Incidence of Nephrolithiasis Following Laparoscopic Roux-En-Y Gastric Bypass: A Longitudinal Follow Up Study

Eric Ratchford, DO, Pandu R Yenumula, MDFRCSIFACS. Michigan State University

OBJECTIVE: Nephrolithiasis is one of the complications associated with Roux-en-Y gastric bypass. There are some population based studies showing increased incidence. There are few prospective studies looking at this problem.. . We present our findings of nephrolithiasis following laparoscopic Roux-en-Y gastric bypass.
METHODS: Patients who underwent laparoscopic Roux-en-Y gastric bypass were interviewed regarding development of renal stones and the data was collected prospectively. Patients who had revisional bariatric surgery were excluded. The roux limb length varied from 75 to 150 cm.
RESULTS: Of the 266 patients eligible for participation, 191 (72%) patients were available for the study. Follow up ranged from six months to 3.5 years. The majority of subjects were female (85%), and age ranged from 24-66 years of age. Fourteen patients were diagnosed with an upper urinary tract calculus following RYGB with an incidence of 7.3% . Seven of these patients had previous renal stones and only seven (3.6%) had new onset of renal stones. Four required operative intervention (29%). Twenty-two had a previous diagnosis of upper urinary tract calculus prior to their RYGB. Previous history of nephrolithiasis is a significant predictor of stone risk after laparoscopic RYGB (p = 0.01).
CONCLUSION: The new incidence of nephrolithiasis after RYGB is only 3.6% and there is a higher chance of developing recurrent real stones in patients with previous nephrolithiasis.