Sexual Dysfunction and Infertility in the Male Spina Bifida Patient

Nanfu Deng; Nannan Thirumavalavan; Jonathan A. Beilan; Alexander J. Tatem; Mark S. Hockenberry; Alexander W. Pastuszak; Larry I. Lipshultz


Transl Androl Urol. 2018;7(6):941-949. 

In This Article

Causes of Infertility in Spina Bifida men

Spermatogenic Defects

Causes of infertility can be broadly classified as defects in spermatogenesis and/or sperm transport. Spermatogenic defects often lead to poor sperm quality and may be related to a marked decrease in spermatogenic cells as seen in testicular biopsies. Hultling et al. examined semen analyses obtained from either unassisted or assisted ejaculates of nine spina bifida men 22 to 39 years old and found that only 5 of 9 men had enough sperm in their ejaculates for fertilization via assisted reproductive technology (ART); four men produced no spermatozoa in their ejaculates.[18] Four out of the 5 men with enough sperm for fertilization had sperm counts that were described as "extremely low", and only 1 of the 5 men had more than 10,000 live sperm on semen analysis. Among the five men with enough isolated sperm, very few showed normal morphology. These results, albeit from a small study, indicate that neurological deficits associated with spina bifida may exert a downstream effect on spermatogenesis resulting in both oligo- and/or azoospermia with abnormal sperm morphology.

This finding may be explained by the lack of testicular neurological innervation that is observed in men with spina bifida. This may potentially alter normal testis development, which is supported by testicular biopsies from infertile men with spina bifida. A preliminary study by Reilly and Oates on ten spina bifida males with higher spinal cord lesions causing impotence revealed that all men in the study were azoospermic following assisted ejaculation, and all ten testicular biopsies revealed Sertoli cell only histology.[19] Furthermore, a comparison of sperm motility and morphology between men with spina bifida and men who suffered spinal cord injuries showed that men with spina bifida had much poorer sperm quality, further suggesting that normal gonadal development and spermatogenesis are dependent on adequate gonadal innervation from an early age.[18,20] Cryptorchidism, the failure of a testis to fully descend into the scrotum during development, occurs at a higher rate in spina bifida males. Incidence has been reported between 15% to 58%, whereas it occurs only at 1–3% in full term males without spina bifida.[21–24] Biopsies at time of orchidopexy in these patients showed germ cell aplasia, delayed maturation, and severely reduced quantity of germ cells in some.[25]

Failure of Sperm Transport

While proper spermatogenesis is a key component of fertility, delivery of sperm into the female reproductive tract is equally important for natural conception. Major impediments to this delivery of sperm include issues surrounding erectile function and ejaculation.

Erectile dysfunction. The prevalence of erectile dysfunction in this patient population varies from 12% to 75%. Of note, the prevalence in young, neurotypical men is only 15% in men younger than 45 years.[26–28] When stratified by level of neurological lesion, approximately 36% of men with lesions at or below T10 and 86% of men with lesions above T10 suffered from erectile dysfunction, suggesting that higher lesions correlate with worse erectile function.[27,29,30] Diamond et al. found that out of 52 post-pubertal males with spina bifida, 70% could have erections.[29] Other smaller studies have observed different rates of erectile function in men with spina bifida. For instance, out of 12 men in a study by Cass et al., 92% (11 of 12) of spina bifida men had erections.[8] In a study by Bomalaski et al., 56% (9 of 16) of spina bifida men reported normal erections.[9] In contrast, Shurtleff et al. observed only one of 28 spina bifida men had normal erections.[31] These data illustrate how the exact prevalence of erectile dysfunction in spina bifida men has yet to be clearly defined. Lee et al. attempted to evaluate the severity of erectile dysfunction in 17 spina bifida men in their 20s using the Sexual Health Inventory for Men (SHIM) questionnaire and found that 59% (10 of 17) suffered from severe erectile dysfunction; 12% (2 of 17) had moderate erectile dysfunction, 18% (3 of 17) had mild to moderate erectile dysfunction, 6% (1 of 17) had mild erectile dysfunction, and 6% (1 of 17) had no dysfunction.[32]

In a study by Decter et al. of 57 spina bifida men over 18 years old, 72% had erections and 35% successfully engaged in sexual intercourse.[10] In a separate questionnaire study of 22 spina bifida men with a mean age of 24 years who were not stratified by neurological lesion level, 95% of the men claimed to have achieved erections by visual stimulation only, while 86% achieved erections by tactile stimulation.[15] However, when asked about their satisfaction with erections, only 27% of those who achieved erections were satisfied with their penile rigidity, suggesting that the majority of perceived erections may be inadequate for intercourse and thus sperm delivery.

