Validation of laparoscopic surgical skills training outside the operating room: a long road.

BACKGROUND: Surgical skills training outside the operating room is beneficial. The best methods have yet to be identified. The authors aimed to document the predictive validity of simulation training in three different studies. METHODS: Study 1 was a prospective, randomized, multicenter trial comparing performance in the operating room after training on a laparoscopic simulator and after no training. The Global Operative Assessment of Laparoscopic Skills (GOALS) was used to evaluate operative performance. Study 2 retrospectively reviewed the operative performance of junior residents before and after implementation of a laparoscopic skills training curriculum. Operative time was the variable used to determine resident improvement. Study 3 was a prospective, randomized trial evaluating intern operative performance of laparoscopic cholecystectomy in a porcine model before and after training on a simulator. Operative performance was assessed using GOALS. RESULTS: All three studies failed to demonstrate predictive validity. With GOALS used as the assessment tool, no difference was found between trained and untrained residents in studies 1 and 3. In study 2, the trained group took significantly longer to complete a laparoscopic cholecystectomy than the untrained group. CONCLUSIONS: No correlation was found between the three types of training outside the operating room, and no improved operative performance was observed. Possible explanations include too few subjects, training introduced too late in the learning curve, and training criteria that were too easy. Additionally, simulator training focuses on precision, which may actually increase task time. Awareness of these issues can improve the design of future studies.

The relationship between regional myocardial perfusion at rest and arteriographic lesions in patients with coronary atherosclerosis.

Measurements of mean left ventricular (LV) and regional myocardial blood flow rates were made at rest in 161 patients with 133Xe and a multiplecrystal scintillation camera. Myocardial perfusion rates were correlated with assessments of the degree of coronary artery disease made from the arteriograms obtained during the same studies. In patients with normal coronary arteries without heart failure, the presence of hypertension, aortic stenosis, or aortic insufficiency was not associated with changes in mean LV perfusion from the control value of 61+/-7 ml/100 g-min. However, mean LV perfusion was significantly reduced in patients with normal coronary arteries who had cariomyopathy and impaired ventricular performance. Mean LV perfusion was not significantly different from control values in patients with "mild" coronary artery disease (less than 50% obstruction) or in patients with significant isolated disease (greater than 50% obstruction) of the left anterior descending (lad) artery. Significant reductions in mean LV perfusion were found in patients with greater than 50% obstruction of two coronary arteries (LAD + right or LAD + circumflex) and in patients with triple-vessel disease. The average perfusion rate for regions distal to LAD obstructions in patients with isolated LAD disease was not lower than the LAD perfusion in control patients, but was significantly reduced in patients with LAD + right coronary artery disease (43+/-14 ml/100 g-min). In the latter group average perfusion distal to the LAD lesion was significantly lower than the average regional perfusion rate for the remainder of the LV. However, the mean blood flow rate for the remainder of the LV was also significantly lower than control values despite the lack of significant circumflex disease. The data demonstrate that the presence of radiographically "mild" or significant isolated LAD coronary disease is not associated with reductions in mean LV perfusion at rest, but that mean LV perfusion is reduced in the presence of significant disease of two or three coronary artieries. None of the patients experienced angina during the resting studies and most had clinical evidence of ventricular failure. The observation of depressed LV perfusion in this group, as in the patients with cardiomyopathy, raises the possibility that a lowered resting blood supply may be adequate for a reduced level of performance of a diseased ventricle. The lack of selective reductions of regional perfusion at rest in the majority of the patients with LAD lesions suggests that regional myocardial blood flow must be measured during an intervention which increases myocardial oxygen consumption in order to assess the physiological significance of lesions which are observed at coronary arteriography.

Tissue ingrowth and bowel adhesion formation in an animal comparative study: polypropylene versus Proceed versus Parietex Composite.

