E. Matt Ritter

Virtual reality simulation for the operating room: proficiency-based training as a paradigm shift in surgical skills training.

Summary Background Data:To inform surgeons about the practical issues to be considered for successful integration of virtual reality simulation into a surgical training program. The learning and practice of minimally invasive surgery (MIS) makes unique demands on surgical training programs. A decade ago Satava proposed virtual reality (VR) surgical simulation as a solution for this problem. Only recently have robust scientific studies supported that vision Methods:A review of the surgical education, human-factor, and psychology literature to identify important factors which will impinge on the successful integration of VR training into a surgical training program. Results:VR is more likely to be successful if it is systematically integrated into a well-thought-out education and training program which objectively assesses technical skills improvement proximate to the learning experience. Validated performance metrics should be relevant to the surgical task being trained but in general will require trainees to reach an objectively determined proficiency criterion, based on tightly defined metrics and perform at this level consistently. VR training is more likely to be successful if the training schedule takes place on an interval basis rather than massed into a short period of extensive practice. High-fidelity VR simulations will confer the greatest skills transfer to the in vivo surgical situation, but less expensive VR trainers will also lead to considerably improved skills generalizations. Conclusions:VR for improved performance of MIS is now a reality. However, VR is only a training tool that must be thoughtfully introduced into a surgical training curriculum for it to successfully improve surgical technical skills.

Design of a Proficiency-Based Skills Training Curriculum for the Fundamentals of Laparoscopic Surgery

Currently, no optimal curriculum exists for the Fundamentals of Laparoscopic Surgery (FLS) manual skills training program. The objective was to create a proficiency-based training curriculum that would allow both successful completion of the FLS manual skills exam and improved performance in the operating room. Two experienced laparoscopic surgeons performed 5 consecutive repetitions of all 5 FLS tasks. The mean performance times for both subjects were determined. Error parameters for each task were also recorded and used to establish a maximum allowable error parameter for each task. These data were used to create both error- and time-based proficiency levels for each task based on the importance of the task and the amount of resources consumed when practicing the task. This type of objective proficiency level was determined for each of the 5 FLS tasks. We have developed a proficiency-based training curriculum for the psychomotor skills portion of FLS. Work is under way to evaluate and validate this curricular design.

Prospective, Randomized, Double-Blind Trial of Curriculum-Based Training for Intracorporeal Suturing and Knot Tying

BACKGROUND Advanced surgical skills such as laparoscopic suturing are difficult to learn in an operating room environment. The use of simulation within a defined skills-training curriculum is attractive for instructor, trainee, and patient. This study examined the impact of a curriculum-based approach to laparoscopic suturing and knot tying. STUDY DESIGN Senior surgery residents in a university-based general surgery residency program were prospectively enrolled and randomized to receive either a simulation-based laparoscopic suturing curriculum (TR group, n=11) or standard clinical training (NR group, n=11). During a laparoscopic Nissen fundoplication, placement of two consecutive intracorporeally knotted sutures was video recorded for analysis. Operative performance was assessed by two reviewers blinded to subject training status using a validated, error-based system to an interrater agreement of >or=80%. Performance measures assessed were time, errors, and needle manipulations, and comparisons between groups were made using an unpaired t-test. RESULTS Compared with NR subjects, TR subjects performed significantly faster (total time, 526+/-189 seconds versus 790+/-171 seconds; p < 0.004), made significantly fewer errors (total errors, 25.6+/-9.3 versus 37.1+/-10.2; p < 0.01), and had 35% fewer excess needle manipulations (18.5+/-10.5 versus 27.3+/-8.6; p < 0.05). CONCLUSIONS Subjects who receive simulation-based training demonstrate superior intraoperative performance of a highly complex surgical skill. Integration of such skills training should become standard in a surgical residencys skills curriculum.

Relationship Between Tissue Ingrowth and Mesh Contraction

Contraction is a well-documented phenomenon occurring within two months of mesh implantation. Its etiology is unknown, but it is suggested to occur as a result of inadequate tissue ingrowth into the mesh and has been associated with hernia recurrence. In continuation of our previous studies, we compared tissue ingrowth characteristics of large patches of polyester (PE) and heavyweight polypropylene (PP) and their effect on mesh contraction. The materials used were eight PE and eight PP meshes measuring 10 × 10 cm2. After random assignment to the implantation sites, the meshes were fixed to the abdominal wall fascia of swine using interrupted polypropylene sutures. A necropsy was performed three months after surgery for evaluation of mesh contraction/shrinkage. Using a tensiometer, tissue ingrowth was assessed by measuring the force necessary to detach the mesh from the fascia. Histologic analysis included inflammatory and fibroblastic reactions, scored on a 0–4 point scale. One swine developed a severe wound infection that involved two PP meshes and was therefore excluded from the study. The mean area covered by the PE meshes (87 ± 7 cm2) was significantly larger than the area covered by the PP meshes (67 ± 14 cm2) (p = 0.006). Tissue ingrowth force of the PE meshes (194 ± 37 N) had a trend toward being higher than that of the PP meshes (159 ± 43 N), although it did not reach statistical significance. There was no difference in histologic inflammatory and fibroblastic reactions between mesh types. There was a significant correlation between tissue ingrowth force and mesh size (p = 0.03, 95% CI: 0.05–0.84). Our results confirm those from previous studies in that mesh materials undergo significant contraction after suture fixation to the fascia. PE resulted in less contraction than polypropylene. A strong integration of the mesh into the tissue helps prevent this phenomenon, which is evidenced by a significant correlation between tissue ingrowth force and mesh size.

Objective psychomotor skills assessment of experienced and novice flexible endoscopists with a virtual reality simulator

The objective of this study was to determine whether the GI Mentor II virtual reality simulator can distinguish the psychomotor skills of intermediately experienced endoscopists from those of novices, and do so with a high level of consistency and reliability. A total of five intermediate and nine novice endoscopists were evaluated using the EndoBubble abstract psychomotor task. Each subject performed three repetitions of the task. Performance and error data were recorded for each trial. The intermediate group performed better than the novice group in each trial. The differences were significant in trial 1 for balloons popped (P = .001), completion time (P = .04), and errors (P = .03). Trial 2 showed significance only for balloons popped (P = .002). Trial 3 showed significance for balloons popped (P = .004) and errors (P = .008). The novice group showed significant improvement between trials 1 and 3 (P < 0.05). No improvement was noted in the intermediate group. Measures of consistency and reliability were greater than 0.8 in both groups with the exception of novice completion time where test-retest reliability was 0.74. The GI Mentor II simulator can distinguish between novice and intermediate endoscopists. The simulator assesses skills with levels of consistency and reliability required for high-stakes assessment.

The pretrained novice: Using simulation-based training to improve learning in the operating room

Enabling trainees to acquire advanced technical skills before they begin the operating room experience benefits both trainee and patient. Whether medical students who had received exclusively simulation-based training could perform laparoscopic suturing and knot-tying as well as senior surgery residents was determined. Simulators were used to train 11 fourth-year medical students with no previous suturing experience to perform intracorporeal suturing and to successfully tie a free-hand intracorporeal knot. Students’ skills were assessed by the performance of the fundal suturing portion of a Nissen fundoplication in a porcine model. Their operative performance was evaluated for time, needle manipulations, and total errors. Results were compared to those of 11 senior-level surgery residents performing the same task. The study concluded that trainees could learn advanced technical skills such as laparoscopic suturing and knot tying by using simulation exclusively. The trainees and senior level surgery residents had a similar number of needle manipulations.

Real-Time Objective Assessment of Knot Quality With a Portable Tensiometer Is Superior to Execution Time for Assessment of Laparoscopic Knot-Tying Performance:

Objective: Laparoscopic intracorporeal knot tying is a difficult skill to acquire. Currently, time to complete a knot is the most commonly used metric to assess the acquisition of this skill; however, without a measure of knot quality, time is a poor indicator of skills mastery. Others have shown that knot quality can be accurately assessed with a tensiometer, but obtaining this type of assessment has typically been cumbersome. We investigated a new method of real-time assessment of knot quality that allows for more practical use of knot quality as a performance metric. Methods: Eleven experienced endoscopic surgeons tied 100 intracorporeal knots in a standard box trainer. Each of the knots was immediately tested using the InSpec 2200 benchtop tensiometer (INSTRON, Canton MA) where a knot quality score (KQS) is generated based on the load handling properties of the knotted suture. The execution time was also recorded for each knot. Results: The assessment of all knots ended with one of two end points: knots that slipped (n = 48)or knots that held until the suture broke (n = 52). Knots that slip are generally of poorer quality than those that held. Execution time did not correlate with knot-quality score (r= 0.009, P= .9), and the mean execution time did not differ significantly between slipped and held knots (65 vs 68 seconds, P= .8). No completion time criteria were able to accurately predict slipped versus held knots. The mean KQS difference between held and slipped knots was highly significant (24 vs 12, P< .0001). A knot with a KQS exceeding 20 was nearly 10 times more likely to hold than slip. Conclusion: Time to complete a knot is a poor metric for the objective assessment of intracorporeal knot-tying performance in the absence of a measure of knot quality. Real-time evaluation of the knot quality can accurately distinguish welltied knots from poorly tied knots. This mode of assessment should be incorporated into training curriculum for surgical knot tying.

