Walter Gantert

Causes and Prevention of Laparoscopic Bile Duct Injuries: Analysis of 252 Cases from a Human Factors and Cognitive Psychology Perspective

ObjectiveTo apply human performance concepts in an attempt to understand the causes of and prevent laparoscopic bile duct injury. Summary Background DataPowerful conceptual advances have been made in understanding the nature and limits of human performance. Applying these findings in high-risk activities, such as commercial aviation, has allowed the work environment to be restructured to substantially reduce human error. MethodsThe authors analyzed 252 laparoscopic bile duct injuries according to the principles of the cognitive science of visual perception, judgment, and human error. The injury distribution was class I, 7%; class II, 22%; class III, 61%; and class IV, 10%. The data included operative radiographs, clinical records, and 22 videotapes of original operations. ResultsThe primary cause of error in 97% of cases was a visual perceptual illusion. Faults in technical skill were present in only 3% of injuries. Knowledge and judgment errors were contributory but not primary. Sixty-four injuries (25%) were recognized at the index operation; the surgeon identified the problem early enough to limit the injury in only 15 (6%). In class III injuries the common duct, erroneously believed to be the cystic duct, was deliberately cut. This stemmed from an illusion of object form due to a specific uncommon configuration of the structures and the heuristic nature (unconscious assumptions) of human visual perception. The videotapes showed the persuasiveness of the illusion, and many operative reports described the operation as routine. Class II injuries resulted from a dissection too close to the common hepatic duct. Fundamentally an illusion, it was contributed to in some instances by working too deep in the triangle of Calot. ConclusionsThese data show that errors leading to laparoscopic bile duct injuries stem principally from misperception, not errors of skill, knowledge, or judgment. The misperception was so compelling that in most cases the surgeon did not recognize a problem. Even when irregularities were identified, corrective feedback did not occur, which is characteristic of human thinking under firmly held assumptions. These findings illustrate the complexity of human error in surgery while simultaneously providing insights. They demonstrate that automatically attributing technical complications to behavioral factors that rely on the assumption of control is likely to be wrong. Finally, this study shows that there are only a few points within laparoscopic cholecystectomy where the complication-causing errors occur, which suggests that focused training to heighten vigilance might be able to decrease the incidence of bile duct injury.

Effects of Previous Treatment on Results of Laparoscopic Heller Myotomy for Achalasia

Until recently, pneumatic dilatation andintrasphincteric injection of botulinum toxin (Botox)have been used as initial treatments for achalasia, withmyotomy reserved for patients with residual dysphagia. It is unknown, however, whether thesenonsurgical treatments affect the performance of asubsequent myotomy. We compared the results oflaparoscopic Heller myotomy and Dor fundoplication in 44patients with achalasia who had been treated withmedications (group A, 16 patients), pneumatic dilatation(group B, 18 patients), or botulinum toxin (group C, 10patients). The last group was further subdivided according to whether there was (C2, 4 patients)or was not (C1, 6 patients) a response to the treatment.Results for groups A, B, C1, and C2, respectively, were:anatomic planes identified at surgery (% of patients) — 100%, 89%, 100%, and 25%;esophageal perforation (% of patients) — 0%, 5%,0%, and 50%; hospital stay (hrs)-26 ± 8, 38± 25, 26 ± 11, and 72 ± 65; andexcellent/good results (% of patients) — 87%, 95%, 100%, and50%. These results show that: (1) previous pneumaticdilatation did not affect the results of myotomy; (2) inpatients who did not respond to botulinum toxin, the myotomy was technically straightforward and theoutcome was excellent; (3) in patients who responded tobotulinum toxin, the LES muscle had become fibrotic(perforation occurred more often in this setting, and dysphagia was less predictably improved);and (4) myotomy relieved dysphagia in 91% of patientswho had not been treated with botulinum toxin. Thesedata support a strategy of reserving botulinum toxin for patients who are not candidates forpneumatic dilatation or laparoscopic Hellermyotomy.

