Is there a connection between the clinical response after an external fixation test or a subsequent lumbar fusion and the pre-test intervertebral kinematics?
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.
Lund
Teija
T
ORTON Orthopaedic Hospital, Invalid Foundation, Helsinki, Finland. teija.lund@invalidisaatio.fi
Oxland
Thomas R
TR
Nydegger
Thomas
T
Schlenzka
Dietrich
D
Laine
Timo
T
Heini
Paul
P
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