title: The impact of adjacent segment degeneration on the clinical outcome after lumbar spinal fusion.
abstract: METHODS
  A retrospective study.
  
  
  OBJECTIVE
  To determine the impact of the adjacent segment degeneration (ASD) on the clinical outcome after lumbar fusion.
  
  
  BACKGROUND
  Few studies have analyzed correlation between clinical outcomes and ASD.
  
  
  METHODS
  From January 2000 to December 2004, 217 patients who underwent lumbar fusion and have more than 2 years of follow-up were evaluated. The patients were divided into 3 groups: fusion was carried out on 1 (A), 2 (B), and more than 3 segments (C). UCLA grading scale was used to evaluate the ASD on radiograph preoperative, postoperative, and last follow-up. The clinical outcome was evaluated and the association between clinical outcome and ASD was evaluated by the Spearman correlation.
  
  
  RESULTS
  ASD occurred 11.6% (13/112 cases) in group A, 14.5% (9/62 cases) in group B, and 16.3% (7/43 cases) in group C. Among them, the cases which had progressed more than 2 level of degenerative grade were 0 in group A, 7 cases (77.8%) in group B, and 6 cases (85.7%) in group C. In group A, 5 cases with ASD had down graded 1 level in clinical outcome. In group B, all 9 cases with ASD had down graded more than 1 level in clinical outcome; 1 level aggravation in 1, 2 level in 5, and 3 level in 1 case. In group C, all 7 cases with ASD also had down graded more than 1 level in clinical outcome; 1 level aggravation in 2, 2 level in 5 cases. Finally, the more the change of the degenerative grade is severe, the more the clinical outcome is worse (P < 0.05).
  
  
  CONCLUSIONS
  The impact of ASD on clinical outcome after fusion showed a significant correlation, especially with the ASD after multiple-segments fusion. Careful attention is needed in multiple-segments fusion such as degenerative lumbar deformity.
authors.affiliation: Department of Orthopedic Surgery, School of Medicine, Chungnam National University, Daejeon, Korea. jyyang@cnu.ac.kr
authors.forename: Jun Young
authors.initials: JY
authors.lastname: Yang
authors.forename: June-Kyu
authors.initials: JK
authors.lastname: Lee
authors.forename: Ho-Sup
authors.initials: HS
authors.lastname: Song
mesh_terms: D005260:Female; D006801:Humans; D015994:Incidence; D007405:Intervertebral Disc Displacement / Q000000981:diagnostic imaging* / Q000453:epidemiology; D007738:Kyphosis / Q000601:surgery; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000000981:diagnostic imaging* / Q000453:epidemiology; D011859:Radiography; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013123:Spinal Fusion / Q000706:statistics & numerical data; D013130:Spinal Stenosis / Q000601:surgery; D013168:Spondylolisthesis / Q000601:surgery*; D016896:Treatment Outcome