A neurophysiological study of patients undergoing radical prostatectomy.

24 men suffering from localized prostatic cancer undergoing radical retropubic nerve-sparing prostatectomy were investigated by the following electrophysiological methods: Bulbocavernosus reflexes elicited from the penile skin or the posterior urethra, sensory thresholds in the posterior urethra, cerebral evoked potentials after stimulation of the pudendal nerve or the posterior urethra. 15 men were examined 4-33 months postoperatively only, 5 men were examined only preoperatively and 4 men were examined both pre- and postoperatively. 10 men suffering from minor problems due to benign prostatic hyperplasia served as controls. In patients with localized cancer of the prostate, the findings did not differ from those in the control group. In the operated group the findings were pathological in a large proportion of the patients, indicating injuries both to nervous pathways running through the pelvic nerve plexus and in the pudendal nerve. The conclusions were: Localized cancer of the prostate has minimal or no risk at all of impaired functioning in the pelvic nervous pathways. Radical retropubic prostatectomy may in some cases be undertaken without any objective evidence of injury to these nervous pathways, but is often followed by findings indicating such injury. The dorsal nerve of the penis may be affected by the operation. Transcranial stimulation of the motor cortex is a useful method in the evaluation of prolonged or absent bulbocavernosus reflexes.