Multiple Reflex Pathways Contribute to Bladder Activation by Intraurethral Stimulation in Persons with Spinal Cord Injury

Urology, 2017 · DOI: 10.1016/j.urology.2017.07.041 · Published: November 1, 2017

Simple Explanation

This study investigates the use of electrical stimulation to improve bladder function in individuals with spinal cord injuries (SCI). Lower urinary tract dysfunction is common after SCI, and current treatments have significant side effects. The research focuses on stimulating specific areas within the urethra to activate reflex pathways that control bladder function. The goal is to find ways to enhance bladder activation and improve bladder emptying through targeted electrical stimulation. The study found that co-stimulation of multiple areas in the urethra, using different stimulation frequencies, can lead to better bladder contractions compared to stimulating a single area. This suggests that activating multiple nerve pathways can improve bladder control in people with SCI.

Study Duration

Not specified

Participants

17 subjects (13 males, 4 females) at least one year post suprasacral SCI

Evidence Level

Not specified

Key Findings

1
Multiple reflex pathways are recruited through stimulation that contributed to bladder activation.
2
The size of reflex bladder contractions evoked by stimulation was dependent on stimulation location or reflex activated and stimulation frequency.
3
The latency of reflex responses to stimulation in the proximal and distal urethra varied, indicating activation of separate neural pathways.

Research Summary

This study investigated the effects of electrical co-stimulation of two individual sites in the urethra on bladder function in individuals with spinal cord injury (SCI). The results showed that electrical stimulation of proximal and distal urethral afferents produced bladder activation through two separate pathways. Selective co-stimulation of these pathways can produce enhanced bladder activation, suggesting that activating multiple nerve pathways can improve bladder control in people with SCI.

Practical Implications

Urinary Incontinence Treatment

Stimulation with different frequencies may be used to treat urinary incontinence and increase continent volumes.

On-Demand Voiding

Electrical stimulation can generate stimulation-evoked bladder contractions for on-demand voiding.

Improved Bladder Emptying

Co-stimulation of multiple afferent reflex pathways can enhance activation of spinal circuits and may enable improved bladder emptying in SCI when stimulation of a single pathway is not sufficient.

Study Limitations

1
In ten subjects, several factors limited the ability to evaluate intraurethral stimulation, including absence of distension-evoked bladder contractions (n=4), stimulation amplitude limited by uncomfortable sensations (n=3), inability to insert the stimulation catheter (n=1), and voluntary subject withdrawal (n=2).
2
Injury level and completeness of injury were reported by patients and have not been confirmed by MR imaging.
3
Future work needed includes additional animal studies with controlled SCI lesions and nerve transections to confirm the origin of reflex contributions, as well as additional clinical testing of these nerve targets in humans with SCI.

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