds of preliminary tests: payload, block transfer, and ex vivo test. Measurements showed that the proposed robot has a payload capability >15 N with 7 mm diameter. Conclusions The proposed robot is effective and appropriate for SILS, overcoming inadequate triangulation and improving workspace and traction force capability.

Effect of femoral tunnel positions on graft stress in outside-in ACL reconstruction surgery during continuous knee motion: A simulation study


Background: Previous studies regarding the optimal femoral tunnel location for an anterior cruciate ligament (ACL) reconstruction were based on static experiments at specific angles, and did not consider continuous motion of the knee. Methods: Twenty-four surgical sites were set and continuous kinematic data, obtained from motion analysis, was used to describe knee movement. The bending angle and stress of the ACL graft as well as the length of the femoral tunnel was calculated through multi-flexible body dynamics analysis. Results: The lowest stress was found at both 5 mm and 10 mm radius at a proximal posterior of 45°, and the highest stress was also found at a distal 15 mm radius. Relatively high stresses were also identified between the distal and anterior regions as well as the distal and posterior regions at 15 mm radius. Conclusion: Considering the availability of surgery, it was identified that the optimum femoral tunnel location is at 10 mm radius locations at a proximal posterior of 45°.

An automatic and accurate registration method for electro-anatomical map and CT surface


Background Electro-anatomical maps (EAM) and CT surface registration are widely used for catheter navigation in atrial fibrillation ablations. However, few studies have investigated the registration algorithm. Moreover, some of them are semiautomatic, so that physicians must be proficient; some are inaccurate for catheter navigation. A both automatic and accurate registration method is needed. Method A Hausdorff distance based approach (HD) was proposed for EAM/CT registration. First, using principal axes based registration, EAM/CT pairs were coarsely aligned. Then, using Hausdorff distance as the fine objective function, EAM/CT pairs were finely aligned. Results Six real EAM/CT pairs were collected from five patients and 38 simulated pairs were generated. Each pair was aligned using Carto-Merge, a stochastic approach (SA) and HD. Considering the balance of operability, accuracy and robustness, HD obtained the best EAM/CT registration results among the three approaches. Conclusion Experiments validate that the proposed method registers EAM and CT surface both automatically and accurately.

Compact teleoperated laparoendoscopic single-site robotic surgical system: Kinematics, control, and operation


Background To date a variety of teleoperated surgical robotic systems have been developed to improve a surgeon's ability to perform demanding single-port procedures. However typical large systems are bulky, expensive, and afford limited angular motion, while smaller designs suffer complications arising from limited motion range, speed, and force generation. This work was to develop and validate a simple, compact, low cost single site teleoperated laparoendoscopic surgical robotic system, with demonstrated capability to carry out basic surgical procedures. Methods This system builds upon previous work done at the University of Hawaii at Manoa and includes instrument and endoscope manipulators as well as compact articulated instruments designed to overcome single incision geometry complications. A robotic endoscope holder was used for the base, with an added support frame for teleoperated manipulators and instruments fabricated mostly from 3D printed parts. Kinematics and control methods were formulated for the novel manipulator configuration. Results Trajectory following results from an optical motion tracker and sample task performance results are presented. Conclusions Results indicate that the system has successfully met the goal of basic surgical functionality while minimizing physical size, complexity, and cost.

Natural orifice transluminal endoscopic surgery with a snake-mechanism using a movable pulley


Background Natural orifice transluminal endoscopic surgery is an emerging technique. We aimed to develop an advanced surgical robot mechanism for natural orifice surgery. Methods We propose the active-controlled overtube-type platform with multiple channels for an endoscopic camera and surgical tools. To make such a platform, we suggest an advanced snake mechanism comprising movable pulleys to make a snake mechanism with multiple degrees of freedom and high operating force. Results The stiffness and maneuverability of the active-controlled platform appeared satisfactory. Using prototypes and ex vivo experiments, we confirmed that the mechanism was suitable for a snake-like robotic platform for natural orifice surgery. Conclusions The suggested snake mechanism using movable pulleys has the advantages of stiffness and maneuverability. This new mechanism can be an alternative platform for natural orifice surgery.

Generative Anatomy Modeling Language (GAML)


Background This paper presents the Generative Anatomy Modeling Language (GAML) for generating variation of 3D virtual human anatomy in real-time. This framework provides a set of operators for modification of a reference base 3D anatomy. The perturbation of the 3D models is satisfied with nonlinear geometry constraints to create an authentic human anatomy. Methods GAML was used to create 3D difficult anatomical scenarios for virtual simulation of airway management techniques such as Endotracheal Intubation (ETI) and Cricothyroidotomy (CCT). Difficult scenarios for each technique were defined and the model variations procedurally created with GAML. Conclusion This study presents details of the GAML design, set of operators, types of constraints. Cases of CCT and ETI difficulty were generated and confirmed by expert surgeons. Execution performance pertaining to an increasing complexity of constraints using nonlinear programming was in real-time execution.

Pose optimization and port placement for robot-assisted minimally invasive surgery in cholecystectomy


Background Pose optimization and port placement are critical issues for preoperative preparation in robot-assisted minimally invasive surgery (RMIS), and affect the robot performance and surgery quality. Methods This paper proposes a method for pose optimization and port placement for RMIS in cholecystectomy that considers both the robot and surgery requirements. The robot pose optimization was divided into optimization of the positioning joint configuration and optimization of the end effector configuration. To determine the optimal location for the trocar port placement, the operational workspace was defined as the evaluation index. The port area was divided into many sub-areas, and that with the maximum operational workspace was selected as the location for the port placement. Results Considering the left robotic arm as an example, the location for the port placement and joints angles for robotic arm configuration were discussed and simulated using the proposed method. Conclusion This research can provide guidelines for surgeons in preoperative preparation.

Comparison of reaction forces on the anterior cruciate and anterolateral ligaments during internal rotation and anterior drawer forces at different flexion angles of the knee joint


Background Having a complicated anatomy, the knee joint has been further detailed and a new formation defined, the anterolateral ligament (ALL), in recent studies. While the importance of this ligament, which previously was associated with Segond fractures, was explained via clinical, radiologic and biomechanical studies, and basically, is thought to be a fixator structures for the tibia against internal rotation stress. Although in recent studies efficient surgical treatment was applied to patients who underwent anterior cruciate ligament (ACL) operation, some patients having a positive pivot test highlights the clinical importance of the ALL. The aim of this study is to evaluate reaction forces of different flexion angles on the tibia during internal rotation and anterior drawer tests on both the ALL and ACL, and to examine theimportance of this ligament in knee biomechanics by a finite element analysis method. Method In this study, normal anatomy knee joint was modelled using Computed Tomography images from lower extremity length in DICOM format. 0°, 15°,30°,45°,60°,75° and 90° angles of flexion were applied, respectively, to these models and reaction force vectors formed on both ligaments were examined separately and as total vector and size by applying internal rotation and anterior drawer forces on each model. Non-linear analysis was conducted using ANSYS (version 17) with the same limit conditions applied to all models. Results After all models were examined, in general when comparing reaction forces, those on the ACL were found to be higher. However, when vectoral directions were examined, forces on ALL increased with increased flexion ratio and internal rotation momentum. Beyond 30° flexion, the tensile force on the ALL is increased and compressive overload on the ACL occurs. Conclusion The ALL plays an important role in stability, especially against internal rotation forces, and an increased knee joint flexion ratio increases the stability contribution ratio. In particular, at 30° and higher angles, ACL reflects an antagonist effect and contributes to knee joint stability for rotational and mediolateral transposition.

