Laparoscopic ultrasonography during laparoscopic cholecystectomy

Background: This study assessed the effectiveness of laparoscopic ultrasonography in demonstrating biliary anatomy, confirming suspected pathology, and detecting unsuspected pathology. Methods: Laparoscopic ultrasonography was performed on 48 patients (17 M:31 M) who underwent laparoscopic cholecystectomy. An Aloka 7.5-MHz linear laparoscopic ultrasound transducer was used for scanning. Results: Gallbladder stones were confirmed by laparoscopic ultrasonography in all patients and unsuspected pathology was found in five patients. Two patients were found to have common bile duct stones by laparoscopic ultrasonography and this was confirmed by laparoscopic cholangiography. Laparoscopic ultrasound was found to be helpful during dissection in four patients, particularly in a patient with Mirizzi syndrome. The entire common bile duct was visualized by laparoscopic ultrasonography in 40 patients but was poorly seen in eight patients. The mean time taken for the examination was 9 min (range 4–18 min). Conclusion: Laparoscopic ultrasound is useful during laparoscopic cholecystectomy. Received: 8 November 1995/Accepted: 5 May 1996     

Abnormal cholangiograms during laparoscopic cholecystectomy

Background: Laparoscopic common bile duct exploration (LCBDE) is more expensive and time consuming than its conventional counterpart. Therefore, it should only be performed when there is near certainty that stones are present. The purpose of this study was to identify patients who should be spared LCBDE despite an abnormal intraoperative cholangiogram. Methods: Of 700 consecutive laparoscopic cholecystectomies performed between 1989 and 1994 by a single surgeon (R.J.F.), 41 had abnormal intraoperative cholangiograms (6%). All 41 patients were treated by either immediate CBDE (19) (conventional or laparoscopic) or had postoperative follow-up cholangiograms (22). The patients were retrospectively assigned to one of three groups. Group I patients had a single ``soft' indicator of choledocholithiasis. Group II patients had one or more of the following: (1) a highly suspicious abnormal intraoperative cholangiogram, (2) two or more ``soft' indicators of choledocholithiasis, or (3) preoperative clinical findings such as elevated liver function studies or positive preoperative radiological studies. Group III patients had proven choledocholithiasis. Results: In group I, there were 11 patients, none of whom underwent immediate CBDE. Eight of the 11 (73%) had normal follow-up cholangiograms due to either spontaneous stone passage or a false-positive intraoperative cholangiogram. There were 27 patients in group II; 19 underwent immediate CBDE with 100% stone recovery. The remaining 8 had delayed treatment and in five stones were recovered, while three had normal postoperative cholangiograms suggesting spontaneous stone passage. In group III, all three had negative follow-up cholangiograms despite proven choledocholithiasis. Spontaneous stone passage in this group seemed highly likely. Conclusions: The finding of a single soft indicator results in a low rate of stone recovery postoperatively, and these patients should not undergo LCBDE. In this series, spontaneous stone passage seemed highly likely in at least 3/22 (14%) and possibly as high as 14/22 (64%). Received: 29 March 1996/Accepted: 29 July 1996     

A prospective comparison of laparoscopic ultrasound vs intraoperative cholangiogram during laparoscopic cholecystectomy

Background: The laparoscopic ultrasound (US) probe provides a new modality for evaluating biliary anatomy during laparoscopic cholecystectomy (LC). Methods: We performed a laparoscopic US examination in 65 patients without suspected common bile duct (CBD) stones prior to the performance of a laparoscopic cholangiogram (IOC). We then compared the cost, time required, surgeon's assessment of difficulty, and interpretations of findings. Results: There was a significant difference in the cost of US versus the cost of IOC ($362 ± 12 versus $665 ± 12; p < 0.05). Surgeons who had performed >10 US (EXP) were compared with those who had performed ≤10 (NOV). There were significant differences between the EXP and NOV groups in ease of examination, visualization of biliary anatomy, and accuracy of measurement of the CBD. Conclusions: The use of laparoscopic US for the accurate evaluation of the CBD and biliary anatomy requires that the surgeon has surpassed the learning curve, which we have defined as having performed >10 US exams. Received: 1 May 1998/Accepted: 21 October 1998     

