PERCUTANEOUS SACRAL NERVE ROOT NEUROMODULATION FOR INTRACTABLE INTERSTITIAL CYSTITIS:

Sacral nerve stimulation: neuromodulation for voiding dysfunction and pain

Voiding dysfunction, which includes incontinence, retention, and chronic pelvic pain, is a relatively frequent problem that can be difficult to manage. Neuromodulation via stimulation of the sacral nerves has been shown to improve these symptoms, although the exact mechanisms remain elusive. Techniques for nerve stimulation may vary, depending on the disease, location of pain, and the patient's anatomy. In addition to placement of electrodes on the sacral nerve roots, modulation has also been reported by peripheral branches of the sacral nerves including the pudendal and posterior tibial nerves. Newer surgical techniques have significantly decreased the morbidity of the procedures and increased the probability of a successful outcome.

A prospective, single-blind, randomized crossover trial of sacral vs pudendal nerve stimulation for interstitial cystitis

OBJECTIVE

To compare sacral nerve stimulation (SNS) with pudendal nerve stimulation (PNS) for interstitial cystitis (IC).

PATIENTS AND METHODS

Twenty-two patients with well-documented, refractory IC had a tined lead placed at S3 and a second electrode implanted at the pudendal nerve via a posterior approach. In a blinded, randomized design, each lead was tested for 7 days. The best lead was implanted to a pulse generator and patients were followed at 1, 3 and 6 months.

RESULTS

The time required to place a sacral lead was 27.4 min, and a pudendal lead 19.6 min (P = 0.039). Of the 22 patients, 17 (77%) responded and had a permanent implant placed. PNS was chosen as the better lead in 77% and SNS in 24%. The order in which the lead was stimulated had no effect on the final lead implanted and there was no 'carry-over' effect. The overall reduction in symptoms was 59% for PNS and 44% for SNS (P = 0.05). At 6 months after implantation, voids improved by 41% (PNS) and 33% (SNS), and mean voided volume increased 95% and 21%, respectively; validated IC questionnaires improved markedly and complications were minimal.

CONCLUSIONS

This is the first 'blinded' study of SNS vs PNS for IC. A pudendal lead was implanted successfully in all patients, and most chose PNS as better than SNS; the improvement was sustained over time.

Interaction between neurotransmitter antagonists and effects of sacral neuromodulation in rats with chronically hyperactive bladder

OBJECTIVE

To investigate to what extent antagonists of spinal neurotransmitters interact with the effects of sacral neuromodulation in a rat model of a chronically hyperactive urinary bladder.

MATERIALS AND METHODS

In female rats the urinary bladder was instilled with turpentine oil 2.5% to induce cystitis. After surviving for 10 days the rats were anaesthetized with urethane, the bladder catheterized and connected to a pressure transducer. Stimulating electrodes were placed in the sacral foramina bilaterally. The spinal cord was exposed by a laminectomy, and a small pool was placed on the cord for intrathecal administration of neurotransmitter antagonists. Sacral neuromodulation was applied before and after administering the antagonists. The antagonists used were: memantine, an antagonist for N-methyl-D-aspartate (NMDA) receptors; CNQX, an antagonist for non-NMDA receptors, and L-NAPNA, a blocker of nitric oxide synthase.

RESULTS

With no electrical neuromodulation, memantine and L-NAPNA abolished the cystitis-induced bladder contractions for approximately 4 and approximately 37 min, respectively. The effect of CNQX was similar to that of artificial cerebrospinal fluid. Electrical sacral modulation with no antagonists also transiently abolished the bladder contractions; at the highest intensity used, the pause was 2-3 min. Superfusion of the spinal cord with CNQX reduced this effect of neuromodulation significantly, whereas memantine had no influence, and L-NAPNA increased the neuromodulation-induced pause.

CONCLUSIONS

The results suggest that non-NMDA receptors are involved in the effects of sacral neuromodulation, whereas NMDA receptors appear to have no role. Nitric oxide is essential for maintaining the chronic hyperactive state of the urinary bladder.

Intravesical Heparin and Peripheral Neuromodulation on Interstitial Cystitis

INTRODUCTION

We wanted to evaluate the therapeutic effect of intravesical heparin and peripheral neuromodulation on patients with interstitial cystitis.

MATERIALS AND METHODS

From March 2002 to August 2003, 8 female and 2 male subjects conform to the NIDDK criteria and not responsive to the previous conventional treatments were included in the study. Wisconsin pain scores, maximal cystometric capacities, and night and day voiding frequencies were determined and these studies were repeated in the 2nd and 12th months of the treatment with 10,000 units intravesical heparin and peripheral neuromodulation. Frequency of the treatment was once a week during first 8 weeks, once in 2 weeks in the following 8 weeks, and once in 3 weeks four times. Then, it was decreased to once a month.

RESULTS

The mean follow-up period was 13 months (12-16 months). Day and night voiding frequency were significantly better in the 2nd and 12th months, when compared to pretreatment values. The Wisconsin pain scores were 62.5 +/- 13.9% and 62.8 +/- 15.2% in the 2nd and the 12th months, respectively. The average increase in the maximum cystometric capacity was 54.8 +/- 27.4% and 52.5 +/- 31.6% in the 2nd and the 12th months, respectively.

CONCLUSIONS

Intravesical heparin and peripheral neuromodulation combination seems to be an alternative for patients with interstitial cystitis not responsive to other treatments.