Role of intraoperative cholangiogram (IOC) in diagnosing residual stones and variable anatomy in laparoscopic cholecystectomy (LC)

Abstract

Background: Incidence of common bile duct (CBD) stones on Intra-operative Cholangiogram (IOC) ranges from 8-15% and it causes complications in 15% of these patients. IOC has high sensitivity (97%) and specificity (99%) but routine use causes increasing costs and operating time. Studies have indicated that IOC is not indicated if preoperative liver enzymes are normal. We evaluated efficacy of IOC in diagnosing stones and abnormal anatomy. Materials and Methods: A retrospectively analysis was performed of patients undergoing LC from January 2018-June 2018. We investigated pre-operative liver function tests (LFTs), if patients underwent pre-operative endoscopic retrograde cholangiopancreatography (ERCP), Endoscopic ultrasound (EUS) or Magnetic resonance cholangiopancreatography (MRCP), IOC findings, post-op complications and need of post-operative interventions (ERCP). Results: This study included 55 females, 28 males. The median age was 52yrs. 5 patients had markedly raised serum bilirubin (>80μmol/L). They underwent MRCP or EUS followed by pre-operative ERCP. 6 Patients had borderline raised bilirubin (>25μmol/L) and 7 had raised ALP (>147 IU/L). None of these patients showed stones on IOC. The incidence of stone and abnormal anatomy (abnormal insertion of cystic duct) on IOC was 6.4% and 3.6% respectively. All patients with stones had normal LFTs. The Sensitivity of IOC for stone was 100%, Specificity was 88%, Positive Predictive Value was 50% and Negative Predictive Value was 100%. False positive rate was 6.4%. There were no complications from IOC or missed retained stones. Conclusion: IOC is often only performed in patients with mild deranged pre-operative LFTs. In our HPB department we routinely perform IOC in LC. Our incidence rate (6.4%) of stones in such patients indicates IOC has role in detecting coincidental stones. Performing post-operative ERCP during same admission potentially prevents complications. In addition, recognizing abnormal anatomy on IOC is useful for cautious dissection.