Department of Spine Surgery, Affiliated Hospital of Southwest Medical University, No. 25 Taiping Street, Luzhou City, 646000, China.
Eur Spine J. 2020 Nov;29(11):2769-2777. doi: 10.1007/s00586-020-06551-z. Epub 2020 Jul 30.
To investigate the morphological characteristics and para-positions of the facets of lateral atlantoaxial joints (FLAJs) in patients with congenital atlantoaxial dislocation (CAAD) and to propose a classification system for the FLAJs.
A total of 93 cases of CAAD were included in this retrospective study. The obliquity and slippage of the FLAJs in the sagittal and coronal planes were measured and observed in the CT images of all of the cases. The obliquity and slippage of the FLAJs represented the morphological characteristics and the para-positions, respectively, and were used as classification parameters. Accordingly, a classification system for the FLAJs was established. We additionally investigated the correlation between the classifications of the FLAJs and various types of CAAD. The classifications of the FLAJs in 34 patients with irreducible AAD (IAAD) were also investigated.
One hundred eighty-six FLAJs in 93 patients were classified into 6 types (namely, A, B1, B2, C, D1, and D2) for obliquity and 3 types (namely, S, S, and S) for slippage. Among the 186 FLAJs, type B1 and type S were the most common obliquity and slippage types, respectively. There were 11 combination types for obliquity and 5 combination types for slippage of bilateral FLAJ in 93 patients. Most of the patients (69.7%, 47/70) with anteroposterior AAD had accompanying slippage and anteversion of the FLAJ in the sagittal plane. Rotational AAD was found in 10 patients with asymmetrical slippage in both FLAJs in the sagittal plane. Lateral translational AAD was found in 6 patients with an S-type FLAJ in the coronal plane. In 5 patients with lateral angular AAD, FLAJs of types D1 and S were observed on one side. Among the 34 patients with IAAD, 31 patients had both obliquity and slippage in the FLAJs on one or both sides.
The morphological characteristics and para-positions of the FLAJs on both sides largely determine the types of AAD in patients with CAAD. The types of obliquity and slippage of the FLAJ are related to the reducibility of AAD.
探讨先天性寰枢椎脱位（CAAD）患者寰枢外侧关节（FLAJ）的关节面形态特征和方位，提出 FLAJ 的分类系统。
回顾性分析 93 例 CAAD 患者的 CT 图像，测量并观察矢状面和冠状面 FLAJ 的倾斜和滑移情况。FLAJ 的倾斜和滑移分别代表形态特征和方位，作为分类参数。据此建立 FLAJ 的分类系统。还研究了 FLAJ 分类与各种类型 CAAD 的关系。还研究了 34 例不可复位寰枢椎脱位（IAAD）患者的 FLAJ 分类。
93 例患者的 186 个 FLAJ 分为 6 种（A、B1、B2、C、D1 和 D2）倾斜型和 3 种（S、S 和 S）滑移型。186 个 FLAJ 中，B1 型和 S 型分别为最常见的倾斜和滑移类型。93 例患者双侧 FLAJ 的倾斜有 11 种组合类型，滑移有 5 种组合类型。大多数（69.7%，47/70）前向后寰枢椎脱位患者伴有 FLAJ 在矢状面的滑移和前倾角。10 例旋转性寰枢椎脱位患者双侧 FLAJ 在矢状面存在不对称性滑移。6 例冠状面 S 型 FLAJ 患者发生横向平移性寰枢椎脱位。5 例侧向角状寰枢椎脱位患者单侧 FLAJ 为 D1 型和 S 型。34 例 IAAD 患者中，31 例单侧或双侧 FLAJ 存在倾斜和滑移。
双侧 FLAJ 的形态特征和方位在很大程度上决定了 CAAD 患者的寰枢椎脱位类型。FLAJ 的倾斜和滑移类型与寰枢椎脱位的可复位性有关。
