Gastric Band Surgery and Kidney Stones

Patients who undergo bariatric surgery in order to overcome severe obesity may be at an increased risk for urolithiasis, the development of stones in the kidney, bladder, or urinary tract. However, recent studies have shown that patients who undergo gastric banding procedures may have a lower risk for urolithiasis than gastric bypass patients.

Two studies published in the Journal of Urology examined the risks for urolithiasis in bariatric patients. It was discovered that patients who undergo gastric banding or gastric bypass tend to have a significant reduction in urinary volume after surgery. Gastric banding patients appear to have a more significant reduction in urinary volume than gastric bypass patients.

However, although they experience less of a reduction in urinary volume, gastric bypass patients are more likely to have elevated levels of urinary oxalate, an organic acid found in urine. Roux-en-Y gastric bypass surgery, in which the normal digestive flow and absorption process is interrupted, seems to carry the highest risk for the development of stones. These patients have a higher incidence of hyperoxaluria, an excessive amount of urinary oxalate, and hypocitraturia, an abnormally low level of citrate in the urine, two significant risk factors for urolithiasis.

People who are considering undergoing bariatric surgery should be aware of the possibility of developing kidney or bladder stones after surgery. To offset these risks, weight loss surgery patients should be instructed to get plenty of fluids on a daily basis and to consider taking calcium citrate with Vitamin D supplements and Vitamin B-12 and B-complex supplements.