Innervation of the human vulvar vestibule: A comprehensive review

Pain of the vulvar vestibule, including provoked vestibulodynia, is prevalent among women, yet challenging to treat due to its multifactorial etiology. Recent evidence indicates a neuroproliferative subtype in which hypersensitivity of the vulvar vestibule is due, in part, to hyperinnervation. Detailed knowledge regarding the innervation of the vulvar vestibule is crucial to understanding and treating pain conditions impacting this region. The purpose of this review is to consolidate the current evidence regarding the innervation of the human vulvar vestibule and discuss the implications of this innervation for pathological conditions affecting this tissue. A comprehensive review of the literature was conducted using keywords including vulvar vestibule, innervation, and vestibulodynia to identify articles concerning the innervation of the vulvar vestibule. Fifteen studies published between 1998 and 2017 were reviewed. Evidence from immunohistochemical investigations support that the vulvar vestibule has nociceptive, mechanosensory, sympathetic, and parasympathetic innervation. In pathological samples, hyperinnervation supports the neuroproliferative etiology of provoked vestibulodynia. Additionally, there is some evidence supporting the role of the pudendal nerve in vulvar vestibule innervation, although no cadaveric studies have been reported to date. Progress has been made in our understanding of the innervation of the vulvar vestibule, though further research into the origin of sensory and autonomic innervation of this region is needed. Advancing the knowledge of vulvar vestibule innervation is crucial towards improving our understanding of the function of this tissue, in addition to informing the etiology and management of pain syndromes impacting this region.