Abstract：
OBJECTIVE: The present study utilized recently developed in-construct measurements in simulations of cervical deformity surgery in order to assess undercorrection and predict distal junctional kyphosis (DJK).
METHODS: A retrospective review of a database of operative cervical deformity patients was analyzed for severe DJK and mild DJK. C2-lower instrumented vertebra (LIV) sagittal angle (SA) was measured postoperatively, and the correction was simulated in the preoperative radiograph in order to match the C2-LIV by using the planning software. Linear regression analysis that used C2 pelvic angle (CPA) and pelvic tilt (PT) determined the simulated PT that matched the virtual CPA. Linear regression analysis was used to determine the C2-T1 SA, C2-T4 SA, and C2-T10 SA that corresponded to DJK of 20° and cervical sagittal vertical axis (cSVA) of 40 mm.
RESULTS: Sixty-nine cervical deformity patients were included. Severe and mild DJK occurred in 11 (16%) and 22 (32%) patients, respectively; 3 (4%) required DJK revision. Simulated corrections demonstrated that severe and mild DJK patients had worse alignment compared to non-DJK patients in terms of cSVA (42.5 mm vs 33.0 mm vs 23.4 mm, p < 0.001) and C2-LIV SVA (68.9 mm vs 57.3 mm vs 36.8 mm, p < 0.001). Linear regression revealed the relationships between in-construct measures (C2-T1 SA, C2-T4 SA, and C2-T10 SA), cSVA, and change in DJK (all R > 0.57, p < 0.001). A cSVA of 40 mm corresponded to C2-T4 SA of 10.4° and C2-T10 SA of 28.0°. A DJK angle change of 10° corresponded to C2-T4 SA of 5.8° and C2-T10 SA of 20.1°.
CONCLUSIONS: Simulated cervical deformity corrections demonstrated that severe DJK patients have insufficient corrections compared to patients without DJK. In-construct measures assess sagittal alignment within the fusion separate from DJK and subjacent compensation. They can be useful as intraoperative tools to gauge the adequacy of cervical deformity correction.
METHODS: A retrospective review of a database of operative cervical deformity patients was analyzed for severe DJK and mild DJK. C2-lower instrumented vertebra (LIV) sagittal angle (SA) was measured postoperatively, and the correction was simulated in the preoperative radiograph in order to match the C2-LIV by using the planning software. Linear regression analysis that used C2 pelvic angle (CPA) and pelvic tilt (PT) determined the simulated PT that matched the virtual CPA. Linear regression analysis was used to determine the C2-T1 SA, C2-T4 SA, and C2-T10 SA that corresponded to DJK of 20° and cervical sagittal vertical axis (cSVA) of 40 mm.
RESULTS: Sixty-nine cervical deformity patients were included. Severe and mild DJK occurred in 11 (16%) and 22 (32%) patients, respectively; 3 (4%) required DJK revision. Simulated corrections demonstrated that severe and mild DJK patients had worse alignment compared to non-DJK patients in terms of cSVA (42.5 mm vs 33.0 mm vs 23.4 mm, p < 0.001) and C2-LIV SVA (68.9 mm vs 57.3 mm vs 36.8 mm, p < 0.001). Linear regression revealed the relationships between in-construct measures (C2-T1 SA, C2-T4 SA, and C2-T10 SA), cSVA, and change in DJK (all R > 0.57, p < 0.001). A cSVA of 40 mm corresponded to C2-T4 SA of 10.4° and C2-T10 SA of 28.0°. A DJK angle change of 10° corresponded to C2-T4 SA of 5.8° and C2-T10 SA of 20.1°.
CONCLUSIONS: Simulated cervical deformity corrections demonstrated that severe DJK patients have insufficient corrections compared to patients without DJK. In-construct measures assess sagittal alignment within the fusion separate from DJK and subjacent compensation. They can be useful as intraoperative tools to gauge the adequacy of cervical deformity correction.
摘要：
目的：本研究在颈椎畸形手术的模拟中使用了最近开发的结构内测量，以评估矫正不足和预测远端交界性后凸(DJK)。
方法：回顾性分析了严重DJK和轻度DJK的颈椎手术畸形患者数据库。术后测量C2-下器械椎骨（LIV）矢状角（SA），并在术前X线片中使用计划软件模拟校正，以匹配C2-LIV。使用C2骨盆角（CPA）和骨盆倾斜（PT）的线性回归分析确定了与虚拟CPA匹配的模拟PT。线性回归分析用于确定C2-T1SA，C2-T4SA,和C2-T10SA对应于20°的DJK和40mm的颈椎矢状垂直轴（cSVA）。
结果：共纳入69例颈椎畸形患者。严重和轻度DJK发生在11例（16％）和22例（32％）患者中，分别为3（4%）需要DJK修订。模拟校正表明，重度和轻度DJK患者在cSVA方面与非DJK患者相比有更差的对准（42.5mmvs33.0mmvs23.4mm，p<0.001）和C2-LIVSVA（68.9毫米vs57.3毫米vs36.8毫米，p<0.001)。线性回归揭示了构造内度量之间的关系(C2-T1SA，C2-T4SA,和C2-T10SA），cSVA,和DJK的变化（所有R>0.57，p<0.001）。40mm的cSVA对应于10.4°的C2-T4SA和28.0°的C2-T10SA。10°的DJK角度变化对应于5.8°的C2-T4SA和20.1°的C2-T10SA。
结论：模拟颈椎畸形矫正表明，与没有DJK的患者相比，严重的DJK患者矫正不足。构造内措施评估融合内的矢状对准，与DJK和下方补偿分开。它们可以用作术中工具来衡量宫颈畸形矫正的充分性。
方法：回顾性分析了严重DJK和轻度DJK的颈椎手术畸形患者数据库。术后测量C2-下器械椎骨（LIV）矢状角（SA），并在术前X线片中使用计划软件模拟校正，以匹配C2-LIV。使用C2骨盆角（CPA）和骨盆倾斜（PT）的线性回归分析确定了与虚拟CPA匹配的模拟PT。线性回归分析用于确定C2-T1SA，C2-T4SA,和C2-T10SA对应于20°的DJK和40mm的颈椎矢状垂直轴（cSVA）。
结果：共纳入69例颈椎畸形患者。严重和轻度DJK发生在11例（16％）和22例（32％）患者中，分别为3（4%）需要DJK修订。模拟校正表明，重度和轻度DJK患者在cSVA方面与非DJK患者相比有更差的对准（42.5mmvs33.0mmvs23.4mm，p<0.001）和C2-LIVSVA（68.9毫米vs57.3毫米vs36.8毫米，p<0.001)。线性回归揭示了构造内度量之间的关系(C2-T1SA，C2-T4SA,和C2-T10SA），cSVA,和DJK的变化（所有R>0.57，p<0.001）。40mm的cSVA对应于10.4°的C2-T4SA和28.0°的C2-T10SA。10°的DJK角度变化对应于5.8°的C2-T4SA和20.1°的C2-T10SA。
结论：模拟颈椎畸形矫正表明，与没有DJK的患者相比，严重的DJK患者矫正不足。构造内措施评估融合内的矢状对准，与DJK和下方补偿分开。它们可以用作术中工具来衡量宫颈畸形矫正的充分性。
