Does Correction of Preoperative Coronal Imbalance Make a Difference In Outcomes of Adult Deformity Patients?

Purpose: To evaluate the clinical outcomes and radiographic results of deformity surgery on patients with greater than 4cm of coronal imbalance.

Methods: 36 patients, mean age 51 years(range 18-77) with at least 4cm of preoperative coronal imbalance who underwent a thoracic/lumbar fusion for deformity correction were evaluated with a mean follow-up of 49 months(range 24-124). Radiographs were measured pre-operatively, post-operatively, and at last follow-up. Outcomes were measured using the Oswestry Disability Index(ODI).

Results: The average pre-op coronal imbalance was 61mm(range 40-142), and corrected post-op to an average of 35mm(range 0-84)(p<0 .0001) for an average correction of 43%. 89%(32/36) patients had postoperative improvement their coronal imbalance. Oswestry scores improved by a mean 15 points, 45 to 30(p< 0.0001). The were divided into three groups based on the C7 plumb line measurements at last follow-up: 0-2cm(n="9);" 2-4cm(n="14)," and>4cm(13) of coronal imbalance. There were no significant differences in the 3 groups in regard to the severity of the pre-op coronal imbalance, or their pre-op and post-op ODI scores. All three groups had significant improvement in ODI scores(p<0 .05).

Conclusion: There was significant improvement in clinical outcomes following surgical treatment of patients with > 4cm of coronal imbalance. There was no significant difference in outcomes based on the severity of the residual imbalance whether it was greater or less than 4cm. However,89%(32/36) had significant postoperative improvement in their coronal imbalance(p<0 .001). This data suggests that the absolute amount of residual postoperative coronal imbalance may not be as important a factor in patient outcomes is fact there was significant improvement their balance.