Effects of Genital Nerve Stimulation Amplitude on Bladder Capacity in Spinal Cord Injured Subjects.

Shauh-Der Yeh,Dennis J Bourbeau,Chellappan Praveen Rajneesh,Chih-Wei Peng,Kenneth J Gustafson,Shih-Ching Chen,Chih-Hwa Chen,Bor-Shing Lin

doi:10.1155/2019/1248342

Abstract

Background/Purpose Few studies have investigated the effects of changing the amplitude of dorsal genital nerve stimulation (GNS) on the inhibition of neurogenic detrusor overactivity in individuals with spinal cord injury (SCI). The present study determined the acute effects of changes in GNS amplitude on bladder capacity gain in individuals with SCI and neurogenic detrusor overactivity. Methods Cystometry was used to assess the effects of continuous GNS on bladder capacity during bladder filling. The cystometric trials were conducted in a randomized sequence of cystometric fills with continuous GNS at stimulation amplitudes ranging from 1 to 4 times of threshold (T) required to elicit the genitoanal reflex. Results The bladder capacity increased minimally and maximally by approximately 34% and 77%, respectively, of the baseline bladder capacity at 1.5 T and 3.2 T, respectively. Stimulation amplitude and bladder capacity were significantly correlated (R = 0.55, P = 0.01). Conclusion This study demonstrates a linear correlation between the stimulation amplitude ranging from 1 to 4T and bladder capacity gain in individuals with SCI in acute GNS experiments. However, GNS amplitude out of the range of 1-4T might not be exactly a linear relationship due to subthreshold or saturation factors. Thus, further research is needed to examine this issue. Nevertheless, these results may be critical in laying the groundwork for understanding the effectiveness of acute GNS in the treatment of neurogenic detrusor overactivity.

Highlights

Neurogenic detrusor overactivity (NDO), a condition associated with spinal cord injury (SCI), is characterized by uninhibited bladder contractions in response to bladder filling; these contractions reduce bladder capacity and urinary continence [1, 2]
Sacral nerve stimulation (SNS) [4] therapy and transcutaneous tibial nerve stimulation (TTNS) [5,6,7] therapy have been used to treat subjects with SCI and NDO. Both TTNS and sacral nerve stimulation (SNS) therapies have been reported to significantly improve urinary continence by increasing bladder capacity in subjects with incomplete SCI [5,6,7], a few recent studies report that TTNS and SNS did not produce a satisfactory outcome in related clinic trials [8, 9]
Two-factor Analysis of variance (ANOVA) indicated that the absolute bladder capacity was dependent on the stimulation amplitude (P = 0.048), but the individual variation did not demonstrate a significant effect on the absolute bladder capacity (P = 0.179). These results indicated that there was no significant difference in bladder capacity gain between subjects with incomplete and complete SCI

Summary

Introduction

Neurogenic detrusor overactivity (NDO), a condition associated with spinal cord injury (SCI), is characterized by uninhibited bladder contractions in response to bladder filling; these contractions reduce bladder capacity and urinary continence [1, 2]. Pharmacological treatments such as antimuscarinic medication effectively treat neurogenic bladder; they often cause side effects and deteriorate the subjects’ quality of life [2, 3]. Sacral nerve stimulation (SNS) [4] therapy and transcutaneous tibial nerve stimulation (TTNS) [5,6,7] therapy have been used to treat subjects with SCI and NDO Both TTNS and SNS therapies have been reported to significantly improve urinary continence by increasing bladder capacity in subjects with incomplete SCI [5,6,7], a few recent studies report that TTNS and SNS did not produce a satisfactory outcome in related clinic trials [8, 9]. One possible explanation may be attributable to the fact that the therapeutic mechanism of these approaches might require the neuromodulation of supraspinal-mediated neural pathways [10]

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Results

Discussion

Conclusion