Background: Obesity alone and rapid weight loss induced by bariatric surgery are recognized risk factors for the development of cholelithiasis. This study aimed to identify the predictive factors for gallstone formation after bariatric surgery. Patient and methods: The files of all morbidly obese patients underwent bariatric surgery in our unit during the period from March 2003 till October 2010 were reviewed and analyzed. All patients underwent routine preoperative ultrasonography and selective concomitant cholecystectomy was done in all patients with ultrasonographic-confirmed cholelithiasis. After excluding cases with prior and concomitant cholecystectomies, patients were divided into two groups; those who developed gallstones and those who did not and the two groups were compared. Results: Of the 143 reviewed files 135 were eligible to be included in the study. The incidence of cholelithiasis before surgery was 25.9% (35 cases). 19 cases (19%) of the 100 cases free at surgery developed gallstone at a mean of 13.2 months. Comparing the two groups, no significant difference was revealed regarding gender, age, preoperative BMI or type of the operation. But the percent of excess weight loss was significantly higher in the group that formed gallstones. Conclusion: Gender, age, preoperative BMI and type of the operation were not predictive of gallstones formation after bariatric surgery. The percent of excess weight loss was the only predictive postoperative factor.
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