title: No difference in long-term trunk muscle strength, cross-sectional area, and density in patients with chronic low back pain 7 to 11 years after lumbar fusion versus cognitive intervention and exercises.
abstract: BACKGROUND
  Reduced muscle strength and density observed at 1 year after lumbar fusion may deteriorate more in the long term.
  
  
  OBJECTIVE
  To compare the long-term effect of lumbar fusion and cognitive intervention and exercises on muscle strength, cross-sectional area, density, and self-rated function in patients with chronic low back pain (CLBP) and disc degeneration.
  
  
  METHODS
  Randomized controlled study with a follow-up examination at 8.5 years (range, 7-11 years).
  
  
  METHODS
  Patients with CLBP and disc degeneration randomized to either instrumented posterolateral fusion of one or both of the two lower lumbar levels or a 3-week cognitive intervention and exercise program were included. Isokinetic muscle strength was measured by a Cybex 6000 (Cybex-Lumex, Inc., Ronkonkoma, NY, USA). All patients had previous experience with the test procedure. The back extension (E) flexion (F) muscles were tested, and the E/F ratios were calculated. Cross-sectional area and density of the back muscles were measured at the L3-L4 segment by computed tomography. Patients rated their function by the General Function Score.
  
  
  METHODS
  Trunk muscle strength, cross-sectional area, density, and self-rated function.
  
  
  RESULTS
  Fifty-five patients (90%) were included at long-term follow-up. There were no significant differences in cross-sectional area, density, muscle strength, or self-rated function between the two groups. The cognitive intervention and exercise group increased trunk muscle extension significantly (p<.05), and both groups performed significantly better on trunk muscle flexion tests (p<.01) at long-term follow-up. On average, self-rated function improved by 56%, cross-sectional area was reduced by 8.5%, and muscle density was reduced by 27%.
  
  
  CONCLUSIONS
  Although this study did not assess the morphology of muscles likely damaged by surgery, trunk muscle strength and cross-sectional area above the surgical levels are not different between those who had lumbar fusion or cognitive intervention and exercises at 7- to 11-year follow-up.
authors.affiliation: Division of Orthopedic Surgery, Department of Orthopedics, Oslo University Hospital, Rikshospitalet, Pb 4950 Nydalen, 0424 Oslo, Norway. anne.froholdt@ous-hf.no
authors.forename: Anne
authors.initials: A
authors.lastname: Froholdt
authors.forename: Inger
authors.initials: I
authors.lastname: Holm
authors.forename: Anne
authors.initials: A
authors.lastname: Keller
authors.forename: Ragnhild B
authors.initials: RB
authors.lastname: Gunderson
authors.forename: Olav
authors.initials: O
authors.lastname: Reikeraas
authors.forename: Jens I
authors.initials: JI
authors.lastname: Brox
mesh_terms: D000328:Adult; D002908:Chronic Disease; D015928:Cognitive Behavioral Therapy; D005081:Exercise Therapy / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017116:Low Back Pain / Q000523:psychology / Q000534:rehabilitation / Q000601:surgery; D008159:Lumbar Vertebrae; D008297:Male; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000473:pathology*; D020127:Recovery of Function; D013123:Spinal Fusion; D013995:Time; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome