The effects of epidural anesthesia on the urethral closure pressure profile in patients with prostatic enlargement.

In 10 patients with obstructive manifestations of prostatic enlargement the urethral closure pressure profile was observed before and after the effective blockade of thoracolumbar sympathetic outflow by epidural anesthesia. While epidural anesthesia significantly decreased urethral closure pressure considerable profile responses still remained in these patients. This fact suggests that the bulk of the prostatic tissue is responsible for the bladder outlet obstruction, since urethral closure pressure persists despite urethral smooth and skeletal muscular relaxation as a result of epidural anesthesia. After transurethral resection of the prostatic tissue in these patients the urethral closure pressure did decrease to zero. The result of the prostatic resection is to decrease the urethral closure pressure and, thereby, increase the efficiency of voiding.