Preoperative and Postoperative Sagittal Alignment and Compensatory Mechanisms in Patients With Posttraumatic...

Secondary posttraumatic spinal kyphosis is a fixed deformity that has an asymptomatic presentation in most patients, but in some, persistent pain and disability can develop refractory to conservative treatment, which may result in the need for corrective surgery. Our aim was to analyze the modification of sagittal alignment and the variation in compensation mechanisms of spinal-pelvic segments before and after surgical correction in a group of patients with symptomatic posttraumatic kyphosis.

A retrospective cohort study of 16 consecutive patients from the beginning of 2007 until the beginning of 2017 who underwent surgery due to thoracolumbar sagittal deformities was performed. Regional kyphosis (RK), thoracic kyphosis (TK), lumbar lordosis (LL), lower lumbar lordosis (LLL), lumbar lordosis under the deformity (LLUD), pelvic incidence (PI), pelvic tilt (PT), sagittal vertical axis (SVA), and PI-LL were measured in preoperative and postoperative lateral full spine x rays. Statistical analysis was performed with the nonparametric Wilcoxon test to compare preoperative and postoperative radiologic variables.

Sixteen patients were included with a median age of 47.5 years (32-62 years), the median time elapsed from the accident until corrective surgery was 7 months (2-33 months), the median follow-up time was 16.5 months (6-80 months), and the most used corrective strategy was pedicle subtraction osteotomy (11/16 patients). Statistically and radiologically significant improvements were observed in RK (33.5° versus 12°, P < .001) and LLUD (68.5° versus 61°, P = .017), with a noticeable decrease in PI-LL (15° versus 9.5°, P = .233). There were no statistically significant results regarding TK, LL, LLL, PI, PT, or SVA.

Osteotomies are an effective tool to correct angular deformities at a local level after spine trauma. Posttraumatic kyphosis results in the compensation of sagittal imbalance through modification of segmental alignment of the mobile spine under the deformity.

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This work shows the compensation mechanisms after post-traumatic kyphosis in patients with previously healthy spines.