The MISTELS program to measure technical skill in laparoscopic surgery : evidence for reliability.

BACKGROUND: The McGill Inanimate System for Training and Evaluation of Laparoscopic Skills (MISTELS) is a series of five tasks with an objective scoring system. The purpose of this study was to estimate the interrater and test-retest reliability of the MISTELS metrics and to assess their internal consistency. METHODS: To determine interrater reliability, two trained observers scored 10 subjects, either live or on tape. Test-retest reliability was assessed by having 12 subjects perform two tests, the second immediately following the first. Interrater and test-retest reliability were assessed using intraclass correlation coefficients. Internal consistency between tasks was estimated using Cronbach's alpha. RESULTS: The interrater and test-retest reliabilities for the total scores were both excellent at 0.998 [95% confidence interval (CI), 0.985-1.00] and 0.892 (95% CI, 0.665-0.968), respectively. Cronbach's alpha for the first assessment of the test-retest was 0.86. CONCLUSIONS: The MISTELS metrics have excellent reliability, which exceeds the threshold level of 0.8 required for high-stakes evaluations. These findings support the use of MISTELS for evaluation in many different settings, including residency training programs.

Does a special interest in laparoscopy affect the treatment of acute cholecystitis?

BACKGROUND: We tested the hypothesis that the treatment of patients with acute cholecystitis (AC) would be improved under the care of laparoscopic specialists. METHODS: The records of patients undergoing cholecystectomy for AC from 1 January 1996 to 31 December 1998 were reviewed retrospectively. Of 170 patients, 48 were cared for by three laparoscopic specialists (LS group), whereas 122 were treated by nine general surgeons who perform only laparoscopic cholecystectomy (LC) (GS group). The rates of successful LC, complications, and length of hospital stay were compared. Multivariate analysis was used to control for baseline differences. RESULTS: The patients in the GS group were older (median age, 63 vs 53 years; p = 0.01). In all, 31 LS patients (65%), as compared with 44 GS patients (36%), had successful laparoscopic treatment (p = 0.001). The operating time was the same (median, 70 min). The proportion of patients with postoperative complications was similar in the two groups (37% in the GS vs 31% in the LS group; p = 0.6). The median postoperative hospital stay (3 vs 5 days; p <0.01) was shorter in the LS group. On logistic regression analysis, significant predictors of a successful laparoscopic operation included LS group (p <0.01) and age (p = 0). Predictors of prolonged length of hospital stay were age (p <0.01) and comorbidity score (p <0.01), with LS group status not a significant factor (p = 0.21). CONCLUSIONS: Patients with AC are more likely to undergo successful LC if cared for by a surgeon with an interest in laparoscopy. However, length of hospital stay is influenced more by patient factors in a multivariate model.

A simplified simulator for the training and evaluation of laparoscopic skills.

BACKGROUND: Laparoscopic skills can be measured objectively in a video-laparoscopic cart simulator system. These scores have been shown to be sufficiently sensitive to distinguish differences in performance between residents at different levels of training. The purpose of this study was to compare a simplified mirrored-box simulator to the video-laparoscopic cart system. METHODS: A total of 22 surgical residents performed seven structured tasks in both simulators in random order. Scores reflected precision and speed. The tasks were transferring, cutting, clip + divide, looping, mesh placement + fixation, and suturing with intracorporeal and extracorporeal knots. RESULTS: There were no significant differences in mean raw scores between the simulators for six of the seven tasks. Resident total scores correlated well between simulators (r = 0.68, p = 0.001). Resident ranking also correlated well (r = 0.69, p < 0. 001). CONCLUSIONS: A mirrored-box simulator was shown to provide a reasonable reflection of relative performance of laparoscopic skills. Practical, effective laparoscopic skills training and evaluation can be accomplished without the need for cumbersome equipment.

Comparison of laparoscopic performance in vivo with performance measured in a laparoscopic simulator.