Micropuncture laparoscopic cholecystectomy

Background: Laparoscopic cholecystectomy (LC) significantly reduces the discomfort and disability typically associated with open cholecystectomy, but there is still room for improvement. Methods: In order to further reduce the trauma of access, we have introduced a technique of micropuncture laparoscopic cholecystectomy (MPLC) that utilizes three 3-mm cannulae in addition to the standard 10-mm cannula at the umbilicus. MPLC was performed in 25 patients (median age, 52 years; m/f, three of 22) with symptomatic cholelithiasis. Results: The operation was completed in all patients. The median duration of surgery was 75 min (range, 45–180). Sixteen patients were discharged the same day and nine patients the next day. All the patients had an uncomplicated recovery. Only eight patients requested postoperative analgesia while in hospital. Micropuncture exploration of the bile duct was carried out in one patient. Conclusions: MPLC is a feasible and safe technique that appears to improve on the benefits of LC; it makes the operation even more feasible as a day-surgery procedure. Received: 28 January 1998/Accepted: 7 May 1998     

Alterations in hepatic function during laparoscopic surgery

Background: Very few studies have been done on the consequences of pneumoperitoneum on hepatic function. At present, there is no consensus on the physiopathological hepatic implications of pneumoperitoneum. The purpose of this clinical study was to evaluate the effects of pneumoperitoneum on hepatic function in 52 patients treated with laparoscopic procedures. Methods: Thirty-two laparoscopic cholecystectomies and 20 nonhepatobiliary laparoscopic procedures were performed in 52 patients (12 men and 40 women) with a mean age of 44 years (range, 15–74). All patients had normal values on preoperative liver function tests. The anesthesiologic protocol was uniform, with drugs at low hepatic metabolism. The 32 cholecystectomies were randomized into 22 performed with pneumoperitoneum at 14 mmHg and 10 performed at 10 mmHg. All nonhepatobiliary laparoscopic procedures were performed with a pneumoperitoneum of 14 mmHg. The postoperative serologic levels of AST, ALT, bilirubin, and prothrombin time were measured at 6, 24, 48, and 72 h. The serologic changes were related to the procedure, the duration, and the level of pneumoperitoneum. Results: Mortality and morbidity were nil. All 52 patients had a postoperative increase in AST, ALT, bilirubin, and lengthening in prothrombin time. Slow return to normality occurred 48 or 72 h after operation. The increase of AST and ALT was statistically significant and correlated both to the level (10 versus 14 mmHg) and the duration of pneumoperitoneum. Conclusions: The duration and level of intraabdominal pressure are responsible for changes of hepatic function during laparoscopic procedures. Although no symptom appears in patients with normal hepatic function, patients with severe hepatic failure should probably not be subjected to prolonged laparoscopic procedures. Received: 23 May 1997/Accepted: 28 October 1997     

Hemodynamic consequences of high- and low-pressure capnoperitoneum during laparoscopic cholecystectomy

Background: Peritoneal insufflation to 15 mmHg diminishes venous return and reduces cardiac output. Such changes may be dangerous in patients with a poor cardiac reserve. The aim of this study was to investigate the hemodynamic effects of high (15 mmHg) and low (7 mmHg) intraabdominal pressure during laparoscopic cholestectomy (LC) Methods: Twenty patients were randomized to either high- or low-pressure capnoperitoneum. Anesthesia was standardized, and the end-tidal CO₂ was maintained at 4.5 kPa. Arterial blood pressure was measured invasively. Heart rate, stroke volume, and cardiac output were measured by transesophageal doppler. Results: There were 10 patients in each group. In the high-pressure group, heart rate (HR) and mean arterial blood pressure (MABP) increased during insufflation. Stroke volume (SV) and cardiac output were depressed by a maximum of 26% and 28% (SV 0.1 > p > 0.05, cardiac output p > 0.1). In the low-pressure group, insufflation produced a rise in MABP and a peak rise in both stroke volume and cardiac output of 10% and 28%, respectively (p < 0.05). Conclusions: Low-pressure pneumoperitoneum is feasible for LC and minimizes the adverse hemodynamic effects of peritoneal insufflation. Received: 23 May 1997/Accepted: 11 March 1998     

