Posttraumatic erectile potential of spinal cord injured men: how physiologic recordings supplement subjective reports.

OBJECTIVE: To investigate by means of a neurophysiologic model the remaining erectile function in spinal cord injured men. DESIGN: A nonrandomized control trial. SETTING: A Referred Care Center. SUBJECTS: Forty-seven spinal cord injured men and 7 noninjured controls. INTERVENTION: The subject penile responses were recorded by a penile strain gauge during two sessions--one to obtain baseline responses, and one with reflexogenic stimulation (masturbation) and psychogenic stimulation (film). MEASURES: Average tumescence, maximal tumescence, percentage rigidity, and duration of tumescence and rigidity. RESULTS: Significant results were found for subjects with lower lesions using psychogenic stimulation as their optimal mode compared with reflexogenic stimulation as an alternate mode, and for subjects with higher lesions using reflexogenic stimulation as their optimal mode, compared with psychogenic stimulation as an alternate mode. The responses with optimal stimulation modes were comparable to those achieved by controls. CONCLUSION: The findings validate the neurophysiologic model of posttraumatic erectile potential as a function of the lesion type and stimulation source. The results were comparable to those of noninjured subjects; the potential for normal function is present and may be amenable to sexual rehabilitation or use in conjunction with new oral drug treatments for impotence.

Sympathetic skin responses and psychogenic erections in spinal cord injured men.

Sympathetic skin responses (SSR) are a simple procedure to investigate sympathetic activity. More specifically, SSR elicited from median nerve stimulation and recorded from the feet and genitals assess sympathetic activity resulting from thoracic-lumbar (TL) innervation. Since TL innervation is also involved in the mediation of psychogenic erection in spinal cord injured men, this study investigated the relationship between SSR and psychogenic erection in spinal cord injured subjects. The results support a general association between SSR and psychogenic erection and show that subjects who maintain SSR responses in the feet and genitals generally maintain psychogenic erections as well. Inconsistent cases are discussed from a theoretical and clinical perspective and overall results are discussed in terms of their clinical application in the evaluation of sexual function in spinal cord injured men.

Clinical approach to erectile dysfunction in spinal cord injured men. A review of clinical and experimental data.

Despite the many developments in the area of sexual dysfunction, rehabilitation settings seldom investigate the remaining sexual function following spinal cord injury, or offer differential diagnoses of sexual dysfunction in spinal cord injured men. This article attempts to show how sexual rehabilitation should begin with a thorough assessment of the sexual function of paraplegic and tetraplegic men. Assessment includes a basic neurological examination of the perineal area and an extended clinical interview on sexual function and visceral function. The interpretation of patient evaluation is discussed in terms of a classification system adapted to sexual purposes and in terms of the differential diagnoses between sexual dysfunctions of organic, and those of predominantly psychogenic origin in the spinal cord injured patient. The organic or psychogenic contribution is discussed in terms of sophisticated procedures, where assessment of nocturnal penile tumescence (NPT) is critically evaluated and where alternatives such as urodynamic findings and skin potentials are discussed. Treatment strategies, such as intracavernous injections and cognitive-behavioural strategies adapted to different lesion types, are discussed.

Sexual function in spinal cord injury men. I. Assessing sexual capability.

Precise diagnoses are seldom made upon complaints of sexual dysfunction by spinal cord injured men. The dysfunction is inevitably attributed to the neurological condition and available treatments are offered with little knowledge of the individual residual capacity or other contributing factors. Current practice emphasizes these treatment approaches, but the high rejection rate associated with the most widely used technique of intracavernous injections suggests that remaining sexual function should also be investigated. This study explores remaining function using physiological recording techniques and classifying the subjects according to the innervation of the reproductive system. The results show that, with objective measurements and proper classification of the subjects, 100% of individuals with high lesions maintain penile responses to reflexogenic stimulation and up to 90% of those with lower lesions maintain penile responses to psychogenic stimulation. These latter subjects also show naturally occurring emissions in 100% of the cases when they suffer from lesions to the conus terminalis and when they use psychogenic stimulation as a means of inducing erection and emission. Results from subjective reports reveal that spinal cord injured men underestimate their sexual capacity, while diagnoses based on clinical findings are better predictors.

Erectile mechanism in paraplegia.

Erection is generally viewed as a reflex mechanism that can receive higher CNS influences. Paraplegic men who have lost reflex activity from the genital area are, therefore, treated as irreversibly impotent. However, the innervation of the male reproductive system suggests that two neural pathways innervate the genitals. In theory, the second (thoracic-lumbar) pathway should compensate for the loss of the first (sacral) pathway in cases of low spinal lesions. Clinical practice, however, ignores the TL pathway as a basis for treatment of spinal cord-injured men. This study used an animal model to demonstrate that the TL pathway could mediate penile responses in paraplegic rats. Eighty-five percent (85%) of spinal animals showed penile responses following hypothalamic (MPOA) stimulation despite a complete loss of peripheral erectile reflexes. These results not only have important implications from a clinical perspective, they further document the physiology of erection and support the view that erection is not a primary parasympathetic activity, but probably results from a sequence of sympathetic processes.

Higher CNS control of penile responses in rats: the effect of hypothalamic stimulation.

The effect of electrical stimulation of the medial preoptic area (MPOA) of the hypothalamus on penile responses in rats was investigated. No females were present and penile responses were observed through the use of an inclined mirror. MPOA stimulation was found to elicit two types of penile responses: penile movement within the sheath and protrusion of the penis outside the penile sheath. While these responses also occurred spontaneously during the nonstimulation control sessions, they occurred in significantly higher frequencies following MPOA stimulation. The results also produced an unexpected finding. While studies on the effect of hypothalamic stimulation on copulation show stimulation-bound effects, MPOA stimulation in the absence of a receptive female consistently triggered penile responses as a poststimulation effect.