Uyen B. Chu

Obesity and laparoscopic repair of ventral hernias

BACKGROUND Laparoscopic ventral hernia repair (LVHR) is gaining acceptance and compares favorably with open repair. Patients who are morbidly obese (MO) traditionally have been considered poor surgical candidates for ventral hernia repair because of their associated comorbidities and risk of postoperative wound infection and hernia recurrence. In this study we evaluated our experience with LVHR in patients who are obese and those who are morbidly obese. METHODS All 64 patients undergoing LVHR at the University of Kentucky between September 1997 and October 2000, representing 66 hernias, were entered prospectively into a database. Data before, during, and after surgery were collected as well as follow-up data. Patients were divided into three groups on the basis of body mass index (BMI): normal to overweight (BMI < or = 29); obese (BMI 30-39), and MO (BMI > or = 40). RESULTS There were 16 patients in the MO group, most of them women. The mean BMI was 43.9 (range, 40-60), and the mean age was 45.6 years (range, 25-68 years). The location of defects was similar among the groups, as were the number of prior repairs. The operative time and length of stay for the MO group tended to be longer than for the other two groups. Five minor complications occurred in the MO group. During a follow-up period ranging from 1 to 35 months, there were no recurrences. CONCLUSION Laparoscopic repair of ventral hernias in patients who are morbidly obese is both safe and feasible, and can be performed with minimal morbidity. At this writing, there have been no recurrences, but long-term follow-up evaluation is required.

Evaluating minimally invasive surgery training using low-cost mechanical simulations.

Background: The goal of this study was to develop, test, and validate the efficacy of inexpensive mechanical minimally invasive surgery (MIS) model simulations for training faculty, residents, and medical students. We sought to demonstrate that trained and experienced MIS surgeon raters could reliably rate the MIS skills acquired during these simulations. Methods: We developed three renewable models that represent difficult or challenging segments of laparoscopic procedures; laparoscopic appendectomy (LA), laparoscopic cholecystectomy (LC), and laparoscopic inguinal hernia (LH). We videotaped 10 students, 12 surgical residents, and 1 surgeon receiving training on each of the models and again during their posttraining evaluation session. Five MIS surgeons then assessed the evaluation session performance. For each simulation, we asked them to rate overall competence (COM) and four skills: clinical judgment (respect for tissue) (CJ), dexterity (economy of movement) (DEX), serial/simultaneous complexity (SSC), and spatial orientation (SO). We computed intraclass correlation (ICC) coefficients to determine the extent of agreement (i.e., reliability) among ratings. Results: We obtained ICC values of 0.74, 0.84, and 0.81 for COM ratings on LH, LC, and LA, respectively. We also obtained the following ICC values for the same three models: CJ, 0.75, 0.83, and 0.89; DEX, 0.88, 0.86, and 0.89; SSC, 0.82, 0.82, and 0.82; and SO, 0.86, 0.86, and 0.87, respectively. Conclusions: We obtained very high reliability of performance ratings for competence and surgical skills using a mechanical simulator. Typically, faculty evaluations of residents in the operating room are much less reliable. In contrast, when faculty members observe residents in a controlled, standardized environment, their ratings can be very reliable.

A valid method of laparoscopic simulation training and competence assessment.

