1242 INCIDENCE O F NEPHROLITHIASIS IN SPINAL NEURAL TUBE DEFECTS

adolescents and adults. Risk factors for stone formation were analyzed and bacteriuria was invariably present. Urinary tract reconstruction andor diversion was noted in 80% of the patients. Vesicoureteral reflw, pelvicalicectasis, renal scar- ring and a thoracic level spinal defect were also associated with an increased risk of stone formation. Standard thera- pies for stone disease had limited efficacy and recurrence was noted in the majority of patients. Further research into the metabolic and infectious factors in these patients may help to determine the etiology of these stones and provide insight into appropriate prophylactic therapy.

REFERENCES

1. Cass, A.: Urinary tract complications in myelomeningocele pa- tients. J. Urol., 1 1 5 102, 1976.

2. Kass, E. J . and Koff, S. A.: Bladder augmentation in the pediat- ric neuropathic bladder. J . Urol., 1 2 9 552, 1983.

3. Kaplan, W. E.: Management of myelomeningocele. Urol. Clin. N. Amer., 1 2 93, 1985.

4. Goldwasser, B. and Webster, G. D.: Augmentation and subse- quent enterocystoplasty. J. Urol., 135: 215, 1986.

5. Palmer, L. S., Franco, I., Kogan, S. J., Reda, E., Gill, B. and Levitt, S. B.: Urolithiasis in children following augmentation cystoplasty. J. Urol., 1 5 0 726, 1993.

6. Kronner, K M. Casale, A. J., Cain, M. P., Zerin, M. J., Keating, M. A. and Rink, R. C.: Bladder calculi in the pediatric aug- mented bladder. J . Urol., 1 6 0 1096, 1998.

7. Khoury, A. E., Salomon, M., Doche, R., Soboh, F., Ackerley, C., Javanthi, R.. McLorie. G. A. and Mittelman. M. W.: Stone formation aker augmentation cystoplasty: the' role of intesti- nal mucus. J Urol., 1 5 8 1133, 1997. -

8. Franco, I. and Levitt, S. B.: Urolithiasis in the patient with augmentation cystoplasty: pathogenesis and management. AUA Update Series, vol. 16, lesson 2, 1997.

9. Drach, G. W.: Urinary lithiasis: etiology, diagnosis, and medical management. In: Campbell's Urology, 6th ed. Edited by P. C. Walsh, A. B. Retik, T. A. Stamey and E. D. Vaughan. Philadel- phia: W. B. Saunders Co., vol. 3, chapt. 58, pp. 208b2156, 1992.

10. Myers, M. T., Elder, J. S. and Sivit, C. J.: Unenhanced helical CT in the evaluation of the urinary tract in children with conti- nent urinary tract reconstruction: comparison with sonogra- phy. Read at annual meeting of Society for Pediatric Radiol- ogy, abstract 23, Tuscon, Arizona, May 7-8, 1998.

11. Wan, J., Fleenor, S., Kielczewski, P. and McGuire, E. J.: Urinary tract status of patients with neurogenic dysfunction present- ing with upper tract nephrolithiasis. J. Urol., 1 4 6 1126, 1992.

12. Bauer, S. B.: Neurogenic vesical dysfunction in children. In: Campbell's Urology, 6th ed. Edited by P. C. Walsh, A. B. Retik, T. A. Stamey and A. J. Wein. Philadelphia: W. B. Saunders Co., vol. 2, chapt. 42, pp. 1634-1668, 1992.

13. Hunt, G. M., Bishop, M. C., Whitaker, R. H. and Doyle, P. T.: Sensory level and renal prognosis in myelomeningocele. Zeitschr. Kinderchir., 34 384, 1981.

14. Blaivas, J. G., Sinha, H. P., Zayed, A. A. and Labib, K. B.: Detrusor-external sphincter dyssynergia: a detailed electro- myographic study. J. Urol., 1 2 5 545, 1981.

15. Drach, G. W., Dretler, S., Fair, W., Finlayson, B., Gillenwater, J., Griffith, D., Lingeman, J. and Newman, D.: Report of the United States cooperative study of extracorporeal shock wave lithotripsy. J. Urol., 1 3 5 1127, 1986.

16. Fabrizio, M. D., Behari, A. and Bagley, D. H.: Ureteroscopic management of intrarenal calculi. J. Urol., 1 5 9 1139, 1998.

DISCUSSION

Dr. John Woodard. Calcium containing stones are more common and occur more commonly in patients with spinal injury or immobile patients. Since many of your patients with stones have high dysraphism lesions, did you try to correlate the level of immobility with the incidence of stones in these patients?

Dr. Ganesh V. Raj. Our observation that higher level lesions are associated with stone disease was intriguing. There is a considerable amount of work in the literature that neither proves nor disproves any association of higher level spinal lesion with a urological anomaly. Regarding your question on calcium, we have not studied this but our metabolic analyses are still under way. To date we have not seen a high propensity for calcium stones.

Dr. Steven G. Docimo. I think that calciuria is a steady state process. It is a change in mobility and not just static immobility that increases calcium in the urine.

Dr. Antoine E. Khoury. I suspect that if you do 24-hour urinalysis in these patients you will find that urine calcium is not high but urine citrate is low. It is not a matter of the upper tract or the level of the lesion. The reason you see those stones is that you have performed augmentation in these patients. You have instilled this metabolic abnormality in them.

Doctor Raj. I agree. In fact, our preliminary metabolic evaluation supports the idea that hypocitruria is the main or 1 of the main etiological factors. You are right. We do see more stones in patients with augmented than nonreconstructed bladders.

Dr. James Wolpert. Do you have a rigorous bladder irrigation program? We try to encourage our families t o perform bladder irrigation at least 3 times weekly. We find that there are few bladder stones.

Doctor Raj. Most of these patients perform clean intermittent catheterization 3 times daily and we encourage bladder irrigation.