Preservation of replaced left hepatic artery during robotic-assisted minimally invasive esophagectomy: A case series


Objective Finding of a significant replaced left hepatic artery (RLHA) during esophagectomy is relatively rare, with an incidence of approximately 5%. Sparing of the artery may be required to avoid complications of liver ischemia. Robotic assistance during esophagectomy may provide a technically superior method of artery preservation with minimally invasive approaches. Methods This is a retrospective case series of patients undergoing robotic-assisted minimally invasive esophagectomy (RAMIE) identified to have a significant RLHA at time of surgery. Results Five patients with a significant RLHA were identified from a series of over 100 RAMIE operations. Preservation of RLHA was accomplished in all cases without need for conversion, no intra-operative complications, and no post-operative liver dysfunction. The stomach was suitable and used for conduit reconstruction in all patients. Conclusions Sparing of the RLHA during RAMIE is feasible and effective. The robotic assisted approach may obviate the need for open conversion during these complex minimally invasive operations.

Experimental evaluation of magnified haptic feedback for robot-assisted needle insertion and palpation


Background Haptic feedback has been proven to play a key role in enhancing the performance of teleoperated medical procedures. However, due to safety issues, commercially-available medical robots do not currently provide the clinician with haptic feedback. Methods This work presents the experimental evaluation of a teleoperation system for robot-assisted medical procedures able to provide magnified haptic feedback to the clinician. Forces registered at the operating table are magnified and provided to the clinician through a 7-DoF haptic interface. The same interface is also used to control the motion of a 6-DoF slave robotic manipulator. The safety of the system is guaranteed by a time-domain passivity-based control algorithm. Results Two experiments were carried out on stiffness discrimination (during palpation and needle insertion) and one experiment on needle guidance. Conclusions Our haptic-enabled teleoperation system improved the performance with respect to direct hand interaction of 80%, 306%, and 27% in stiffness discrimination through palpation, stiffness discrimination during needle insertion, and guidance, respectively.

Design and evaluation of a variable stiffness manual operating platform for laparoendoscopic single site surgery (LESS)


Background Most of the existing robotic platforms for LESS have workspace and load capacity weaknesses, because of the limitation of one single incision. We have developed a LESS manual operating platform of which the stiffness of the insertion tube is controllable. Methods The system included two dexterous tool manipulators, a stereo-vision module and a variable stiffness insertion tube (VSIT), which was designed using phase-change material (mixed indium, gallium and stannum). Experiments to evaluate the effectiveness of the VSIT were set up. Peg transfer tasks and trajectory tracking tasks were conducted to assess the initial performance of the overall system. Results The experimental results for stiffness characteristic suggested that the rigidity of the VSIT with a straight-forward pose was considerably increased by about four times in the rigid mode. Peg transfer tasks and trajectory tracking tasks were performed successfully with an average time of 97 s and 52 s, respectively. Conclusions The experimental results for stiffness characteristic showed that the manual operating platform had great promise for solving large workspace, high manipulation force and stability problems in LESS. The tool manipulators had the ability to achieve basic operations.

MRI guided focused ultrasound robotic system for animal experiments


Background In this paper an MRI-guided focused ultrasound (MRgFUS) robotic system was developed that can be used for conducting experiments in small animals.The target for this robotic system regarding motion was to move a therapeutic ultrasound transducer in two Cartesian axes. Methods A single element spherically focused transducer of 3 cm diameter, focusing at 7 cm and operating at 0.4 MHz was used. The positioning device incorporates only MRI compatible materials. The propagation of ultrasound is a bottom to top approach. The 2-D positioning device is controlled by custom-made software and a custom-made electronic system which controls the two piezoelectric motors. Results The system was tested successfully in agar/silica/evaporated milk phantom for various tasks (robot motion, MR compatibility, and MR thermometry). The robotic system is capable of moving the focused ultrasound transducer to perform MR-guided focused ultrasound experiments in small animals. Conclusions This system has the potential to be deployed as a cost effective solution for performing experiments in small animals.

Physiological motion modeling for organ-mounted robots


Background Organ-mounted robots passively compensate heartbeat and respiratory motion. In model-guided procedures, this motion can be a significant source of information that can be used to aid in localization or to add dynamic information to static preoperative maps. Methods Models for estimating periodic motion are proposed for both position and orientation. These models are then tested on animal data and optimal orders are identified. Finally, methods for online identification are demonstrated. Results Models using exponential coordinates and Euler-angle parameterizations are as accurate as models using quaternion representations, yet require a quarter fewer parameters. Models which incorporate more than four cardiac or three respiration harmonics are no more accurate. Finally, online methods estimate model parameters as accurately as offline methods within three respiration cycles. Conclusions These methods provide a complete framework for accurately modelling the periodic deformation of points anywhere on the surface of the heart in a closed chest.

Application of a customized 3D printed reduction aid after external fixation of the femur and tibia: Technical note


Background To construct a fracture-specific reduction aid by means of virtual reduction technology and 3D printing to reduce malreduced, externally fixed, long bone fractures. Technique Following application of an external fixator to a malreduced long bone fracture, we performed postoperative computed tomography to visualise the fragments and their position relative to Schanz screws. DICOM data were transferred to 3D planning software, and the fracture was then virtually reduced. Subsequently, a reduction aid was designed to cover the Schanz screws in such a way that it would maintain the position of the new fragments. Following 3D printing, the solid reduction aid could be applied onto the Schanz screws. The reduction aid fit only in the reduced position of the fracture, thus maintaining correct bone alignment. Conclusion Our reduction technique can be applied during the temporary external fixation period on the preexisting external fixator or as a reduction aid during definitive treatment.

A research review on clinical needs, technical requirements, and normativity in the design of surgical robots


Nowadays robots play an important role in society, mainly due to the significant benefits they provide when utilized for assisting human beings in the execution of dangerous or repetitive tasks. Medicine is one of the fields in which robots are gaining greater use and development, especially those employed in minimally invasive surgery (MIS). However, due to the particular conditions of the human body where robots have to act, the design of these systems is complex, not only from a technical point of view, but also because the clinical needs and the normativity aspects are important considerations that have to be taken into account in order to achieve better performances and more secure systems for patients and surgeons. Thus, this paper explores the clinical needs and the technical requirements that will trace the roadmap for the next scientific and technological advances in the field of robotic surgery, the metrics that should be defined for safe technology development and the standards that are being elaborated for boosting the industry and facilitating systems integration.

Development of an in vivo visual robot system with a magnetic anchoring mechanism and a lens cleaning mechanism for laparoendoscopic single-site surgery (LESS)


Background Surgical robot systems which can significantly improve surgical procedures have been widely used in laparoendoscopic single-site surgery (LESS). For a relative complex surgical procedure, the development of an in vivo visual robot system for LESS can effectively improve the visualization for surgical robot systems. Methods In this work, an in vivo visual robot system with a new mechanism for LESS was investigated. A finite element method (FEM) analysis was carried out to ensure the safety of the in vivo visual robot during the movement, which was the most important concern for surgical purposes. A master–slave control strategy was adopted, in which the control model was established by off-line experiments. Results The in vivo visual robot system was verified by using a phantom box. The experiment results show that the robot system can successfully realize the expected functionalities and meet the demands of LESS. Conclusion The experiment results indicate that the in vivo visual robot with high manipulability has great potential in clinical application.

