Correlation between range of motion and outcome after lumbar total disc replacement: 8.6-year follow-up.
METHODS
Retrospective radiographic and chart review.


OBJECTIVE
To examine the relationship between lumbar total disc replacement (TDR) range of motion (ROM) and clinical outcome at 8.6-year follow-up.


BACKGROUND
There are no studies on the relationship between TDR motion and clinical outcomes.


METHODS
We reviewed 38 patients who underwent 1 or 2-level TDR implantation with 51 TDR. Flexion-extension ROM was measured on lateral radiographs. Clinical outcomes were measured at 8.6 years by modified Stauffer-Coventry scores, Oswestry Disability Questionnaires (ODQ), and subjective ratings of back pain, leg pain, and disability. Spearman rank correlation coefficient was used to determine if ROM was correlated with clinical outcome. Patients were divided into 2 groups by motion (< or = 5 degrees and > 5 degrees ). Statistical differences in outcome were sought.


RESULTS
Spearman rank correlation coefficient revealed weak-to-moderate but statistically significant associations between ROM and outcome for postoperative back pain (r = -0.35, P = 0.034), ODQ (r = -0.33, P = 0.046), and modified Stauffer-Coventry scores (r = 0.42, P = 0.0095). Patients with motion of > 5 degrees had superior outcomes in ODQ (mean difference 12.6 points, P = 0.026) and Stauffer-Coventry scores (mean difference 2.2 points, P = 0.015).


CONCLUSIONS
The radiographic ROM at 8.6-year follow-up was positively correlated with several outcomes measures. Patients with motion > 5 degrees had clinically modest but statistically better outcomes in ODQ and modifiedStauffer-Coventry scores. Longer follow-ups will be necessary to measure fully the impact of TDR ROM on outcome.
Huang
Russel C
RC
Spine Surgery Service, Hospital for Special Surgery, New York, NY 10021, USA. russelhuang@yahoo.com
Girardi
Federico P
FP
Cammisa
Frank P
FP
Lim
Moe R
MR
Tropiano
Patrick
P
Marnay
Thierry
T
D000328:Adult; D000368:Aged; D019643:Arthroplasty, Replacement / Q000379:methods*; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D007403:Intervertebral Disc / Q000473:pathology / Q000601:surgery*; D007405:Intervertebral Disc Displacement / Q000150:complications / Q000503:physiopathology / Q000601:surgery*; D017116:Low Back Pain / Q000209:etiology / Q000503:physiopathology; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009068:Movement; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology*; D012189:Retrospective Studies; D016896:Treatment Outcome