How often are common bile duct stones found in children suspected of having them?

This read stemmed from a literature search looking for articles addressing missed CBD stones in children not suspected of having them (no hx of jaundice, pancreatitis, normal CBD on U/S etc..). Instead I ran into this interesting article, out of Sick Kids in Toronto, looking at kids with findings consistent with CBD stones who were either managed by pre-operative ERCP, or had undergone an intra-operative cholangiogram, followed by ERCP when the IOC was positive.

202 patients with gallbladder stones, 48 of whom (23.7%) had suspected CBD stones. Preoperative ERCP, which was performed on a third of patients with suspected CBD stones, was positive in 21.4% of cases. Most of the rest of patients with suspected CBD stones underwent an IOC, which was positive in 6.5% of cases. Based on their results, the authors recommended an IOC as the initial investigative study since it involves less risk to the patient than does an ERCP, which was negative in around 80% of cases.

An IOC seems to be an excellent way to avoid unnecessary ERCP's, as long as a skilled gastroenterologist with a high ERCP success rate is available (to avoid a situation where a CBD stones are identified intraop, and an attempt at ERCP fails post op!). What is interesting about this study is the discrepancy between the finding of stones in the preoperative ERCP group and the IOC group. This could be because the ERCP may be more sensitive than the IOC, but potentially there might have been a selection bias, where patients who were more likely to have CBD stones (elevated bilirubin (8 vs 2), markedly dilated CBD (14 vs. 7) etc...) might have been selected to undergo and ERCP vs IOC.

Reference
Mah et al. Management of suspected CBD stones in children: role of selective IOC and ERCP. Journal of pediatric surgery (2004)39 :808-812