BACKGROUND: Laparoscopic skill was measured objectively through a series of seven tasks in an inanimate laparoscopic simulator. Seven analogous skills were tested in an in vivo porcine model. These skills included transferring, cutting, clipping, placement of a ligating loop, mesh placement, and suturing with an intracorporeal and extracorporeal knot. Scoring of each task rewarded precision and speed. METHODS: Twelve PGY3 residents were given a baseline evaluation in the simulator and in the animal model. They were then randomized to either five practice sessions in the simulator (group A) or no practice (group B). Each group was retested in the simulator and in the animal (final test). Scores in vivo were compared by t-test for baseline versus final evaluation for each group. Linear regression analysis was used to correlate in vivo and in vitro scores for each task and for the total score (sum of all scores). RESULTS: Group A showed significant improvement in performance in vivo for cutting, clipping, mesh placement, and suturing with an intracorporeal and extracorporeal knot, as well as in the total score (p < 0.05). Group B showed significant improvement in suturing with an intracorporeal and extracorporeal knot, and in the total score. The magnitude of improvement from baseline to final evaluation was significantly greater for group A (p < 0.05). There was significant correlation between in vitro and in vivo total scores and the score for each task (p < 0.05) except for placement of the ligating loop and mesh. CONCLUSIONS: Performance in an in vitro laparoscopic simulator correlated significantly with performance in an in vivo animal model. Practice in the simulator resulted in improved performance in vivo.

The effect of practice on performance in a laparoscopic simulator.

BACKGROUND: Laparoscopic skill was measured objectively in a simulator. Seven tasks were scored in terms of precision and speed. These tasks included transferring, cutting, clip+ divide, placement of a ligating loop, mesh placement+ fixation, and suturing with intracorporeal and extracorporeal knot. METHODS: After baseline evaluation, 12 surgical residents were randomized to either five weekly practice sessions (Group A) or no practice (Group B). Each group was then retested. Performance scores were compared for baseline versus final test, and improvement (baseline to final) for Group A versus Group B. Group A residents had a total of seven repetitions of each task (baseline, five practices, final). Linear regression analysis was used to test for the correlation between score and repetition number. RESULTS: Group A showed significant improvement in their scores (baseline to final) for each task and for the total score (sum of all tasks) (p < 0.05). Group B showed significant improvement in four of seven tasks and for the total score. The magnitude of improvement of Group A versus Group B residents was significantly greater for four of seven tasks (peg transfer, placement of ligating loop, and both suturing skills) and for the total score. The final total score for Group A was 219 +/- 14% of baseline (p < 0.0001), whereas Group B was only 162 +/- 35% of baseline (p = 0.07) and not statistically significant. For Group A residents, there was a highly significant correlation between trial number and performance score (p < 0.05) for each individual task and for the total score. CONCLUSIONS: Laparoscopic skill can be measured objectively in a simulator, and performance improves progressively with practice. These skills can be incorporated into the training and evaluation of residents in laparoscopic surgery.

Development of a model for training and evaluation of laparoscopic skills.

BACKGROUND: Interest in the training and evaluation of laparoscopic skills is extending beyond the realm of the operating room to the use of laparoscopic simulators. The purpose of this study was to develop a series of structured tasks to objectively measure laparoscopic skills. This model was then used to test for the effects of level of training and practice on performance. METHODS: Forty-two subjects (6 each of surgical residents PGY1 to PGY5, 6 surgeons who practice laparoscopy and 6 who do not) were evaluated. Each subject viewed a 20-minute introductory video, then was tested performing 7 laparoscopic tasks (peg transfers, pattern cutting, clip and divide, endolooping, mesh placement and fixation, suturing with intracorporeal or extracorporeal knots). Performance was measured using a scoring system rewarding precision and speed. Each candidate repeated all 7 tasks and was rescored. Data were analyzed by linear regression to assess the relationship of performance with level of residency training for each task, and by ANOVA with repeated measures to test for effects of level of training, of repetition, and of the interaction between level of training and repetition on overall performance. Student's t test was used to evaluate differences between laparoscopic and nonlaparoscopic surgeons and between each of these groups and the PGY 5 level of surgical residents. RESULTS: Significant predictors of overall performance were (a) level of training (P = 0.002), (b) repetition (P < 0.0001), and (c) interaction between level of training and practice (P = 0.001). There was also a significant interaction between level of training and the specific task on performance scores (P = 0.006). When each task was evaluated individually for the 30 residents, 4 of the 7 tasks (tasks 1, 2, 6, 7) showed significant correlation between PGY level and score. A significant difference in performance scores between laparoscopic and nonlaparoscopic surgeons was seen for tasks 1, 2, and 6. CONCLUSIONS: A model was developed to evaluate laparoscopic skills. Construct validity was demonstrated by measuring significant improvement in performance with increasing residency training, and with practice. Further validation will require correlation of performance in the model with skill in vivo.

Comparison of adhesion formation and tensile strength after three laparoscopic herniorrhaphy techniques.

