Abstract
Background: Bariatric surgeries are a common practice in society. The most common bariatric surgeries are laparoscopic sleeve gastrectomy and Roux-en-Y gastric bypass. This study reveals a significant correlation with the formation of kidney stones after bariatric surgeries.
Objective: To measure the prevalence of renal calculi formations among patients who underwent bariatric surgery in Riyadh, Saudi Arabia, 2020-2021 and consider it a serious complication in the long run.
Methodology: The study used a quantitative correlation design with a random selection sample out of 302 participants (>18 years) who underwent bariatric surgery. The chi-squared test was used to test the statistical significance between the categories. The continuous variables of pre-and post-surgery BMI are mentioned as mean, SD, 95% confidence interval, and the parametric t-test and paired t-test of pre- and post-surgery BMI as it followed normal distribution.
Results: Overall, 33/302 (10.9%) participants were found to have postbariatric renal calculi after a 6-month period due to significant rapid weight loss [19 (57.6%)]. Additionally, 2/33 (6.1%) patients had leakage postoperatively, especially with gastric bypass [5 patients (19.2%)]. Overall, 20 (60.6%) patients having postbariatric renal calculi were found to have a family history of renal calculi, with a significant p-value of 0.0126. A history of DM, HTN, anti-HTN medication, gout, recurrent UTI, vitamin D intake, high oxalate intake, and dehydration were all found to significantly increase the risk of renal calculi. The awareness of postoperative lifestyle modification was significant. Finally, significant weight loss regarding BMI in gastric sleeve surgery from pre-surgery (44.8 ± 10.2) to post-surgery (31.6 ± 9.4) and in gastric bypass from 44.3 ± 5.3 to 30.8 ± 6.3 was observed.
Conclusion: The majority of 33 patients who had postbariatric renal calculus showed a relationship with rapid and significant weight loss 6 months post-surgery as seen with gallbladder stones. Besides, it was found that the renal calculi risk has a significant relationship to postoperative leakage. In addition, there were significant risk factors to escalate the calculus formation. Although these patients had numerous symptoms, the most common were urgency, dysuria, hematuria, and passing small amount of urine in each voiding. The most significant risks for renal calculi included a history of kidney stones, diabetes, hypertension, and antihypertensive medication. The awareness of life modifications was excellent in these patients; however, the patients generally ignored such modifications. Lifestyle modification after weight reduction surgery is an important factor to prevent kidney stones.

Key words: General surgery, bariatric surgery, renal calculi, Roux-en-Y gastric bypass, gastric banding, sleeve gastrectomy, dietitian, family medicine.