Intraoperative Assessment of Coronal Balance with Long Cassette Radiographs in Adult Thoracolumbar Deformity Correction.

Abstract

To describe the use of intraoperative anteroposterior long cassette radiographs (APLCRs) to guide kickstand rod application in adult spinal deformity. A retrospective chart review was performed to identify patients with adult thoracolumbar and coronal plane deformity undergoing open segmental decompression with spinopelvic fixation and deformity correction between October 2017 and June 2019 who had APLCRs after rod placement. In patients with persistent intraoperative coronal deviations, a kickstand rod was placed. This supplemental rod was anchored to an iliac screw and to the construct via a pair of side-to-side connectors. A distractor was expended between a vice grip plyer on the kickstand and side-to-side connector to apply a lateralizing force to reduce the degree of deviation. Of 15 patients who underwent T3-ilium fusion with spinal deformity correction with intraoperative APLCRs, 7 underwent kickstand placement. Mean preoperative coronal deviation was similar between cohorts (4.3 cm vs. 2.2 cm, P = 0.09), but was greater intraoperatively in the kickstand cohort (4.3 cm vs. 0.6 cm, P < 0.001). Postoperative coronal deviation was similar between groups (2.1 cm vs. 1.8 cm, P = 0.37). Preoperative fractional lumbar curve was significantly greater in patients requiring a kickstand (23° vs. 35°, P = 0.02), but the major thoracolumbar curve was similar between groups (43° vs. 35°, P = 0.14). Intraoperative APLCRs can help guide application of a kickstand rod in adult thoracolumbar deformity correction. Patients with a greater fractional lumbar curve may derive greater benefit of kickstand usage, independent of major curve magnitude.