Trifecta nerve complex: potential anatomical basis for microsurgical denervation of the spermatic cord for chronic orchialgia.

PURPOSE We identified structural abnormalities in the spermatic cord nerves that may explain how microsurgical denervation of the spermatic cord provides pain relief in patients with chronic orchialgia. MATERIALS AND METHODS We retrospectively reviewed a prospective database to compare spermatic cord biopsy specimens from 56 men treated with a total of 57 procedures for microsurgical denervation of the spermatic cord for chronic orchialgia vs a control group of men without pain treated with cord surgery, including varicocelectomy in 4 and radical orchiectomy in 6. Tissue biopsies were obtained from mapped regions of the spermatic cord in all cases. Biopsies stained with hematoxylin and eosin were examined by an independent pathologist. Three human cadaveric spermatic cords were dissected to confirm localization of the nerve distribution identified on pathological mapping. RESULTS We identified a median of 25 small diameter (less than 1 mm) nerve fibers in the spermatic cord. Of the 57 procedures for orchialgia 48 (84%) showed wallerian degeneration in 1 or more of these nerves but only 2 of 10 controls (20%) had such degeneration (p = 0.0008). In decreasing order of nerve density the 3 primary sites (trifecta nerve complex) of these changes were the cremasteric muscle fibers (19 nerves per patient), perivasal tissues and vasal sheath (9 nerves per patient), and posterior cord lipomatous/perivessel tissues (3 nerves per patient). Cord nerve distribution mapped by the biopsies was confirmed by cadaveric dissection. CONCLUSIONS In men with chronic orchialgia there appears to be wallerian degeneration in reproducible patterns in the spermatic cord nerve fibers. Transection of these nerves may explain the effect of the denervation procedure.