BACKGROUND: The optimal prosthesis for laparoscopic ventral hernia repair would combine excellent parietal surface tissue ingrowth with minimal visceral surface adhesiveness. Currently, few data are available from randomized trials comparing the commercially available prostheses. METHODS: In a pig model designed to incite adhesions, three 10 x 15-cm pieces of mesh (Proceed, Parietex Composite [PCO], and polypropylene [PPM]) were randomly positioned intraperitoneally in each of 10 animals using sutures and tack fixation. After a 28-day survival, the amount of shrinkage, the area and peel strength of visceral adhesions, the peak peel strength, the work required to separate mesh from the abdominal wall, and a coefficient representing the adhesiveness of tissue ingrowth were averaged for each type of mesh and then compared with the averages for the other prostheses. The histologic appearance of each prosthesis was documented. RESULTS: Proceed had more shrinkage (99.6 cm2) than PCO (105.8 cm2) or PPM (112 cm2), although the difference was not statistically significant. The mean area of adhesions to PCO (11%) was significantly less than for Proceed (48%; p < 0.008) or PPM (46%; p < 0.008). Adhesion peel strength was significantly less for PCO (5.9 N) than for Proceed (12.1 N; p < 0.02) or PPM (12.9 N; p < 0.02). According to a filmy-to-dense scale of 1 to 5, adhesions were more filmy with PCO (1.7) than with PPM (2.9) or Proceed (3.7) (p < 0.007). Peak peel strength from the abdominal wall was significantly higher for PCO (17.2 N) than for Proceed (10.7 N) or PPM (10 N; p < 0.002). The histology of each prosthesis showed a neoperitoneum only with PCO. CONCLUSIONS: With less shrinkage, fewer and less dense adhesions to the viscera, and significantly stronger abdominal wall adherence and tissue ingrowth at 28 days in this animal study, PCO was superior to both Proceed and PPM in all categories. Furthermore, PCO demonstrated all the favorable qualities needed in an optimal prosthesis for laparoscopic ventral hernia repair, including the rapid development of a neoperitoneum.

A comparative study of adhesion formation and abdominal wall ingrowth after laparoscopic ventral hernia repair in a porcine model using multiple types of mesh.

BACKGROUND: The ideal mesh for laparoscopic ventral hernia repair is not yet identified. METHODS: We laparoscopically placed polypropylene (PPM), expanded polytetrafluoroethylene (ePTFE), and polyester with antiadhesive collagen layer (PCO) in eight pigs using sutures and tacks for fixation. After 28-day survival, we compared adhesion formation, fibrous ingrowth, and shrinkage among the types of mesh. RESULTS: Mean area of adhesions to PCO (8.25%) was less than that to ePTFE (57.14%, p < 0.001) or PPM (79.38%, p < 0.001). Adhesions peel strength was less for PCO (2.3 N) than for PPM (16.1 N, p < 0.001) or ePTFE (8.8 N, p = 0.02). Peel strength of mesh from the abdominal wall was less for ePTFE (1.3 N/cm of mesh width) than for PCO (2.8 N/cm, p = 0.001) or PPM (2.1 N/cm, p = 0.05). ePTFE area (94.4 cm(2)) was less than that for PCO (118.6 cm(2), p < 0.001) or PPM (140.7 cm(2), p < 0.02). CONCLUSION: PCO had fewer and less severe adhesions than ePTFE or PPM while facilitating excellent ingrowth of the adjacent parietal tissue.

Construct validity for the LAPSIM laparoscopic surgical simulator.

BACKGROUND: The skills required for laparoscopic surgery are amenable to simulator-based training. Several computerized devices are now available. We hypothesized that the LAPSIM simulator can be shown to distinguish novice from experienced laparoscopic surgeons, thus establishing construct validity. METHODS: We tested residents of all levels and attending laparoscopic surgeons. The subjects were tested on eight software modules. Pass/fail (P/F), time (T), maximum level achieved (MLA), tissue damage (TD), motion, and error scores were compared using the t-test and analysis of variance. RESULTS: A total of 54 subjects were tested. The most significant difference was found when we compared the most (seven attending surgeons) and least experienced (10 interns) subjects. Grasping showed significance at P/F and MLA (p < 0.03). Clip applying was significant for P/F, MLA, motion, and errors (p < 0.02). Laparoscopic suturing was significant for P/F, MLA, T, TD, as was knot error (p < 0.05). This finding held for novice, intermediate, and expert subjects (p < 0.05) and for suturing time between attending surgeons and residents (postgraduate year [PGY] 1-4) (p < 0.05). CONCLUSIONS: LAPSIM has construct validity to distinguish between expert and novice laparoscopists. Suture simulation can be used to discriminate between individuals at different levels of residency and expert surgeons.

