Sagittal alignment and the Bryan cervical artificial disc.
OBJECTIVE
The authors evaluated cervical spine radiographs to determine sagittal alignment in patients who underwent one- or two-level arthroplasty with the Bryan cervical artificial disc prosthesis.


METHODS
The curvature of the surgically treated spinal segments and the overall curvature of the cervical spine were evaluated in 13 patients who underwent 16 cervical arthroplasty device placements. Preoperative and postoperative lateral radiographs were reviewed and compared using standardized techniques for measuring spinal curvature. Patients who underwent a single-level cervical arthroplasty had a 4.7 degrees mean reduction (p < 0.05) in lordosis after cervical artificial disc replacement. The three patients who underwent two-level cervical arthroplasty had no significant changes in the sagittal alignment.


CONCLUSIONS
Patients who underwent arthroplasty with a Bryan cervical artificial disc had a focal loss of lordosis (that is, kyphosis) at the treated levels after single-level procedures. Nevertheless, there was no significant change in the overall sagittal curvature of the cervical spine after single-level artificial disc replacements. The patients who underwent two-level artificial disc placement had no significant changes in lordosis at the treated levels or in the overall curvature. The likely source of this outcome appears to be the endplate milling procedures that reorient the vertebral endplates.
Johnson
J Patrick
JP
Cedars-Sinai Institute for Spinal Disorders, Los Angeles, California 90048, USA. johsonjp@cshs.org
Lauryssen
Carl
C
Cambron
Helen O
HO
Pashman
Robert
R
Regan
John J
JJ
Anand
Neel
N
Bray
Robert
R
D000328:Adult; D019643:Arthroplasty, Replacement / Q000379:methods; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D005260:Female; D006801:Humans; D007403:Intervertebral Disc / Q000000981:diagnostic imaging / Q000601:surgery*; D007738:Kyphosis / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D008875:Middle Aged; D019736:Prostheses and Implants; D011859:Radiography; D013123:Spinal Fusion / Q000379:methods