Neuroanatomy and neurophysiology related to sexual dysfunction in male neurogenic patients with lesions to the spinal cord or peripheral nerves

Study design: Review article. Objectives: The neuroanatomy and physiology of psychogenic erection, cholinergic versus adrenergic innervation of emission and the predictability of outcome of vibration and electroejaculation require a review and synthesis. Setting: University Hospital Belgium. Methods: We reviewed the literature with PubMed 1973-2008. Results: Erection, emission and ejaculation are separate phenomena and have different innervations. It is important to realize, which are the afferents and efferents and where the motor neuron of the end organ is located. When interpreting a specific lesion it is important to understand if postsynaptic fibres are intact or not. Afferents of erection, emission and ejaculation are the pudendal nerve and descending pathways from the brain. Erection is cholinergic and NO-mediated. Emission starts cholinergically (as a secretion) and ends sympathetically (as a contraction). Ejaculation is mainly adrenergic and somatic. For vibratory-evoked ejaculation, the reflex arch must be complete; for electroejaculation, the postsynaptic neurons (paravertebral ganglia) must be intact. Conclusion: Afferents of erection, emission and ejaculation are the pudendal nerve and descending pathways from the brain. Erection is cholinergic and NO-mediated. Emission starts cholinergically (as a secretion) and ends sympathetically (as a contraction). Ejaculation is mainly adrenergic and somatic. In neurogenic disease, a good knowledge of neuroanatomy and physiology makes understanding of sexual dysfunction possible and predictable. The minimal requirement for the success of penile vibration is a preserved reflex arch and the minimal requirement for the success of electroejaculation is the existence of intact post-ganglionic fibres. Spinal Cord (2010) 48, 182-191; doi: 10.1038/sc.2009.172; published online 5 January 2010