Insight into the da Vinci® Xi – technical notes for single-docking left-sided colorectal procedures


Background The adoption of robot-assisted laparoscopic colorectal surgery has been hampered by issues with docking, operative duration, technical difficulties in multi-quadrant access, and cost. The da Vinci® Xi has been designed to overcome some of these limitations. We describe our experience with the system and offer technical insights to its application in left-sided colorectal procedures. Methods Our initial series of left-sided robotic colorectal procedures was evaluated. Patient demographics and operative outcomes were recorded prospectively using a predefined database. Results Between March 2015 and April 2016, 54 cases of robot-assisted laparoscopic left-sided colorectal procedures were successfully completed with no cases of conversion. The majority were low anterior resections for colorectal malignancies. Using the da Vinci® Xi Surgical System, multi-quadrant surgery involving dissection from the splenic flexure to the pelvis was possible without redocking. Conclusions The da Vinci® Xi simplifies the docking procedure and makes single-docking feasible for multi-quadrant left-sided colorectal procedures.

Ultrasound image based visual servoing for moving target ablation by high intensity focused ultrasound


Background Although high intensity focused ultrasound (HIFU) is a promising technology for tumor treatment, a moving abdominal target is still a challenge in current HIFU systems. In particular, respiratory-induced organ motion can reduce the treatment efficiency and negatively influence the treatment result. In this research, we present: (1) a methodology for integration of ultrasound (US) image based visual servoing in a HIFU system; and (2) the experimental results obtained using the developed system. Materials and methods In the visual servoing system, target motion is monitored by biplane US imaging and tracked in real time (40 Hz) by registration with a preoperative 3D model. The distance between the target and the current HIFU focal position is calculated in every US frame and a three-axis robot physically compensates for differences. Because simultaneous HIFU irradiation disturbs US target imaging, a sophisticated interlacing strategy was constructed. Results In the experiments, respiratory-induced organ motion was simulated in a water tank with a linear actuator and kidney-shaped phantom model. Motion compensation with HIFU irradiation was applied to the moving phantom model. Based on the experimental results, visual servoing exhibited a motion compensation accuracy of 1.7 mm (RMS) on average. Moreover, the integrated system could make a spherical HIFU-ablated lesion in the desired position of the respiratory-moving phantom model. Conclusions We have demonstrated the feasibility of our US image based visual servoing technique in a HIFU system for moving target treatment.

A combined registration and finite element analysis method for fast estimation of intraoperative brain shift; phantom and animal model study


Background Finite element models for estimation of intraoperative brain shift suffer from huge computational cost. In these models, image registration and finite element analysis are two time-consuming processes. Methods The proposed method is an improved version of our previously developed Finite Element Drift (FED) registration algorithm. In this work the registration process is combined with the finite element analysis. In the Combined FED (CFED), the deformation of whole brain mesh is iteratively calculated by geometrical extension of a local load vector which is computed by FED. Results While the processing time of the FED-based method including registration and finite element analysis was about 70 s, the computation time of the CFED was about 3.2 s. The computational cost of CFED is almost 50% less than similar state of the art brain shift estimators based on finite element models. Conclusions The proposed combination of registration and structural analysis can make the calculation of brain deformation much faster.

Impedance and admittance control for respiratory-motion compensation during robotic needle insertion – a preliminary test


Background Many robotic needle-biopsy systems have been developed to enhance the accuracy of needle-biopsy intervention. These systems can reduce the intervention time and the radiation exposure of clinicians. However, respiratory-motion compensation is needed to ensure the accuracy and efficiency of needle biopsy intervention. Methods Human respiratory-motion data were acquired using three inertial measurement units (IMUs), and respiratory motion was simulated using the Stewart-Gough platform. Robotic needle intervention was performed using impedance and admittance control algorithms for respiratory-motion compensation using the Stewart-Gough platform and a gelatin phantom. Results The impedance and admittance control algorithms can be used to compensate for respiratory motion during robotic needle insertion. The admittance control algorithm exhibits better performance than the impedance control algorithm. Conclusions The impedance and admittance control algorithms can be applied for respiratory-motion compensation during robotic needle insertion. However, further study is needed for them to become clinically feasible.

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Trans-oral robotic surgery (TORS) for the treatment of lingual tonsillitis. When conventional therapies fail


Background Lingual tonsillitis is an underestimated but serious health problem. This paper describes the feasibility and efficacy of the trans-oral robotic surgical approach in cases of lingual tonsillitis. Materials and Methods From February 2012 to April 2014, 10 patients affected by lingual tonsillitis resistant to medical treatments underwent transoral robotic lingual tonsillectomy at the authors’ Institution. Results The surgical robotic procedure was completed in all cases and there was no need to change the operative approach once started. The mean set-up time was 13.2 ± 5.2 min, while mean operating time was 28 ± 12 min. The mean amount of tissue removed was 16.5 ± 13 cm3. No major intra-operative and post-operative complications were registered. After 15.2 ± 12 months of follow-up, no relapses were reported and patients did not complain of any further symptoms. Conclusion Lingual tonsillitis seems to be safely and effectively managed by trans-oral robotic surgery. The data are encouraging and worthy of further evaluation. Copyright © 2016 John Wiley & Sons, Ltd.

Novel technique of robotic extralevator abdominoperineal resection with gracilis flap closure


Background The purpose of this paper is to introduce a robotic assisted approach to extralevator abdominoperineal excision in the modified Lloyd-Davis position with reconstruction of the perineum using pedicled gracilis flaps, and to discuss outcomes in a cohort of six patients. Methods Data was collected by chart review on six patients who underwent extralevator excision with gracilis flap reconstruction from 10/2013 to 06/2015. Technical details, operative data, oncologic outcomes, and wound healing complications were evaluated. Results There were no instances of intraoperative perforation or positive circumferential resection margin, and one case of locoregional recurrence. Two patients experienced flap venous congestion and one patient developed a perineal abscess. All patients went on to complete healing. Conclusions The combination of a minimally invasive robotic assisted extralevator abdominoperineal excision performed in the modified Lloyd-Davis position with reconstruction of the perineum with pedicled gracilis flaps has excellent oncologic outcomes and acceptable wound healing complications. Copyright © 2016 John Wiley & Sons, Ltd. StartCopTextCopyright © 2016 John Wiley & Sons, Ltd.

Morphometric measurement of the cervical spine for minimally invasive pedicle screw fixation using reverse engineering and three-dimensional reconstruction


Background Percutaneous cervical pedicle screw fixation has been proven to be an effective method of cervical screw instrumentation, which has the advantages of less invasiveness and low blood loss. Emerging evidence has indicated that the cervical spinous process plays an important role in percutaneous spine surgery. However, there is a limited amount of information on the fundamental research of pedicle and its associated imaging parameter measurement. The purpose of this study was to measure the anatomic data of the pedicle screw channel (PSC) using reverse engineering and three-dimensional reconstruction, and also to discuss the three-dimensional relationship between the cervical spinous process and the pedicle screw channel. Methods Twenty adult subjects (10 males, 10 females, age range 19–46 years) were studied using the method of three-dimensional CT reconstruction and reverse engineering. The centrum was divided into 10 equal parts from front to back. The bisectors were defined as borderline depths of the centrum, from front to back, 100%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, 0% of borderline depths were presented. Then, a 3D coordinate system was constructed to measure all the data, including the radius of the inscribed circle, the length of the PSC, the insertion angle, the distances from entry point to cervical spinous process and skin depth. All the indexes were measured from 70% to 90% borderline depth. Results The radius of the inscribed circles from C3 to C7 at 90% borderline depth were 2.94 ± 0.55 mm, 3.04 ± 0.40 mm, 3.15 ± 0.36 mm, 3.28 ± 0.47 mm, 3.89 ± 0.54 mm, respectively. The lengths of the PSC were between 25 and 32 mm. The insertion angles for 70% to 90% borderline depth were 28.33°, 34.28°, 37.92°, respectively. The relationship between the PSC and spinous process was measured as the distance from the entry point to the end of the spinous process, which were, respectively, 26.91 mm, 28.18 mm, 30.03 mm, 35.67 mm, 41.99 mm from C3 to C7.The distance from the skin to the entry point of C3-7 increased gradually. Conclusions The measurements of this study could provide detailed information for percutaneous cervical screw fixation. The data of the relationship between the cervical spinous process and the pedicle screw channel present valuable technical information for the d[...]

