title: A randomized clinical trial of the effectiveness of mechanical traction for sub-groups of patients with low back pain: study methods and rationale.
abstract: BACKGROUND
  Patients with signs of nerve root irritation represent a sub-group of those with low back pain who are at increased risk of persistent symptoms and progression to costly and invasive management strategies including surgery. A period of non-surgical management is recommended for most patients, but there is little evidence to guide non-surgical decision-making. We conducted a preliminary study examining the effectiveness of a treatment protocol of mechanical traction with extension-oriented activities for patients with low back pain and signs of nerve root irritation. The results suggested this approach may be effective, particularly in a more specific sub-group of patients. The aim of this study will be to examine the effectiveness of treatment that includes traction for patients with low back pain and signs of nerve root irritation, and within the pre-defined sub-group.
  
  
  METHODS
  The study will recruit 120 patients with low back pain and signs of nerve root irritation. Patients will be randomized to receive an extension-oriented treatment approach, with or without the addition of mechanical traction. Randomization will be stratified based on the presence of the pre-defined sub-grouping criteria. All patients will receive 12 physical therapy treatment sessions over 6 weeks. Follow-up assessments will occur after 6 weeks, 6 months, and 1 year. The primary outcome will be disability measured with a modified Oswestry questionnaire. Secondary outcomes will include self-reports of low back and leg pain intensity, quality of life, global rating of improvement, additional healthcare utilization, and work absence. Statistical analysis will be based on intention to treat principles and will use linear mixed model analysis to compare treatment groups, and examine the interaction between treatment and sub-grouping status.
  
  
  CONCLUSIONS
  This trial will provide a methodologically rigorous evaluation of the effectiveness of using traction for patients with low back pain and signs of nerve root irritation, and will examine the validity of a pre-defined sub-grouping hypothesis. The results will provide evidence to inform non-surgical decision-making for these patients.
  
  
  BACKGROUND
  This trial has been registered with http://ClinicalTrials.gov: NCT00942227.
authors.affiliation: Rehabilitation Agency, Intermountain Healthcare, Salt Lake City, Utah, USA. julie.fritz@hsc.utah.edu
authors.forename: Julie M
authors.initials: JM
authors.lastname: Fritz
authors.forename: Anne
authors.initials: A
authors.lastname: Thackeray
authors.forename: John D
authors.initials: JD
authors.lastname: Childs
authors.forename: Gerard P
authors.initials: GP
authors.lastname: Brennan
mesh_terms: D000328:Adult; D002985:Clinical Protocols; D002986:Clinical Trials as Topic / Q000379:methods; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D007403:Intervertebral Disc / Q000503:physiopathology; D007405:Intervertebral Disc Displacement / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy; D017116:Low Back Pain / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D008159:Lumbar Vertebrae / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000379:methods; D011237:Predictive Value of Tests; D011843:Radiculopathy / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D015203:Reproducibility of Results; D012107:Research Design / Q000592:standards*; D013126:Spinal Nerve Roots / Q000503:physiopathology; D014143:Traction / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data*