Laparoscopic Repair of Paraesophageal Hiatal Hernias

BACKGROUND Regardless of symptoms, paraesophageal hiatal hernias should be repaired in order to prevent complications. This study reports the University of California San Francisco experience with laparoscopic repair of paraesophageal hiatal hernias, emphasizing the technical steps essential for good results. PATIENTS AND METHODS From May 1993 to September 1997, 55 patients, 27 women and 28 men, with a mean age of 67 years (range, 35-102 years) underwent laparoscopic repair of paraesophageal hernias at the University of California San Francisco. Symptoms, which had been present an average of 85 months before surgery, consisted mainly of pain (55%), heartburn (52%), dysphagia (45%), and regurgitation (41%). Of the four patients who presented with acute illness, two had gastric obstruction, one had severe dyspnea, and one had gastric bleeding. Endoscopy demonstrated esophagitis in 25 (69%) of 36 patients, and 24-hour pH-monitoring demonstrated acid reflux in 22 (67%) of 33 patients. Manometry detected severely impaired distal esophageal peristalsis in 17 (52%) of 33 patients. The preferred operation consisted of reduction of the hernia, excision of the sack and the gastric fat pad, closure of the enlarged hiatus without mesh, and construction of a fundoplication anchored by sutures within the abdomen. RESULTS Of the 55 patients, the operations of 49 were completed laparoscopically using the following reconstructions: Guarner (270-degree) fundoplication (30 patients); Nissen fundoplication (10 patients); and gastropexy (9 patients). Five (9%) operations were converted to laparotomies. The average operating time was 219 minutes; the average blood loss was less than 25 mL; resumption of an unrestricted diet, 27 hours; and mean hospital stay, 58 hours. Intraoperative technical complications occurred in five (9%) patients. One patient died during surgery from a sudden pulmonary embolus. Two (4%) patients required a second operation for recurrent paraesophageal hernias. CONCLUSIONS Laparoscopic repair of paraesophageal hiatal hernias is safe and effective, but the operation is difficult and good results hinge on details of the operative technique and the surgeons experience. In this series, the crus could always be closed securely without using mesh. We realized early that a fundoplication should be a routine step, because it corrects reflux and is the best method to secure the gastroesophageal junction in the abdomen.

Comparison of thoracoscopic and laparoscopic Heller myotomy for achalasia.

For more than three decades experts have debated the relative merits of thoracoscopic Heller myotomy (no antireflux procedure) vs. laparoscopic Heller myotomy plus Dor fundoplication for treatment of achalasia. The aim of this study was to compare the results of these two methods with respect to (1) relief of dysphagia, (2) incidence of postoperative gastroesophageal reflux, and (3) hospital course. Sixty patients with esophageal achalasia were operated on between 1991 and 1996. Thirty underwent a thoracoscopic Heller myotomy and 30 had a laparoscopic Heller myotomy with a Dor fundoplication. The two groups were similar with respect to demographic characteristics, clinical findings, and extent of manometric abnormalities. Preoperative pH monitoring showed abnormal reflux in two patients in the laparoscopic group. Average hospital stay was 84 hours for the thoracoscopic group and 42 hours for the laparoscopic group. Excellent (no dysphagia) or good (dysphagia less than once a week) results were obtained in 87% of patients in the thoracoscopic group and in 90% of patients in the laparoscopic group. Postoperative pH monitoring showed abnormal reflux in 6 (60%) of 10 patients in the thoracoscopic group and in 1 (10%) of 10 patients in the laparoscopic group. The two patients in the laparoscopic group who had reflux preoperatively had normal reflux scores postoperatively. Laparoscopic Heller myotomy with Dor fundoplication was found to be superior to thoracoscopic Heller myotomy. Both operations relieved dysphagia, but the laparoscopic approach avoided postoperative reflux and even corrected reflux present preoperatively. In addition, the patients were more comfortable and left the hospital earlier following a laparoscopic myotomy. Whether it is truly possible to perform a Heller myotomy without an antireflux procedure in a way that relieves dysphagia and regularly avoids reflux remains questionable.

Barrett's esophagus: a surgical disease ☆

Barrett’s metaplasia can develop in patients with gastroesophageal reflux disease (GERD), and metaplasia can evolve into dysplasia and adenocarcinoma. The optimal treatment for Barrett’s metaplasia and dysplasia is still being debated. The study reported herein was designed to assess the following: (1) the incidence of Barrett’s metaplasia among patients with GERD; (2) the ability of laparoscopic fundoplication to control symptoms in patients with Barrett’s metaplasia; (3) the results of esophagectomy in patients with high-grade dysplasia; and (4) the character of endoscopic follow-up programs of patients with Barrett’s disease being managed by physicians throughout a large geographic region (northern California). Five-hundred thirty-five patients evaluated between October 1989 and February 1997 at the University of California San Francisco Swallowing Center had a diagnosis of GERD established by upper gastrointestinal series, endoscopy, manometry, and pH monitoring. Thirty-eight symptomatic patients with GERD and Barrett’s metaplasia underwent laparoscopic fundoplication. Eleven other consecutive patients with high-grade dysplasia underwent transhiatal esophagectomies. Barrett’s metaplasia was present in 72 (13 %) of the 53 5 patients with GERD. The following results were achieved in patients who underwent laparoscopic fundoplication (n = 38): Heartburn resolved in 95% of patients, regurgitation in 93% of patients, and cough in 100% of patients. With regard to transhiatal esophagectomy (n = 11), the average duration of the operation was 339 ±89 minutes. The only significant complications were two esophageal anastomotic leaks, both of which resolved without sequelae. Mean hospital stay was 14 ±5 days. There were no deaths. The specimens showed high-grade dysplasia in seven patients and invasive adenocarcinoma (undiagnosed preoperatively) in four (36%). These results can be summarized as follows: (1) Barrett’s metaplasia was present in 13 % of patients with GERD being evaluated at a busy diagnostic center; (2) laparoscopic fundoplication was highly successful in controlling symptoms of GERD in patients with Barrett’s metaplasia; (3) in patients with high-grade dysplasia esophagectomy was performed safely (invasive cancer had eluded preoperative endoscopic biopsies in one third of these patients); and (4) even though periodic endoscopic examination of Barrett’s disease is universally recommended, this was actually done in fewer than two thirds of patients being managed by a large number of independent physicians in this geographic area.

