Gallstone size related to incidence of post cholecystectomy retained common bile duct stones

The morbidity of unexpected retained common bile duct (CBD) stones after cholecystectomy is a significant problem. We hypothesise that smaller size gallstones are associated with a higher incidence of this condition.

A retrospective analysis of emergency and elective cholecystectomies was performed between Oct 2004-Aug 2009 at our hospital. Gallstone number and size in the histological report for each patient was recorded. Only proven CBD stones found on ERCP performed on patients with unexpected readmissions within a six month period of their surgery were included.

In total 1085 cholecystectomies met the inclusion criteria during this period and were considered in the study, 98 emergency, 987 elective. Of the patients, 809 were female, 206 were male, median age 50 (range 19-92). 25 patients, 2.3% as overall incidence, had a subsequent post-operative ERCP confirming retained CBD stones (median gallstone size 5 mm). The remaining 1060 patients did not present with complications relating to a proven retained CBD stone (median gallstone size 14 mm), p = 0.012.

Patients who had small gallstones were significantly more likely to represent with retained CBD stones. Multiple gallstones within the gallbladder also seemed to be significant risk factor. We were unable to correlate an emergency procedure, patient sex or age as being higher risk groups for retained CBD stones. If gallstone number and size can accurately be determined by pre-operative imaging then it is patients with multiple small stones that should be most rigorously targeted for intra operative CBD assessment and action if found.