Subaraman Ramchandran, Themistocles S. Protopsaltis, Daniel Sciubba, Justin K. Scheer, Cyrus M. Jalai, Alan Daniels, Peter G. Passias, Virginie Lafage, Han Jo Kim, Gregory Mundis, Eric Klineberg, Robert A. Hart, Justin S. Smith, Christopher Shaffrey, Christopher P. Ames


February 2018, Volume 27, Issue 2, pp 416 - 425 Original Article Read Full Article 10.1007/s00586-017-5395-x

First Online: 28 November 2017

Purpose

Reciprocal mechanisms for standing alignment have been described in thoraco-lumbar deformity but have not been studied in patients with primary cervical deformity (CD). The purpose of this study is to report upper- and infra-cervical sagittal compensatory mechanisms in patients with CD and evaluate their changes post-operatively.

Methods

Global spinal alignment was studied in a prospective database of operative CD patients. Inclusion criteria were any of the following: cervical kyphosis (CK) > 10°, cervical scoliosis > 10°, cSVA (C2–C7 Sagittal vertical axis) > 4 cm or CBVA (Chin Brow Vertical Angle) > 25°. For this study, patients who had previous fusion outside C2 to T4 segments were excluded. Patients were sub-classified by increasing severity of cervical kyphosis [CL (cervical lordosis):  10°] and cSVA (cSVA-low 0–4 cm, cSVA-mid 4–6 cm, cSVA-high > 6 cm) and were compared for pre- and 3-month post-operative regional and global sagittal alignment to determine compensatory recruitment.

Results

75 CD patients (mean age 61.3 years, 56% women) were included. Patients with progressively larger CK had a progressive increase in C0–C2 (CL = 34°, CK-low = 37°, CK-high = 44°, p = 0.004), C2Slope and T1Slope-CL (p 

Conclusions

Patients with cervical malalignment compensate with upper cervical hyper-lordosis, presumably for the maintenance of horizontal gaze. As cSVA increases, patients also tend to exhibit increased pelvic retroversion. Following surgical treatment, there was relaxation of upper cervical compensation.


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