An electromyographic study of detrusor sphincter dyssynergia in the neurogenic vesical dysfunction. Part 1. Its type and further sub-typing based on the analysis of motor units

Abstract

Simultaneous recordings of electromyography of the external urethral sphincter (EUS) and bladder pressure were performed in 73 patients. The majority (69 cases) were afflicted with neurogenic vesical dysfunction, while four with benign prostatic hypertrophy (BPH) were also examined as control. Detrusor sphincter dyssynergia (DSD), whereby EUS failed to relax on voiding attempt, was noted in 64 patients. By examining the patterns of DSD throughout the voiding, it was possible to classify them into three distinct types as done by Blaivas. Type 1 was found in 7 patients, Type 2 in 10 patients, and Type 3 in 47 patients. Synergic urethral sphincter activity (Type 0) was found in other 9 patients including all four with BPH. Voiding dysfunction as evaluable by residual urine rate tended to increase as the type deteriorated from 1 to 3. Analysis of motor units revealed that the units noted during continent phase of the bladder disappeared (A0), decreased (A1), and retained or rather increased their activity (A2) during voiding attempt with (B1) or without (B0) recruitment of new units. A0B1 was found in 3 patients, A1B1 in 7, A2B1 in 32, A2B0 in 4, and A1B0 in 2. Again there was a tendency for voiding function to deteriorate as motor units sub-type changed from A0 to A1 and A2. The analysis of these motor units activities suggested that abnormal continence reflex (i.e. failure of vesicourethral and urethrourethral relaxation reflex and exaggeration of urethrourethral contraction reflex) might be contributing to the genesis of DSD.