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

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.

Transcutaneous Electrical Stimulation for Neurogenic Bladder Dysfunction Following Spinal Cord Injury: Meta-Analysis of Randomized Controlled Trials

“…All of the studies measured changes after a range of 2-12 weeks of treatment. Several studies were excluded due to results contaminated with non-SCI participants (25-27) and without the control group (6,(28)(29)(30)(31). Besides, one study did not provide spinal injury details, for example, the level, completeness, and SCI phase (32).…”

The 2019 yearbook of Neurorestoratology

“…McCrery et al [34] reported that sacral neuromodulation was a safe and effective approach to improve urinary urgency incontinence symptoms in a majority of patients with urinary dysfunction and fecal incontinence, when conservative treatlents failed. Yeh et al [35] reported a linear correlation between the amplitude of dorsal genital nerve stimulation (GNS) ranging from 1 to 4 times the threshold and bladder capacity gain stimulation in acute SCI patients with neurogenic detrusor overactivity. Bourbeau et al [36] also found that short term at home GNS could reduce urinary incontinence and help subjects to achieve adequate bladder control.…”

Can Wireless Transcutaneous Nerve Stimulation Applied to the Genital Nerve Manage Urinary Incontinence Following Spinal Cord Injury and Multiple Sclerosis?

“…We recommend that patients experience the device first on their arm, and the identified moderate currents are expected to be used in urinary applications. For effective bladder inhibition with wireless-GEN, a moderate stimulation current needs to be used [12,13,15,16]. This current can be ascertained by palpating the anus and identifying moderate anal reflex contractions.…”

“…Muscle is a proxy for sensory nerve activation that mediates neuromodulation because only motor responses are easily measured. For effective bladder inhibition with wireless-GEN, a moderate stimulation current needs to be used [12,13,15,16]. This current can be ascertained by palpating the anus and identifying moderate anal reflex contractions.…”

“…Some shaving of genital hair is advised for good electrode contact. For Program #1, the 15 Hz stimulation frequency is within the range of frequencies effective for bladder inhibition [8,9,[16][17][18][19][20], and the pulse duration is 300 microseconds, which is considered adequate. The program also uses continuous stimulation for up to one hour [12,20].…”