BACKGROUND The purpose of our study was to evaluate the construct validity of laparoscopic technical performance measures and the face validity of three laparoscopic simulations. MATERIALS AND METHODS Subjects (N = 27) of varying levels of surgical experience performed three laparoscopic simulations, representing appendectomy (LA), cholecystectomy (LC), and inguinal hemiorrhaphy (LH). Five laparoscopic surgeons, blinded to the identity of the subjects, rated the subjects on procedural competence on a binary scale and in four skills categories on a 5-point scale: clinical judgment, dexterity, serial/simultaneous complexity, and spatial orientation. Using a task-specific checklist, non-clinical staff assessed the technical errors. The level of surgical experience was correlated with the ratings, the technical errors, and the time for each procedure. Subject responses to a survey regarding the utility of the inanimate models were evaluated. RESULTS Years of experience directly correlated with the skills ratings (all P < 0.001) and with the competence ratings across the three procedures (P < 0.01). Experience inversely correlated with the time for each procedure (P < 0.01) and the technical error total across the three models (P < 0.05). Nearly all subjects agreed that the corresponding procedures were well represented by the simulations (LA 96%, LC 96%, LH 100%). CONCLUSION The laparoscopic simulations demonstrated both face and construct validity. Regardless of the level of surgical experience, the subjects found the models to be suitable representations of actual laparoscopic procedures. Task speed improved with surgical experience. More importantly, the quality of performance increased with experience, as shown by the improvement in the skills assessments by expert laparoscopic surgeons.

Laparoscopic Dissecting Instruments

The authors provide an overview of laparoscopic dissecting instruments and discuss early development, surgical options, and special features. End effectors of different shapes and functions are described. A comparison of available energy sources for laparoscopic instruments includes discussion of thermal dissection, ultrasonic dissection, and water-jet dissection. The ergonomic risks and challenges inherent in the use of current laparoscopic instruments are outlined, as well as ergonomic issues for the design of future instruments. New directions that laparoscopic instrumentation may take are considered in connection with developing technology in robotics, haptic feedback, and MicroElectroMechanical Systems. Copyright

Determinants of competency judgments by experienced laparoscopic surgeons

Background: The definitive criteria for assessing competence remain elusive. In our study, we aimed to identify the determinants of competence assessment used by individual laparoscopic surgeons. Methods: In a blinded fashion, five laparoscopic surgeons rated 27 subjects on three laparoscopic simulations in four skill categories: clinical judgment, dexterity, serial/simultaneous complexity, and spatial orientation. The raters then assessed overall subject competence for each procedure. Point-biserial correlational analyses and cluster analyses were performed to ascertain the relationships among the various scales. Results: All of the correlations between the skills’ ratings and competence judgments were statistically significant (p < .05). No skill rating was consistently more highly correlated with the competence rating. There were no distinct patterns of correlations for each rater or each procedure. One factor emerged from each cluster analysis of the skills measures. Conclusions: The results suggest that the four skills scored in the study are highly correlated with each other and are important in determining competence. The cluster analyses revealed that the surgeon raters shared a common perception of competence.

Laparoscopic incisional hernia repair: a technical advance

Incisional hernia is the most common complication after abdominal surgery. In order to reduce accompanying symptomatology, some patients must modify their activities, lifestyle, and employment; thus, the outcome of incisional hernia may have major social and economic implications. Although 10% to 30% of patients undergoing laparotomy will develop an incisional hernia, subsequent conventional open repair often fails to adequately address this substantial problem. The recurrence rate for primary tissue repairs may approach the 35% range, which is higher than the primary occurrence rate; when repaired for recurrence, rates have been reported greater than 50%. Although the advent of prosthetic repair has significantly reduced the recurrence rate compared with that of primary suture repair, it remains in the 10% to 24% range. Gradual decreases in recurrence rates have been realized over the last decade as minimally invasive techniques have been increasingly utilized. For example, in some series, the recurrence rate of initial incisional hernias has been reduced to 2% to 9%. Moreover, multiple studies demonstrate that laparoscopic repair of incisional hernia results in a short length of stay and quick return to normal activities. The recurrence rate after laparoscopic repair of a recurrent hernia ranges between 9% and 12%, which is an improvement when compared with recurrence rates of 20% after conventional repair with prosthetic material. Clearly, the laparoscopic approach to repair of incisional hernia has significantly improved the management of this problem.

