Post-cholecystectomy pain is a common clinical problem, occurring in at least 10% of the 700,000 patients who undergo cholecystectomy in the United States each year. Some of the causes may be related to biliary problems (e.g. stone formation), but in most cases the cause is unknown.
Therefore, many patients undergo ERCP to clarify whether the pain is related to stone formation, neoplastic or sphincter of Oddi dysfunction (SOD), or endoscopic treatment such as biliary and/or pancreatic sphincterotomy, but its value is unclear and there is a risk of complications.
In 2002, the National Institutes of Health meeting recommended sphincter manometry for patients with type I and type II SOD; however, no studies have shown the value of sphincter manometry in predicting the outcome of sphincterotomy (EST) in patients with type III SOD. The value of sphincter manometry in predicting the outcome of sphincterotomy (EST) in patients with type III SOD.
To address this situation, Peter B. Cotton et al. from the Medical College of South Carolina, USA, did a multicenter RCT study to evaluate the efficacy and safety of EST in patients with post-cholecystectomy pain (without significant liver function abnormalities or biliary dilatation), and the results were published in the May 28, 2014 issue of JAMA.
Study Methods.
The study was a randomized, double-blind clinical study that selected patients with post-cholecystectomy pain from seven medical centers in the United States who were between 18 and 65 years of age, had no significant liver function abnormalities or biliary tract dilatation, had no prior history of pancreatitis, no history of sphincter intervention, and whose pain was ineffective for acid control or antispasmodic medications, and had no significant abnormalities on upper gastrointestinal endoscopy or imaging.
Exclusion criteria were: direct bilirubin, alkaline phosphatase, amylase, and lipase levels twice above normal or transaminases three times above normal for the past 6 months; daily use of narcotic analgesics for the past 1 month; pancreatic split or biliary split with abnormalities suggested by ultrasound endoscopy; severe psychological disorders or other serious physical disorders; and pregnancy.
Eligible patients were operated by ERCP performed by experienced endoscopists, and sphincter manometry was first performed on all patients, and then patients were randomly divided into EST and sham-operated groups in a 2:1 ratio. Postoperatively, pancreatic duct stents were placed in both groups to reduce the incidence of pancreatitis.
Patients with pancreatic duct hypertension in the EST group were randomized 1:1 to the double sphincterotomy group and the biliary sphincterotomy group alone, as specialists perform pancreatic sphincterotomy in the treatment of biliary pain and pancreatic duct hypertension.
Patients were followed up by the researchers by telephone for the first time at 1 week after surgery and monthly thereafter for 12 months.
The primary indicator of the study was treatment success, and secondary indicators were the association between sphincter pressure and other clinical characteristics of the patients with the primary indicator and the incidence of postoperative complications.
Study results.
From August 6, 2008 to March 21, 2013, 214 patients were eligible and included, 73 in the sham-operated group and 141 in the EST group, with no statistically significant differences in the general condition of the two groups. 64% of the patients had abnormal pancreatic ductal sphincter pressure and 12% had abnormal biliary sphincter pressure.
The RAPID score decreased significantly in both groups at 3 months of follow-up; the treatment success rate after 12 months of follow-up was 37% in the sham-operated group and 23% in the EST group, with a statistically significant difference.
Postoperative pancreatitis occurred in 15% of patients in the sham-operated group and 11% in the EST group, and the difference was not statistically significant. Duodenal perforation occurred in one patient in the double sphincterotomy group and required surgical intervention, and microperforation due to postoperative pancreatitis occurred in one patient in the sham-operated group. No other complications such as bleeding or infection occurred in either group.
In the EST group with concurrent pancreatic ductal sphincter hypertension, 47 patients underwent double sphincterotomy of the bile duct and pancreatic duct, of which 14 (30%) successfully resolved the problem, and 51 underwent biliary sphincterotomy alone, of which 10 (20%) were treated successfully, with no statistically significant difference.
Clinical characteristics of the patients, such as age, reason for cholecystectomy, pain characteristics, and psychological disorders, were not significantly related to treatment success. In addition, pancreatic ductal sphincter hypertension (with or without biliary hypertension) was not associated with the main index, and the treatment success rate was not necessarily higher in patients with sphincter hypertension than in patients with normal sphincter pressure.
Conclusions and Discussion.
The researchers found that EST did not necessarily reduce patient pain more than the sham-operated group in patients with post-cholecystectomy pain and no significant abnormalities in liver function or bile duct dilatation, and furthermore, sphincter manometry was not always a valid reflection of the therapeutic effect of EST. The results will have a significant impact on the clinical use of EST in patients with type III SOD.
However, the study had certain shortcomings, such as the study’s overly strict definition of treatment success, a portion of the included patients came from another observational study or had concomitant abdominal discomfort, and patients in the sham-operated group also experienced ERCP intubation, manometry, and stent placement, which were somehow considered to have a therapeutic effect.
In conclusion, this study suggests that performing sphincter manometry and EST does not provide more pain relief than the sham-operated group in patients with post-cholecystectomy pain without significant abnormalities in liver function or bile duct dilatation, and thus ERCP and EST are not recommended for such patients.