Nerves at the ventral prostatic capsule contribute to erectile function: initial electrophysiological assessment in humans.
BACKGROUND
Recent microanatomical studies have identified a significant amount of nerve fibers along the ventral circumference of the prostate capsule and confirmed the concept of a periprostatic nerve network. However, functional investigations have not yet proved whether nerve fibers distributed on the prostate capsule, particularly those outside the neurovascular bundle (NVB), contribute to erection.


OBJECTIVE
To confirm whether nerve fibers distributed on the prostate capsule contribute to erectile function, the present study was performed using electrophysiologic testing.


METHODS
The circumference of the prostate capsule was electrically stimulated during radical retropubic prostatectomy (RRP) in 12 patients with clinically localized prostate cancer (PCa). We defined the ventromedian circumference of the prostate capsule as the 12 o'clock position and the posterolateral position of the typical NVB as the 5 o'clock position. Periprostatic nerve fibers at the 12, 1, 2, 3, 4, and 5 o'clock positions of the midprostate were stimulated using bipolar electrodes.


METHODS
Changes in pressure at the middle of the urethra were measured using an inserted balloon catheter to detect increases in cavernosal pressure.


CONCLUSIONS
Although the study included only 12 patients, every stimulation at all positions between 1 and 5 o'clock evoked urethral pressure responses in all patients. Mean pressure response was most powerful for 5 o'clock stimulation and decreased with stimulated points further from the 5 o'clock position.


CONCLUSIONS
We demonstrated that electrostimulation at not only the posterolateral but also the anterior and lateral circumference of the prostate capsule can increase cavernosal pressure. These findings indicate that the periprostatic nerve network contributes to erections.
Department of Urology, Tohoku University School of Medicine, Sendai, Japan.
Yasuhiro
Y
Kaiho
Haruo
H
Nakagawa
Hideo
H
Saito
Akihiro
A
Ito
Shigeto
S
Ishidoya
Seiichi
S
Saito
Yoichi
Y
Arai
D000368:Aged; D004558:Electric Stimulation; D055724:Electrophysiological Phenomena; D006801:Humans; D008297:Male; D008875:Middle Aged; D010410:Penile Erection / Q000502:physiology*; D011467:Prostate / Q000294:innervation*