Kurt E. Roberts

The Role of Haptic Feedback in Laparoscopic Simulation Training

INTRODUCTION Laparoscopic virtual reality simulators are becoming a ubiquitous tool in resident training and assessment. These devices provide the operator with various levels of realism, including haptic (or force) feedback. However, this feature adds significantly to the cost of the devices, and limited data exist assessing the value of haptics in skill acquisition and development. Utilizing the Laparoscopy VR (Immersion Medical, Gaithersburg, MD), we hypothesized that the incorporation of force feedback in the simulated operative environment would allow superior trainee performance compared with performance of the same basic skills tasks in a non-haptic model. METHODS Ten medical students with minimal laparoscopic experience and similar baseline skill levels as proven by performance of two fundamentals of laparoscopic surgery (FLS) tasks (peg transfer and cutting drills) voluntarily participated in the study. Each performed two tasks, analogous to the FLS drills, on the Laparoscopy VR at 3 levels of difficulty, based on the established settings of the manufacturer. After achieving familiarity with the device and tasks, the students completed the drills both with and without force feedback. Data on completion time, instrument path length, right and left hand errors, and grasping tension were analyzed. The scores in the haptic-enhanced simulation environment were compared with the scores in the non-haptic model and analyzed utilizing Students t-test. RESULTS The peg transfer drill showed no difference in performance between the haptic and non-haptic simulations for all metrics at all three levels of difficulty. For the more complex cutting exercise, the time to complete the tasks was significantly shorter when force feedback was provided, at all levels of difficulty (158+/-56 versus 187+/-51 s, 176+/-49 versus 222+/-68 s, and 275+/-76 versus 422+/-220 s, at levels 1, 2, and 3, respectively, P<0.05). Data on instrument path length, grasping tension, and errors showed a trend toward a benefit from haptics at all difficulty levels, but this difference did not achieve statistical significance. CONCLUSIONS In the more advanced tasks, haptics allowed superior precision, resulting in faster completion of tasks and a trend toward fewer technical errors. In the more basic tasks, haptic-enhanced simulation did not demonstrate an appreciable performance improvement among our trainees. These data suggest that the additional expense of haptic-enhanced laparoscopic simulators may be justified for advanced skill development in surgical trainees as simulator technology continues to improve.

Complications of transvaginal natural orifice transluminal endoscopic surgery: a series of 102 patients.

Objective:To review the complications encountered in our facility and in previously published studies of transvaginal (TV) natural orifice transluminal endoscopic surgery (NOTES) to date. Background:TV NOTES is currently observed with critical eyes from the surgical community, despite encouraging data to suggest improved short-term recovery and pain. Methods:All TV NOTES procedures performed in female patients between 18 and 65 years of age were included. The median follow-up was 90 days. The TV appendectomies and ventral hernia repairs were pure NOTES, through a SILS port in the vagina, whereas TV cholecystectomies were hybrid procedures with the addition of a 5-mm port in the umbilicus. Results:A total of 102 TV NOTES procedures, including 72 TV cholecystectomies, 24 TV appendectomies, and 6 TV ventral hernia repairs, were performed. The average age was 37 years old and body mass index was 29 kg/m2. Three major and 7 minor complications occurred. The first major complication was a rectal injury during a TV access port insertion. The second major complication was an omental vessel bleed after a TV cholecystectomy. The third complication was an intra-abdominal abscess after a TV appendectomy. Seven minor complications were urinary retention (4), transient brachial plexus injury, dislodgement of an intrauterine device, and vaginal granulation tissue. Conclusions:As techniques in TV surgery are adopted, inevitably, complications may occur due to the inherent learning curve. Laparoscopic instruments, although adaptable to TV approaches, have yet to be optimized. A high index of suspicion is necessary to identify complications and optimize outcomes for patients.

Designing and validating a customized virtual reality-based laparoscopic skills curriculum.

OBJECTIVE We developed and instituted a laparoscopic skills curriculum based on a virtual reality simulator, LapSim (Surgical Science, Göteborg, Sweden). Our goal was to improve basic skills in our residents. The hypothesis of this study is that performance in our course will differentiate levels of experience in the training program, establishing construct validity for our curriculum. DESIGN We designed a novel curriculum that consisted of 17 practice modules and a 7-part examination. All residents who completed the curriculum successfully were included in this study. Performance to complete the examination was analyzed. Data were stratified by level of training. SETTING University surgical skill training laboratory. PARTICIPANTS In all, 29 residents of all levels of training and 3 attending surgeons completed the curriculum. RESULTS The average number of practice repetitions required was 243. To complete the examination component, junior residents (R1-R3) required more repetitions than senior residents (R4, R5), 28.3 versus 13.9, respectively (p < 0.002). Tasks on camera and instrument navigation as well as coordination did not reveal significant differences. The complex grasping task demonstrated significant differences in repetitions required for each level of training: 19.5 attempts for R1, 17.2 for R2, 13 for R3, 8.5 for R4, and 3 for R5 (p < 0.04). The 2 cutting drills, which required precise use of the left hand, required 7.9 repetitions for junior residents versus 2.7 for senior residents (p < 0.009). A clip application drill differentiated among junior residents with 39.4, 19.8, and 8.5 repetitions required for R1, R2, and R3, respectively (p < 0.05). Senior residents performed equivalent to attendings on this drill. A lifting and grasping drill differentiates among junior residents, senior residents, and attendings (p < 0.03). CONCLUSIONS Individual performance in our curriculum correlates with the level of training for many drills, which establishes construct validity for this curriculum. Noncontributory drills may need to be revised or removed from the curriculum. Successful completion of this curriculum may lead to improved resident technical performance.

