Disorders of pelvic nerves may cause chronic sexual pain in women and men.19,20 These long nerves are subject to the same injuries and diseases as peripheral nerves that run through other parts of the body. Nerve compression, injuries resulting in formation of neuromata, and peripheral sensitization all can occur in the pelvis.
During your vulvar exam, work with the patient to localize the area that is painful (eg, clitoris, anus, posterior left vestibule), and if surface conditions do not explain her pain, determine which nerve likely innervates that sensory area. Patients with generalized vulvodynia (GV) may have trouble isolating specific areas of pain, as burning and itching nerve pain may be felt broadly. Patients may sense unilateral conditions as involving the entire vulva, due to global PF responses. Your careful history and neuroanatomy-based exam will clarify which pelvic nerves may be pain generators.
Because the pudendal nerve (PN) is the main sensory nerve of the external genitalia, mentally visualize the course of its 3 main branches through the PF while palpating. Inspect for scarring from surgery or childbirth that may have lacerated a nerve branch, creating a neuroma. Neuromata are only occasionally large enough to be palpable and may present as small areas of exquisite tenderness. Consider whether pain is localized to a single PN branch or if the whole nerve itself is involved, deeper in the PF proximal to its division into branches. The landmark of the ischial spine, under which the pudendal neurovascular bundle passes, is quite easy to locate by single-digit vaginal exam; specific pain elicited at this point by light touch is suggestive of PN involvement. If the PN is compressed here or proximally in its path from the sacral nerve roots, all its branches will be affected, including the rectal branch, generating pain that includes the anal area.
Digitally guided transvaginal, or transperineal, perineural pudendal nerve injections (PNPI) at the ischial spine avoid expense, sedation, and x-ray exposure for a patient. Such injections are simple for ob/gyns to perform in-office, and many gained experience using them for childbirth analgesia. If a PNPI alleviates a patient’s pain temporarily, the PN is a component that needs to be addressed. An image-guided PNPI from the posterior approach can be planned with an interventional radiologist if clinical suspicion for PN pain remains high despite a negative (ineffective) injection, or if a patient needs sedation for the procedure.
Pain located in the field of one branch of the PN, or of the perineal branch of the posterior femoral cutaneous nerve, can be evaluated by performing specific small-volume anesthetic injections directed to a convenient point along a branch’s usual course, or where you think a neuroma may be. Nerve branch injections that relieve pain indicate involvement of that branch primarily, or secondarily from myofascial abnormalities as discussed below.
Clitoral pain (clitorodynia) and the related pain disorder persistent genital arousal may result from multiple etiologies, but irritation or compression of the dorsal branch of the PN usually plays a role. Some cases of clitoral pain result from surgical injury to the nerves above the clitoris (the ilioinguinal, iliohypogastric, and genitofemoral) so check for suprapubic and groin scarring. Diagnostic blocks of these, and of the dorsal branch, performed along their course well away from the clitoris, will clarify their involvement and direct therapy.