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.