Several techniques for laparoscopic inguinal herniorrhaphy have been described in the literature: laparoscopic extraperitoneal mesh repair (EXTRA), transabdominal preperitoneal mesh repair (TAPP), and intraperitoneal onlay mesh repair (IPOM). To evaluate the incidence of adhesion formation and the tensile properties of these techniques, young male pigs underwent mesh placement using the above techniques. The animals had follow-up for 6 weeks, and no trocar site adhesions were observed. No intraperitoneal adhesions resulted in the group that underwent EXTRA technique. One case of filmy omental adhesions was observed with the TAPP technique, and two cases of adhesions were associated with the IPOM technique, one minimal and one case of dense adhesions to the bladder. The tensile strength of mesh incorporation into abdominal fascia was compared for the three techniques and measured using a tensiometer. The IPOM technique resulted in the weakest tensile strength of 0.53 +/- 0.01 kg (mean +/- SEM), whereas both the EXTRA and TAPP were comparable and significantly stronger (p < 0.05), with tensiometric values of 0.69 +/- 0.03 and 0.60 +/- 0.02 kg, respectively. We concluded that IPOM, although technically the easiest procedure to perform, is associated with the highest risk of adhesion formation and the lowest tensile strength. In comparison, the EXTRA and the TAPP techniques had the advantages of better tissue incorporation and tensile strength. Adhesion formation was not observed with the EXTRA technique, in which the peritoneum was not violated, and was uncommon and minimal with the TAPP technique.

Incarcerated paraumbilical incisional hernia and abscess--complications of a spilled gallstone.

Gallstones may fall into the peritoneal cavity during performance of cholecystectomy. They are more easily retrieved in an open operation. Some controversy exists as to what should be done with gallstones lost during laparoscopic cholecystectomy (LC) because complications of abandoned stones have been reported. This case report describes a patient who presented with an incarcerated hernia and an associated abscess cavity containing a large spilled gallstone, which on computed tomography scan suggested a possible abdominal wall tumor. Spilled stones may cause subsequent problems and should be removed whenever possible, but should not be an indication for conversion to open operation.

Factors determining conversion to laparotomy in patients undergoing laparoscopic cholecystectomy.

Laparoscopic cholecystectomy (LC) has been performed increasingly in an outpatient setting. Conversion from LC to open cholecystectomy (OC) is sometimes required. To predict conversion to OC, a single institutional study of 1,676 consecutive patients in whom LC was attempted was performed. Factors evaluated were age, sex, history of acute cholecystitis, pancreatitis, or jaundice, previous abdominal surgery, abnormalities of liver function tests, thickened gallbladder wall identified by preoperative ultrasound, obesity or morbid obesity, and cumulative institutional experience in LC. Conversion to OC was required in 90 of 1,676 (5.4%) patients. Significant preoperative predictors of conversion were acute cholecystitis, increasing age, male sex, obesity, and thickened gallbladder wall found by ultrasound. Nonobese women younger than age 65 years with symptoms of biliary colic and normal gallbladder wall thickness found by preoperative ultrasound required conversion only 1.9% of the time. These predictors may be useful in planning a program of ambulatory or short stay surgical units for patients undergoing LC and for comparing data between series.

Cholecystectomy without operative cholangiography. Implications for common bile duct injury and retained common bile duct stones.

OBJECTIVE: This study evaluated the selective use of endoscopic retrograde cholangiopancreatography (ERCP) in the context of laparoscopic cholecystectomy (LC) while minimizing the use of operative cholangiography. SUMMARY BACKGROUND DATA: There has been a long-standing debate between routine and selective operative cholangiography that has resurfaced with LC. METHODS: Prospective data were collected on the first 1300 patients undergoing LC at McGill University. Preoperative indications for ERCP were recorded, radiologic findings were standardized, and technical points for a safe LC were emphasized. RESULTS: A total of 106 patients underwent 127 preoperative ERCPs. Fifty patients were found to have choledocholithiasis (3.8%), and clearance of the common bile duct (CBD) with endoscopic sphincterotomy was achieved in 45 patients. The other five patients underwent open cholecystectomy with common duct exploration. Intraoperative cholangiography (IOC) was attempted in only 54 patients (4.2%), 6 of whom demonstrated choledocholithiasis. Forty-nine postoperative ERCPs were performed in 33 patients and stones were detected in 17 (1.3%), with a median follow-up time of 22 months. Endoscopic duct clearance was successful in all of these. The incidence of CBD injury was 0.38%, and a policy of routine operative cholangiography might only have led to earlier recognition of duct injury in one case. The rate of complication for all ERCPs was 9% and the associated median duration of the hospital stay was 4 days. The median duration of the hospital stay after open CBD exploration was 13 days. CONCLUSIONS: LC can be performed safely without routine IOC. The selective use of preoperative and postoperative ERCP will clear the CBD of stones in 92.5% of patients.