Defining Surgical Therapy for Pseudomembranous Colitis With Toxic Megacolon

Background Pseudomembranous colitis has increased in incidence and severity over the past 10 years. Toxic megacolon is a rare but reported presentation of severe pseudomembranous colitis. This article reviews the reported cases of Clostridium difficile with toxic megacolon in the literature and introduces an additional case that underscores the importance of early diagnosis in guiding appropriate therapy. Methods A systematic review of the literature was performed to identify previous reports of pseudomembranous colitis presenting with toxic megacolon, and the outcomes of each of these cases was analyzed. The review was focused on atypical presentations in immunocompromised patients. Results Seventeen cases of C. difficile colitis presenting as toxic megacolon were identified. The overall mortality rate was 50% (9/18). Fifteen patients underwent surgery with an associated mortality rate of 50%. Thirteen patients had a subtotal colectomy. Seven of the patients (39%) were taking immunosuppressant medications, and 5 (28%) patients presented with atypical symptoms. Three (76%) of those were immunosuppressed. In several cases, failure to make an early diagnosis of C. difficile colitis resulted in a worse outcome because appropriate therapy was delayed. Conclusions Toxic megacolon is well-established as an unusual presentation of C. difficile colitis. These patients are less likely to present with typical symptoms such as diarrhea or typical risk factors like recent administration of antibiotics, so diagnosis can be a challenge. A patient presenting with toxic megacolon without a history of inflammatory bowel disease should be assumed to have C. difficile colitis until proven otherwise, and medical or surgical therapy administered accordingly.

ΔF508 mutation results in impaired gastric acid secretion

The cystic fibrosis transmembrane conductance regulator (CFTR) is recognized as a multifunctional protein that is involved in Cl– secretion, as well as acting as a regulatory protein. In order for acid secretion to take place a complex interaction of transport proteins and channels must occur at the apical pole of the parietal cell. Included in this process is at least one K+ and Cl– channel, allowing for both recycling of K+ for the H,K-ATPase, and Cl– secretion, necessary for the generation of concentrated HCl in the gastric gland lumen. We have previously shown that an ATP-sensitive potassium channel (KATP) is expressed in parietal cells. In the present study we measured secretagogue-induced acid secretion from wild-type and ΔF508-deficient mice in isolated gastric glands and whole stomach preparations. Secretagogue-induced acid secretion in wild-type mouse gastric glands could be significantly reduced with either glibenclamide or the specific inhibitor CFTR-inh172. In ΔF508-deficient mice, however, histamine-induced acid secretion was significantly less than in wild-type mice. Furthermore, immunofluorescent localization of sulfonylurea 1 and 2 failed to show expression of a sulfonylurea receptor in the parietal cell, thus further implicating CFTR as the ATP-binding cassette transporter associated with the KATP channels. These results demonstrate a regulatory role for the CFTR protein in normal gastric acid secretion.

Stump appendicitis: a surgeon's dilemma.

The authors make the point that completion appendectomy in cases of stump appendicitis should be performed laparoscopically when possible guided by CT scan findings.

Two-Port Laparoscopic Appendectomy: Minimizing the Minimally Invasive Approach

BACKGROUND Three laparoscopic ports are traditionally required to complete a laparoscopic appendectomy. We describe a novel, innovative 2-port laparoscopic technique, in which intracorporeal appendectomy can be completed safely with standard instrumentation. MATERIALS AND METHODS Eight consecutive patients were prospectively assigned to undergo 2-port laparoscopic appendectomies for presumed appendicitis. The technique involves the placement of one 12-mm infraumbilical port for the working instruments and one 5-mm left lower quadrant port for the camera. A suture is tied in a loop to the anterior abdominal wall in the right lower quadrant, which is subsequently used as an axle. A pretied suture placed on the appendix is passed through the loop suture and then through the port to the outside of the abdomen. This technique allows exposure of the base of the appendix and compensates for the lack of the third port usually required for the retraction of the appendix. The mesoappendix and appendix are stapled and removed from the abdomen in an extrication bag. RESULTS All 8 laparoscopic procedures were completed without difficulty. The mean operative time was 64.1 min. Length of hospitalization was 1 d or less. No major complications were encountered. One minor postoperative complication occurred in which the patient developed periumbilical cellulitis, which was completely resolved at the 1-wk postoperative visit. CONCLUSION In times where surgeons are focusing on transluminal approaches to access the abdominal cavity, we favor laparoscopy for the enhanced exposure, instrument diversity, and overall patient safety. Two-port laparoscopic appendectomy is a safe, novel laparoscopic technique, which minimizes minimally invasive surgery even further to a new level of decreased invasiveness and improved cosmesis.