The fate of the dropped gallstones during laparoscopic cholecystectomy

Stones can be spilled from the gallbladder during laparoscopic cholecystectomy. These stones can be left in the peritoneal cavity or trapped at the trocar site. The potential late sequel and associated morbidity are not well documented. We reviewed the records of four patients who underwent laparoscopic cholecystectomy at Mount Sinai Medical Center in New York City who suffered from late complications attributed to gallstones left in the peritoneal cavity or abdominal wall. Four patients presented 1–14 months after laparoscopic cholecystectomy with intraabdominal and abdominal wall abscesses. The spillage of gallstones was noticed during the initial operation only in one of the patients. Three patients required laparotomy and open drainage of intraabdominal abscesses with drainage of pus and gallstones after failed attempts at percutaneous drainage. Two patients underwent local exploration of an abdominal wall abscess containing stones. Stones left in the abdominal cavity or trapped in trocar sites after laparoscopic cholecystectomy can cause serious late complications requiring repeated surgical interventions. Every effort should be made in order to avoid spillage of stones during dissection of the gallbladder and cystic duct and during retrieval of the gallbladder through the abdominal wall. Received: 10 January 1996/Accepted: 2 April 1997     

Jaundice following laparoscopic cholecystectomy

We report the first case of obstructive cholangitis after laparoscopic cholecystectomy, related to intraperitoneal retained gallstones. Received: 19 December 1996/Accepted: 16 May 1997     

Bile duct injuries during laparoscopic cholecystectomy

Background: With the introduction of laparoscopic cholecystectomy, an increase in the incidence of bile duct injury two to three times that seen in open cholecystectomy was witnessed. Although some of these injuries were blamed on the ``learning curve,' many occurred long after the surgeon had passed his initial experience. We are still seeing these injuries today. Methods: To better understand the mechanism behind these injuries, in the hope of reducing the injury rate, 177 cases of bile duct injury during laparoscopic cholecystectomy were reviewed. All records were studied, including the initial operative reports and all subsequent treatments. Videotapes of the procedures were available for review in 45 (25%) of the cases. All X-ray studies, including interoperative cholangiograms and ERCPs, were reviewed. Results: The vast majority of the injuries seen in this review (71%) were a direct result of the surgeon misidentifying the anatomy. This misidentification led to ligation and division of the common bile duct in 116 (65%) of the cases. Cholangiograms were performed in only 18% (32 patients) of cases, and in only two patients was the bile duct injury recognized as a result of the cholangiogram. Review of the X-rays showed that in each instance of common bile duct ligation and transection in which a cholangiogram was performed the impending injury was in evidence on the X-ray films but ignored by the surgeon. Conclusions: From this review, several conclusions can be drawn. First and foremost, the majority of bile duct injuries seen with laparoscopic cholecystectomy can either be prevented or minimized if the surgeon adheres to a simple and basic rule of biliary surgery; NO structure is ligated or divided until it is absolutely identified! Cholangiography will not prevent bile duct injury, but if performed properly, it will identify an impending injury before the level of injury is extended. And lastly, the incidence of bile duct injury is not related to the laparoscopic technique but to a failure of the surgeon to translate his knowledge and skills from his open experience to the laparoscopic technique. Received: 14 May 1996/Accepted: 1 July 1996     

Hemodynamic and pulmonary changes during and after laparoscopic cholecystectomy

Background: The cardiopulmonary changes experienced by patients who undergo laparoscopic cholecystectomy (LC) and the prognostic value of patient characteristics are not well understood. Methods: Cardiorespiratory changes were investigated in 120 patients undergoing LC or open cholecystectomy (OC). The results and their relation to patient variables were statistically evaluated. Results: The most significant cardiorespiratory changes were (A-a)PO₂ increase during OC; decrease of pH and compliance and increase of peak airway pressure during LC; impairment of arterial blood gas mean values and respiratory muscle strength; atelectasis and pneumonia (five cases) after OC; and lamellar atelectasis (two cases) after LC. Significant adverse prognostic factors related to intra- and postoperative LC cardiorespiratory changes were ASA class greater than I, FEF_75–85% < 900 ml, and PaO₂ < 10.4 kPa (PPV, 71.4% and 46.6%, respectively). Conclusions: LC carries no significant cardiorespiratory changes provided that intraoperative monitoring of hemodynamics and respiratory parameters is done for the study of blood gas values in all patients at risk.     

