title: Lumbar Muscle Cross-Sectional Areas Do Not Predict Clinical Outcomes in Adults With Spinal Stenosis: A Longitudinal Study.
abstract: BACKGROUND
  Minimal longitudinal data exist regarding the role of lumbar musculature in predicting back pain and function. In cross-sectional study designs, there is often atrophy of the segmental multifidus muscle in subjects with low back pain compared with matched controls. However, the cross-sectional design of these studies prevents drawing conclusions regarding whether lumbar muscle characteristics predict or modify future back pain or function.
  
  
  OBJECTIVE
  The primary objective of this study is to determine whether the cross-sectional area (CSA) of lumbar muscles predict functional status or back pain at 6- or 12-month follow-up in older adults with spinal degeneration. The secondary objective is to evaluate whether these muscle characteristics improve outcome prediction above and beyond the prognostic information conferred by demographic and psychosocial variables.
  
  
  METHODS
  Secondary analysis of a randomized controlled trial.
  
  
  METHODS
  A total of 209 adults aged 50 years and older with clinical and radiographic spinal stenosis from the Lumbar Epidural steroid injection for Spinal Stenosis (LESS) trial.
  
  
  METHODS
  Using baseline magnetic resonance images, we calculated CSAs of the lumbar multifidus, psoas, and quadratus lumborum muscles using a standardized protocol by manually tracing the borders of each of the muscles. The relationship between lumbar muscle CSAs and baseline measures was assessed with Pearson or Spearman correlation coefficients. The relationship between lumbar muscle characteristics and 6- and 12-month Roland Morris Disability Questionnaire (RDQ) and back pain Numeric Rating Scale (NRS) responses was further evaluated with multivariate linear regression. A hierarchical approach to the regression was performed: a basic model with factors of conceptual importance including age, gender, BMI, and baseline RDQ score formed the first step. The second and third steps evaluated whether psychosocial variables or muscle measures conferred additional prognostic information to the basic model.
  
  
  METHODS
  Function as measured by the RDQ and back pain as measured by the NRS at 6- and 12-month follow-up.
  
  
  RESULTS
  Lumbar muscle CSA was not a significant predictor of 6- or 12-month RDQ or pain score in multivariate analyses.
  
  
  CONCLUSIONS
  Cross-sectional areas of lumbar muscles do not predict function or pain at medium- and long-term follow-up in adults with lumbar spinal stenosis.
  
  
  METHODS
  III.
authors.affiliation: Division of Rehabilitation Medicine, Weill Cornell Medical College, 525 E 68(th) Street, Baker 16, New York, NY 10065(∗). Electronic address: alg9109@med.cornell.edu.
authors.forename: Alfred C
authors.initials: AC
authors.lastname: Gellhorn
authors.affiliation: Department of Rehabilitation Medicine, University of Washington, Seattle WA; VA Puget Sound Health System, Seattle, WA(†).
authors.forename: Pradeep
authors.initials: P
authors.lastname: Suri
authors.affiliation: Department of Rehabilitation Medicine, University of Washington, Seattle, WA; Comparative Effectiveness, Cost, and Outcomes Research Center, University of Washington, Seattle, WA(‡).
authors.forename: Sean D
authors.initials: SD
authors.lastname: Rundell
authors.affiliation: Department of Rehabilitation Medicine, University of Washington, Seattle, WA(§).
authors.forename: Nathan
authors.initials: N
authors.lastname: Olafsen
authors.affiliation: Department of Rehabilitation Medicine, University of Washington, Seattle, WA(‖).
authors.forename: M Jake
authors.initials: MJ
authors.lastname: Carlson
authors.affiliation: Department of Rehabilitation Medicine, University of Washington, Seattle, WA(¶).
authors.forename: Steve
authors.initials: S
authors.lastname: Johnson
authors.affiliation: Department of Rehabilitation Medicine, University of Washington, Seattle, WA(#).
authors.forename: Adrielle
authors.initials: A
authors.lastname: Fry
authors.affiliation: Dallas VA Medical Center, Dallas, TX(∗∗).
authors.forename: Thiru M
authors.initials: TM
authors.lastname: Annaswamy
authors.affiliation: Department of Anesthesia, Critical Care, and Pain Medicine, Beth Israel Deaconess Medical Center, Boston, MA(††).
authors.forename: Christopher
authors.initials: C
authors.lastname: Gilligan
authors.affiliation: VA Puget Sound Health System, Seattle, WA(‡‡).
authors.forename: Bryan
authors.initials: B
authors.lastname: Comstock
authors.affiliation: VA Puget Sound Health System, Seattle, WA(§§).
authors.forename: Patrick
authors.initials: P
authors.lastname: Heagerty
authors.affiliation: Department of Rehabilitation Medicine, University of Washington, Seattle, WA; Comparative Effectiveness, Cost, and Outcomes Research Center, University of Washington, Seattle, WA(‖‖).
authors.forename: Janna
authors.initials: J
authors.lastname: Friedly
authors.affiliation: Comparative Effectiveness, Cost, and Outcomes Research Center, University of Washington, Seattle, WA; Department of Radiology, Neurological Surgery, and Health Services, University of Washington, Seattle, WA(¶¶).
authors.forename: Jeffrey G
authors.initials: JG
authors.lastname: Jarvik
mesh_terms: D000328:Adult; D000368:Aged; D064131:Back Muscles / Q000187:drug effects / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007268:Injections, Epidural; D016015:Logistic Models; D008137:Longitudinal Studies; D017116:Low Back Pain / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology; D008161:Lumbosacral Region; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D015588:Observer Variation; D010147:Pain Measurement; D011237:Predictive Value of Tests; D018570:Risk Assessment; D012720:Severity of Illness Index; D013130:Spinal Stenosis / Q000150:complications / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D013256:Steroids / Q000008:administration & dosage*; D016896:Treatment Outcome
chemical_list: D013256:Steroids