Distance-based time series classification approach for task recognition with application in surgical robot autonomy


Background Robotic-assisted surgery allows surgeons to perform many types of complex operations with greater precision than is possible with conventional surgery. Despite these advantages, in current systems, a surgeon should communicate with the device directly and manually. To allow the robot to adjust parameters such as camera position, the system needs to know automatically what task the surgeon is performing. Methods A distance-based time series classification framework has been developed which measures dynamic time warping distance between temporal trajectory data of robot arms and classifies surgical tasks and gestures using a k-nearest neighbor algorithm. Results Results on real robotic surgery data show that the proposed framework outperformed state-of-the-art methods by up to 9% across three tasks and by 8% across gestures. Conclusion The proposed framework is robust and accurate. Therefore, it can be used to develop adaptive control systems that will be more responsive to surgeons' needs by identifying next movements of the surgeon. Copyright © 2016 John Wiley & Sons, Ltd.

Segmentation and three-dimensional reconstruction of lesions using the automated breast volume scanner (ABVS)


Background Ultrasound is an effective tool for breast cancer diagnosis. However, its relatively low image quality makes small lesion analysis challenging. This promotes the development of tools to help clinicians in the diagnosis. Methods We propose a method for segmentation and three-dimensional (3D) reconstruction of lesions from ultrasound images acquired using the automated breast volume scanner (ABVS). Segmentation and reconstruction algorithms are applied to obtain the lesion's 3D geometry. A total of 140 artificial lesions with different sizes and shapes are reconstructed in gelatin-based phantoms and biological tissue. Dice similarity coefficient (DSC) is used to evaluate the reconstructed shapes. The algorithm is tested using a human breast phantom and clinical data from six patients. Results DSC values are 0.86 ± 0.06 and 0.86 ± 0.05 for gelatin-based phantoms and biological tissue, respectively. The results are validated by a specialized clinician. Conclusions Evaluation metrics show that the algorithm accurately segments and reconstructs various lesions. Copyright © 2016 John Wiley & Sons, Ltd.

Investigation of active tracking for robotic arm assisted magnetic resonance guided focused ultrasound ablation


Background Focused ultrasound surgery (FUS) is a technique that does not need invasive access to the patient while allowing precise targeted therapy. Magnetic resonance (MR) guided FUS provides capabilities for monitoring treatments. Because the targeted tumours are distributed at different positions, focus repositioning becomes necessary. Methods An MR compatible robot was used to increase the operational range of FUS application. Active tracking was developed to detect the robotic arm with regard to the MR coordinate system. The purpose of this study was to construct active tracking to allow a wide spatial range of repositioning the FUS transducer that is fast and accurate. The technique was characterised and validated by a series of positioning tests to prove its efficiency for guiding the robot. Results In the calibration range, tracking achieved an RMS accuracy of 0.63 mm. Results of phantom ablation showed a focal scanning precision Δx = 0.4 ± 0.37 mm, Δy = 0.4 ± 0.28 mm and Δz = 0.7 ± 0.66 mm. Conclusions The active tracking localisation can be considered a feasible approach for the MR guided FUS system positioned by a robot. Copyright © 2016 John Wiley & Sons, Ltd.

A virtual-reality simulator and force sensation combined catheter operation training system and its preliminary evaluation


Background Endovascular surgery benefits patients because of its superior short convalescence and lack of damage to healthy tissue. However, such advantages require the operator to be equipped with dexterous skills for catheter manipulation without resulting in collateral damage. To achieve this goal, a training system is in high demand. Methods A training system integrating a VR simulator and a haptic device has been developed within this context. The VR simulator is capable of providing visual cues which assist the novice for safe catheterization. In addition, the haptic device cooperates with VR simulator to apply sensations at the same time. The training system was tested by non-medical subjects over a five days training session. Results The performance was evaluated in terms of safety criteria and task completion time. The results demonstrate that operation safety is improved by 15.94% and task completion time is cut by 18.80 s maximum. Moreover, according to subjects′ reflections, they are more confident in operation. Conclusions The proposed training system constructs a comprehensive training environment that combines visualization and force sensation. Copyright © 2016 John Wiley & Sons, Ltd.

Technical feasibility and safety of an intraoperative head-up display device during spine instrumentation


Background The primary aim of this study was to determine the safety and feasibility of capturing and streaming neuronavigation images onto a head-up display during spine instrumentation. Methods Using a novel device, neuronavigation images were captured and transferred wirelessly via a password-encrypted network to the head-up display. At the end of the procedure, the surgeons completed a survey to gather their opinions of the system. Results Forty pedicle screws were placed using the head-up display. The average screw placement time was slightly shorter when the head-up display was used (4.13 min with vs. 4.86 min without). The post-procedure survey demonstrated that 79% of surgeon's responses were positive. Conclusion A wearable head-up display can benefit current neuronavigation systems, but larger, outcomes-based trials are needed. Higher processing speed would allow streaming of higher resolution images. Along with an enlarged display, these may significantly improve utilization of this technology. Copyright © 2016 John Wiley & Sons, Ltd.

Development and testing of a grasper for NOTES powered by variable stiffness pneumatic actuation


Background In natural orifice transluminal endoscopic surgery (NOTES) the peritoneal cavity is reached through natural orifices (mouth, rectus and transvaginal duct), by means of little cuttings in the walls of hollow organs. Due to narrow spaces, NOTES needs robotic systems to assure operation/movement precision and patient safety. Variable stiffness actuation (VSA) assures both requirements. Methods The authors developed a grasper for NOTES, provided with VSA, to use as an end-effector for snail robot devices. The present paper deals with basic concepts of VSA and describes the design and architecture of the grasper. Characterization and functional experiments were performed and results analysed. Results A finite element model developed for the actuator design was validated, performance grasper characteristic curves were obtained, VSA was validated, and the gripping capability of several objects was assessed. Conclusion The grasper satisfies technical design specifications. On the basis of the results obtained, a control system can be developed to test grasper in a simulated surgery environment.

A novel optimal coordinated control strategy for the updated robot system for single port surgery


Background Research into robotic systems for single port surgery (SPS) has become widespread around the world in recent years. A new robot arm system for SPS was developed, but its positioning platform and other hardware components were not efficient. Special features of the developed surgical robot system make good teleoperation with safety and efficiency difficult. Methods A robot arm is combined and used as new positioning platform, and the remote center motion is realized by a new method using active motion control. A new mapping strategy based on kinematics computation and a novel optimal coordinated control strategy based on real-time approaching to a defined anthropopathic criterion configuration that is referred to the customary ease state of human arms and especially the configuration of boxers' habitual preparation posture are developed. Results The hardware components, control architecture, control system, and mapping strategy of the robotic system has been updated. A novel optimal coordinated control strategy is proposed and tested. Conclusions The new robot system can be more dexterous, intelligent, convenient and safer for preoperative positioning and intraoperative adjustment. The mapping strategy can achieve good following and representation for the slave manipulator arms. And the proposed novel control strategy can enable them to complete tasks with higher maneuverability, lower possibility of self-interference and singularity free while teleoperating.

