Role of the pudendal nerves on the dynamics of micturition in the dog evaluated by pressure flow EMG and pressure flow plot studies.

The role of the pudendal nerves on the dynamics of micturition was studied using 16 decerebrated dogs. The voiding cycles were analyzed by pressure flow EMG and pressure flow plot studies under 3 conditions: control, after unilateral, and after bilateral pudendal nerve transection. In the control condition, highly reproducible reflex micturition with bladder contraction and spasmodic rhythmic sphincter contractions was demonstrated. Two patterns were noted following pudendal nerve transection: reflex micturition and overflow incontinence. Even though reflex micturition could be achieved in 9 out of 16 dogs after bilateral transection, there was decreased bladder emptying as well as absence of spasmodic rhythmic sphincter contractions. Overflow incontinence developed in the remaining 7 dogs (5 dogs after bilateral transection and 2 dogs after unilateral transection). It appears that the pudendal nerves play an important role in emptying the bladder of the dog.