Browse Day: June 12, 2008

Neuroanatomy

Antegrade ejaculation requires coordination of three separate events: (1) closure of the bladder neck, (2) seminal emission, and (3) ejaculation. The sympathetic fibers that mediate seminal emission emanate primarily from the T12 to L3 thoracolumbar spinal cord. In the midretroperitoneum, after leaving the sympathetic trunk, the fibers converge toward midline and form the hypogastric plexus near the aortic bifurcation. From the hypogastric plexus, sympathetic fibers travel via pelvic nerves to innervate the vas deferens, seminal vesicles, prostate, and bladder neck. Ejaculation is mediated by combined autonomic and somatic innervation originating at the sacral and lumbar spinal cord levels. Sympathetic stimulation tightens the bladder neck, while pudendal somatic innervation from S2 to S4 causes relaxation of the external urethral sphincter and rhythmic contraction of bulbourethral and perineal muscles. Preservation of ejaculatory capacity requires preservation of paravertebral sympathetic ganglia and their fibers that converge at the superior hypogastric plexus around the aortic bifurcation. Sympathetic chains and postganglionic sympathetic fibers can be prospectively identified, meticulously dissected, and preserved.

Nerve-sparing RPLND may be of two types: nerve dissecting or nerve avoiding. With nerve dissection, about 90% of patients will be left with normal ejaculatory status postoperatively. Despite pathologic stage II disease in patients selected for this procedure, recurrences in the retroperitoneum are rare. In addition, spontaneous recovery of ejaculation has been reported following a modified RPLND. Modified, nerve-avoiding RPLND templates were designed to avoid the contralateral sympathetic fibers responsible for ejaculation and were developed for use in clinical stage I or IIA disease. These template dissections do not attempt to identify specific nerve fibers. Instead, their design minimizes trauma to the hypogastric plexus by limiting the contralateral dissection to the level above the takeoff of inferior mesenteric artery. This method avoids transsection of the contralateral nerves and results in preservation of ejaculation rates ranging from 51% to 88%. These rates are higher for a right-sided, nerve-avoiding template dissection compared to modified, left-sided dissection. Preservation of ejaculation appears to be more successful when nerves are prospectively identified and spared, compared to modified template dissection, although duration of operation is usually longer for the former. Regardless of technique, retrograde ejaculation is a potential risk with any RPLND; therefore, preoperative sperm banking is recommended. alpha-Adrenergic drugs such as ephedrine, pseudoephedrine, and imipramine occasionally promote antegrade ejaculation in patients who are anejaculatory following RPLND. The low number of reported such cases suggests substantial case selection, and many patients will probably not respond to alpha-adrenergic stimulation. Transrectal electroejaculation provides an option for patients who fail sympathomimetic agents.

Cancer treatment information