SmartSIM - a virtual reality simulator for laparoscopy training using a generic physics engine


Virtual reality (VR) training simulators have started playing a vital role in enhancing surgical skills, such as hand–eye coordination in laparoscopy, and practicing surgical scenarios that cannot be easily created using physical models. We describe a new VR simulator for basic training in laparoscopy, i.e. SmartSIM, which has been developed using a generic open-source physics engine called the simulation open framework architecture (SOFA). This paper describes the systems perspective of SmartSIM including design details of both hardware and software components, while highlighting the critical design decisions. Some of the distinguishing features of SmartSIM include: (i) an easy-to-fabricate custom-built hardware interface; (ii) use of a generic physics engine to facilitate wider accessibility of our work and flexibility in terms of using various graphical modelling algorithms and their implementations; and (iii) an intelligent and smart evaluation mechanism that facilitates unsupervised and independent learning.

Differential analysis of muscle fatigue induced elbow and wrist tremor in controlled laparoscopic manoeuvring


Background Fatigue induced hand tremor (FIT) is a primary limiting concern for the prolonged surgical intervention in minimally invasive surgery (MIS) and robot-assisted-minimally invasive surgery (RAMIS). A thorough analysis is necessary to understand the FIT characteristics in laparoscopic tool movement. The primary aim of this study is to perform a differential analysis of the elbow and wrist tremor due to muscle fatigue in laparoscopic manoeuvring. Methods We have introduced a joint angle based tremor analysis method, which enables us to perform a differential study of FIT characteristics at the individual joint. Experimental data was acquired from a group of subjects during static and dynamic laparoscopic movement in an imitative RAMIS master manipulation scenario. A repetitive task was performed with a total span of 1 h for observing the effect of muscle fatigue. Along with the joint angle variation, surface electromyography (sEMG) signal was also studied in the analysis. Results The wrist tremor is more predominant than tremor generated at the elbow, especially in highly fatigued condition. The high-frequency tremor (>4 Hz) is contributed by the wrist joint. Moreover, the variation of the wrist and elbow tremor ratio was found to be dependent upon the experience of the surgeons. Conclusions In this work, we have investigated the attribution of elbow and wrist joints in FIT during laparoscopic tool manipulation. The outcomes may be useful for the design of robot-assisted surgical manipulator, and can be used for quality assessment of surgical training as well.

Safety margins in robotic bone milling: from registration uncertainty to statistically safe surgeries


Background When robots mill bone near critical structures, safety margins are used to reduce the risk of accidental damage due to inaccurate registration. These margins are typically set heuristically with uniform thickness, which does not reflect the anisotropy and spatial variance of registration error. Methods A method is described to generate spatially varying safety margins around vital anatomy using statistical models of registration uncertainty. Numerical simulations are used to determine the margin geometry that matches a safety threshold specified by the surgeon. Results The algorithm was applied to CT scans of five temporal bones in the context of mastoidectomy, a common bone milling procedure in ear surgery that must approach vital nerves. Safety margins were generated that satisfied the specified safety levels in every case. Conclusions Patient safety in image-guided surgery can be increased by incorporating statistical models of registration uncertainty in the generation of safety margins around vital anatomy.

Data-driven methods towards learning the highly nonlinear inverse kinematics of tendon-driven surgical manipulators


Background Accurate motion control of flexible surgical manipulators is crucial in tissue manipulation tasks. The tendon-driven serpentine manipulator (TSM) is one of the most widely adopted flexible mechanisms in minimally invasive surgery because of its enhanced maneuverability in torturous environments. TSM, however, exhibits high nonlinearities and conventional analytical kinematics model is insufficient to achieve high accuracy. Methods To account for the system nonlinearities, we applied a data driven approach to encode the system inverse kinematics. Three regression methods: extreme learning machine (ELM), Gaussian mixture regression (GMR) and K-nearest neighbors regression (KNNR) were implemented to learn a nonlinear mapping from the robot 3D position states to the control inputs. Results The performance of the three algorithms was evaluated both in simulation and physical trajectory tracking experiments. KNNR performed the best in the tracking experiments, with the lowest RMSE of 2.1275 mm. Conclusions The proposed inverse kinematics learning methods provide an alternative and efficient way to accurately model the tendon driven flexible manipulator.

The development and error analysis of a kinematic parameters based spatial positioning method for an orthopedic navigation robot system


Background Spatial positioning is the key function of a surgical navigation robot system, and accuracy is the most important performance index of such a system. Methods The kinematic parameters of a six degrees of freedom (DOF) robot arm were used to form the transformation from intraoperative fluoroscopy images to a robot's coordinate system without C-arm calibration and to solve the redundant DOF problem. The influences of three typical error sources and their combination on the final navigation error were investigated through Monte Carlo simulation. Results The navigation error of the proposed method is less than 0.6 mm, and the feasibility was verified through cadaver experiments. Error analysis suggests that the robot kinematic error has a linear relationship with final navigation error, while the image error and gauge error have nonlinear influences. Conclusions This kinematic parameters based method can provide accurate and convenient navigation for orthopedic surgeries. The result of error analysis will help error design and assignment for surgical robots.

Dynamic updating atlas for heart segmentation with a nonlinear field-based model


Background Segmentation of cardiac computed tomography (CT) images is an effective method for assessing the dynamic function of the heart and lungs. In the atlas-based heart segmentation approach, the quality of segmentation usually relies upon atlas images, and the selection of those reference images is a key step. The optimal goal in this selection process is to have the reference images as close to the target image as possible. Methods This study proposes an atlas dynamic update algorithm using a scheme of nonlinear deformation field. The proposed method is based on the features among double-source CT (DSCT) slices. The extraction of these features will form a base to construct an average model and the created reference atlas image is updated during the registration process. A nonlinear field-based model was used to effectively implement a 4D cardiac segmentation. Results The proposed segmentation framework was validated with 14 4D cardiac CT sequences. The algorithm achieved an acceptable accuracy (1.0–2.8 mm). Conclusion Our proposed method that combines a nonlinear field-based model and dynamic updating atlas strategies can provide an effective and accurate way for whole heart segmentation. The success of the proposed method largely relies on the effective use of the prior knowledge of the atlas and the similarity explored among the to-be-segmented DSCT sequences.

BROMETH: Methodology to design safe reconfigurable medical robotic systems


Background This research paper deals with the development of a medical robotized control system for supracondylar humeral fracture treatment. Concurrent access to shared resources and applying reconfiguration scenarios can jeopardize the safety of the system. Methods A new methodology is proposed in this paper, termed BROMETH, to guarantee the safety of such critical systems from their specification to their deployment, and passing through certification and implementation. The solution is applied to a real case study named Browser-based Reconfigurable Orthopedic Surgery (abbrev. BROS), a robotized platform dedicated to the treatment of supracondylar fractures, to illustrate the paper's contribution. This work starts from a medical issue, namely supracondylar humeral fracture treatment, to establish a new informatics solution, namely a new methodology to design safe reconfigurable medical robotic systems. Results The results of the experiments performed on real SCH fracture radiographies were quite satisfactory. Conclusions Clinical experiments can then be performed after deploying the system on real hardware.

