title: Characteristics of Back Muscle Strength in Patients with Scheduled for Lumbar Fusion Surgery due to Symptomatic Lumbar Degenerative Diseases.
abstract: METHODS
  Cross sectional study.
  
  
  OBJECTIVE
  To evaluate characteristics of back muscle strength in patients scheduled for lumbar fusion surgery.
  
  
  BACKGROUND
  Little is known regarding muscle strength in patients with symptomatic lumbar degenerative diseases who require fusion surgery.
  
  
  METHODS
  Consecutive 354 patients scheduled for posterior lumbar interbody fusion due to symptomatic degenerative diseases were approached for participation. 316 patients were enrolled. Before surgery, muscle strength was assessed by measuring maximal isometric extension strength at seven angular positions (0°, 12°, 24°, 36°, 48°, 60°, and 72°) and mean isometric strength was calculated. The Oswestry Disability Index (0-100) and visual analogue scale (0-100) for back pain were recorded. Muscle strength was compared according to gender, age (<60, 60-70, and ≥70 years) and scheduled fusion level (short, <3; long, ≥3).
  
  
  RESULTS
  Isometric strength was significantly decreased compared with previously reported results of healthy individuals, particularly at extension positions (0°-48°, p<0.05). Mean isometric strength was significantly lower in females (p<0.001) and older patients (p<0.05). Differences of isometric strength between short and long level fusion were not significantly different (p>0.05). Isometric strengths showed significant, but weak, inverse correlations with age and Oswestry Disability Index (r<0.4, p<0.05).
  
  
  CONCLUSIONS
  In patients with symptomatic lumbar degenerative diseases, back muscle strength significantly decreased, particularly at lumbar extension positions, and in females and older patients.
authors.affiliation: Division of Sports Medicine, Department of Physical Medicine and Rehabilitation, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Won Hah
authors.initials: WH
authors.lastname: Park
authors.affiliation: Department of Orthopedic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Chong Suh
authors.initials: CS
authors.lastname: Lee
authors.affiliation: Department of Orthopedic Surgery, Bundang CHA Medical Center, CHA University, Seoul, Korea.
authors.forename: Kyung Chung
authors.initials: KC
authors.lastname: Kang
authors.affiliation: Division of Sports Medicine, Department of Physical Medicine and Rehabilitation, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Yong Gon
authors.initials: YG
authors.lastname: Seo
keywords: Back muscle strength; Lumbar osteoarthritis; Spinal fusion