Pain Relief in Laparoscopic Cholecystectomy—A Review of the Current Options

Abstract:  Pain relief after laparoscopic cholecystectomy (LC) is an issue of great practical importance. Pain after LC has several origins: incisional, local visceral, peritoneal, and referred. Several modalities have been employed for achieving effective and safe analgesia: nonsteroidal anti‐inflammatory drugs (NSAIDs) and cyclooxygenase‐2 (COX‐2) inhibitors, gabapentinoids, local anesthetics, and transversus abdominis plane (TAP) block. They have their advantages and disadvantages, and multimodal approaches are often followed because of the multiple sources of pain. Among COX‐2 inhibitors, parecoxib and valdecoxib are useful, and fears regarding their cardiovascular adverse effects in noncardiac surgery (such as LC) have not been substantiated when used in short term. Gabapentin is useful but more data are needed regarding pregabalin because of inconsistent results. Local anesthetics (LA) can be particularly useful, both port‐site infiltration and intraperitoneal instillation in the intra‐operative period. Factors enhancing the effectiveness of these agents include early instillation before creating the pneumoperitoneum, larger volume of medium used for instillation, and favorable pharmacological characteristics of the agent. Combination of LA with either NSAID/COX‐2 inhibitors or fibrin sealant appears to be effective, although more research is required for determining the exact combinations and efficacy using direct comparisons with single‐modality interventions. Finally, newer procedures such as TAP block appear promising if replicated.▪

Construct and face validity of a virtual reality–based camera navigation curriculum

INTRODUCTION Camera handling and navigation are essential skills in laparoscopic surgery. Surgeons rely on camera operators, usually the least experienced members of the team, for visualization of the operative field. Essential skills for camera operators include maintaining orientation, an effective horizon, appropriate zoom control, and a clean lens. Virtual reality (VR) simulation may be a useful adjunct to developing camera skills in a novice population. No standardized VR-based camera navigation curriculum is currently available. We developed and implemented a novel curriculum on the LapSim VR simulator platform for our residents and students. We hypothesize that our curriculum will demonstrate construct and face validity in our trainee population, distinguishing levels of laparoscopic experience as part of a realistic training curriculum. METHODS Overall, 41 participants with various levels of laparoscopic training completed the curriculum. Participants included medical students, surgical residents (Postgraduate Years 1-5), fellows, and attendings. We stratified subjects into three groups (novice, intermediate, and advanced) based on previous laparoscopic experience. We assessed face validity with a questionnaire. The proficiency-based curriculum consists of three modules: camera navigation, coordination, and target visualization using 0° and 30° laparoscopes. Metrics include time, target misses, drift, path length, and tissue contact. We analyzed data using analysis of variance and Students t-test. RESULTS We noted significant differences in repetitions required to complete the curriculum: 41.8 for novices, 21.2 for intermediates, and 11.7 for the advanced group (P < 0.05). In the individual modules, coordination required 13.3 attempts for novices, 4.2 for intermediates, and 1.7 for the advanced group (P < 0.05). Target visualization required 19.3 attempts for novices, 13.2 for intermediates, and 8.2 for the advanced group (P < 0.05). Participants believe that training improves camera handling skills (95%), is relevant to surgery (95%), and is a valid training tool (93%). Graphics (98%) and realism (93%) were highly regarded. CONCLUSIONS The VR-based camera navigation curriculum demonstrates construct and face validity for our training population. Camera navigation simulation may be a valuable tool that can be integrated into training protocols for residents and medical students during their surgery rotations.

“Triangle of safety”: anatomic considerations in transvaginal natural orifice surgery

BackgroundThe introduction of transvaginal (TV) natural orifice transluminal endoscopic surgery (NOTES) brings the loss of traditionally used cutaneous landmarks for safe peritoneal access. This video describes the use of landmarks within the posterior vaginal fornix to define a “triangle of safety” wherein the peritoneal cavity can be accessed while minimizing the risk of injury to surrounding structures.MethodsThe triangle of safety is best identified in the following way. The cervix and posterior fornix are visualized. Then an imaginary clock located at the base of the cervix is envisioned. The superior two corners of the triangle are represented by the 4 and 8 o’clock positions on this imaginary clock. Sometimes the cervix needs to be grasped and elevated anteriorly so that the inferior apex of the triangle delineated by the center of the rectovaginal fold is better visualized.ResultsDuring hybrid TV NOTES, the rectovaginal pouch of Douglas is visualized from the umbilicus, and the vaginal port can then be safely passed through the center of the triangle. It is important that the vaginal port should be angled upward, aiming toward the umbilicus to avoid injury to the rectum. During pure TV NOTES, the incision is made with electrocautery from the 5 o’clock position to the 7 o’clock position within the triangle. The peritoneum is sharply entered, and the colpotomy is dilated with the surgeons’ fingers.ConclusionsThe triangle of safety defines a set of landmarks between the base of the cervix and the rectovaginal fold. It allows for a safe TV access for hybrid and pure TV NOTES while minimizing the risk of injury to surrounding structures.