ConoSurf: Open-source 3D scanning system based on a conoscopic holography device for acquiring surgical surfaces


Background A difficulty in computer-assisted interventions is acquiring the patient's anatomy intraoperatively. Standard modalities have several limitations: low image quality (ultrasound), radiation exposure (computed tomography) or high costs (magnetic resonance imaging). An alternative approach uses a tracked pointer; however, the pointer causes tissue deformation and requires sterilizing. Recent proposals, utilizing a tracked conoscopic holography device, have shown promising results without the previously mentioned drawbacks. Methods We have developed an open-source software system that enables real-time surface scanning using a conoscopic holography device and a wide variety of tracking systems, integrated into pre-existing and well-supported software solutions. Results The mean target registration error of point measurements was 1.46 mm. For a quick guidance scan, surface reconstruction improved the surface registration error compared with point-set registration. Conclusions We have presented a system enabling real-time surface scanning using a tracked conoscopic holography device. Results show that it can be useful for acquiring the patient's anatomy during surgery.

Neurosurgical robotic arm drilling navigation system


Background The aim of this work was to develop a neurosurgical robotic arm drilling navigation system that provides assistance throughout the complete bone drilling process. Methods The system comprised neurosurgical robotic arm navigation combining robotic and surgical navigation, 3D medical imaging based surgical planning that could identify lesion location and plan the surgical path on 3D images, and automatic bone drilling control that would stop drilling when the bone was to be drilled-through. Three kinds of experiment were designed. Results The average positioning error deduced from 3D images of the robotic arm was 0.502 ± 0.069 mm. The correlation between automatically and manually planned paths was 0.975. The average distance error between automatically planned paths and risky zones was 0.279 ± 0.401 mm. The drilling auto-stopping algorithm had 0.00% unstopped cases (26.32% in control group 1) and 70.53% non-drilled-through cases (8.42% and 4.21% in control groups 1 and 2). Conclusions The system may be useful for neurosurgical robotic arm drilling navigation.

A prospective, randomized, controlled trial of robot-assisted vs freehand pedicle screw fixation in spine surgery


Background The purpose of this study was to compare the accuracy and safety of an instrumented posterior lumbar interbody fusion (PLIF) using a robot-assisted minimally invasive (Robot-PLIF) or a conventional open approach (Freehand-PLIF). Methods Patients undergoing an instrumented PLIF were randomly assigned to be treated using a Robot-PLIF (37 patients) and a Freehand-PLIF (41 patients). Results For intrapedicular accuracy, there was no significant difference between the groups (P = 0.534). For proximal facet joint accuracy, none of the 74 screws in the Robot-PLIF group violated the proximal facet joint, while 13 of 82 in the Freehand-PLIF group violated the proximal facet joint (P < 0.001). The average distance of the screws from the facets was 5.2 ± 2.1 mm and 2.7 ± 1.6 mm in the Robot-PLIF and Freehand-PLIF groups, respectively (P < 0.001). Conclusion Robotic-assisted pedicle screw placement was associated with fewer proximal facet joint violations and better convergence orientations.

A prognostic model for predicting urinary incontinence after robot-assisted radical prostatectomy


Background The aim of this study is to develop a novel prognostic model for estimating the risk of postoperative urinary incontinence (UI) after robot-assisted radical prostatectomy (RARP). Methods Participants comprised 131 men who underwent RARP at our hospital from 2011 to 2013. Cox regression analyses were performed to evaluate associations between UI and preoperative factors including filling cystometry and pressure-flow study results and magnetic resonance imaging. Results Logistic regression analyses revealed significant associations between membranous urethral length or levator thickness and UI at 3 and 6 months. Stratification produced high (membranous urethral length < 9.5 mm or levator thickness < 9.0 mm) and low (membranous urethral length ≥ 9.5 mm and levator thickness ≥ 9.0 mm) UI risk groups. These inter-group differences in UI rate were significant. Conclusions We developed a novel prognostic model based on preoperative patient data that can be used for patient counselling.

Robotic-assisted minimally invasive surgery of the spine (RAMISS): a proof-of-concept study using carbon dioxide insufflation for multilevel posterior vertebral exposure via a sub-paraspinal muscle working space


Background Open posterior spinal procedures involve extensive soft tissue disruption, increased hospital length of stay, and disfiguring scars. Our aim was to demonstrate the feasibility of using robotic-assistance for minimally invasive exposure of the posterolateral spine with and without carbon dioxide (CO2 ) insufflation. Methods Sheep specimens underwent minimally invasive subperiosteal dissection of the spine during three trials. The da Vinci S Surgical system was used for access with and without working space support via CO2 insufflation. Results Without insufflation, a sub-paraspinal muscle tunnel measuring 16 cm was developed between two 5 cm incisions. With insufflation, the one-sided tunnel length was 12.5 cm but without the soft tissue trauma and obstructed visualization experienced without CO2. Conclusions The use of robot-assistance for minimally invasive access to the posterior spine appears to be feasible. The use of CO2 insufflation greatly improved our ability to visualize and access the posterior vertebral elements.

Robotic, laparoscopic, and open colectomy: a case-matched comparison from the ACS-NSQIP


Background This study aimed to compare perioperative outcomes of patients undergoing robotic, laparoscopic, and open colectomy using a procedure-targeted database. Methods Retrospective review of patients undergoing elective colectomy in 2013 was conducted using the procedure-targeted database of the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP). Robotic, laparoscopic, and open groups were matched (1:1:1) based on age, gender, body mass index, surgical procedure, diagnosis and ASA classification. Demographics, comorbidities, and short-term (30 day) outcomes were compared. Results Out of 12 790 patients, 387 fulfilled criteria per group after matching. Univariate comparison showed operating time was longer (P < 0.001) and hospital stay was shorter (P < 0.001) in the robotic group. Morbidity (P < 0.001), superficial SSI (P < 0.001), bleeding requiring transfusion (P < 0.001), ventilator dependency (P = 0.003), and ileus (P < 0.001) rates were lower in the robotic group. After adjusting for confounders, outcomes were comparable between the groups except hospital stay which was shorter in the robotic group (P < 0.001). Conclusions ACS-NSQIP data demonstrated several short-term advantages of robotic surgery compared with laparoscopic and open surgery.

The role of visual and direct force feedback in robotics-assisted mitral valve annuloplasty


Background The objective of this work was to determine the effect of both direct force feedback and visual force feedback on the amount of force applied to mitral valve tissue during ex vivo robotics-assisted mitral valve annuloplasty. Methods A force feedback-enabled master–slave surgical system was developed to provide both visual and direct force feedback during robotics-assisted cardiac surgery. This system measured the amount of force applied by novice and expert surgeons to cardiac tissue during ex vivo mitral valve annuloplasty repair. Results The addition of visual (2.16 ± 1.67), direct (1.62 ± 0.86), or both visual and direct force feedback (2.15 ± 1.08) resulted in lower mean maximum force applied to mitral valve tissue while suturing compared with no force feedback (3.34 ± 1.93 N; P < 0.05). Conclusions To achieve better control of interaction forces on cardiac tissue during robotics-assisted mitral valve annuloplasty suturing, force feedback may be required.

