title: Symptomatic nerve root changes on contrast-enhanced MR imaging after surgery for lumbar disk herniation.
abstract: OBJECTIVE
  The significance of postoperative nerve root changes (enhancement, thickening, and displacement) is still a topic of debate. The purpose of this study was to evaluate the association between nerve root changes and residual or recurrent symptoms after lumbar surgery with contrast-enhanced MR imaging.
  
  
  METHODS
  A total of 120 patients with 140 postoperative lumbar disk lesions causing residual or recurrent pain underwent contrast-enhanced MR imaging. The levels at which diskectomies had been performed were retrospectively evaluated for nerve root enhancement (NRE), thickening, and displacement. Association between nerve root changes and corresponding clinical presentations were statistically assessed. Nerve root changes in recurrent disk herniation (RDH) and postoperative epidural fibrosis (PEF) were also evaluated with clinical symptoms.
  
  
  RESULTS
  Ninety-two (65.7%) of the 140 disks demonstrated NRE. Regarding the association with clinical symptoms, the sensitivity was 91.7%, the specificity was 73.2%, the positive predictive value (PPV) was 83.7%, and the negative predictive value was 85.4% (P = .000). Nerve root thickening and displacement were significantly associated with the clinical symptoms, especially when NRE was combined (PPV, 87.7% and 87.2%, respectively). When RDH was combined with all 3 nerve root changes, the PPV was increased up to 94.1%. However, in PEF, the association between nerve root changes and clinical symptoms was not significant unless all 3 nerve root changes were combined.
  
  
  CONCLUSIONS
  In patients with residual or recurrent pain after surgery for lumbar disk herniation, nerve root changes on contrast-enhanced MR imaging were well associated with clinical symptoms, of which NRE was the most significant finding.
authors.affiliation: Department of Radiology, Daejeon St. Mary's Hospital, The Catholic University of Korea, Daejeon, Korea. yslee1074@medimail.co.kr
authors.forename: Y S
authors.initials: YS
authors.lastname: Lee
authors.forename: E S
authors.initials: ES
authors.lastname: Choi
authors.forename: C J
authors.initials: CJ
authors.lastname: Song
mesh_terms: D000293:Adolescent; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D017586:Diskectomy / Q000009:adverse effects* / Q000379:methods; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007405:Intervertebral Disc Displacement / Q000175:diagnosis* / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000601:surgery*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011843:Radiculopathy / Q000175:diagnosis* / Q000209:etiology; D012189:Retrospective Studies; D013126:Spinal Nerve Roots / Q000473:pathology*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D003287:Contrast Media