Static versus dynamic plating for multilevel anterior cervical discectomy and fusion.
BACKGROUND
Dynamic anterior plates have been popularized to promote cervical spine fusion by allowing controlled settling, thereby promoting load sharing across the construct. To date these proposed benefits have been largely theoretical and there are no studies confirming any benefits over more traditional static plates.


OBJECTIVE
To compare the clinical and radiographic outcomes of patients undergoing an instrumented multilevel anterior cervical discectomy and fusion (ACDF) with either a static or dynamic plate design.


METHODS
A retrospective clinical and radiographic study.


METHODS
From 1997 to 2002, 52 patients with either radiculopathy or myelopathy underwent two- or three-level ACDF with either static or dynamic plate fixation.


METHODS
Functional outcome, fusion status, radiographic measurements.


METHODS
A statically locked plating system was used in 21 patients, and a dynamic plating system was used in 31 patients. Functional outcome, fusion status, plate migration, settling, and adjacent-level disc space impingement were evaluated.


RESULTS
Clinical outcome was found to be similar between the statically and dynamically plated groups. Eighty-four percent of patients in both groups experienced good or excellent results at final follow-up. We observed a higher rate of nonunion in patients treated with a dynamic plate (16% [5 of 31]) compared with a rate of 5% (1 of 21) in those patients treated with a static plate (p=.05). Settling of the construct and plate migration was similar between the study groups at all time points.


CONCLUSIONS
This study failed to confirm our hypothesis that a dynamic plate (that allows angular motion between the screws and plate) confers any clinical or radiographic advantage over earlier design static plates. A higher rate of nonunion was actually seen in the dynamically plated patients; however, clinical results were similar between the two groups.
DuBois
Christian M
CM
St. Croix Orthopaedics, 1991 Northwestern Avenue, South Stillwater, MN 55105, USA.
Bolt
Patrick M
PM
Todd
Andrew G
AG
Gupta
Purnendu
P
Wetzel
F Todd
FT
Phillips
Frank M
FM
D001860:Bone Plates; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D017586:Diskectomy / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D008875:Middle Aged; D011843:Radiculopathy / Q000601:surgery; D011859:Radiography; D020127:Recovery of Function; D012189:Retrospective Studies; D013118:Spinal Cord Diseases / Q000601:surgery; D013123:Spinal Fusion / Q000295:instrumentation* / Q000379:methods; D016896:Treatment Outcome