Risks of blind versus open approach to celiotomy for laparoscopic surgery.

Patients undergoing laparoscopic cholecystectomy had celiotomy either by a blind (Veress needle) approach (n = 781) or by fascial and peritoneal incision with insertion of a 10-mm sheath under direct vision (n = 247). The blind approach was associated with three small bowel injuries and one tear of the left common iliac artery. No intestinal or vascular injuries occurred in the open insertion group. The difference was not statistically significant. The mean duration of surgery was 81.4 +/- 1.3 min in the blind group compared with 72.6 +/- 2.0 min in the open group (p < 0.001). There was no significant difference in postoperative stay or in return to normal activity between the two groups. It is recommended that blind access to the peritoneal cavity for laparoscopy be abandoned in favor of an open approach because the blind approach confers no advantages and places the patient at risk for unrecognized visceral or vascular injury even though these injuries may not occur at a statistically significant frequency.

Laparoscopic cholecystectomy in pregnancy.

Pregnancy has generally been considered a contraindication to laparoscopic cholecystectomy. The authors present a case of laparoscopic cholecystectomy in a 37-year-old patient who was 18 weeks pregnant. Laparoscopic cholecystectomy can be safely accomplished during pregnancy, provided that the open technique of insertion of the first cannula is used, and all subsequent trocars be inserted under direct vision.

Laparoscopic closure of perforated duodenal ulcer.

Simple patch closure is a treatment option for perforated duodenal ulcer. A 46-year-old male was admitted with evidence of perforation of a duodenal ulcer. The decision was made to carry out laparoscopy to confirm the diagnosis and to close the perforation. This was accomplished without difficulty by suture closure of an anterior perforation and application of an omental patch. The patient had an uneventful recovery. Laparoscopy can be of value in the diagnosis and treatment of perforated duodenal ulcer. The principles of management should be essentially similar to those adhered to during open surgery.

Role of the teaching hospital in the development of a laparoscopic cholecystectomy program.

Laparoscopic cholecystectomy was introduced at McGill University-affiliated hospitals in a planned manner to evaluate the safety and results of this new procedure while training attending and resident surgeons. Laparoscopy was performed with the intent of carrying out cholecystectomy in 500 consecutive patients (70% female, 30% male), whose age averaged 48 years (range from 7 to 93 years). Thirty-seven percent had undergone intra-abdominal surgery previously, and 9.1% had had acute cholecystitis. There were two common-bile-duct injuries and one major small-bowel injury. The procedure had to be converted to open cholecystectomy in 25 (5%) patients. There were no deaths. The mean duration of surgery was 88 minutes. Fifty-five percent of patients were discharged home in 24 hours or less after surgery, and 75% were back to normal activity within 1 week of discharge. Fourteen attending staff and 8 senior residents achieved competence to carry out laparoscopic cholecystectomy independently.

Laparoscopic cholecystectomy: a treatment option for gallbladder disease in children.

Laparoscopic cholecystectomy was performed safely in two children ages 7 and 15 years. Special considerations were required in the younger child because of the discrepancy between the length of the instruments and the size of the peritoneal cavity. Both children remained in hospital less than 24 hours and were able to resume normal diet and activity quickly. Pediatric surgeons with special training in laparoscopic surgery may want to use this treatment modality for children with biliary tract disease.

Effects of pirenzepine on acute mucosal erosions, gastric acid and mucosal blood flow in the spinal rat stomach.

The aim of this study was to examine the effects of varying doses of pirenzepine, a selective muscarinic subtype M1 antagonist, on the prevention of acute gastric mucosal lesions in male Sprague-Dawley rats subjected to spinal cord section at the C7 level. It was also intended to evaluate the effects of the drug on gastric acid output and gastric mucosal blood flow. Pirenzepine 1, 2.5 and 5 mg/kg every 2 h all caused a significant reduction in mean total ulcer length (p less than 0.01) compared to controls. This was associated with a significant decrease in acid output (p less than 0.05). There was no significant effect on gastric mucosa blood flow as measured by hydrogen gas clearance. These results indicate that the protective effects of pirenzepine on gastric mucosa, in the spinal rat model, are associated with the acid-inhibitory action of the drug and not on mucosal blood flow effects.

Treatment of established spinal injury-induced gastric erosions in rats with cimetidine and 16,16-dimethyl prostaglandin E2.

