Introduction: Preoperative neck mobility and cervical deformity may influence alignment goals and success. The authors hypothesize that flexion-extension parameters are predictive of the maintenance of normal cervical alignment and the achievement of sagittal balance.
Methods: Perioperative radiographs for 85 patients undergoing long-segmentfusion for ASD were retrospectively reviewed. Preoperative cervical flexion-extension views were obtained in symptomatic patients. Cervical flexion and extension sagittal paramters included C1-C2 angle, C0-C2 angle, C2-C7 plumb line (CPL), and C2-C7 cervical lordosis (CL). In scoliosis studies, T1 slope (T1S) minus CL (T1S-CL), T2-T12 thoracic kyphosis (TK), L1-S1 lumbar lordosis (LL), as well as spinopelvic and global sagittal parameters. CD was defined as CPL>4cm, CL<0°, or T1S-CL<0° or =15°.
Results: 85 patients (mean age 64 ± 11.1) were identified (21.5 months follow-up). LL changed from 30° to 53° (p<0.0001), SVA 7.5 to 3.9 cm(p<0.0001), TPA 27° to 18°(p<0.0001), T1S-CL 10° to 14° (p=0.021), CL from 17° to 12°(p=0.013), and CPL 2.8 to 3.0 cm(p=0.172). CD increased from 41(48%) to 47(55%) patients and All symptomatic patients(24%, n=20) had CD(100%). Increased C0-C2 preoperative range of
motion correlated with suboptimal TPA(?=-.492,p=0.022). C0-C2 was an independent predictor of suboptimal TPA correction(ß=-0.599,95% CI:-1.182 to -0.016,p=0.028). In patients with limited preoperative CL (CL<30°,n =11), preoperative C1-C2 range of correlated highly with suboptimal TPA correction (-.588,p=0.014), as well as C0-C2 (-.657,p=0.014). C0-C2 mobility was a predictor of TPA correction on linear regression analysis of patients with suboptimal preoperative CL (ß=-0.657, p=0.028). Preoperative range of motion correlated
strongly with postoperative thoracic compensation, when normalized by the number of remaining
unfused thoracic vertebral segments (C1-C2 ?=-.762, p<0.0001,CL ?=.501,p=0.029)
Conclusions: Preoperative cervical flexion-extension radiographs aid in identifying patients at risk for suboptimal deformity correction. An increased preoperative upper cervical range of motion (C0-C2, C1-C2) is
predictive of a suboptimal global deformity correction.
Patient Care: This study aims to further elucidate the relationship of preoperative cervical alignment with postoperative outcomes after thoracolumbar surgery for adult spinal deformity. This investigation adds further relevance to understanding cervical deformity prior to thoracolumbar surgery for ASD. This work highlights that either increased preoperative upper cervical range of motion, especially with decreased C2-C7 range of motion is associated with diminished global alignment correction. Therefore, cervical flexion-extension studies in symptomatic patients can potentially be useful in the assessment of at risk patients for suboptimal global correction.
Learning Objectives: 1. Understand the relationship of cervical deformity with thoracolumbar deformity.
2. Understand the utility of preoperative flexion-extension views for planning thoracolumbar fusion in adult spinal deformity patients.
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