Single-incision robotic cholecystectomy: A special emphasis on utilization of transparent glove ports to overcome limitations of single-site port


Background The current robotic platform overcomes some limitations of single-incision laparoscopic cholecystectomy (SILC), however, whether robotic surgery is a safe and feasible approach must be investigated. Methods Patients referred for elective surgery willing to undergo single-incision robotic cholecystectomy (SIRC) by consent were enrolled. All procedures were performed by the same team using the same surgical equipment. Results Thirty patients underwent SIRC. The mean overall operation time was 53.80 ± 15.20 min (range 32–80) and mean console time was 16.67 ± 5.63 min (range 11–30). The mean postoperative stay was 1.30 ± 0.54 days (range 1–3). There were no perioperative major complications. Conclusion SIRC can be rapidly learnt and safely performed while overcoming the ergonomic difficulties encountered during SILC. SIRC can be a viable alternative treatment for gallbladder diseases in selected patients with strong interest in cosmetic outcomes who are willing to pay the higher costs associated with SIRC.

Comparative study of surgical knots using a domestically produced Chinese surgical robot, laparoscope, or barehanded approach


Background We conducted a comparative analysis of the first domestically produced Chinese surgical robot, ‘MicroHand’, laparoscopic, and barehanded approaches in tying surgical knots. Methods Four surgeons performed square or triple knots individually using the three approaches and documented the operational time, circumference, the bearable tension and action trajectory for each knot. Results MicroHand took more time than the barehanded method but nearly the same as with the laparoscope. The barehanded method generated the smallest knots among the three approaches and MicroHand produced smaller square knots than those by laparoscope. MicroHand and barehanded methods produced square knots displaying higher bearable tension than those produced by the laparoscope. For the action trajectory, MicroHand operated in a smaller space than that needed by the laparoscope. Conclusions The square knots produced by MicroHand were tighter and more solid than those by laparoscope, although the triple knots generated by the two methods were similar. Also MicroHand required a smaller operational space than the laparoscope.

A hierarchical task analysis of shoulder arthroscopy for a virtual arthroscopic tear diagnosis and evaluation platform (VATDEP)


Background Shoulder arthroscopy is a minimally invasive surgical procedure for diagnosis and treatment of a shoulder pathology. The procedure is performed with a fiber optic camera, called arthroscope, and instruments inserted through very tiny incisions made around the shoulder. The confined shoulder space, unintuitive camera orientation and constrained instrument motions complicates the procedure. Therefore, surgical competence in arthroscopy entails extensive training especially for psychomotor skills development. Conventional arthroscopy training methods such as mannequins, cadavers or apprenticeship model have limited use attributed to their low-fidelity in realism, cost inefficiency or incurring high risk. However, virtual reality (VR) based surgical simulators offer a realistic, low cost, risk-free training and assessment platform where the trainees can repeatedly perform arthroscopy and receive quantitative feedback on their performances. Therefore, we are developing a VR based shoulder arthroscopy simulation specifically for the rotator cuff ailments that can quantify the surgery performance. Development of such a VR simulation requires a through task analysis that describes the steps and goals of the procedure, comprehensive metrics for quantitative and objective skills and surgical technique assessment. Methods We analyzed shoulder arthroscopic rotator cuff surgeries and created a hierarchical task tree. We introduced a novel surgery metrics to reduce the subjectivity of the existing grading metrics and performed video analysis of 14 surgery recordings in the operating room (OR). We also analyzed our video analysis results with respect to the existing proposed metrics in the literature. Results We us[...]

Robotic versus open liver resections: A case-matched comparison


Background Most hepatic resections are currently performed using an open approach. Robotic surgery might enable the transition of these procedures to minimally invasive surgery. Methods Pre-, peri- and post-operative data of all patients who underwent a liver resection from 2009/2012 to 2001/2015, were collected prospectively. All robotic resection patients were matched 1:1 to patients who underwent open surgery. Pre- and perioperative data, up to 30 days, were analyzed. Results Sixteen robotic and open hepatic resections were identified. Fewer complication events and shorter lengths of stay (LOS, 7.9 versus 11 days, P = 0.0603) were observed for robotic resections. Length of stay in the intermediate care unit (IMC) was shorter after the robotic procedure (10 h vs 16.6 h, P = 0.0699). Operating room (OR) time was significantly longer in the robotic resection cohort (352.8 vs 239.6 min, P = 0.0215). All tumor margins were negative. Conclusions This preliminary comparison demonstrates the general feasibility of minor robotic liver resection in selected cases.

Prediction of forearm bone shape based on partial least squares regression from partial shape


Background Computer-assisted corrective osteotomy using a mirror image of the normal contralateral shape as reference is increasingly used. Instead, we propose to use the shape predicted by statistical learning to deal with cases demonstrating bilateral abnormality, such as bilateral trauma, congenital disease, and metabolic disease. Methods Computed tomography (CT) scans of 100 normal forearms were used in this study. The whole bone shape was predicted from its partial shape based on statistical learning of the other 99 bones. Accuracy was evaluated by average symmetric surface distance (ASD), and translational and rotational errors. Results ASDs for predicted shapes were 0.71–1.03 mm. Mean absolute translational and rotational errors were 0.48–1.76 mm and 0.99–6.08°, respectively. Conclusion Normal bone shape was predicted with an acceptable accuracy from its partial shape using statistical learning. Predicted shape can be an alternative to a mirror image, which may enable reduced radiation exposure and examination costs.

Early experience of laparoscopic and robotic hybrid pancreaticoduodenectomy


Background Laparoscopic surgery and robotic surgery have their own merits and demerits. The aim of this study was to evaluate early experiences of hybrid pancreaticoduodenectomy (PD) and to identify the learning curve of robotic surgery. Methods Sixteen patients underwent hybrid PD from August 2015 to February 2016. The outcomes were compared with those of an open PD group by the same operator during the same period. The resection time and anastomosis time were analyzed. Results Six patients in the hybrid PD group developed complications. The postoperative hospital stay in the hybrid surgery group was significantly shorter than the open PD group (10.9 ± 3.2 vs 16.9 ± 8.8 days). The total operative time of hybrid surgery was significantly longer than that of open surgery (414.7 ± 47.0 vs 266.0 ± 51.1 minutes). In hybrid surgery, the actual operation time reduced with experience, particularly anastomosis time. Conclusion Hybrid PD is feasible and safe. The learning curve of hybrid surgery, particularly robotic anastomosis, is relatively short.

Endoluminal surgical triangulation 2.0: A new flexible surgical robot. Preliminary pre-clinical results with colonic submucosal dissection


Background Complex intraluminal surgical interventions of the gastrointestinal tract are challenging due to the limitation of existing instruments. Our group has developed a master–slave robotic flexible endoscopic platform that provides instrument triangulation in an endoluminal environment. Materials and Methods Colonic endoscopic submucosal dissections (ESD) were carried out in eight pigs. The robot was introduced transanally. A combination of adapted tele-operated instruments was used. Specimens were inspected and measured. Results Out of 18 ESDs in total, 12 were successfully completed. Among the completed procedures, two perforations and one system failure occurred and were managed intraoperatively. There was no major bleeding. Mean size of the removed specimens was 18.2 ± 9.8 cm2 and mean total procedure time was 73 ± 35.5 min. Conclusions Experimental colorectal ESDs using the flexible surgical robot were feasible and reflected a short learning curve. After some technical improvements the system might allow for a wider adoption of complex endoluminal surgical procedures.

