Geometric results of anterior cervical plate stabilization in degenerative disease.
METHODS
Consecutive case retrospective computerized analysis of lateral radiographs.


OBJECTIVE
To investigate the time evolution of the geometry of anterior cervical discectomy and fusion using a new computer-aided measurement technique.


BACKGROUND
Prior clinical studies have reported benefits and complications of anterior cervical plate stabilization, but have not comprehensively described changes in sagittal geometry following arthrodesis and plating. High fusion success rates have been reported for single-level discectomy and fusion, whereas multilevel procedures have demonstrated lower clinical success rates with increased hardware failure and pseudarthrosis rates.


METHODS
Sagittal alignment data were collected from lateral radiographs of 51 patients with 52 operations for single- or multiple-level anterior cervical discectomy and fusion, both with and without anterior cervical plate stabilization. Intervertebral angulation and separation at the operated segments before surgery, immediately after surgery, and at long-term follow-up were compared using a computer-aided technique.


RESULTS
Single-level anterior cervical discectomy and fusion with plate stabilization lost 0.9 degrees of the operatively obtained lordosis after surgery compared to 7.5 degrees for single-level fusions with bone alone (P = 0.0001). In multilevel anterior cervical discectomy and fusion, the bottommost level of the anterior cervical discectomy and fusion construct was much more prone to collapse than the remaining levels (mean bottom-level loss of 4.0 degrees vs. mean 0.2 degrees increase at the remaining levels, P < 0.0001).


CONCLUSIONS
Anterior cervical plate stabilization helps maintain operatively obtained segmental distraction and lordosis following anterior cervical discectomy and fusion. In multilevel procedures, this study found that postoperative collapse is largely localized to the bottommost level, where hardware failure and pseudarthrosis have been observed most often by others.
Herrmann
Ariel M
AM
Stanford University, Stanford, California, USA.
Geisler
Fred H
FH
D000328:Adult; D000368:Aged; D001860:Bone Plates; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D017586:Diskectomy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D013122:Spinal Diseases / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000601:surgery*; D013123:Spinal Fusion; D016896:Treatment Outcome