title: Why do inguinal hernia patients have pain? Histology points to compression neuropathy.
abstract: OBJECTIVE
  The purpose of this study is to describe the known soft tissue neuro-histology factors associated with compression neuropathy in relation to the incidence of preoperative pain in primary inguinal hernia. Enlargement of the ilioinguinal nerve occurs in 63% of patients with primary inguinal hernia; compression neuropathy has similar gross features.
  
  
  METHODS
  Patients completed pain questionnaires pertaining to preoperative pain and the quality of pain experienced. During routine inguinal hernia repair, nerve segments were sampled for histologic evaluation.
  
  
  RESULTS
  Twenty-two thickened nerve segments (63% of total) with proximal and distal specimens were resected for examination and comparison. We quantified various histologic indicators including nerve diameter, fascicle count, myxoid content within the epineurium, perineurium and endoneurium. Increased preoperative patient pain scores correlate with increased nerve diameter, increased fascicle count and increased myxoid material both within the perineurium and endoneurium.
  
  
  CONCLUSIONS
  These findings support the concept that preoperative hernia pain is associated with compression neuropathy.
authors.affiliation: Cascade Hernia Institute, Puyallup, WA, USA. Electronic address: bob@meridiansurgerycenterwa.com.
authors.forename: Robert
authors.initials: R
authors.lastname: Wright
authors.affiliation: Department of Pathology, Stanford University, School of Medicine, Stanford, CA, USA. Electronic address: donborn@stanford.edu.
authors.forename: Donald E
authors.initials: DE
authors.lastname: Born
authors.affiliation: Pacific Northwest University of Health Sciences, Yakima, WA, USA. Electronic address: ndsouza@pnwu.edu.
authors.forename: Natasha
authors.initials: N
authors.lastname: D'Souza
authors.affiliation: Pacific Northwest University of Health Sciences, Yakima, WA, USA. Electronic address: lhurd413@gmail.com.
authors.forename: Larissa
authors.initials: L
authors.lastname: Hurd
authors.affiliation: Creighton University, Omaha, NE, USA. Electronic address: RachelGill@creighton.edu.
authors.forename: Rachel
authors.initials: R
authors.lastname: Gill
authors.affiliation: University of Denver, Denver, CO USA. Electronic address: Daniel.wright210@gmail.com.
authors.forename: Daniel
authors.initials: D
authors.lastname: Wright
mesh_terms: D006552:Hernia, Inguinal / Q000150:complications* / Q000473:pathology / Q000601:surgery; D059685:Herniorrhaphy; D006801:Humans; D007264:Inguinal Canal / Q000294:innervation* / Q000473:pathology*; D009408:Nerve Compression Syndromes / Q000175:diagnosis / Q000209:etiology* / Q000473:pathology; D009437:Neuralgia / Q000175:diagnosis / Q000209:etiology* / Q000473:pathology; D010147:Pain Measurement; D057234:Preoperative Period; D011446:Prospective Studies
keywords: Compression neuropathy; Inguinal hernia; Preoperative pain