title: Is there a connection between the clinical response after an external fixation test or a subsequent lumbar fusion and the pre-test intervertebral kinematics?
abstract: METHODS
  Evaluation of a possible correlation of clinical symptoms of chronic low back pain (LBP) patients before and after application of external spinal fixation (ESF) with three-dimensional motion patterns.
  
  
  OBJECTIVE
  To determine whether the intervertebral kinematics in chronic LBP patients correlate with pain relief after stabilization of the suspected painful segments.
  
  
  BACKGROUND
  Chronic LBP is a complex clinical entity with mechanical, biochemical, and psychosocial components. Although clinically controversial, ESF has been shown to reduce intervertebral motion, and thus, it provides a mechanism to investigate the mechanical aspect of LBP.
  
  
  METHODS
  Thirty-four chronic LBP patients were tested with ESF of the suspected painful segments. The subjective pain relief experienced by the patients during the test and 2 years after spinal fusion surgery was determined, along with the Oswestry Disability Index. Before removal of ESF, the three-dimensional intervertebral kinematics of the painful segments (specifically range of motion, coupling patterns, and motion asymmetries) were analyzed with a precision optoelectronic camera system during active trunk motions. A series of linear correlations were performed between the clinical measures and the motion parameters.
  
  
  RESULTS
  The subjective pain relief during the ESF test was nominally, but not significantly, associated with lateral bending asymmetry ( = 0.22) and "abnormal" axial rotation-lateral bending coupling ( = 0.13). The improvement in the Oswestry Disability Index both post-test and at 2 years after lumbar fusion surgery was significantly correlated with the extension range of motion ( = 0.049 and = 0.036, respectively) and the extension-to-flexion range of motion ratio ( = 0.035 and = 0.044, respectively).
  
  
  CONCLUSIONS
  The "abnormal" motion patterns of chronic LBP patients did not correlate with subjective pain relief after ESF of the suspected symptomatic levels or with the midterm outcome of subsequent lumbar fusion surgery. The results suggest that preserved motion of the symptomatic segments before surgery is positively correlated with the clinical result of the subsequent spinal fusion in case of a positive ESF test result.
authors.affiliation: ORTON Orthopaedic Hospital, Invalid Foundation, Helsinki, Finland. teija.lund@invalidisaatio.fi
authors.forename: Teija
authors.initials: T
authors.lastname: Lund
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Oxland
authors.forename: Thomas
authors.initials: T
authors.lastname: Nydegger
authors.forename: Dietrich
authors.initials: D
authors.lastname: Schlenzka
authors.forename: Timo
authors.initials: T
authors.lastname: Laine
authors.forename: Paul
authors.initials: P
authors.lastname: Heini
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D002908:Chronic Disease; D004185:Disability Evaluation; D016267:External Fixators; D005260:Female; D005387:Finland; D006801:Humans; D017116:Low Back Pain / Q000503:physiopathology / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011237:Predictive Value of Tests; D016059:Range of Motion, Articular; D013122:Spinal Diseases / Q000601:surgery; D013123:Spinal Fusion / Q000295:instrumentation / Q000379:methods; D016896:Treatment Outcome