Complications of laparoscopic cholecystectomy in Switzerland

Background: We set out to analyze the technical aspects, intraoperative complications, morbidity, and mortality of laparoscopic cholecystectomy in a multi-institutional study representative of Switzerland. Methods: Data were collected from 10,174 patients from 82 surgical services. A total of 353 different parameters per patient were included. Results: We found intraoperative complications in 34.4% of patients and had a conversion rate of 8.2%. This rate was significantly increased in patients with complicated cholelithiasis and in those with previous upper—but not lower—abdominal surgery. In most cases, conversions to open procedures were required because of technical difficulties due to inflammatory changes and/or unclear anatomical findings at the time of operation. Bleeding was a common intraoperative complication, that significantly increased the risk of conversion. Patients with loss of gallstones in the peritoneal cavity had increased rates of abscesses. The rate of common bile duct injuries was 0.31%, but it decreased significantly as the laparoscopic experience of the surgeon increased. The rate of common bile duct injuries was not increased in patients with acute cholecystitis or in the 1.32% of patients undergoing laparoscopic common bile duct exploration. Intraoperative cholangiography did not reduce the risk of common bile duct injuries, but it allowed them to be diagnosed intraoperatively in 75% of patients. Local complications were recorded in 4.79% of patients, and systemic complications were seen in 5.59%. The mortality rate was 0.2%. Conclusions: Although laparoscopic cholecystectomy is a safe procedure, the rate of conversion to open cholecystectomy is still substantial. The conversion rate depends both on the indication and intraoperative complications. There is still a 10.38% morbidity associated with the procedure; however, the incidence of common bile duct injuries, which decreases with growing laparoscopic experience, was relatively low. Received: 14 October 1997/Accepted: 21 January 1998     

Selection criteria for laparoscopic cholecystectomy in an ambulatory care setting

Background: The ambulatory care center offers patient convenience and reduced costs after uneventful laparoscopic cholecystectomy. Methods: A prospectively accumulated database of 1,750 cholecystectomies performed by one surgeon in a hospital setting was analyzed to test criteria for ambulatory cholecystectomy. Proposed criteria included age less than 65, absence of upper abdominal operations, and elective operations in healthy patients at low risk for common bile duct stones. Results: Of 1,750 cholecystectomies, only 605 patients met all criteria for outpatient care. Discharge (from the in-hospital setting) was accomplished within 24 h of operation in 92% (first 3 years) and 98% (last 4 years) of selected cases. Only one patient (0.2%, 1/605) was converted to an open procedure; another was readmitted 30 h postoperatively with hemorrhage from the liver bed. Conclusions: Laparoscopic cholecystectomy can be performed safely in an ambulatory care setting, given careful selection and education of patients and documented experience of the surgical team. Received: 1 April 1997/Accepted: 27 May 1997     

Randomized comparison between low-pressure laparoscopic cholecystectomy and gasless laparoscopic cholecystectomy

Background: Laparoscopic cholecystectomy using low-pressure pneumoperitoneum (8 mmHg) minimizes adverse hemodynamic effects, reduces postoperative pain, and accelerates recovery. Similar claims are made for gasless laparoscopy using abdominal wall lifting. The aim of this study was to compare gasless laparoscopic cholecystectomy to low-pressure cholecystectomy with respect to postoperative pain and recovery. Methods: Thirty-six patients were randomized to low-pressure or gasless laparoscopic cholecystectomy using a subcutaneous lifting system (Laparotenser). Results: The characteristics of the patients were similar in the two groups. The procedure was completed in all patients in the low-pressure group, but two patients in the gasless group were converted to pneumoperitoneum. There were no significant differences in postoperative pain and analgesic consumption, but patients in the gasless group developed shoulder pain more frequently (50% vs 11%, p < 0.05). Gasless operation took longer to perform (95 vs 72.5 min, p= 0.01). Conclusions: Gasless and low-pressure laparoscopic cholecystectomy were similar with respect to postoperative pain and recovery. The gasless technique provided inferior exposure and the operation took longer, but the technique may still have value in high-risk patients with cardiorespiratory disease. Received: 10 August 1998/Accepted: 12 February 1999     

