Study Design. Multicenter, prospective, consecutive case series.
Objective. To assess prevalence and type of cervical deformity among adults with thoracolumbar (TL) deformity and to assess for associations between cervical deformities and different types of TL deformities.
Summary of Background Data. Cervical deformity can present concomitantly with TL deformity and have implications for the management of TL deformity.
Methods. Multicenter, prospective, consecutive series of adult (age >18 yr) patients with TL deformity. Parameters included pelvic tilt (PT), pelvic incidence (PI), lumbar lordosis (LL), C2–C7 sagittal vertical axis (C2–C7SVA), C7–S1SVA, and C2–C7 lordosis. Cervical deformity was defined as cervical lordosis more than 0° (cervical kyphosis [CK]) or C2–C7SVA more than 4 cm (cervical positive sagittal malalignment [CPSM]). Patients were stratified by the Scoliosis Research Society-Schwab classification of adult TL deformity, including curve type (N = sagittal deformity, T = thoracic scoliosis, L = lumbar scoliosis, and D = T + L scoliosis) and modifier grades: PT (0: <20°, +: 20°–30°, ++: >30°), C7–S1SVA (0: <4 cm, +: 4–9.5 cm, ++: >9.5 cm), and PI-LL mismatch (0: <10°, +: 10–20°, ++: >20°).
Results. A total of 470 patients met criteria (mean age = 52 yr). Mean cervical lordosis and C2–C7SVA were −8° and 3.2 cm, respectively. CK and CPSM prevalence were 31% and 29%, respectively, and prevalence of CK and/or CPSM was 53%. CK prevalence differed by curve type (N = 15%, L = 27%, D = 37%, T = 49%; P < 0.001); CPSM prevalence did not differ by curve type (P = 0.19). Higher PT grades had lower CK prevalence (0 = 40%, += 27%, ++= 15%; P < 0.001) but greater CPSM prevalence (0 = 23%, += 28%, ++= 45%; P = 0.001). Similarly, higher SVA grades had lower CK prevalence (0 = 40%, += 23%, ++= 11%; P < 0.001) but greater CPSM prevalence (0 = 24%, += 24%, ++= 48%; P < 0.001). Higher PI-LL grades had lower CK prevalence (0 = 35%, += 31%, ++= 22%; P = 0.034) but no CPSM association (P = 0.46).
Conclusion. Cervical deformity is highly prevalent (53%) in adult TL deformity. C7–S1SVA, PT, and PI-LL modifiers are associated with cervical deformity prevalence. These findings suggest that TL deformity evaluation should include assessment for concomitant cervical deformity and that further study is warranted to define their potential clinical impact.
Level of Evidence: 3
Cervical deformity is highly prevalent (53%) in adult thoracolumbar (TL) deformity. C7&#x2013;S1 sagittal vertical axis, pelvic tilt, and pelvic incidence and lumbar lordosis modifiers are associated with cervical deformity prevalence. These findings suggest that TL deformity evaluation should include assessment for concomitant cervical deformity and that further study is warranted to define their potential clinical impact.
*Department of Neurosurgery, University of Virginia, Charlottesville, VA
†Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, NY
‡Department of Orthopaedic Surgery, University of California, Davis, Sacramento, CA
§University of California San Diego, School of Medicine, San Diego, CA
¶Department of Neurosurgery, Weill Cornell Medical College, New York City, NY
‖San Diego Center for Spinal Disorders, La Jolla, CA
**Department of Orthopaedic Surgery, Baylor Scoliosis Center, Plano, TX
††Department of Orthopedic Surgery, University of California, San Francisco, San Francisco, CA
‡‡Department of Orthopaedic Surgery, Oregon Health & Science University, Portland, OR
§§Department of Orthopaedic Surgery, University of Kansas Medical Center, Kansas City, KS
¶¶Rocky Mountain Hospital for Children, Denver, CO; and
‖‖Department of Neurological Surgery, University of California, San Francisco, CA.
Address correspondence and reprint requests to Justin S. Smith, MD, PhD, Department of Neurosurgery, University of Virginia Health Sciences Center, Box 800212, Charlottesville VA, 22908; E-mail: firstname.lastname@example.org
Acknowledgment date: September 10, 2013. First revision date: March 2, 2014. Second revision date: April 16, 2014. Acceptance date: April 27, 2014.
The manuscript submitted does not contain information about medical device(s)/drug(s).
The International Spine Study Group (ISSG) is funded through research grants from DePuy Spine and individual donations.
Relevant financial activities outside the submitted work: board membership, consultancy, grants, employment, expert testimony, payment for lecture, stocks, patents, royalties, payment for development of educational presentations.