Sacral neuromodulation is an invasive, yet promising, technique under investigation for treatment of refractory IC (117). Sacral neuromodulation is not FDA approved for IC, and larger studies are required to confirm efficacy.
Nerve Entrapment Abdominal cutaneous nerve injury or entrapment may occur spontaneously or within weeks to years after transverse suprapubic skin or laparoscopy incisions. The ilioinguinal (T12 and L1, L2) or iliohypogastric (T12 and L1, L2) nerves may become trapped between the transverse and internal oblique muscles, especially when the muscles contract. Alternatively, the nerve may be ligated or traumatized during the surgery (118).
Femoral nerve injury, one of the most commonly injured nerves in gynecologic laparotomy, can result when deep lateral retractor blades compress the nerve between the blade and the lateral pelvic side wall (119). Symptoms of nerve entrapment include sharp, burning, aching pain and paresthesias in the dermatomal distribution of the involved nerve. Femoral nerve damage results in an inability to ﬂex at the hip joint or to extend at the knee (119). With nerve entrapment, hip ﬂexion and exercise or activity exacerbates pain and rest or infiltration with a local anesthetic relieves pain (120). The pain is usually judged as coming from the abdomen, not the skin.
Pudendal neuropathy is another form of nerve pain that can result from vaginal surgery, especially with lateral mesh attachments, childbirth, and even chronic constipation or pelvic ﬂoor muscle abnormalities. Vulvar surgical procedures including episiotomies, laser hair removal, and Bartholin’s gland removal may injure branches of the pudendal nerve, namely the vestibular, rectal, or clitoral branches (121).
Nantes criteria for pudendal neuropathy are: (i) pain in the area innervated by the pudendal nerve (i.e., ipsilateral clitoris/penis, distal urethra, labia/scrotum, perineum, and anus); pain is increased while sitting; (iii) patient is not awakened by pain; (iv) no sensory loss on clinical examination (sensory deficits are suggestive of a sacral nerve root lesion); resolution of pain with administration of pudendal nerve block (122).
On examination, the point of maximal tenderness or pain should be localized with the fingertip. The maximal point of tenderness in an iliohypogastric or ilioinguinal injury is usually at the rectus margin, medial and inferior to the anterior iliac spine. For the pudendal nerve the maximal tenderness is usually near the ischial spine. A tentative diagnosis can be confirmed by a diagnostic nerve block with 3 to 5 mL of 0.25% bupivacaine. Patients usually report immediate relief of symptoms after injection, and at least 50% of patients experience relief lasting longer than a few hours over a week or two.
Many patients may require no further intervention after a series of weekly nerve blocks, although some patients require physical therapy or the addition of medications that down-regulate nerve firing. If injection successfully produces only limited pain relief and there are no contributory visceral or psychological factors, radiofrequency nerve ablation or surgical decompression of the involved nerve may be recommended. Medication for neuropathic pain, such as topical local anesthetics, anticonvulsants or antidepressants, often is effective.