Laparoscopic management of Meckel's diverticulum.

el’s diverticulum. Technetium has a high affinity for parietal cells of gastric mucosa. Because 95% of Meckel’s diverticulum contains ectopic gastric mucosa, this scan theoretically should identify most of Meckel’s diverticula. Accordingly, the sensitivity, specificity, and overall diagnostic accuracy of the scan is 80 %t o85% ,95% ,an d90% ,respectively. 2 Th efalse-negative rate is 1.7%, whereas the false-positive rate is only 0.05%, because of the abnormal accumulation of isotopes seen in intestinal duplications, Barrett’s esophagus, ulcers, inflammatory bowel disease, intussusception, arteriovenous malformations, an dneoplasm. 3 Patient swit hpersisten tgastrointestina lbleeding requiring multiple transfusions, whose source is unidentified by routine upper and lower endoscopy, angiography, and 99m Tc-pertechnetate scanning, must eventually undergo an abdominal exploration, often with endoscopic assistance; these patients usually have a midgut source, such as a Meckel’s diverticulum, small bowel stromal tumor, or arteriovenous malformation. Obviously, patients with a positive lesion on the 99m Tc-pertechnetate scan must undergo an abdominal exploration to remove the possible Meckel’s diverticulum. In both situations, the initial operative approach may be either laparoscopic or laparotomy, depending on a number of patient and physician factors.

A criterion-referenced approach to assessing perioperative skills in a VR environment

The need for technical competence brought about by the advent of minimally invasive surgery (MIS) has caused educators to re-evaluate the methods used to train surgeons and to judge their competence. Additionally, the extensive training required to become competent is an attendant problem. To help solve these problems, we have begun to develop a method for training and evaluating perioperative MIS surgical competency using an immersive virtual reality (VR) trainer for surgical preparation. This paper presents and summarizes the results of our pilot-test development of a criterion-referenced approach to evaluating performance. Because of the high degree of internal consistency of responses from master surgeons using our system, we have confidence that this approach is viable.

Laparoscopic management of Crohn's disease.

years. 5 In addition, surgical intervention in patients with Crohn’s disease has been shown to improve overall quality of life. A prospective quality of life study conducted by Thirlby et al revealed that conventional surgical resection in patients with inflammatory bowel disease significantly restored the HealthRelated Quality of Life (HRQL) score to match the general population. The improved score was most significant in patients less than 41 years old. All Crohn’s patients’ scores improved regardless of the disease site, previous operation, or extent of the disease. 6 In Crohn’s disease, the most common operations involve the small intestine: strictureplasty of small bowel (54.6%), ileocecal resection (29.6%), and small bowel resection (7.2%). The most common site of Crohn’s disease is in the ileum, with or without involvement of the cecum or proximal right colon. The probability that a patient with ileocecal disease will require surgical resection is 88% to 96% during the course of the disease. 7 Patients with isolated colorectal involvement are less likely to require surgery. 4 Subtotal, total, and partial colectomy account for less than 7% of operations performed for Crohn’s disease. Laparoscopic approaches to the above operations may shift the balance of treatment toward earlier surgical intervention. Since its introduction by Jacobs et al in 1991, 8 laparoscopic ileocolectomy has been used with increasing frequency because it reduces the narcotic requirement, duration of ileus, and length of hospital stay (LOS), compared with conventional resection. 9,10 The presence of Crohn’s disease, however, adds another level of complexity to this operation. Unlike patients with benign polyps, Crohn’s disease patients have friable, thickened, and shortened mesentery, secondary to treatment with steroids, inflammation, or the disease. In addition, surgical patients traditionally have complications of the disease such as abscesses, fistulas, perforation, or obstruction, further increasing the risk of intra-abdominal complications. 11 Despite surgeons’ initial reluctance, an increasing number of studies support the role of laparoscopic resection in Crohn’s disease. Although operative time is longer, the morbidity and mortality rates are not significantly different from those associated with conventional open techniques; the advantages are that postoperative LOS is shorter, return to work quicker, narcotic requirements lower, and cosmesis improved. 10-13