title: Outcome of lumbar epidural steroid injection is predicted by assay of a complex of fibronectin and aggrecan from epidural lavage.
abstract: METHODS
  A single-center, prospective, consecutive case series of patients undergoing epidural lavage before the treatment of radiculopathy due to lumbar disc herniation.
  
  
  OBJECTIVE
  To determine whether a novel complex of fibronectin and aggrecan predicts clinical response to epidural steroid injection (ESI) for the indication of radiculopathy from lumbar herniated nucleus pulposus (HNP).
  
  
  BACKGROUND
  ESI for lumbar radiculopathy due to HNP is widely used despite variable effectiveness for this indication. With increased attention aimed at cost containment, it would be beneficial to identify those in whom ESI may be helpful. There are currently no accurate diagnostic tests to predict response to ESI in back pain and sciatica syndromes. We have previously investigated biomarkers of disc degeneration associated with radiculopathy.
  
  
  METHODS
  We embarked to determine whether a molecular complex of fibronectin and aggrecan predicts clinical response to ESI for the indication of radiculopathy from HNP. This prospective study was conducted at a single center and included 26 patients with radiculopathic pain and magnetic resonance imaging positive for HNP, who elected ESI. Epidural lavage with physiologic saline was performed immediately before ESI. The lavage fluid was assayed for the fibronectin-aggrecan complex (FAC) by using a heterogeneous sandwich enzyme-linked immunosorbent assay. The results were compared with the interval improvement in the physical component summary (PCS) score of the Medical Outcomes Study Short Form-36 instrument (SF-36) after injection compared with baseline.
  
  
  RESULTS
  The mean improvement from baseline PCS in patients with the FAC was 22.9 (SD, 12.4) and without the complex was 0.64 (SD, 3.97; P < 0.001). Differences in total SF-36 improvement were also highly significant (P < 0.001). The presence of the FAC predicts a clinically significant increase in PCS after lumbar ESI by receiver-operating-characteristic analysis (area under the curve = 0.97; P < 0.001). There was no significant difference in age (P = 0.25), sex (P = 0.84), laterality (P = 0.06), lumbar spinal level (P = 0.75), or payer type (worker's compensation vs. private insurance; P = 0.90) between groups with and without the marker.
  
  
  CONCLUSIONS
  A molecular complex of fibronectin and aggrecan predicts response to lumbar ESI for radiculopathy with HNP. The biomarker is accurate, objective, and not affected by demographic or psychosocial variables in this series.
authors.affiliation: Department of Orthopaedic Surgery, Stanford University, Palo Alto, CA, USA.
authors.forename: S Raymond
authors.initials: SR
authors.lastname: Golish
authors.forename: Lewis S
authors.initials: LS
authors.lastname: Hanna
authors.forename: Robert P
authors.initials: RP
authors.lastname: Bowser
authors.forename: Pasquale X
authors.initials: PX
authors.lastname: Montesano
authors.forename: Eugene J
authors.initials: EJ
authors.lastname: Carragee
authors.forename: Gaetano J
authors.initials: GJ
authors.lastname: Scuderi
mesh_terms: D000328:Adult; D053674:Aggrecans / Q000378:metabolism*; D001416:Back Pain / Q000175:diagnosis / Q000188:drug therapy* / Q000209:etiology; D004797:Enzyme-Linked Immunosorbent Assay; D004824:Epidural Space / Q000378:metabolism; D005260:Female; D005353:Fibronectins / Q000378:metabolism*; D006801:Humans; D007268:Injections, Epidural; D007405:Intervertebral Disc Displacement / Q000150:complications / Q000175:diagnosis; D008159:Lumbar Vertebrae; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013256:Steroids / Q000008:administration & dosage / Q000627:therapeutic use*; D011795:Surveys and Questionnaires; D007507:Therapeutic Irrigation; D016896:Treatment Outcome
chemical_list: D053674:Aggrecans; D005353:Fibronectins; D013256:Steroids