Passias Peter G, Bortz Cole A, Segreto Frank, Horn Samantha, Pierce Katherine E, Alas Haddy, Brown Avery E, Lafage Renaud, Lafage Virginie, Smith Justin S, Line Breton, Eastlack Robert, Sciubba Daniel M, Klineberg Eric O, Soroceanu Alexandra, Burton Douglas C, Schwab Frank J, Bess Shay, Shaffrey Christopher I, Ames Christopher P
Department of Orthopedics, NYU Langone Orthopedic Hospital, New York, NY, USA.
Department of Orthopedics, Hospital for Special Surgery, New York, NY, USA.
J Spine Surg. 2019 Jun;5(2):236-244. doi: 10.21037/jss.2019.06.04.
The study aims to evaluate differences in alignment and clinical outcomes between surgical cervical deformity (CD) patients with a subaxial upper-most instrumented vertebra (UIV) and patients with a UIV at C2. Use of CD-corrective instrumentation in the subaxial cervical spine is considered risky due to narrow subaxial pedicles and vertebral artery anatomy. While C2 fixation provides increased stability, the literature lacks guidelines indicating extension of CD-corrective fusion from the subaxial spine to C2.
Included: operative CD patients with baseline (BL) and 1-year postop (1Y) radiographic data, cervical UIV ≥ C2. Patients were grouped by UIV: C2 or subaxial (C3-C7) and propensity score matched (PSM) for BL cSVA. Mean comparison tests assessed differences in BL and 1Y patient-related, radiographic, and surgical data between UIV groups, and BL-1Y changes in alignment and clinical outcomes.
Following PSM, 31 C2 UIV and 31 subaxial UIV patients undergoing CD-corrective surgery were included. Groups did not differ in BL comorbidity burden (P=0.175) or cSVA (P=0.401). C2 patients were older (64 . 58 yrs, P=0.010) and had longer fusions (9 . 6 levels, P=0.002). Overall, patients showed BL-1Y improvements in TS-CL (P<0.001), cSVA (P=0.005), McGS (P=0.004). Cervical flexibility was maintained at 1Y regardless of UIV, assessed by CL flexion (-0.2° . 6.0°, P=0.115) and extension (13.9° 9.9°, P=0.366). While both subaxial and C2 patients showed BL-1Y improvements in McGS (both P<0.030), C2 patients improved to a larger degree (7.3° . 6.2°). Between UIV groups, there were no differences in BL-1Y changes in HRQLs, overall complication rates, or operative complication rates (all P>0.05).
C2 UIV patients showed similar cervical range of motion and baseline to 1-year functional outcomes as patients with a subaxial UIV. C2 UIV patients also showed greater baseline to 1-year horizontal gaze improvement and had complication profiles similar to subaxial UIV patients, demonstrating the radiographic benefit and minimal functional loss associated with extending fusion constructs to C2. In the treatment of adult cervical deformities, extension of the reconstruction construct to the axis may allow for certain clinical benefits with less morbidity than previously acknowledged.
本研究旨在评估颈椎畸形（CD）手术患者中，最下位固定节段（UIV）位于下颈椎与位于C2的患者在对线情况和临床结局方面的差异。由于下颈椎椎弓根狭窄和椎动脉解剖结构的原因，在下颈椎使用CD矫正器械被认为具有风险。虽然C2固定可提供更高的稳定性，但文献中缺乏关于将CD矫正融合从下颈椎延伸至C2的指导原则。
纳入标准：有基线（BL）和术后1年（1Y）影像学数据的手术治疗的CD患者，颈椎UIV≥C2。患者按UIV分组：C2或下颈椎（C3-C7），并根据BL cSVA进行倾向得分匹配（PSM）。均值比较检验评估UIV组之间BL和1Y患者相关、影像学和手术数据的差异，以及BL-1Y对线和临床结局的变化。
PSM后，纳入31例接受CD矫正手术的C2 UIV患者和31例下颈椎UIV患者。两组在BL合并症负担（P=0.175）或cSVA（P=0. forty1）方面无差异。C2组患者年龄更大（64.58岁，P=0.010），融合节段更长（9.6个节段，P=0.002）。总体而言，患者在TS-CL（P<0.001）、cSVA（P=0.005）、McGS（P=0.004）方面显示出BL-1Y改善。无论UIV如何，通过CL前屈（-0.2°.6.0°，P=0.115）和后伸（13.9°.9.9°，P=0.366）评估，颈椎灵活性在1Y时得以维持。虽然下颈椎和C2组患者在McGS方面均显示出BL-1Y改善（均P<0.030），但C2组患者改善程度更大（7.3°.6.2°）。在UIV组之间，HRQLs的BL-1Y变化、总体并发症发生率或手术并发症发生率无差异（均P>0.05）。
C2 UIV患者与下颈椎UIV患者在颈椎活动范围和基线至1年功能结局方面相似。C2 UIV患者在基线至1年水平凝视改善方面也更大，且并发症情况与下颈椎UIV患者相似，表明将融合结构延伸至C2具有影像学益处且功能损失最小。在成人颈椎畸形的治疗中,将重建结构延伸至枢椎可能带来某些临床益处，且发病率低于先前认识。
