CBDS occur in 7-20% of all patients undergoing a gallstone operation and may complicate the course of surgery.
Although intraoperative x-ray investigation was routinely performed to diagnose CBDS in the pre-laparoscopic era, its use during the laparoscopic era has been debated. Consequently, other techniques for diagnosing CBDS have been introduced. For example, preoperative liver function test (LFT; s-bilirubin and s-ALP) results, if abnormal, might be diagnostic for CBDS. However, some patients might have normal LFT despite coexisting CBDS. Ultrasonography is the major diagnostic modality used to diagnose gallstones, but is less helpful for diagnosing CBDS. Computed tomography is rarely useful for diagnosing gallstones. Magnetic-resonance-cholangio-pancreatography (MRCP) has high specificity and sensitivity, with accuracy similar to that of ERCP (Endoscopic-Retrograde-Cholangio-Pancreatography), but its accuracy depends on the size and anatomical location of a gallstone. In addition, MRCP is not widely available, and unlike ERCP, does not allow the endoscopic extraction of stones. ERCP is the most common technique used for both the diagnosis and treatment of CBDS. It is, however, expensive, invasive, technically demanding and associated with small but significant morbidity.