Pudendal Nerve Entrapment Michael Hibner, MD, PhD Director, Division of Gynecologic Surgery Director Arizona Center for Chronic Pelvic Pain St. Joseph’s Hospital and Medical Center Assistant Professor of Clinical Ob/Gyn University of Arizona College of Medicine

Pudendal neuralgia Pain caused by the injury to the pudendal nerve. Pain is in: ♀♂ perineum, rectum ♀ vulva, vagina, clitoris ♂ penis, scrotum (not testicles)

Anatomy Originates in S2-S4 Exits pelvis through greater sciatic foramen Wraps around sacrospinous ligament Enters perineal region Provides motor, sensory and autonomic innervation to pelvic organs, pelvic floor muscles and external genitalia

Neuropathic pain Burning Paresthesia Allodynia Hyperesthesia

Pudendal neuralgia Injury to the pudendal nerve most commonly caused by the entrapment of pudendal nerve (PNE) Analogous to carpal tunnel syndrome PNE may be Idiopathic Traumatic Iatrogenic

Area of distribution Only the area in yellow concerns the pudendal nerve. The red area concerns the iliohypogastric nerve, the ilioinguinal nerve and the genitofemoral nerve. The blue area concerns the inferior cluneal nerve which is a branch of the posterior cutaneous nerve of the thigh. These differents areas co-inside which means that there is not necessarily loss of sensitivity A. iliohypogastric, ilioinguinal and genitofemoral nerves B. pudendal nerve C. inferior cluneal nerve (perineal ramifications of the posterior cutaneous nerve of the thigh)

Pudendal neuralgia may present as Urinary hesitancy, urgency and frequency. Interstitial Cystitis Prostatodynia Anal spasm/pain Scrotal/Labial pain/Vulvodynia Pain with orgasm or sexual arousal Persistent sexual arousal

Pain with pudendal neuralgia Usually only present when sitting down Not present when lying down or standing up Not present on the toilet Progressively getting worse Worsening as the day goes by

Pain is… Not responsive to pain medications Some response to antiseizure meditations (Neurontin, Lyrica) antidepressants (Amitryptiline)

Diagnosis History Physical examination PNMTL Quantitive threshold sensory testing Diagnostic CT guided injection

Diagnosis of PNE Mean time to make the diagnosis is 4 years with a range of 1-15 years. The number of physicians consulted before the diagnosis is made is 10-30.

Physical Examination Rule out other reasons for chronic pelvic pain Rule out vulvar/vaginal/rectal/perineal lesions Rule out other neuropathies Obturator Inferior cluneal Sciatic Rule out coccygodynia Rule out piriformis muscle syndrome

Physical Examination No motor deficits Pain on the vaginal/rectal examination Area of the ischial spine Obturator internus muscle Levator ani muscle

Laboratory testing

PNMTL

Therapy for PNE Behavioral changes Conservative therapy Surgery Physical therapy Oral medications CT guided injections Surgery

Medical treatment Gabapentin (Neurontin) Amitryptiline (Elavil) Start slowly Titrate to 50 -150 mg/day Pregabaline (Lyrica) Start 75 mg BID May increase to 600 mg/day Beladonna and Opium (B&O) suppository

CT guided injections

CT guided injection – Alcock’s canal

Surgery Offered to the patients in whom physical examination ruled out other causes for neuropathy Offered only to the patients that had an immediate improvement after the injection No age limits or duration limits, but results better in younger patients with a shorter period of compression

Surgery – transgluteal approach 30 angle 6-7 cm 3 fb

Surgery - transgluteal

Surgery cranial medial

Surgery

Surgery

Surgery

Incidence of PNE at Various Sites Sacrospinous Ligament – 58% Sacrotuberous Ligament – 69% Falciform Process – 42% Ischial Spine – 11% Piriformis – Sacrospinous Ligament – 17% Obturator Fascia – 48% Unilateral entrapment in 70% of patients.

Results No improvement Worse 33% 1% No pain or Moderate improvement significant improvement Moderate improvement 23% 44%

Results First improvement 3-4 months from surgery Maximum improvement 1 year Worse results (30% success) if Age > 70 Symptoms > 10 years

Postop Management Hospital stay 1 day No postop restrictions * Early ambulation Continue Neurontin up to 3200 mg/day or Lyrica up to 600 mg/day If no significant improvement – CT guided injection at 4 months