Preservation of ejaculatory function by reconstruction of the canine hypogastric nerve

The hypogastric nerve (HGN) plays a crucial role in the primary functions of ejaculation: sperm transport through the vas deferens, secretion of prostatic fluid, and bladder neck closure. This study was undertaken to explore the possibility of restoring HGN function to the seminal tract and preserving its cross-innervation mechanism to the seminal tract after HGN-HGN reattachment.

Responses of the vas deferens/epididymis, prostate, and bladder neck to electrical stimulation of the lumbar splanchnic nerve (LSN) or the HGN and occurrence of antegrade ejaculation as a result of manual penile stimulation were examined in dogs that had undergone HGN-HGN reattachment. Eighteen months after the procedure had been performed bilaterally, 23 LSNs were electrically stimulated. In 17 LSNs this stimulation elicited elevation of vasal pressure (12 nerves bilaterally); in 18 LNs, bladder neck pressure; and in 15 LSNs, prostate contraction. After retransection of the right HGN in the dogs that had undergone HGN-HGN reattachment, 11 right-sided LSNs were stimulated; in seven LSNs, the stimulation elicited elevation of vasal pressure (five bilaterally), in seven bladder neck pressure, and in six prostate contraction. Twelve left-sided LSNs were stimulated; in seven LSNs, the stimulation elicited elevation of vasal pressure (four bilaterally), in six bladder neck pressure, and in six prostate contracton. Each of the 12 HGN stimulations made proximal to the site that had been sutured in dogs that had HGN-HGN reattachment caused responses of the three organs specified above that were comparable to those in control dogs. Manual penile stimulation elicited antegrade ejaculation in all three dogs examined.

The results of this study show that the function of the HGN in the seminal tract can be preserved after HGN-HGN reattachment and that restoration of its cross-innervation mechanism is possible.