Andrew J. Duffy

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.

Reproductive considerations and pregnancy after bariatric surgery: current evidence and recommendations.

Obesity has reached epidemic proportions in the USA. Bariatric surgery is an important and increasingly utilized treatment option for morbid obesity refractory to medical therapy. Approximately half of all bariatric surgery patients are reproductive-aged women and, thus, represent a unique patient population with specific concerns. This manuscript focuses on issues of increased postoperative fertility, nutritional monitoring and supplementation, safety of pregnancy after bariatric surgery, and effect of pregnancy on postoperative weight loss. Current recommendations regarding management of patients both before and during pregnancy are provided. In addition, we highlight areas where more research on this issue is needed and advocate for a multidisciplinary approach to patient care.

Attrition of categoric general surgery residents: results of a 20-year audit

BACKGROUND Attrition of general surgery residents is of continued concern in graduate medical education. It results in loss of morale and resources and often leaves programs scrambling to find replacement residents. The aim of this study was to evaluate the incidence of attrition of categoric general surgery residents as well as the fate of those who left the general surgery training program among a defined cohort of categoric general surgery residents in a university hospital residency training program. METHODS We retrospectively reviewed the files of all general surgery residents at the Yale University School of Medicine-Yale New Haven Hospital Surgery Program who began as categoric interns from July 1, 1986 to June 30, 2006. Ninety-nine residents were identified. Attrition of residents was divided into withdrawals (changed specialty or left graduate medical education), transfers (transferred to a different program in general surgery), and dismissals (dismissed from the program). RESULTS Among the 99 residents who began as categoric interns from 1986 to 2006, 66 of 99 (67%) were men. Thirty of 99 (30%) failed to complete the general surgery training program. Of these, 21 of 30 (70%) withdrew, 5 of 30 (17%) transferred, and 4 of 30 (13%) were dismissed. Attrition occurred before entering the third clinical year in 23 of 30 (77%). Two of 30 (7%) left graduate medical education. Thirteen of 21 (62%) who withdrew entered primary care or another nonsurgical specialty, whereas 7 of 21 (38%) matriculated into a surgical subspecialty. The attrition rate was 40% (12 of 30) since the academic year 2000. The overall annual attrition rate for the past 20 years was 6.7%. COMMENTS Attrition in our general surgery training remains low. Most who leave remain in graduate medical education and transfer to a different specialty. The overwhelming majority leave before beginning their third clinical year. Although our 6.7% annual attrition rate remains favorable (national attrition rate in general surgery 5.8%), we must continue to analyze the root causes and solutions.

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.

Pure transvaginal appendectomy versus traditional laparoscopic appendectomy for acute appendicitis: a prospective cohort study.

Objective: This report describes the first cohort study comparing pure transvaginal appendectomies (TVAs) to traditional 3-port laparoscopic appendectomies (LAs). Methods: Between August 2008 and August 2010, 42 patients were offered a pure TVA. Patients who did not wish to undergo a TVA underwent a LA and served as the control group. Demographic data, operative time, length of stay, patient controlled analgesia (PCA) 12-hour-morphine utilization, complications, return to normal activity, and return to work were recorded. Results: Eighteen of 40 enrolled patients underwent a pure TVA. Two patients refused to participate in this study. Mean age (TVA: 31.3 ± 2.5 years vs. LA: 28.2 ± 2.3 years, P = 0.36), mean body mass index (TVA: 23.7 ± 1.2 kg/m2 vs. LA: 23.6 ± 0.7 kg/m2, P = 0.96) mean operative time (TVA: 44.4 ± 4.5 minutes vs. LA: 39.8 ± 2.6 minutes, P = 0.38), and mean length of hospital stay (TVA: 1.1 ± 0.1 days vs. LA: 1.2 ± 0.1 days, P = 0.53) were not statistically significant. However, mean postoperative morphine-use (TVA: 8.7 ± 2.0 mg vs. LA: 23.0 ± 3.4 mg, P < 0.01), return to normal activity (TVA: 3.3 ± 0.4 days vs. LA: 9.7 ± 1.6 days, P < 0.01), and return to work (TVA: 5.4 ± 1.1 days vs. LA: 10.7 ± 1.5 days, P = 0.01) were statistically significant. One conversion in the TVA group to a LA was necessary because of inability to maintain adequate pneumoperitoneum. Four complications were observed: 1 intraabdominal abscess and 1 case of urinary retention in the TVA group; 1 early postoperative bowel obstruction and 1 case of urinary retention in the LA group. Conclusions: Pure TVA is a safe and well-tolerated procedure with significantly less pain and faster recovery compared to traditional LA. This study is registered with www.clinicaltrials.gov as NCT00806429.

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.

Factors Influencing the Gut Microbiota, Inflammation, and Type 2 Diabetes

The gut microbiota is a complex community of bacteria residing in the intestine. Animal models have demonstrated that several factors contribute to and can significantly alter the composition of the gut microbiota, including genetics; the mode of delivery at birth; the method of infant feeding; the use of medications, especially antibiotics; and the diet. There may exist a gut microbiota signature that promotes intestinal inflammation and subsequent systemic low-grade inflammation, which in turn promotes the development of type 2 diabetes. There are preliminary studies that suggest that the consumption of probiotic bacteria such as those found in yogurt and other fermented milk products can beneficially alter the composition of the gut microbiome, which in turn changes the host metabolism. Obesity, insulin resistance, fatty liver disease, and low-grade peripheral inflammation are more prevalent in patients with low α diversity in the gut microbiome than they are in patients with high α diversity. Fermented milk products, such as yogurt, deliver a large number of lactic acid bacteria to the gastrointestinal tract. They may modify the intestinal environment, including inhibiting lipopolysaccharide production and increasing the tight junctions of gut epithelia cells.