Abstract
The study design is case–control. To evaluate the impact of preoperative coronal patterns based on the relationship between orientation of L4 coronal tilt and C7 plumb line on immediate postoperative coronal imbalance in degenerative lumbar scoliosis (DLS) patients. Although lumbosacral fractional curve has been long stressed in correction surgery of DLS, there is paucity of literature focusing on preoperative coronal pattern based on the relationship between orientation of L4 coronal tilt and C7 plumb line and its impact on immediate postoperative coronal imbalance in DLS patients. A consecutive series of DLS patients who underwent deformity correction surgery via posterior-only approach were reviewed. According to the relationship between orientation of L4 coronal tilt and C7 plumb line preoperatively, a total of 77 DLS patients who underwent posterior spinal corrective surgery were classified into: 1. Coronal consistency pattern, L4 coronally tilts toward C7 plumb line; 2. Coronal opposition pattern, L4 coronally tilts opposite C7 plumb line. Coronal imbalance was defined as global coronal malalignment (GCM) on either side more than or equal to 20 mm. Whole-spine standing radiographs of both pattern groups were assessed preoperatively and postoperatively. There were 37 patients with coronal consistency pattern and 40 patients with coronal opposition pattern. Compared to patients with coronal opposition pattern, patients with coronal consistency pattern had significantly higher postoperative GCM (P = 0.028), lower amount of GCM correction (P = 0.013) and higher incidence of postoperative coronal imbalance (P = 0.001); further logistic regression analysis revealed coronal consistency pattern was associated with increased odds of postoperative coronal imbalance (odds ratio: 5.981; 95% confidence interval 2.029–17.633; P = 0.001). DLS patients with preoperative coronal consistency pattern carried greater risk for immediate postoperative coronal imbalance following posterior long correction surgery.Level of evidence 3
Highlights
We focused on the orientation of L4 coronal tilt relative to C7 plumb line (C7 PL) to investigate whether the orientation of L4 coronal tilt relative to C7 PL is an independent risk factor for postoperative coronal imbalance
The current study demonstrated that preoperative coronal patterns had great impact on postoperative coronal imbalance, that is, the orientation of L4 coronal tilt relative to C7 PL was associated with incidence of postoperative coronal imbalance in degenerative lumbar scoliosis (DLS) patients
Different from mechanisms of postoperative coronal imbalance in degenerative lumbar scoliosis with different preoperative coronal curve types provided by Bao et al.[2], who believed that asymmetrical osteotomy combined with compression technique on the convex side of the major curve might be the cause, the different surgical outcomes in patients with different preoperative coronal patterns might be due to their different inherent characteristics, regardless of what osteotomy techniques or compression/distraction maneuvers used
Summary
The mean value of GCM in patients with coronal consistency pattern was 21.1 ± 17.4 mm, in patients with coronal opposition pattern was 18.1 ± 18.7 mm, but there was no statistically significant difference in preoperative GCM between two groups (P = 0.473) (Table 2). Patients with consistency pattern had 40.5% (15/37) incidence of coronal imbalance, while patients with opposition pattern had 27.5% (11/40) incidence, but there was no statistically significant difference between two groups (P = 0.227).
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