Sperm motility from the vas deferens of spinal cord injured men is higher than from the ejaculate.

PURPOSE: Recent evidence suggests that the seminal plasma of spinal cord injured men contributes to their distinctive semen profile of normal sperm concentration but low sperm motility and viability. This finding indicates that sperm in these men may be normal before exposure to the seminal and prostatic fluids. To investigate this question we compared vas aspirated to ejaculated sperm in 12 men with spinal cord injury and 14 healthy, age matched controls.

MATERIALS AND METHODS: Ejaculate was collected by penile vibratory stimulation or electroejaculation in spinal cord injured men and by masturbation in controls. Sperm was aspirated via microsurgery from 1 hemisectioned vas deferens in spinal cord injured men and during routine elective vasectomy in controls. Ejaculated and aspirated specimens were compared.

RESULTS: In men with spinal cord injury mean vas aspirated sperm motility and viability plus or minus standard error of mean were significantly higher than mean ejaculated sperm motility and viability (54.4% +/- 5.0% and 74.1% +/- 5.3% versus 14.1% +/- 2.6% and 26.1% +/- 4.9%, respectively). In controls mean vas aspirated sperm motility and viability were not significantly different from mean ejaculated sperm motility and viability (77.5% +/- 5.2% and 88.9% +/- 2.5% versus 74.3% +/- 5.2% and 85.0% +/- 3.5%, respectively).

CONCLUSIONS: In spinal cord injured men sperm motility and viability were significantly higher before contact with seminal fluids. Although aspirated sperm from men with spinal cord injury generally had lower motility and viability than that of controls, implying that epididymal or testicular factors may also have a part, the greatest decrease was observed in the ejaculate. Further study of infertility in these men should focus on prostatic and seminal vesicle factors.