Intraperitoneal bile collections after laparoscopic cholecystectomy

Background: Bile leakage is more common after laparoscopic cholecystectomy than after open surgery. In our department, the rate of postoperative bile collections after open surgery is 0.2% vs 0.6% after laparoscopic cholecystectomy. Methods: We studied 13 cases of intraperitoneal bile collection without common bile duct damage drawn from a total of 5,200 laparoscopic cholecystectomies (0.23%). Clinical presentation, symptoms, method of diagnosis, causes, time of diagnosis, correlation of time of diagnosis with definitive treatment, and postoperative results were analyzed. Results: The symptoms appeared between the 5th and 8th postoperative days. They were observed in patients with either chronic or acute cholecystitis. The main causes were misapplication of clips at the cystic duct and open Luschka's duct. Ultrasound failed for early recognition of bile collections. The definitive diagnosis was made by repeat ultrasonography, CAT scan, and ERCP. Conclusion: The ideal treatment in these cases is a minimally invasive procedure, but since the diagnosis is frequently delayed, open surgery is performed in the majority of patients. However, there were no mortalities in this group of patients. Received: 12 November 1998/Accepted: 15 July 1999/Online publication: 29 August 2000     

Delayed diagnosis of malignant tumors missed at laparoscopic cholecystectomy

Background: The aim of this study was to compare the significance of routine examinations prior to laparoscopic cholecystectomy (LC) with intraoperative abdominal investigation. Preoperative evaluation becomes increasingly important when laparoscopic procedures are performed for the removal of gallstones because other intraabdominal diseases may coexist in these patients, mimicking biliary tract disease. Methods: Over the last 6 years, we treated 816 patients with symptomatic cholecystolithiasis using LC. Prior to surgery, routine tests such as upper abdominal ultrasonography, chest radiography, and standard laboratory blood tests were carried out. Results: Despite these routine tests, coexisting colonic cancers escaped detection in four out of 816 cases. This indicates a risk of more ``missed pathologies' during the course of laparoscopic operations compared to standard laparotomy. Conclusion: The risk of missing coexisting diseases during laparoscopic operations has to be minimized by placing additional emphasis on careful evaluation of anamnesis. Physical examination and additional laboratory tests—such as analysis of tumor markers and blood in the stool—combined with complete abdominal ultrasonography, gastroscopy, and/or complete colonoscopy should be performed prior to LC. Received: 6 October 1996/Accepted: 19 February 1997     

The movement of mucosal cells of the gallbladder within the peritoneal cavity during laparoscopic cholecystectomy

Background: Tumor dissemination to trocar sites following the removal of a gallbladder malignancy by laparoscopic cholecystectomy is well documented. The mode of transfer of malignant cells to those sites remains unclear. Methods: The appearance and movement of gallbladder mucosal cells within the peritoneal cavity during laparoscopic cholecystectomy was prospectively studied in 15 patients. The appearance of cells on laparoscopic instruments, laparoscopic working ports, and also within a 5-μm polycarbonate filter, filtering exhaust carbon dioxide and attached to one of the main working ports, was noted. Results: Four out of 15 gallbladders were perforated during cholecystectomy. Operative choledochography was performed in 11 of the 15 cases. Glandular cells were found on instruments at the end of the procedure in six cases. Cells were also found in two of the 15 polycarbonate filters and on the laparoscopic ports in two of the 15 cases. Conclusion: These findings suggest that cellular contamination of the peritoneal cavity is frequent during laparoscopic cholecystectomy. This may occur when the gallbladder wall is macroscopically breached or when operative choledochography is performed, or by microperforation due to the application of crushing laparoscopic graspers to the gallbladder wall. Glandular cells adhere to instruments in 40% of the operative procedures and may be the main source of dissemination of malignant cells through the peritoneal cavity. Received: 29 January 1996/Accepted: 8 April 1996     

