Examination of Measures and Their Effects for Postoperative Coronal Imbalance in Adult Spinal Deformity Surgery

Abstract

Introduction: Recently, lateral lumbar interbody fusion (LLIF) has been widely used in correction surgery for adult spinal deformity (ASD), and its strong coronal correction force has the potential risk of coronal imbalance (CI) in the patients with residual lumbosacral fractional curve. Here, we investigated measures of postoperative CI and their effectiveness in circumferential minimally invasive surgery (CMIS) using LLIF and percutaneous pedicle screw (PPS) for ASD.

Methods: A total of 105 patients who underwent CMIS using LLIF and PPS at our institution since 2018 were included in this study. Patients were classified into two groups at the time of intraoperative first rod application-group CI (upper instrumented vertebra-central sacrum vertical line (UIV-CSVL) ≥10 mm) and group non CI (UIV-CSVL<10 mm). Pre- and postoperative spinopelvic parameters, L4 tilt, and C7-CSVL were compared. In the group CI, rod rotation technique (RR), S2 alar iliac screw (SAI) distraction (SD), and kickstand rod technique (KR) were performed as necessary, UIV-CSVL and its change were determined immediately after rod application and after various measures, and pre- and postoperative C7-CSVL were evaluated.

Results: Pre- and postoperative L4 tilt were significantly larger in group CI than group non CI. In group CI, improvement of UIV-CSVL was observed by various measures, and the amount of change in UIV-CSVL increased with the addition of measures, and the postoperative C7-CSVL was less than 10 mm in all measures.

Conclusions: Measures for CI and their effectiveness in CMIS for ASD were examined. By performing RR, SD, and KR sequentially, coronal balance could be corrected efficiently intraoperatively.