Measurement of regional myocardial blood flow in man: description and critique of the method using xenon-133 and a scintillation camera.

A method has been devised to measure regional myocardial blood flow in man. The approach consists of selective injection of xenon-133 into a coronary artery and the external monitoring of radioisotope washout curves from multiple areas of the myocardium with a multiple crystal scintillation camera. Rate constants of isotope washout are calculated using a monoexponential model, and the capillary blood flow rates in multiple regions of the heart are calculated by the Kety formula. The pattern of perfusion rates is related to the coronary arteriogram obtained in the same study. Myocardial perfusion patterns obtained in patients with and without coronary artery disease and during atrial pacing are given, as well as examples of results obtained in myocardial aneurysms, in regions of ischemic myocardium supplied by collateral vessels and after tracer injection into an aortocoronary bypass graft. Advantages of the method are discussed along with limitations related to the tracer, the scintillation camera, the form of mathematical analysis and the three dimensional nature of the heart.

Intestinal vascular malformations.

Eleven patients with intestinal vascular malformations (VMs), all diagnosed by angiography, are presented. Two of the VMs were incidental findings in patients treated for other problems; the other nine patients all presented with gastrointestinal hemorrhage, and all had resection of the portion of intestine containing the VM. None has rebled. The specimens from these nine patients revealed a variety of histological findings. One VM was the vasculature of small bowel leiomyoma. Three other specimens contained obvious VMs without associated findings, and one specimen contained no identifiable pathology. In the remaining four specimens, a variety of inflammatory conditions were found on histological study, including one case of Crohn's disease and another of ischemic colitis. In only one of these specimens did we identify the VM. None of these last four cases conforms to the degenerative lesions described by Boley and his colleagues. Therefore, we propose a fourth type of VM that is associated with or perhaps secondary to another disease of the intestine. We precisely localized one VM in the duodenum during operation with the Doppler ultrasonic flow detector, thus enabling us to limit the extent of the resection. We also propose the use of this technique for pinpointing the area where sections should be made for histological study.

Injection sclerotherapy of esophageal varices using ethanolamine oleate.

Fifty-three patients with upper gastrointestinal bleeding and proven esophageal varices were treated by intravascular injection sclerotherapy of the varices using a mixture of ethanolamine oleate, bovine thrombin and cephalothin. An intraesophageal balloon was used to impede craniad flow during the injection. Except in three patients who failed to stop bleeding from nonvariceal lesions, sclerotherapy was 94 percent successful in controlling bleeding. The mortality rate in sclerotherapy patients with ascites was 25 percent compared with 54 to 75% reported elsewhere. There has been no rebleeding from varices after the third treatment week in patients followed up for up to 14 months.

Laparoscopic evaluation of intestinal ischemia using fluorescein and ultraviolet light in a porcine model.

BACKGROUND: The laparoscopic use of fluorescein and ultraviolet light may be a useful diagnostic tool that potentially could reduce the time until diagnosis and the subsequent mortality of mesenteric ischemia. METHODS: Eight pigs were subjected to a pneumoperitoneum pressure of 7 mmHg, and another eight pigs were exposed to a pressure of 14 mmHg. A segment of small bowel was devascularized. Two filters were used to create ultraviolet light. Pigs from each pressure group were given various intravenous fluorescein doses. The ischemic segment of the small intestine and other structures were inspected laparoscopically with the filters attached. A videotape was evaluated by resident and attending surgeons. RESULTS: Ischemic bowel was seen as a darkened silhouette against the viable fluorescent tissue. Overall, the results show that the use of ultraviolet light and fluorescence in the laparoscopic model is adequate for allowing the identification of ischemic bowel. CONCLUSIONS: The laparoscopic use of ultraviolet light combined with intravenous fluorescein dye is an effective diagnostic tool for evaluating mesenteric ischemia in pigs.

The use of a personal digital assistant for wireless entry of data into a database via the Internet.

