title: Correlation of paraspinal atrophy and denervation in back pain and spinal stenosis relative to asymptomatic controls.
abstract: OBJECTIVE
  To determine the relationship among spinal stenosis, back pain, paraspinal muscle denervation, and paraspinal muscle atrophy.
  
  
  METHODS
  A prospective masked, double-controlled study.
  
  
  METHODS
  A university hospital and outpatient spine clinic.
  
  
  METHODS
  Ten asymptomatic subjects, 10 subjects with mechanical low back pain, and 15 subjects with symptomatic spinal stenosis; age range, 55-80 years old.
  
  
  METHODS
  Magnetic resonance imaging measurements of minimum spinal canal diameter, paraspinal muscle cross-sectional area at the level of the L5-S1 disk, and quantified paraspinal electrodiagnostic testing (MiniPM) were performed by examiners blinded to each other's results and to the participants' clinical information.
  
  
  METHODS
  Paraspinal muscle cross-sectional area and MiniPM scores.
  
  
  RESULTS
  A paraspinal cross-sectional area decreased significantly from asymptomatic subjects (3872 mm(2)) to subjects with low back pain (3627 mm(2)) and to subjects with spinal stenosis (2985 mm(2)). In the stenosis group, there was a trend toward increased paraspinal denervation in the subjects with severe spinal stenosis, but this was not statistically significant.
  
  
  CONCLUSIONS
  Symptomatic spinal stenosis results in greater paraspinal muscle atrophy than low back pain alone. The extent of paraspinal atrophy was not significantly explained by the extent of denervation, thus, it may be reversible, and the role of paraspinal muscle rehabilitation in patients with spinal stenosis deserves further study.
authors: Physical Medicine and Rehabilitation, University of Michigan Health System, 325 E. Eisenhower, Suite 200, Ann Arbor, MI 48108, USA. johny@med.umich.edu
authors: John A
authors: JA
authors: Yarjanian
authors: April
authors: A
authors: Fetzer
authors: Karen S
authors: KS
authors: Yamakawa
authors: Henry C
authors: HC
authors: Tong
authors: Matthew
authors: M
authors: Smuck
authors: Andrew
authors: A
authors: Haig
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017116:Low Back Pain / Q000175:diagnosis / Q000209:etiology / Q000601:surgery*; D008159:Lumbar Vertebrae; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009121:Muscle Denervation / Q000379:methods*; D018482:Muscle, Skeletal / Q000294:innervation*; D011446:Prospective Studies; D013130:Spinal Stenosis / Q000150:complications / Q000175:diagnosis*; D013131:Spine / Q000473:pathology*; D016896:Treatment Outcome