The incidence of nephrolithiasis in patients with spinal neural tube defects

Purpose: Bladder stones are common in patients with spinal neural tube defe cts but there are little data on the incidence of renal calculi in this pop ulation. We examined the incidence, nature and risk factors of nephrolithia sis in our clinic population of patients with neural tube defects. Materials and Methods: We retrospectively reviewed the charts and radiologi cal studies of 327 patients followed at our neural tube defects clinic with routine radiological imaging of the urinary tract. Additional confirmatory studies were performed when stones were noted. Results: Renal calculi were identified in 20 patients with neural tube defe cts (6.1%). The incidence of nephrolithiasis increased with age. Renal ston es were noted in 19 patients (10.7%) 12 years old or older. Management of t he stones in these patients resulted in overall 53% stone-free and 87% recu rrence rates after intervention. Major risk factors for new and/or recurren t renal stone formation were bacteriuria in 95% of the cases, lower urinary tract reconstruction in 80%, pelvicalicectasis in 70%, vesicoureteral refl ux in 65%, a thoracic level spinal defect in 60% and renal scarring in 55%. Conclusions: These data suggest that there is a higher incidence of nephrol ithiasis in patients with neural tube defects than in the general populatio n and the risk of stone recurrence is also elevated. Most patients with sto nes had undergone lower urinary tract reconstruction. Other risk factors we re bacteriuria, pelvicalicectasis, vesicoureteral reflux and a thoracic lev el neural tube defect.