Can Laparoscopic Cholecystectomy Prevent Recurrent Idiopathic Acute Pancreatitis?
With great interest, I have read the recent article by Räty et al.1 First of all I would like to express my admiration to the authors, it is well written and I thoroughly enjoyed it. This is the first prospective randomized study on the role of elective laparoscopic cholecystectomy in preventing recurrent idiopathic acute pancreatitis. The authors conclude that elective laparoscopic cholecystectomy is an effective method to prevent idiopathic acute pancreatitis, with a number needed to treat of 5.
However, the study has a few limitations, most importantly the diagnostic workup to exclude biliary stones—namely, transabdominal ultrasound and magnetic resonance cholangiopancreatography in case of elevated liverenzymes. Transabdominal ultrasound has been shown to be unreliable when ruling out biliary stones with sensitivity ranging from 20 to 90%.2 Especially, stones trapped distally in the ductus choledochus, potentially causing acute pancreatitis, are difficult to visualize because of image distortions caused by bowel gasses.3 Moreover, endoscopic ultrasound to detect microlithiasis, biliary sludge, and stones in the ductus choledochus was not performed. Research has shown that endoscopic ultrasound has greater diagnostic properties with a sensitivity and specificity of 94% and 95%, respectively,4 and the ability to detect microlithiasis and biliary sludge present in up to two-thirds of the patients with idiopathic acute pancreatitis.5 Therefore, to make the diagnosis idiopathic acute pancreatitis, a carefully executed diagnostic workup, which includes endoscopic ultrasound, must be performed. This compromises the external validity or generalizability of the study, especially for clinicians who carefully performed the diagnostic workup, and are more sure of the diagnosis idiopathic acute pancreatitis.
In addition, some things remain unclear. Relevant is the proportion of recurrences in the intervention group stratified along the presence of stones found after surgery. This gives insight in the true therapeutic effect considering that stones found postoperatively would be detected on imaging preoperatively. Patients without stones are more likely to be truly idiopathic. Moreover, after interim-analysis at 4 years, the study was ceased because of great effect. What were the subsequent courses of action? Did all patients receive laparoscopic cholecystectomy, or was diagnostic workup enhanced? Finally, how was blinding of allocation and outcome assessment done? These aspects of a randomized controlled trial are crucial and pose a serious risk to the internal validity of the study when they are not performed adequately.