Incisional hernias after laparoscopic vs open cholecystectomy

Background: The aim of this study was retrospectively to compare the incidence of incisional hernia formation at trocar sites in laparoscopic cholecystectomy with that after conventional open cholecystectomy. Methods: In all, 271 patients with cholelithiasis underwent either laparoscopic cholecystectomy (LC group, n= 142) or open cholecystectomy (OC group, n= 129). In the OC group, the surgical approach was to use a right subcostal incision in 20.2%, right transrectal laparotomy in 73.6%, and midlaparotomy in 6.2%. Laparotomy closure was performed by continuous absorbable suture for the peritoneum and discontinuous absorbable stitches for muscle and fascia. Laparoscopic access was achieved by use of four trocars (two 10 mm and two 5 mm). Umbilical port closure was performed by suture of fascia using discontinuous stitches. Closure of the remaining ports was performed by suture of the skin. Results: Both patient groups were statistically similar with respect to general risk factors. Follow-up was performed in 84 (65.1%) OC and 123 (86.6%) LC patients and ranged from 2 to 10 years (mean, 8 years) and 1 to 5 years (mean, 3 years) respectively. Five (5.9%) OC and two (1.6%) LC patients developed incisional hernias, although the difference between groups was not significant. All hernias in OC patients appeared after transrectal laparotomy. The LC hernias appeared at the umbilical port, and one of the patients developed an additional xiphoides port-associated hernia. Conclusions: The laparoscopic technique showed a lower (although not significantly) incidence of incisional hernias than the open procedure. Received: 16 July 1998/Accepted: 27 November 1998     

Duodenal perforations after laparoscopic cholecystectomy

Duodenal perforations after laparoscopic cholecystectomies are rarely reported. The aim of this study is to focus on this complication and to suggest ways to reduce its occurrence and avoid diagnostic mistakes and therapeutical delays that could be fatal. We reviewed four personal cases and a number of others reported in the literature. Duodenal perforations are caused by improper use of the irrigator-aspirator device when retracting the duodenum, or by electrosurgical and laser burns. A duodenal perforation should be suspected in cases of bile leakage, peritonitis, intraabdominal or retroperitoneal collections, high serum or drainage amylase concentration, absence of bile leakage from the biliary tree, and the existence of a retroduodenal mass. Diagnosis requires a gastrografin upper GI series. Differential diagnosis is mainly with biliary lesions and other causes of peritonitis. Relaparoscopy may require intraoperative upper GI endoscopy or Kocher's duodenal mobilization to detect the perforation. Early diagnosis allows primary repair, usually by laparoscopy. Perforations of the duodenal cap are easier to diagnose and have a better prognosis than those of the descending duodenum. A lumbar abscess is a frequent complication. Received: 27 May 1998/Accepted: 14 September 1998     

Initial results of a prospective trial of outpatient laparoscopic cholecystectomy

Background: Whether or not laparoscopic cholecystectomy may be performed safely as an outpatient procedure is controversial. In 1993, a protocol for outpatient laparoscopic cholecystectomy was instituted to determine the benefits and safety of discharging patients within several hours of surgery. Methods: The initial 60 outpatient laparoscopic cholecystectomies performed by one surgeon in a hospital-based outpatient teaching facility between February 1993 to June 1996 were prospectively studied. Results: Fifty-eight (97%) patients were discharged successfully after an average stay in the recovery room of 3 h. There were no deaths. Two patients required overnight observation and three patients required readmission. Two patients (3%) had cystic duct leak. The average hospital stay for all patients undergoing laparoscopic cholecystectomy at the institution (inpatient and outpatient) decreased from 3.2 to 1.5 days and the average hospital cost decreased from $7,800 to $4,600 during this period. Conclusion: Laparoscopic cholecystectomy in an outpatient setting is safe and cost-effective in healthy patients. Received: 3 April 1997/Accepted: 10 June 1997     

The adverse hemodynamic effects of laparoscopic cholecystectomy

Recent studies suggest that significant physiologic derangements can occur during laparoscopic surgery. Eighteen patients admitted for laparoscopic cholecystectomy were studied. The mean age was 46.7 (range 19–78). A standard anesthetic technique, reverse Trendelenburg positioning, and an abdominal insufflation pressure of 15 mmHg with CO₂ were used with all subjects. Central venous pressure (CVP) and arterial pressures were measured invasively. Stroke volume and cardiac index were calculated using quantitative transesophageal echocardiography. Baseline measurements were taken after induction. Additional measurements were taken at 15-min intervals throughout the procedure. There was a statistically significant increase in mean arterial pressure (15.9%), systolic blood pressure (11.3%), diastolic blood pressure (19.7%), and CVP (30.0%) from control baseline values. Significant decreases in stroke volume (29.5%) and cardiac index (29.5%) occurred within 30 min of the induction of pneumoperitoneum and positioning (P<0.05, ANOVA). Laparoscopic cholecystectomy significantly and reversibly decreases cardiac performance. Compromised patients may be at increased risk for complications not previously recognized with this procedure.