STONE DISEASE

Safety and efficacy of percutaneous nephrolithotomy in patients with neurogenic bladder dysfunction
Rubenstein JN, Gonzalez CM, Blunt LW, Clemens JQ, Nadler RB
Department of Urology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
Urology. 2004; 63: 636-40

• Objectives: To review our experience performing percutaneous nephrolithotomy (PNL) on patients with neurogenic bladder dysfunction with special attention paid to the risks of surgical complications and stone recurrence. Patients with neurogenic bladder dysfunction with or without urinary diversion are at increased risk of urolithiasis, surgical complications, and recurrent stone disease.
• Methods: We retrospectively reviewed the 23 patients with neurogenic bladder dysfunction who underwent PNL at our institution. Neurologic lesions included spina bifida, traumatic spinal cord injury, exstrophy/epispadias, neonatal meningitis, stroke, and spine chondrosarcoma. Bladder management included ileal conduit (n = 8), intermittent catheterization (n = 7), indwelling catheter (n = 7), and ureterosigmoidostomy (n = 1).
• Results: We performed 100 procedures on 47 renal units (17 bilateral, 7 with recurrent stones). Urinary tract infection/colonization was seen in 21 of 23 patients, most of whom had more than one organism. The stone-free rate was 96%. Six patients required three or more procedures, each had a complete staghorn calculus. In an average of 36 months of follow-up, 10 patients (46%) had recurrent stone disease requiring intervention, and 5 patients (23%) underwent repeat PNL. The stone composition analysis revealed mainly infection-related stones.
• Conclusions: PNL in patients with neurogenic voiding dysfunction is safe and effective, with outcomes comparable to that of patients without such lesions. The complication rate is small but statistically significant. It is important to obtain adequate urine cultures, because renal pelvis and bladder culture data may differ and affect the outcome. Risk factors for recurrent stone disease include a high spinal cord lesion, indwelling urinary catheter, and ureterosigmoidostomy.
  
  
• Editorial Comment
  Patients with neurogenic bladders with or without urinary diversion have a high incidence of chronic urinary tract infections and stones. Results with shock wave lithotripsy have been disappointing with regard to stone free rates and recurrent stone disease. As such, many of these patients are best managed with percutaneous nephrostolithotomy (PCNL). Unfortunately, infectious and other complications are common in this patient population.
  Nadler and colleagues reviewed their series of 23 patients with neurogenic bladder dysfunction who underwent 100 PCNL procedures on 47 renal units to assess success and complication rates. With aggressive second look flexible nephroscopy in all but 2 patients, an impressive stone free rate of 96% was achieved. Moreover, despite documented urinary tract infection in 91% of patients, only one case of urosepsis occurred, after initial percutaneous access. The authors attribute their low infectious complication rate to pre-operative treatment of positive urine cultures, percutaneous access and collecting system drainage the day prior to PCNL and aggressive culture-specific intravenous antibiotics after drainage. However, despite their high stone free rate, recurrent stones occurred in 46% of patients within 36 months.
  This study highlights the potential complications of treating stones in this patient population as well as the high rate of recurrence despite a stone free state. However, it is encouraging that with careful pre- and intra-operative measures, complication rates can be minimized. While the practice of routinely obtaining percutaneous access a day or more prior to the procedure has never been shown in controlled trials to reduce infectious complications, and I personally have not adopted this practice, it does allow renal pelvic urine to be assessed prior to initiating lengthy manipulation of the urinary tract. In addition, although the authors advocate oral antibiotics for 2 days prior to admission, I favor a more prolonged course of 1-2 weeks of culture specific antibiotics to assure at least superficial sterilization of the urinary tract.

Dr. Margaret S. Pearle
Associate Professor of Urology
University of Texas Southwestern Med Ctr
Dallas, Texas, USA