Procedure gives voiding control to SCI patients

New York-Preliminary results from the first two U.S. patients to undergo surgery to create a somatic-autonomic reflex pathway for micturition suggest the procedure may be an effective, safe treatment for neurogenic bladder secondary to spinal cord injury, report urologists from New York University.

Assessments performed during postoperative follow-up periods of 15 months for one patient and 9 months for the second show the procedure has afforded voluntary voiding control using stimulation of the L5 dermatome to precipitate detrusor contraction, has reduced neurogenic overactivity in the storage phase, and has allowed both patients to be continent without anticholinergic medication. Bowel function improved in one patient, and neither patient experienced adverse effects on sexual function, kidney function, or serious complications, reported Christopher E. Kelly, MD, assistant professor of urology at New York University School of Medicine.

"This procedure for addressing neurogenic bladder dysfunction after spinal cord injury has several advantages, as the surgery is unilateral only and is relatively mild while it permits voluntary control of the bladder without any need for implanted electrodes, leads, or mechanical devices," Dr. Kelly said.

At NYU, a multidisciplinary team of urologists, neurosurgeons, and neurophysiologists performs the surgery. First, a limited laminectomy is performed and the cauda equine nerve roots exposed. Then, using intraoperative neurophysiologic testing, the S3 nerve root is isolated, separated from the ventral root, and cut. Next, the left L5 ventral nerve root is isolated and anastomosed between the S2/3 ventral roots using 9-0 Prolene. The L5 dorsal root is left intact as the trigger of micturition after axonal regeneration.

The NYU clinical trial currently is enrolling men and women, 18 to 65 years old. Patients must be within 2 to 15 years of complete motor traumatic spinal cord injury above T11, but should otherwise be in good general health. They must have an intact reflex arc in one L4 or L5 segment, an intact detrusor reflex, and neurogenic overactive bladder with detrusor external sphincter dyssynergia (DESD) and increased postvoid residual. Persons with conal and caudal equinal lesions, an acontractile detrusor, incomplete lesions, or a lesion not caused by traumatic spinal cord injury are excluded.

Both patients operated on so far are men who are 2 years post-injury. One is 40 years old and has a T6 complete lesion; the other is 32 years old and has a T11 complete lesion.

Prior to surgery, both patients managed voiding with clean, intermittent catheterization and anticholinergic medication to reduce incontinence. Preoperative videourodynamic studies showed compliance was mildly decreased in one patient and was normal in the other.

No complications were encountered during the surgery, and both were discharged after an average stay of 3 days.

Outcomes are being assessed during quarterly follow-up visits for the first 2 years and semiannual visits thereafter, Evaluations include history and physical exam, monitoring of laboratory values and urine culture, upper urinary tract studies, and videourodynamics. Patients also complete questionnaires about their sexual and bowel functions and maintain voiding and bowel diaries.

Voiding reflex induced by stimulation of the L5 dermatome was first observed after 15 months in the first patient and after 9 months in the second. At last follow-up, Qmax values for the precipitated detrusor contraction in the two patients were 9 cc/sec and 16 cc/sec, respectively, and values for maximum detrusor pressure on voiding were 59 cm H₂O and 44 cm H₂O, respectively. Bladder capacity increased in both patients from 359 cc to 596 cc and from 425 cc to 524 cc, respectively.

Postoperatively, DESD was mild. Compliance improved in one patient, with a mild preoperative decrease, and was stable in the other. Bowel function changed in only the second patient, who reported a significant improvement within 3 months after surgery.

"We postulate two possible reasons for the improved bowel function," observed Dr. Kelly. "It may be secondary to discontinuation of anticholinergic medication or reinnervation of the large bowel parasympathetic ganglion."

Over the longer term, the only adverse events reported included single cases of uncomplicated urinary tract infection in each patient and one complicated UTI episode in one patient.