Advances in the management of infertility in men with spinal cord injury

Abstract

Couples with a spinal cord injured male partner require assisted ejaculation techniques to collect semen that can then be further used in various assisted reproductive technology methods to achieve a pregnancy. The majority of men sustaining a spinal cord injury regardless of the cause or the level of injury cannot ejaculate during sexual intercourse. Only a small minority can ejaculate by masturbation. Penile vibratory stimulation and electroejaculation are the two most common methods used to retrieve sperm. Other techniques such as prostatic massage and the adjunct application of other medications can be used, but the results are inconsistent. Surgical sperm retrieval should be considered as a last resort if all other methods fail. Special attention must be paid to patients with T6 and rostral levels of injury due to the risk of autonomic dysreflexia resulting from stimulation below the level of injury. Bladder preparation should be performed before stimulation if retrograde ejaculation is anticipated. Erectile dysfunction is ubiquitous in the spinal cord injured population but is usually easily managed and does not pose a barrier to semen retrieval in these men. Semen analysis parameters of men with spinal cord injury are unique for this population regardless of the method of retrieval, generally presenting as normal sperm concentration but abnormally low sperm motility and viability. When sperm retrieval is desired in this population, emphasis should be placed on initially trying the simple methods of penile vibratory stimulation or electroejaculation before resorting to more advanced and invasive surgical procedures.

Figure 1

Innervation of the penis and mechanism for erection. (a) Sympathetic penile innervation from segments T10-L2 pass via the sympathetic chain, inferior mesenteric and superior hypogastric plexuses to the pelvic plexus via the hypogastric nerve. Parasympathetic penile innervation arises from segments S2-S4 to the pelvic plexus via the pelvic nerve. The pudendal nerve innervates the external sphincter, bulbospongiosus and ischiocavernosus muscles and also provides sensory fibers to the dorsal nerve of the penis. (b) Cyclic GMP (cGMP) is responsible for the vascular changes which occur in the corpora cavernosa that result in erection. Cyclic GMP is hydrolyzed by PDE-5 to GMP resulting in loss of penile tumescence. The process is initiated by endogenous nitric oxide (NO) activation of guanylate cyclase which results in increased conversion of GTP to cGMP. The inhibition of PDE-5 results in the maintenance of high levels of cGMP.

Figure 2

Penile vibratory stimulation (PVS) (a) various over-the-counter devices, often called wand massagers, have been used for PVS in men with SCI. The Personal FertiCare^® (b) and the Viberect X3^® (c), are devices that have been specifically engineered for the purpose of PVS in men with SCI. (d) The correct placement of two FertiCare devices, which is a recommended method when one device fails to induce ejaculation.

Figure 3

Electroejaculation machine with an attached rectal probe.

Figure 4

Recommended algorithm for sperm retrieval from men with spinal cord injury. Adapted from Brackett et al.

Figure 5

Immunocytochemistry and confocal microscopy images of sperm cells. (a) Sperm cells from men with SCI showing ASC signals in the equatorial segment of sperm cells from men with SCI. (b) No signal in the non-SCI control sperm. (c) Caspase-1 signal in the midpiece of SCI sperm. (d) No signal in non-SCI sperm.