External sphincter dyssynergia: an abnormal continence reflex.

Area of Science:

• Urology
• Neuroscience
• Rehabilitation Medicine

Background:

• Traumatic upper motor neuron lesions can lead to detrusor-external sphincter dyssynergia (DESD).
• Understanding the temporal characteristics of DESD is crucial for managing bladder dysfunction after spinal cord injury.

Purpose of the Study:

• To investigate the characteristics of detrusor-external sphincter dyssynergia in patients with traumatic upper motor neuron lesions.
• To determine the time course of voiding function recovery and identify optimal timing for intervention.

Main Methods:

• Examined 14 patients with traumatic upper motor neuron lesions within 44 weeks of injury.
• Assessed sacral evoked response latencies, continence reflex, external urethral sphincter (EUS) pressure, electromyographic activity, and post-void residual volumes.
• Utilized propantheline to induce detrusor areflexia for further analysis.

Main Results:

• Sacral evoked response latencies were shortened in male patients.
• Continence reflex was demonstrable in most patients.
• Resting EUS pressure and post-void residual volumes peaked at 12 weeks, while voiding efficiency was optimal at this time.
• Voiding occurred during a negative intravesical pressure slope, independent of detrusor contraction.
• Episodic EUS activity persisted even with detrusor areflexia.

Conclusions:

• Voiding function appears to be optimal around 12 weeks after injury.
• DESD is proposed to be an exaggerated continence reflex resulting from the loss of supraspinal influences.
• A spinal cord pathway for synergic-like voiding may exist, independent of supraspinal control.