Besides neurological lesion level, other comorbidities associated with spina bifida may also contribute to the degree of erectile dysfunction. Decter et al. found that the presence of a ventriculo-peritoneal (VP) shunt was associated with more erectile dysfunction. Out of 57 spina bifida men, only 61% of those with VP shunts experienced erections while 88% of those without VP shunts reported having erections.[10] These results may be explained by the fact that spina bifida patients that require VP shunts have more severe hydrocephalus and extensive neurological deficits.

Ejaculatory dysfunction. Similar to erections, male ejaculation is under specific neurological control. As a result, many patients with spina bifida suffer from ejaculatory dysfunction including anejaculation and retrograde ejaculation. Studies have estimated that up to 75% of spina bifida men are capable of ejaculation, with most experiencing this in a weak, drip-like emission pattern.[8,10,15] These estimates are confounded by the fact that approximately 20% of spina bifida men fail to perceive ejaculation due to loss of sensory innervation.[10] Among 41 spina bifida men who experienced penile erections in study by Decter et al., 66% [27] experienced ejaculation while 3 of the 16 men without erections ejaculated, with an overall ejaculation success rate of 53% (30 out of 57 men).[10] Similar to erectile dysfunction, the presence of a VP shunt was associated with more ejaculatory dysfunction as 70% (23 out of 33 patients) of spina bifida men with VP shunts suffered from anejaculation while 83% (20 out of 24 patients) of men without VP shunts ejaculated normally.[10] Additionally, spina bifida men with tethered cord may also suffer from retrograde ejaculation into the bladder due to bladder neck incompetence even though their semen emission mechanism may be intact.[33]

Psychosocial and Physical Restrictions on Sexual Intercourse

Despite having intact neurological control over erection and ejaculation, other physical limitations and social barriers may hinder sexual intercourse and contribute to infertility in spina bifida men. In Decter et al.'s study, all eight men who achieved paternity were ambulatory.[10] Through a video narrative study of seven spina bifida males aged 13 to 28 years old, all subjects viewed their physical conditions (i.e., crutches, leg braces, and wheel-chair bound) as a barrier to maintaining romantic relationships.[17] In a cross-sectional interview study from the Netherlands, more than 60% of wheelchair-dependent spina bifida men perceived their impaired ambulatory status as an obstacle to starting a relationship.[34] However, when Lee et al. correlated scores on SHIM, a validated measure of sexual dysfunction, from 17 spina bifida men with their ambulatory status, ranging from completely bed bound to ambulating without assistance, there was no correlation (P=0.15).[32] Additionally, there was no correlation between ambulatory status and erectile dysfunction as measured by the SHIM (P=0.26).[32] Lack of self-confidence and dependence on others for activities of daily living were mentioned as impediments to exploring romantic relationships.[17] A study by Game et al. found that spina bifida men who engaged in sexual intercourse tended to be older (31.9±5.7 years vs. 27.7±5.5 years, P=0.027) and no longer living with parents.[27] Furthermore, Gatti et al. found that spina bifida patients more than 26 years old were 2.5 times more likely to have a partner compared to those between 18 and 25 years old, and that the odds ratio for sexual activity increased by 1.1 for each year increase in age.[35]

Urinary incontinence is another source of embarrassment that may contribute to social and performance anxiety when it comes to sexual interactions. Cardenas et al. reported that patients with urinary incontinence were 0.77 times less likely to be sexually active.[12] A cross-sectional interview study conducted by Verhoef et al. revealed that close to 50% of incontinent spina bifida men perceived their lack of sphincter control as an obstacle to starting a relationship.[34] Furthermore, continent patients were 2 times more likely to have a partner and 2.2 times more likely to have engaged in sexual contact compared to incontinent counterparts.[34] A separate study conducted by Gatti et al. found that continent spina bifida patients were 3.5 times more likely to have a partner and 2.4 times more likely to be sexually active compared to incontinent patients.[35] Interestingly, sexual function in spina bifida males did not appear to be related to social and economic status.[27] While these data show that the presence of incontinence and physical disability may discourage sexual activity, Lassmann et al. found that sexual activity was not related to the severity of incontinence or extent of ambulatory status as a measure of physical disability and dependence.[11] This underscores the significant effects of disability and incontinence on sexual function as the mere presence of these comorbidities, regardless of their severity, can negatively impact a spina bifida male's ability to engage in intercourse and therefore reach his fertility potential (Table 1).