Visuospatial abilities correlate with performance of senior endoscopy specialist in simulated colonoscopy

Visuospatial abilities have been demonstrated to predict the performance of medical students in simulated endoscopy. However, little has been reported whether differences in visuospatial abilities influence the performance of senior endoscopists or whether their vast endoscopy experience reduces the importance of these abilities. Eleven senior endoscopists were included in our study. Before the simulated endoscopies in GI Mentor II (gastroscopy: case 3, module 1 and colonoscopy: case 3, module 1), the endoscopists performed three visuospatial tests: (1) pictorial surface orientation (PicSOr), (2) card rotation, and (3) cube comparison tests that monitor the ability of the tested person to re-create a three-dimensional image from a two-dimensional presentation as well as mentally manipulate that re-created image. The results of the visuospatial tests were correlated to the performance parameters of the virtual-reality endoscopy simulator. The percent of time spent with clear view in the simulated colonoscopy correlated well with the performance in the visuospatial PicSOr (r= -0.75, P = 0.01), card rotation (r = 0.75, P = 0.01), and cube comparison (r = 0.79, P = 0.004) tests. The endoscopists who performed better in the visuospatial tests also were better at maintaining visualization of the colon lumen. Those who performed better in the PicSOr test formed fewer loops during colonoscopy (r = 0.60, P = 0.05). In the technically less demanding simulated gastroscopy, there were no such correlations. The visuospatial tests performed better in endoscopists not playing computer games. Good visuospatial ability correlates significantly with the performance of experienced endoscopists in a technically demanding simulated colonoscopy, but not in the less demanding simulated gastroscopy.

Remote FLS testing in the real world: ready for “prime time”

IntroductionMaintaining the existing FLS test centers requires considerable investment in human and financial resources. It can also be particularly challenging for those outside of North America to become certified due to the limited number of international test centers. Preliminary work suggests that it is possible to reliably score the FLS manual skills component remotely using low-cost videoconferencing technology. Significant work remains to ensure that testing procedures adhere to standards defined by SAGES for this approach to be considered equivalent to standard on-site testing.ObjectiveTo validate the integrity and validity of the FLS manual skills examination administered remotely in a real-world environment according to FLS testing protocols and to evaluate participants’ experience with the setting.MethodsIndividuals with various levels of training from the University of Toronto completed a pre- and a post-test questionnaire. Participants presented to one of the two FLS testing rooms available for the study, each connected via Skype to a separate room with a FLS proctor who administered and scored the test remotely (RP). An on-site proctor (OP) was present in the room as a control. An invigilator was also present in the testing room to follow directions from the RP and ensure the integrity of test materials.ResultsTwenty-one participants were recruited, and 20 completed the test. There was no significant difference between scores by RP and OP. Interrater reliability between the RP and OP was excellent. One critical error was missed by the RP, but this would not have affected the test outcome. Participants reported being highly satisfied.ConclusionWe demonstrate that proctors located remotely can administer the FLS skills test in a secure and reliable fashion, with excellent interrater reliability compared to an on-site proctor. Remote proctoring of the FLS examination could become a strategy to increase certification rates while containing costs.

A Meandering External Iliac Artery: Potential Doom Outside the Triangle

dentification of the normal anatomy during total extraeritoneal inguinal hernia repair can be challenging. An natomic region in the preperitoneal space, the “Triangle of oom,” is bounded medially by the vas deferens and latrally by the testicular vessels; its base is formed by the eritoneal reflection (A).The triangle typically contains the xternal iliac artery (EIA) and external iliac vein (EIV). ooper’s ligament (CL) is shown for reference. Knowledge of vascular anatomic variances is critical to voiding catastrophic hemorrhage during operations of the elvic preperitoneal space. Aberrant anastomoses between he obturator and external iliac arterial systems, deemed the orona mortis, are well described, are present up to 25% of he time, and are a frequent potential hazard during preeritoneal surgery. Other less common vascular variances ose similar risks, but are unfamiliar to many surgeons. uring total extraperitoneal inguinal hernia repair we enountered an aberrantly located left external iliac artery. The patient presented electively for repair of bilateral inguial hernias. Both a fat-containing right inguinal hernia (RIH) nd left inguinal hernia (LIH) are shown in the CT scan (B). t operation the patient had bilateral indirect hernias. On the eft a large pulsating vessel was identified medial to the iliac ein and outside the boundaries of the Triangle of Doom (C). t gave off the deep inferior epigastric artery and returned to its ormal position lateral to the external iliac vein before proeeding deep to the iliopubic tract. Review of the CT scan (D, highlighted in green) conirmed the vascular structure encountered at operation. he left external iliac artery (EIA) and internal iliac artery IIA) were in their normal anatomic location (D, 1). The eft external iliac artery coursed medially to the external liac vein (D, parts 2 to 7) and returned to its normal ocation in the groin (D, parts 8 to 10). This variant is etter conceptualized in the artistic rendering of the paient’s anatomy (E). Familiarity with the normal anatomy of the preperitoneal pace and careful dissection avoids injury of the external iliac rtery. The meandering external iliac artery is one vascular ariation of which the surgeon should be cognizant.