Anesthetic block of the dorsal penile nerve inhibits vibratory-induced ejaculation in men with spinal cord injuries

Objectives. We investigated which nerve pathways are necessary to achieve e jaculation using penile vibratory stimulation (PVS) in men with spinal cord injury (SCI). Methods. Eight men with SCI were selected based on the presence of a bulboc avernosus reflex (BCR) and consistent antegrade ejaculation with PVS. Level of injury was cervical (4), upper thoracic (4), and lower thoracic (1). Me an age was 30.4 years (range 22 to 38). Usual responses to PVS included aut onomic dysreflexia (4), erection (4), and consistent somatic responses such as abdominal contractions (8). Local anesthesia of the dorsal penile nerve s (penile block) was achieved using 1% plain lidocaine injection. Effective penile block was confirmed by loss of the BCR. Two PVS ejaculation trials were performed: one trial during the penile block and one trial when the pe nile block had worn off. In 4 subjects, the bladder contents were analyzed for retrograde ejaculation. Results. With the penile block, ejaculation was inhibited in 100% of the su bjects. None of the bladder washings demonstrated sperm, indicating absence of retrograde ejaculation. None of the subjects exhibited their usual erec tile response, somatic responses, or signs of autonomic dysreflexia. After the penile block wore off, PVS induced ejaculation in all subjects. If subj ects usually had erection, somatic responses, or signs of autonomic dysrefl exia, these also returned. Conclusions, Our data suggest that ejaculatory response to PVS in SCI men r equires the presence of intact dorsal penile nerves. UROLOGY 55: 915-917, 2 000. (C) 2000, Elsevier Science Inc.