title: MRI and pathology in persistent postherniotomy pain.
abstract: BACKGROUND
  Persistent postherniotomy pain impairs everyday life in 5% to 10% of patients. MRI can potentially be useful in the investigation of pathogenic mechanisms and guide surgeons in mesh removal and neurectomy. No study has investigated interobserver agreement or MRI-specific findings in persistent postherniotomy pain.
  
  
  METHODS
  Thirty-two patients with persistent postherniotomy pain > 1 year after uni- or bilateral groin hernia repair and 6 pain-free postherniotomy controls were MRI scanned, resulting in a total of 32 painful groins, 15 pain-free operated groins, and 29 pain-free unoperated groins scanned. Two blinded observers separately assessed groins using a predefined list of possible MRI pathology and anatomic landmarks. Primary outcomes included interobserver agreement assessed by calculating kappa-coefficients. Secondary outcomes included frequency of MRI pathology in painful groins versus unoperated and pain-free groins.
  
  
  RESULTS
  Interobserver agreement was poor, ranging from kappa = 0.24 to 0.55 ("fair" to "moderate") except for "contrast enhancement in groin" (kappa = 0.69, substantial). Pathologic changes in the form of "contrast enhancement in groin," "edema," and "spermatic cord caliber increased" were significantly more often seen in painful versus unoperated groins (p < 0.02). No significant difference was seen when painful and pain-free operated groins were compared (p < 0.05). No pathologic finding was specific or seen in all painful groins.
  
  
  CONCLUSIONS
  Interobserver agreement is low and MRI-assessed pathology unspecific for persistent postherniotomy pain. Additional studies are required on interobserver agreement for pathology before MRI can be recommended as guidance and indication for surgical treatment of persistent postherniotomy pain.
authors.affiliation: Section of Surgical Pathophysiology, Diagnostics Center, Rigshospitalet, Copenhagen University, Copenhagen, Denmark. eskeaasvang@yahoo.dk
authors.forename: Eske Kvanner
authors.initials: EK
authors.lastname: Aasvang
authors.forename: Karl-Erik
authors.initials: KE
authors.lastname: Jensen
authors.forename: Bente
authors.initials: B
authors.lastname: Fiirgaard
authors.forename: Henrik
authors.initials: H
authors.lastname: Kehlet
mesh_terms: D003287:Contrast Media; D003718:Denmark; D004487:Edema / Q000175:diagnosis*; D005832:Genital Diseases, Male / Q000175:diagnosis*; D006119:Groin; D059685:Herniorrhaphy; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D015588:Observer Variation; D010149:Postoperative Pain / Q000209:etiology* / Q000473:pathology; D013526:Surgical Mesh
chemical_list: D003287:Contrast Media