Virtual environments for training critical skills in laparoscopic surgery.

Surgical training simulations must incorporate not only advanced technical features, such as detailed geometric organ models and physically-based modeling techniques, but also a thorough understanding of the major training issues relating to a particular procedure. We have developed a prototype environment for training laparoscopic cholecystectomy, or gallbladder removal surgery, which focuses a students attention on the critical steps performed during the procedure and provides feedback as to the common errors committed during a session. The current version of our system runs in real-time on a mid-range graphics workstation. The simulation also provides a platform for research into a variety of different areas, including tissue modeling, finite element methods, and generalized simulation authoring.

SURGERY OF THE ESOPHAGUS : Anatomy and Physiology

The esophagus can be divided into three parts: cervical, thoracic, and abdominal. Its blood supply, lymphatic drainage, innervation, and architecture of the esophageal wall are described. The topographic relationships of the esophagus and the gastroesophageal junction with neighboring structures are illustrated from the right and left thoroscopic and the laparoscopic viewpoints. Functionally, the esophagus consists of the upper esophageal sphincter; the esophageal body; and the lower esophageal sphincter. Their coordinated muscular activity transports the food bolus into the stomach, while maintaining a barrier against reflux of esophageal contents into the pharynx and gastric juice into the esophagus.

Development of virtual environments for training skills and reducing errors in laparoscopic surgery

In every surgical procedure there are key steps and skills that, if performed incorrectly, can lead to complications. In conjunction with efforts, based on task and error analysis, in the Videoscopic Training Center at UCSF to identify these key elements in laparoscopic surgical procedures, the authors are developing virtual environments and modeling methods to train the elements. Laparoscopic surgery is particularly demanding of the surgeons spatial skills, requiring the ability to create 3D mental models and plans while viewing a 2D image. For example, operating a laparoscope with the objective lens angled from the scope axis is a skill that some surgeons have difficulty mastering, even after using the instrument in many procedures. Virtual environments are a promising medium for teaching spatial skills. A kinematically accurate model of an angled laparoscope in an environment of simple targets is being tested in courses for novice and experienced surgeons. Errors in surgery are often due to a misinterpretation of local anatomy compounded with inadequate procedural knowledge. Methods to avoid bile duct injuries in cholecystectomy are being integrated into a deformable environment consisting of the liver, gallbladder, and biliary tree. Novel deformable tissue modeling algorithms based on finite element methods will be used to improve the response of the anatomical models.

Results of laparoscopic antireflux surgery for dysphagia and gastroesophageal reflux disease

BACKGROUND Little attention has been paid to nonobstructive dysphagia (dysphagia in the absence of an esophageal stricture) in patients with gastroesophageal reflux disease (GERD). The objectives of this study were to assess (a) the incidence of nonobstructive dysphagia in patients with GERD; and (b) the effects of laparoscopic fundoplication on nonobstructive dysphagia. METHODS Esophageal manometry and pH monitoring identified 666 patients with GERD. Two hundred and eight patients (31 %) without esophageal strictures complained of dysphagia in addition to heartburn and regurgitation. Forty-nine (24%) of these patients underwent laparoscopic fundoplication. Esophageal function tests were repeated postoperatively in 12 patients (25%). Main outcome measures were effects of laparoscopic fundoplication on symptoms and esophageal motor function. RESULTS Dysphagia resolved postoperatively in 44 patients (90%), and improved in 2 patients (4%). Postoperative esophageal manometry showed a significant increase in the length and pressure of the lower esophageal sphincter, without changes in its ability to relax in response to swallowing. CONCLUSIONS About one third of GERD patients without strictures experienced dysphagia; and dysphagia resolved in about 90% of such patients following a laparoscopic fundoplication.