Most research on the beneficial effects of pharmacologic agents on stress-induced acute gastric erosions in animals is directed at prevention. It is only the rare study that has been concerned with treatment of established erosions. A treatment model has been created using cervical cord-injured male Sprague-Dawley rats which consistently developed extensive linear erosions of the glandular portions of the stomach within 12 hr. A group of spinal rats was sacrificed after 12 hr to serve as a base of pretreatment ulcer severity. Treatment of established erosions with cimetidine 25 mg/kg every 2 hr in one group and 16,16-dimethyl prostaglandin E2 (16,16-dmPGE2) 5 micrograms/kg every 2 hr in a second group was compared to saline-treated controls. All drugs were administered by intraperitoneal route. Treatment began 12 hr after the cord transection and continued for another 12 hr at which time the rats were sacrificed. Both cimetidine and 16,16-dmPGE2 significantly inhibited the degree of erosion progression after 12 hr compared to saline controls (P less than 0.05). Acid output studies were carried out on a second set of rats subjected to the same experimental conditions with the addition of pyloric ligation 6 hr prior to sacrifice. A significant decrease in acid output (P less than 0.05) occurred only in the cimetidine group compared to control. It is concluded that both cimetidine and 16,16-dmPGE2 can arrest the progression of erosive changes in the stomach after cervical cord injury in rats. This is likely related to acid reduction by cimetidine and cytoprotection by prostaglandin.

Effects of antacids, cimetidine, and 16,16-dimethyl prostaglandin E2 on acute gastric erosions in a spinal rat.

Acute erosions of the stomach may occur in association with human spinal cord injuries. Erosion of the glandular portion of the stomach also occurs after cervical cord transection in the rat. Reports on the effects of antacids and cimetidine in the prevention of acute "stress" erosions in animals and humans have shown conflicting results. A prostaglandin analog, 16,16-dimethyl prostaglandin E2 (16,16-dmPGE2) has been shown to prevent gastric erosions in rats produced by nonsteroid antiinflammatory compounds. Cimetidine 50 mg/kg (intraperitoneal), 16,16-dmPGE2 10 micrograms/kg (intraperitoneal), and antacid 2 ml (intragastric) were individually given to groups of spinal rats at 0 and 4 hr. 16,16-dmPGE2 and antacid both resulted in significant reduction in mean ulcer length compared to controls after 8 hr (P less than 0.05) whereas cimetidine showed no significant effect, even though cimetidine caused a significant decrease in gastric acid output compared to both 16,16-dmPGE2 and controls (P less than 0.01). It is concluded that cimetidine on this dosage schedule is not effective in the prevention of gastric erosions in a cervical cord section rat model, whereas the ulceroprotective effects of 16,16-dmPGE2 and antacids are significant. It is suggested that the gastric mucosal cells remain vulnerable to injury in the cimetidine-treated spinal rat due to secretory inhibition, but are protected by buffering action of antacids or by "cytoprotective" effects of prostaglandin.

Role of hypothermia in the production of gastric ulcers in a rat spinal cord transection model.

An association between hypothermia and gastric ulceration has been reported in rats in cervical cord section and in restraint models. The present study was designed to determine this relationship in cervical and in lumbar cord sectioned Sprague-Dawley rats. Ambient temperatures were varied by placing the sectioned animals in a room-temperature (23 degrees), incubator (28 degrees), or cold-room (4 degrees) environment for 8 hr. Rectal temperatures were recorded at the beginning and end of all experimental conditions. The endpoint of each study was the presence or absence of ulcers on naked eye examination. The length of each ulcer was measured and the lengths were totaled for each stomach. Cervical section rats became hypothermic at room temperature and developed extensive linear ulcerations of the glandular stomachs. A warm environment reduced both the decrement in core temperature and the degree of ulceration. Lumbar section rats only became hypothermic when exposed to cold and then developed significant ulcers. Hypothermia plays an important role in ulcerogenesis, but other factors are also important since not all the hypothermic rats developed ulcers and exposure of sham-operated rats to cold led to occasional pinpoint ulcer formation in spite of maintenance of a stable core temperature.

Use of biliary drainage in diagnosis of biliary tract disease.

Thirty-five patients with biliary-type symptoms and normal oral cholecystograms were found to have either cholesterol crystals, calcium bilirubinate pigment or leucocytes in gallbladder bile collected through duodenal drainage. All underwent cholecystectomy. The gallbladders all showed histological evidence of chronic cholecystitis and/or cholesterolosis. In addition, four gallbladders contained calculi. Cholecystectomy is recommended as treatment for a selected group of patients with duodenal bile crystals or pigment.