BACKGROUND: Researchers typically record data on a worksheet and at some later time enter it into the database. Wireless data entry and retrieval using a personal digital assistant (PDA) at the site of patient contact can simplify this process and improve efficiency. METHODS: A surgeon and a nurse coordinator provided the content for the database. The computer programmer created the database, placed the pages of the database on the PDA screen, and researched and installed security measures. RESULTS: Designing the database took 6 months. Meeting Health Insurance Portability and Accountability Act of 1996 (HIPAA) requirements for patient confidentiality, satisfying institutional Information Services requirements, and ensuring connectivity required an additional 8 months before the functional system was complete. CONCLUSIONS: It is now possible to achieve wireless entry and retrieval of data using a PDA. Potential advantages include collection and entry of data at the same time, easy entry of data from multiple sites, and retrieval of data at the patient's bedside.

Results of laparoscopically assisted colon resection for carcinoma.

BACKGROUND: Surgical resection is the primary treatment for colorectal carcinoma. Laparoscopically assisted colon resection technically is feasible for both benign and malignant disease. However, the role of laparoscopically assisted colon resection for carcinoma is controversial. METHODS: We prospectively studied our first 100 patients with colorectal carcinoma who successfully underwent laparoscopically assisted colon resection for the carcinoma. RESULTS: The pathologic stages were Dukes' categories A-16, B-52, C-25, and D-7. Operative mortality and morbidity were 2% and 22%, respectively. During a mean follow-up period of 40.3 months, recurrence by stage was zero patients with stage A disease, five patients with stage B disease, nine patients with stage C disease. Thirteen of these patients died as a result of their disease. At this writing, 60 patients are alive without evidence of disease, and 23 have completed the study disease free after more than 60 months. The 5-year survival probabilities by stage were 100% for stage A, 76.8% for stage B, and 51.7% for stage C. CONCLUSIONS: Laparoscopically assisted colectomy for cancer can be performed safely. The recurrence rate after laparoscopically assisted resection appears to be at least as good as after open resection. Results from ongoing prospective, randomized trials are needed to confirm these findings.

Hand-assisted laparoscopic splenectomy for giant spleens.

BACKGROUND: Laparoscopic splenectomy for massive splenomegaly is technically difficult, and the morcellated splenic tissue may be inadequate for histologic study. A hand-assisted technique may provide a technical advantage and allow removal of larger pieces of spleen. METHODS: Patients who underwent hand-assisted laparoscopic splenectomy for massive splenomegaly were reviewed. Demographic information, operative data, and outcomes data were tabulated. RESULTS: Sixteen patients met these criteria. Mean age was 56 years (range, 35-78 years). Operating time averaged 240 min (range, 165-360 min), and median blood loss was 425 cc (range, 100-1800 cc). There were no conversions to an open procedure. Mean weight of extracted spleens was 2008 g (range, 543-4090 g). Postoperative length of stay averaged 3.3 days (range, 2-7 days). There was one postoperative complication (6.25%) and no mortality. CONCLUSIONS: Hand-assisted laparoscopic splenectomy for massive splenomegaly is feasible and safe while preserving the recovery benefits of minimal access surgery. It provides an adequate specimen for histologic study.

Choledocholithiasis: endoscopic versus laparoscopic management.

Choledocholithiasis is present in 6 to 10 per cent of patients who have cholelithiasis. In the era of laparoscopic cholecystectomy, endoscopic retrograde cholangiopancreatography with endoscopic retrograde sphincterotomy (ERCP/ERS) and laparoscopic common bile duct exploration (LSCBDE) have been used to treat choledocholithiasis. The purpose of this study is to compare ERCP/ERS with LSCBDE. A retrospective review of 913 patients undergoing laparoscopic cholecystectomy identified 61 patients who had ERCP/ERS or LSCBDE to treat choledocholithiasis at a community medical center between 1990 and 1996. Outcome parameters were hospital length of stay (LOS), hospital cost, and complications. The results were: ERCP (n=26; LOS, 5.0+/-3.6 days; cost, $11,823+/-$7,000; complications, 23.1%); LSCBDE (n=35; LOS, 3.4+/-2.4 days; cost, $9,100+/-$2,884; complications, 2.9%); and P value (LOS, 0.028; cost, 0.066; complications, 0.034). LSCBDE results in a significantly shorter LOS and significantly fewer complications, and is less costly than ERCP/ERS. LSCBDE, when feasible, should be considered the gold standard for the management of choledocholithiasis.

