General Session: Adult Spinal Deformity - Hall F

Presented by: E. Zgonis

Author(s):

E. Klineberg(1), R. Lafage(2), E. Zgonis(2), V. Lafage(2), M. Gupta(3), P. Passias(4), J. Smith(5), H.J. Kim(2), D. Burton(6), G. Mundis(7), F. Schwab(2), R. Hart(8), C. Shaffrey(5), C. Ames(9), International Spine Study Group (ISSG)

(1) University of California, Davis, Sacramento, CA, United States
(2) Hospital for Special Surgery, New York, NY, United States
(3) Washington University, Saint Louis, MO, United States
(4) New York University Langone Orthopedic Hospital, New York, NY, United States
(5) University of Virginia, Charlottesville, VA, United States
(6) University of Kansas Medical Center, Kansas City, KS, United States
(7) San Diego Center for Spinal Disorders, La Jolla, CA, United States
(8) University of Oregon Health Sciences Center, Portland, OR, United States
(9) University of California, San Francisco, San Francisco, CA, United States

Abstract

Background: Choosing the appropriate surgical approach and osteotomy type is challenging when surgically treating cervical deformity. A pre-operative assessment of flexibility and final alignment would be useful for any surgeon treating this complex problem.

Purpose: To investigate the impact of Pre-operative Extension Lateral Cervical Radiographs on the choice of corrective surgical procedure and determine, if these can also predict the post-operative cervical alignment.

Study Design/Setting: Prospective multicenter database of consecutive patients.

Patient Sample: Cervical deformity patients with a primary cervical or cervicothoracic deformity.

Outcome Measures: Radiographic parameters, surgical osteotomy grade and surgical approach.

Methods: A prospective database of operative cervical deformity patients was analyzed. Inclusion criteria were cervical kyphosis>10°, cervical scoliosis>10°, C2-C7 SVA>4cm or chin-brow vertical angle>25°, and primary deformity in the Cervical or Cervicothoracic spine. The radiographic parameters of the pre-operative extension lateral were compared to pre-operative neutral lateral, and final 3 month alignment XR and type of surgical osteotomy based upon the Ames Classification. Statistical analysis included t-test and chi-squared.

Results: 78/94 patients met the inclusion criteria. Mean age of 60 yo, with mean BMI of 30 and 52% females. 41% of patients had prior cervical surgery, and 69/78 underwent at least one osteotomy. When evaluating the use of grade 1-2 osteotomy vs grade 5,6 or 7; maximal pre-operative extension lateral XR were found to have statically lower T1S (23.1 vs 35.5; p=.019), lower T1S-CL (21.7 vs 36.3; p=.032), lower cSVA (28.2 vs 48.4; p< .001) and lower C2Slope (20.3 vs 37.5; p=.016). Choice of approach was also influenced by the extension XR, with anterior vs posterior chosen for the films with the greatest extension; lower T1S (20 vs 31; p=.05), lower cSVA (15.8 vs 36.3; p=.005), lower T1S-CL (12.9 vs 28.8; p=.014) and lower C2 slope (11.1 vs 28; p=.012). In fact, when the extension XR did not achieve normal alignment T1S-CL > 17, patients were more likely to have and posterior approach (56% vs 36%; p=.041). While surgery created a significant change in all radiographic parameters; the 3month lateral XR and pre-op extension XR were statistically similar for T1S-CL (25.5 vs 23.6; p=.35) and C2Slope (23.8 vs 22.5; p=.55).

Conclusions: Pre-operative lateral extension radiographs had a significant association with surgical approach and grade of osteotomy. The greater the cervical extension, the less need for osteotomy or posterior only approach. The pre-operative extension lateral XR was also statistically similar to the post-operative 3 month lateral XR, and may be used in future studies to predict the final cervical alignment. Obtaining pre-operative maximal extension XR is a critical alignment tool, and should be obtained as a part of the pre-operative surgical plan.