title: Chronic meralgia paresthetica and neurectomy: a clinical pathologic study.
abstract: OBJECTIVE
  To understand the pathologic and clinical correlates of patients with chronic meralgia paresthetica (MP) undergoing lateral femoral cutaneous nerve (LFCN) neurectomy.
  
  
  METHODS
  A retrospective cohort approach was utilized to identify 7 patients undergoing LFCN neurectomy for intractable pain. Control autopsied LFCN was obtained. Clinical, radiologic, and electrophysiologic features were reviewed.
  
  
  RESULTS
  In identified cases, preoperative symptoms included severe lateral thigh pain and numbness. The duration of symptoms prior to surgery ranged from 2 to 15 years. Body mass index (BMI) varied from 20 kg/m(2) to 44.8 kg/m(2) (normal-morbidly obese), with 6 out of 7 patients being obese. No patients were diabetic. Focal nerve indentation at the inguinal ligament was seen intraoperatively and on gross pathology in 4 of 7 cases. Multifocal fiber loss, selective loss of large myelinated fibers, thinly myelinated profiles, regenerating nerve clusters, perineurial thickening, and subperineurial edema were seen. None of these features were observed in control nerve. Morphometric analysis confirmed loss of large myelinated fibers with small and intermediate size fiber predominance. Five patients had varying degrees of intraneural and epineurial inflammation. Six of 7 reported improved pain after neurectomy, sometimes dramatic.
  
  
  CONCLUSIONS
  Patients with chronic MP and intractable pain have an LFCN mononeuropathy with loss of nerve fibers. Pathologic and clinical study supports a compressive pathogenesis as the primary mechanism. Abnormal nerve inflammation coexists and may play a role in pathogenesis. These selected patients typically benefited from neurectomy at a site of inguinal ligament compression.
  
  
  METHODS
  This study provides Class IV evidence that patients with chronic MP LFCN neurectomy experience improvement in MP-related pain.
authors.affiliation: From the Peripheral Neuropathy Research Laboratory (S.E.B., J.K.E., N.P.S., N.S., P.J.B.D., C.J.K.), the Department of Neurosurgery (R.J.S.), and the Department of Anatomic Pathology (M.E.J.), Mayo Clinic and Mayo Foundation, Rochester, MN.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Berini
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Spinner
authors.forename: Mark E
authors.initials: ME
authors.lastname: Jentoft
authors.forename: Janean K
authors.initials: JK
authors.lastname: Engelstad
authors.forename: Nathan P
authors.initials: NP
authors.lastname: Staff
authors.forename: Narupat
authors.initials: N
authors.lastname: Suanprasert
authors.forename: P James B
authors.initials: PJ
authors.lastname: Dyck
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Klein
mesh_terms: D000328:Adult; D000368:Aged; D002908:Chronic Disease; D005260:Female; D005267:Femoral Nerve / Q000601:surgery*; D020428:Femoral Neuropathy; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009408:Nerve Compression Syndromes / Q000601:surgery*; D019635:Neurosurgical Procedures / Q000379:methods*; D012189:Retrospective Studies; D012867:Skin / Q000294:innervation*