Effect of prosthetic material on adhesion formation after laparoscopic ventral hernia repair in a porcine model.

Intraperitoneal placement of prosthetic mesh causes adhesion formation after laparoscopic incisional hernia repair. A prosthesis that prevents or reduces adhesion formation is desirable. In this study, 21 pigs were randomized to receive laparoscopic placement of plain polypropylene mesh (PPM), expanded polytetrafluoroethylene (ePTFE), or polypropylene coated on one side with a bioresorbable adhesion barrier (PPM/HA/CMC). The animals were sacrificed after 28 days and evaluated for adhesion formation. Mean area of adhesion formation was 14% (SD+/-15) in the PPM/HA/CMC group, 40% (SD+/-17) in the PPM group, and 41% (SD+/-39) in the ePTFE group. The difference between PPM/HA/CMC and PPM was significant ( P=0.013). A new visceral layer of mesothelium was present in seven out of seven PPM/HA/CMC cases, six out of seven PPM cases, and two out of seven ePTFE cases. Thus, laparoscopic placement of PPM/HA/CMC reduces adhesion formation compared to other mesh types used for laparoscopic ventral hernia repairs.

Comparison of two composite meshes using two fixation devices in a porcine laparoscopic ventral hernia repair model.

INTRODUCTION: Laparoscopic ventral hernia repair uses tacks to secure mesh. The mesh is designed to maximize tissue ingrowth while minimizing adhesions. We hypothesized: (1) a collagen-coated polyester mesh (PCO) will form fewer adhesions than an ePTFE-polypropylene composite (BC) and (2) absorbable tacks are equivalent to metal tacks. METHODS: In a porcine model of adhesion formation, three pieces of 10x15-cm mesh were placed on the anterior abdominal wall. PCO was secured with absorbable (PLA) or metal tacks (PT), BC with PT. At 28 days, adhesion formation, abdominal-wall adherence, and tissue ingrowth were analyzed. RESULTS: PCO induced fewer adhesions (14.5% vs 53.4%, P = 0.007). On an adhesion scale (0 5), BC scored 3.6 vs 1.75 for PCO (P < 0.03). There was no difference in adhesion strength, tack adhesions, or abdominal-wall peel force. Histology showed equal ingrowth. CONCLUSIONS: PCO induces fewer adhesions than BC. There is no difference in the ingrowth of the two mesh types. The PLA achieves equivalent mesh incorporation to the PT.

Laparoscopic-assisted colectomy: a comparison of dissection techniques.

BACKGROUND AND OBJECTIVES: Mobilization of the colon and dissection of the mesentery are difficult laparoscopic techniques. Traditional methods have been used for this dissection, but often with great difficulty. The ultrasonically activated shears, when introduced in 1993, had the possibility to make this dissection less technically difficult. This is a retrospective review of the use of these shears for these techniques during laparoscopic-assisted colectomy. MATERIALS AND METHODS: Eighty-five patients underwent a laparoscopic-assisted right hemicolectomy or sigmoid resection. Colon mobilization and mesenteric dissection were completed intracorporeally. Complications, operative time, estimated blood loss, and length of stay were compared for resections completed with and without the ultrasonically activated shears. RESULTS: Thirty-six patients had laparoscopic-assisted colectomy without the shears, and 49 patients had the procedure with the shears. There were no complications due to the ultrasonic energy. Use of the shears resulted in shorter operative times (170 min. vs. 187 min., p=0.1989), similar median blood loss (98 mL vs. 95 mL, p=0.7620), and shorter lengths of stay (4.3 days vs. 6.9 days, p=0.0018). CONCLUSIONS: The ultrasonically activated shears are safe and effective for colon mobilization and mesenteric division. The use of the shears may result in shorter operative times and shorter lengths of stay.

Laparoscopic resection of a submucosal gastric lipoma: a case report.

A 51-year-old patient presented with massive upper gastrointestinal bleeding. Endoscopy revealed a submucosal gastric lipoma with secondary bleeding ulcers. The lesion was located on the anterior wall of the antrum. She underwent laparoscopic excision of the mass. The technique is described. She was dismissed from the hospital on the third postoperative day and returned to work on the seventh postoperative day.