The impact of standing regional cervical sagittal alignment on outcomes in posterior cervical fusion surgery.
BACKGROUND
Positive spinal regional and global sagittal malalignment has been repeatedly shown to correlate with pain and disability in thoracolumbar fusion.


OBJECTIVE
To evaluate the relationship between regional cervical sagittal alignment and postoperative outcomes for patients receiving multilevel cervical posterior fusion.


METHODS
From 2006 to 2010, 113 patients received multilevel posterior cervical fusion for cervical stenosis, myelopathy, and kyphosis. Radiographic measurements made at intermediate follow-up included the following: (1) C1-C2 lordosis, (2) C2-C7 lordosis, (3) C2-C7 sagittal vertical axis (C2-C7 SVA; distance between C2 plumb line and C7), (4) center of gravity of head SVA (CGH-C7 SVA), and (5) C1-C7 SVA. Health-related quality-of-life measures included neck disability index (NDI), visual analog pain scale, and SF-36 physical component scores. Pearson product-moment correlation coefficients were calculated between pairs of radiographic measures and health-related quality-of-life scores.


RESULTS
Both C2-C7 SVA and CGH-C7 SVA negatively correlated with SF-36 physical component scores (r = -0.43, P < .001 and r = -0.36, P = .005, respectively). C2-C7 SVA positively correlated with NDI scores (r = 0.20, P = .036). C2-C7 SVA positively correlated with C1-C2 lordosis (r = 0.33, P = .001). For significant correlations between C2-C7 SVA and NDI scores, regression models predicted a threshold C2-C7 SVA value of approximately 40 mm, beyond which correlations were most significant.


CONCLUSIONS
Our findings demonstrate that, similar to the thoracolumbar spine, the severity of disability increases with positive sagittal malalignment following surgical reconstruction.
Department of Neurological Surgery, University of California, San Francisco, San Francisco, California 94143, USA.
Jessica A
JA
Tang
Justin K
JK
Scheer
Justin S
JS
Smith
Vedat
V
Deviren
Shay
S
Bess
Robert A
RA
Hart
Virginie
V
Lafage
Christopher I
CI
Shaffrey
Frank
F
Schwab
Christopher P
CP
Ames
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery*; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000000981:diagnostic imaging; D008141:Lordosis / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D011187:Posture / Q000502:physiology*; D011859:Radiography; D013118:Spinal Cord Diseases / Q000601:surgery; D013123:Spinal Fusion; D016896:Treatment Outcome; D055815:Young Adult