Detrusor and Blood Pressure Responses to Dorsal Penile Nerve Stimulation during Hyper-reflexic Bladder Contraction in Patients with Cervical Cord Injury

OBJECTIVE: To investigate the immediate effect of dorsal penile nerve (DPN) stimulation on detrusor pressure (Pdet) and blood pressure (BP) during hyper-reflexic contractions of the bladder in patients with cervical spinal cord injury (SCI). METHOD: The subjects were eight male patients with cervical SCI who had symptoms of autonomic dysreflexia. During water-cystometry, BP was monitored using an intra-arterial catheter into the radial artery, and was recorded simultaneously with the Pdet. Electrical stimulation was applied to the DPN, using surface electrodes each time a bladder contraction was detected. Baseline BP and BP at the first and the last hyper-reflexic contractions of bladder were measured with Pdet, respectively. RESULTS: As Pdet increased, the BP increased in all cases. The reflex contractions of the bladder were effectively suppressed by DPN stimulation, and as the Pdet decreased during stimulation, radial arterial pressure also decreased immediately and significantly. CONCLUSION: DPN stimulation can lower both Pdet and the elevated BP.

Inhibition of Hyper-reflexic Detrusor Contraction by Sacral Afferent Nerve Stimulation in Spinal Cord Injury

OBJECTIVE: To evaluate the inhibition effects of hyper-reflexic detrusor activity by sacral afferent nerve stimulation in spinal cord injury (SCI) patients. METHOD: The subjects were thirteen patients with SCI who had symptoms of urinary incontinence, because of hyper-reflexic bladder contractions. According to the level and severity of injury, the patients were divided into groups of tetraplegia/paraplegia and complete/incomplete. We applied dorsal penile nerve (DPN) stimulation using portable stimulator during the continuous bladder filling. Stimulation parameters were biphasic rectangular pulses of 25 Hz frequency, 250 microseconds pulse width. Stimulation intensity was twice the threshold of pudendo-anal reflex. The one minute stimulation was repeated to every reflex contraction during the cystometry. Immediate suppressive effect of DPN was analyzed. RESULTS: Of 13 patients who had a reflex bladder, hyper-reflexic detrusor contractions were suppressed effectively in 12 by DPN stimulation. The suppressive effect in groups of level and severity was not statistically significant. CONCLUSION: DPN stimulation for inhibition of hyper-reflexic bladder contraction is an adjunctive method of incontinence management in SCI patients of different level and severity.