Ambulatory urodynamic monitoring assessment of dorsal genital nerve stimulation for suppression of involuntary detrusor contractions following spinal cord injury: a pilot study

Abstract

Study design: A prospective interventional pilot study using within-individual comparisons.

Objectives: To assess the effect of dorsal genital nerve stimulation (DGNS) on urine-storage parameters in participants with spinal cord injury (SCI) and neurogenic detrusor overactivity (NDO) during natural bladder filling.

Setting: The London Spinal Cord Injuries Centre at the Royal National Orthopaedic Hospital, Stanmore, UK.

Methods: Ambulatory urodynamic monitoring (AUM) was carried out with and without DGNS, before and after a week of using DGNS at home. DGNS was applied on-demand by four participants with bladder sensation, and both continuously and intermittently by one participant with absent sensation. A Wilcoxon sign-rank test was used to test paired results of changes within an AUM session.

Results: Urodynamic outcomes were improved using DGNS. Bladder capacity was increased from 244 ± 59 to 346 ± 61 ml (p = 0.0078), a mean change of 46 ± 25%. Maximum detrusor pressure was decreased from 58 ± 18 to 47 ± 18 cmH2O (p = 0.0156), a change of 17 ± 13%, and average peak detrusor pressure was decreased from 56 ± 16 to 31 ± 128 cmH2O (p = 0.0156), a mean reduction of 50 ± 19%. There was an increase in the number of detrusor contractions from the first involuntary detrusor contraction to a strong desire, urgency or incontinence, from 1.5 ± 1.4 to 4.3 ± 1.7, and an increase in time of 23 ± 22 min. There were no changes in baseline outcomes following home use of DGNS.

Conclusions: DGNS may be applied on-demand, intermittently or continuously, to increase bladder capacity, decrease storage pressures and provide extra time. Improvements were made in addition to existing antimuscarinic medication regimes.

Conflict of interest statement

The authors declare that they have no conflict of interest.

Figures

Fig. 1. Equipment set-up.

a Custom Android app used for control of the stimulation device. b Sketch of electrode positioning and connection to the pace stimulator, connected to the smartphone via bluetooth low energy. c Schematic of AUM set up with an example trace seen on the computer at the end of a filling cycle.

Fig. 2. Individual results from AUM recordings across all sessions without (control) and with (Stimulation) DGNS.

From left to the right: maximum detrusor pressure (MDP) can be seen to decrease in all available recordings, including for P01 where MDP was also leak point pressure. Average Peak detrusor pressure (APDP), another measure of pressure within the bladder relevant to a treatment where multiple spikes in pressure are expected (as with on-demand DGNS), decreases were seen in all recordings. Maximum cystometric capacity (MCC) was increased in all participants. Time, in minutes from first involuntary detrusor contraction to end of the test, increased using DGNS in all participants, but not in both sessions for P05, where the participant had several detrusor contractions that neither resulted in leakage or strong desire to void. Time is perhaps the most potent demonstration of how DGNS might be applicable to the daily lives of people living with NDO.