RESUMO
The purpose of this study was to investigate the feasibility of selective detrusor activation without activation of the urethral sphincter by sacral root stimulation in patients. The sacral roots were stimulated using a tripolar electrode. An anodal block was used to prevent the urethral sphincter from contraction. Using square current pulses (700 microseconds, 6-7 mA), no increase in intraurethral pressure was measured, while a normal increase in intravesical pressure occurred. The minimum pulse duration to obtain a complete block was 550 microseconds. The study shows that anodal blocking of action potentials is possible in humans and can result in selective detrusor activation when used in sacral root stimulation.
Assuntos
Terapia por Estimulação Elétrica , Traumatismos da Medula Espinal/reabilitação , Raízes Nervosas Espinhais/fisiologia , Uretra/inervação , Incontinência Urinária/terapia , Potenciais de Ação/fisiologia , Eletrodos Implantados/normas , Estudos de Viabilidade , Humanos , Contração Muscular/fisiologia , Músculo Liso/fisiologia , Fibras Nervosas/fisiologia , Rizotomia , Região Sacrococcígea/inervação , Região Sacrococcígea/fisiologia , Traumatismos da Medula Espinal/complicações , Traumatismos da Medula Espinal/fisiopatologia , Uretra/fisiologia , Incontinência Urinária/etiologiaRESUMO
In the literature the determination of the vibration sensitivity threshold of the penile glans by means of biothesiometry has been introduced as a cost-effective office test for the evaluation of penile neuropathy in impotent men. At our facility we have gained extensive experience with neuro-urophysiological tests for the evaluation of penile innervation. These neuro-urophysiological tests have the disadvantage of complexity, invasiveness and time consumption. In our study both methods were compared in 31 impotent patients. The results showed that penile glans biothesiometry yields consistent results when measurements are repeated during 1 session. However, no relationship was found between the outcome of penile glans biothesiometry and neuro-urophysiological tests of the dorsal penile nerve, which is probably due to the fact that vibration is not an adequate stimulus to the skin of the penile glans that contains free nerve endings (that is pain receptors) only, and hardly any vibration receptors. We conclude that biothesiometric investigation of penile glans innervation is unsuited for the evaluation of penile innervation and cannot replace neuro-urophysiological tests.