Men with spinal cord injury have a smaller prostate than men without

To compare prostate volume and number of ejaculations in men with and without spinal cord injury (SCI).

A total of 31 men aged > or =30 years who had suffered from SCI at the age of 15-30 years >5 years previously were investigated and compared with 31 age-matched controls. Prostate size was measured using transrectal ultrasound and compared between groups. Hormonal status was examined by measuring the levels of prostate-specific antigen, testosterone, prolactin, estradiol and sex hormone-binding globulin. Questions were asked concerning ejaculatory function.

Median prostate size was 20.4 cm(3) (range 9.9-39.7 cm(3)) in the SCI group and 25.7 cm(3) (range 14.5-39.1 cm(3)) in the control group (p=0.002). Testosterone levels were within normal ranges, but a significant difference between the groups was seen (p<0.001). The free androgen index did not differ significantly between the groups. No significant differences in other hormone levels were demonstrated. The control group ejaculated a median of eight times per month (range 1-28 times). Eight men with SCI ejaculated without assistance a median of twice per month (range <1-12 times) (p=0.028). Nine men with SCI achieved ejaculations with penile vibratory stimulation a median of once per month (range <1-4 times) (p=0.004). Fourteen men had either not ejaculated at all or very seldom following the injury.

Men with SCI have a smaller prostate than those without. Further investigations are necessary to elucidate whether the reduced number of ejaculations they experience and the neurological damage contribute to this.