Key Role of Preoperative Recumbent Films in the Treatment of Severe Sagittal Malalignment

Abstract

Study design: Retrospective cohort study.

Objective: To determine if severe sagittal malalignment (SM) patients without fixed deformities require a three-column osteotomy (3CO) to achieve favorable clinical and radiographic outcomes.

Summary of background data: 3CO performed for severe SM has significantly increased in the last 15 years. Not all severe SM patients require a 3CO.

Methods: Severe SM patients (sagittal vertical axis [SVA] >10 cm) who underwent deformity correction between 2002 and 2011. Patients with <33% change in their lumbar lordosis (LL) on a preoperative supine radiograph were classified as stiff deformities, whereas those with ≥33% change were categorized as flexible deformities. The clinical/radiographic outcomes were assessed at minimum two years postoperatively.

Results: Seventy patients met the inclusion criteria, 35 patients with flexible and 35 with stiff deformities. Eighteen flexible-deformity patients underwent a 3CO versus 22 stiff-deformity patients. The remaining patients in each group underwent spinal realignment without a 3CO. The flexible-deformity patients not undergoing a 3CO had overall improvement in all sagittal radiographic parameters. Preoperative LL (22°), LL-pelvic incidence (PI) mismatch (43), SVA (17 cm), and pelvic tilt (PT, 34°) improved to 46°, 18, 6 cm, and 26°, respectively, p < .05. Flexible-deformity patients who underwent a 3CO also had overall improvement in all radiographic parameters. Preoperative LL (8.5°), LL-PI mismatch (47), SVA (19 cm), and PT (37°) improved to 39°, 15, 7 cm, and 24°, respectively (p < .05). Stiff-deformity patients who underwent a 3CO had statistically significant improvement in all radiographic parameters. However, stiff-deformity patients who did not undergo a 3CO had suboptimal improvement in all radiographic parameters, except for SVA (14 cm-9 cm, p < .05). Flexible patients who did not undergo a 3CO had statistical improvement in the SRS domains of function and self-mage as well as in their ODI scores (p < .05).

Conclusion: Severe SM that is flexible can be corrected without a 3CO without compromising clinical and radiographic outcomes.

Level of evidence: Level III.

Keywords: Flexible deformity; Sagittal imbalance; Sagittal malalignment; Stiff deformity; Three-column osteotomy.