Multimodal approach best for diagnosing Mirizzi Syndrome
Mirizzi Syndrome (MS) is a rare medical phenomenon in Singapore and its accurate diagnosis remains a challenge, reports a recent study, which also shows that less than 75 percent of patients are accurately diagnosed prior to surgery.
“MS is a rare sequelae of gallstone disease, but it presents several challenges to the surgeon,” the researchers said, adding that the ease and accuracy of diagnoses can be improved through multimodal approaches.
“In our case series, none of the preoperative investigations allowed the radiologist or endoscopist to confidently report the presence of fistulation in MS. Thus, a multimodality approach … [is] suggested.”
The researchers retrospectively reviewed 65 consecutive MS cases from the Department of General Surgery at the Singapore General Hospital. Clinical presentation, treatment procedure, diagnostic methods, follow-up and complications were extracted from the participants’ electronic records.
At the time of the study, a total of 10,176 cholecystectomies were performed at the Singapore General Hospital, yielding an MS incidence rate of 0.062 percent. One patient who presented with haematemesis was excluded, resulting in an average age in the study cohort of 59.8 years, with majority being female (n=37). [Dig Surg 2017;doi:10.1159/000484256]
Magnetic resonance cholangiopancreatography (MRCP) was the most sensitive imaging modality, suggesting MS in 24 of 27 (88.9 percent) of those who received it. This was followed by computed tomography scans (40 percent) and ultrasonography (US; 11.4 percent).
Moreover, only MRCP could preoperatively identify the presence of fistulae. Of the 12 patients who underwent MRCP and opted for intraoperative confirmation of fistulae, 7.4 percent (n=2) had preoperative images that suggested the presence of fistulae. In comparison, endoscopic retrograde cholangiopancreatography (ERCP), performed on 44 participants, was suggestive of MS in 29 cases (65.9 percent).
The overall preoperative diagnostic accuracy in the cohort, regardless of diagnostic method used, was 73.8 percent (n=48).
“[T]he sensitivity of MRCP was 88.9 percent, and was performed in more than 40 percent of our cohort. The sensitivity of ERCP, on the other hand, was lower at 65.9 percent. However, it remains a valuable adjunct because it allows delineation of the level and extent of biliary obstruction, as well as closer evaluation of ductal abnormalities, including fistulae,” the researchers said. [ANZ J Surg 2012;82:708-713]
“MS is a challenging condition and the multimodal diagnostic approach is recommended to achieve accurate preoperative diagnosis. In cases where the clinical suspicion is high despite equivocal imaging studies, a trial of laparoscopic dissection with a low threshold for open conversion is recommended,” they added.