Evaluation of the new C-arm guiding system ClearGuide® in an orthopaedic and trauma operating theatre


Background The objective was to evaluate whether the new intraoperative C-arm guiding system ClearGuide® (CG) reduces radiation exposure of the staff in an Orthopaedic and Trauma operation theatre. Methods Data of 95 patients CG was used were retrospectively compared using matched-pair analysis with controls without CG. Radiation dose (RD), fluoroscopic time (FT) and operation time (OT) were analysed in ten types of operative procedures. Results Use of CG led to a significant reduction (p ≤ 0.05) of the RD in intramedullary nailing and plate fixation of femoral shaft fractures as well as plating of tibia shaft fractures. Concerning FT, use of CG led to a significant reduction (p ≤ 0.05) while performing kyphoplasties and plate fixation of femoral shaft fractures. Regarding OT, no statistical significance was observed. Conclusions CG as a simple, reproducible and intuitive communication tool for C-arm guidance reduces intraoperative staff radiation exposure especially while fixation of long bone fractures and in spine surgery.

Outcomes in patients undergoing robotic reconstructive uterovaginal anastomosis of congenital cervical and vaginal atresia


Objective To introduce our experience of robotic surgery of reconstructive uterovaginal anastomosis and operative outcomes in congenital cervical and vaginal atresia patients. Methods Clinical observation and follow-up of four patients with congenital cervical and vaginal atresia who underwent robotic reconstruction of cervix and vagina by SIS (small intestinal submucosa, SIS) graft. Results Average patient age was 13.8 ± 2.2. Patients complained of severe periodic abdominal pain. Diagnosis was made according to clinical characteristics, physical examination, MRI and classified by ESHRE/ESGE system. All patients underwent reconstruction of cervix and vagina by uterovaginal anastomosis by SIS graft. Average operation time was 232.5 ± 89.2 min, average blood loss was 225.0 ± 95.7 mL. After surgery, all patients have regular menstruation without pain. Average follow up was 12 months, average vagina length was 8.9 ± 0.3 cm, average vagina width was 2.9 ± 0.1 cm. Conclusion Robotic assisted reconstruction of cervix and vagina is feasible from our experience, enlarged cases and additional studies are required.

The application of a blunt-tip needle to suture the dorsal venous complex in robot-assisted laparoscopic radical prostatectomy


Objectives Complete haemostasis of the dorsal venous complex (DVC) is of great importance in robot-assisted radical prostatectomy. In this study, we investigated the efficacy of blunt-tip needles in the surgery. Methods Cases of robot-assisted laparoscopic radical prostatectomy were reviewed. If a blunt-tip needle had been used to suture the DVC, the patient was recruited to the blunt-tip group. If a regular needle was used, the patient was recruited to the control group. Patient characteristics and perioperative outcomes were recorded. Results One hundred and nine cases were reviewed. A blunt-tip needle was used to suture the DVC in 67 cases, and a regular needle in 42 cases. All characteristics of the two groups are comparable (p > 0.05). In 66 cases in the blunt-tip group, no sutures or coagulations were needed when suturing the DVC, Five cases of DVC-related bleeding were observed in the control group, which is higher than in the blunt-tip group (p = 0.031). At the same time, no catheter was sutured in the blunt-tip group. All patients were followed for at least six months. The continence rate in the blunt-tip group is 89.6%, significantly higher than in the control group (73.8%, p = 0.031). Conclusions Using a blunt-tip needle to suture the DVC may reduce DVC-related bleeding and provide a better surgical field. It may be helpful in improving postoperative continence. However, its effect on positive margin at the apex still needs further investigation.

Robotic guided waterjet cutting technique for high tibial dome osteotomy: A pilot study


Background Oscillating saws generate high levels of heat (up to 150°C), which can lead to tissue necrosis, delayed healing and infection. Abrasive waterjet-cutting techniques have been described as a new tool to perform bone cuts, with less heat generation. Methods Four lower-limbs of four human alcohol conserved cadavers were tested. Navigation references were attached to the tibia and an intraoperative fluoroscopy-based 3D scan was obtained. A 1.2 mm diameter nozzle was attached to a robotic arm, which was guided to follow a pre-specified path. In addition, a self-designed jet-absorber was applied to protect the posterior neurovascular structures. Magnesium was added as an abrasive substance to improve the cutting ability of the waterjet. Results In all four cadavers, the osteotomies could be carried out as planned, resulting in smooth cut surfaces. No damage to the soft-tissues was observed. Conclusions The advantages of abrasive waterjet-cutting give it great potential in orthopaedic surgery. A current disadvantage is the amount of magnesium solute that is left on the surgical field and can be harmful to the patient.

Validation of patient-specific surgical guides for femoral neck cutting in total hip arthroplasty through the anterolateral approach


Background The aim of this study was to validate the effectiveness of neck-cut patient-specific surgical guides (PSGs) for femoral component implantation in total hip arthroplasty (THA) through the anterolateral approach compared with that without PSG. Methods A total of 32 fresh cadaveric hips were included. Anatomical stem implantation with wide-base-contact PSG (AWP group) and without PSG (control group) were compared. The absolute errors between preoperative planning and PSG setting (E1), as well as those between preoperative planning and postoperative component implantation (E2) were evaluated using CT. Results The E1/E2 values of AWP were 0.9±0.3°/0.6±0.6° in the coronal plane, and 1.7±0.8°/1.0±0.9° in the sagittal plane, and 1.0±0.6 mm/1.0±1.1 mm for the medial height. The E2 value in the sagittal plane (P=0.037) and the medial height (P=0.011) of AWP were significantly smaller than those of control group. Conclusions The neck-cut PSG through the anterolateral approach is effective for femoral component implantation.

Robotic longitudinal pancreaticojejunostomy for chronic pancreatitis: Comparison of clinical outcomes and cost to the open approach


Background This study compares clinical and cost outcomes of robot-assisted laparoscopic (RAL) and open longitudinal pancreaticojejunostomy (LPJ) for chronic pancreatitis. Methods Clinical and cost data were retrospectively compared between open and RAL LPJ performed at a single center from 2008–2015. Results Twenty-six patients underwent LPJ: 19 open and 7 RAL. Two robot-assisted cases converted to open were included in the open group for analysis. Patients undergoing RAL LPJ had less intraoperative blood loss, a shorter surgical length of stay, and lower medication costs. Operation supply cost was higher in the RAL group. No difference in hospitalization cost was found. Conclusions Versus the open approach, RAL LPJ performed for chronic pancreatitis shortens hospitalization and reduces medication costs; hospitalization costs are equivalent. A higher operative cost for RAL LPJ is mitigated by a shorter hospitalization. Decreased morbidity and healthcare resource economy support use of the robotic approach for LPJ when appropriate.

Clinical performance and survivorship of navigated floating platform mobile-bearing total knee arthroplasty: A minimum 10-year follow-up


Background The purpose of this study is to report the outcome of navigation-assisted cruciate-retaining total knee arthroplasty (TKA) using one type of cemented, second-generation, floating-platform (FP), mobile-bearing system. Methods Forty-two patients who underwent cruciate retaining TKAs using e.motion-FP prostheses under navigational guidance were retrospectively reviewed. The preoperative diagnosis was osteoarthritis in all knees except one rheumatoid arthritis. The mean follow-up was 132.0 months (range, 120–140 months) and the mean age was 64.0 ± 4.7 years (range, 51–76 years) at the time of index surgery. Clinical and radiographic results as well as mechanical survival rate of this type of prosthesis were investigated at a minimum follow-up of 10 years. Results The mean mechanical femorotibial angle was improved from 11.7° ± 3.3° preoperatively to 1.4° ± 1.7° at the latest follow-up. No prosthesis-related complications occurred. One knee underwent open debridement due to superficial infection at 5 weeks after surgery and the other knee experienced a periprosthetic fracture around the proximal tibia, which was successfully healed after open reduction and internal fixation. Conclusions The e.motion-floating platform mobile-bearing design yielded satisfactory long-term durability and implant performance under navigational guidance.