颅底凹陷症伴寰枢椎脱位患者的寰枢椎侧块关节影像学分型

Radiographic classification of the lateral atlantoaxial joints in basilar invagination with atlantoaxial dislocation

中文关键词:  颅底凹陷症  寰枢椎侧块关节  影像学分型

英文关键词:Basilar invagination  Lateral atlantoaxial joints  Imaging classification

中文摘要:

  【摘要】 目的：分析颅底凹陷症伴寰枢椎脱位患者颅颈交界区三维CT影像学特征，提出寰枢椎侧块关节分型，探讨其对手术决策的意义。方法：回顾分析我院2010年6月~2018年6月收治的颅底凹陷症患者，纳入115例作为观察组，其中男24例，女91例，年龄12~74岁（46.7±8.9岁）。选择年龄、性别相匹配且不伴枕颈区病变的30例作为对照组，其中男6例，女24例，年龄14~76岁（45.8±9.4岁）。观察分析两组患者枕颈区三维CT影像学资料，测量对比两组患者三维CT中寰枢椎侧块关节在冠状面、矢状面上的倾斜角。将观察组侧块关节在冠、矢状面倾角作为寰枢椎侧块关节分型依据，侧块关节滑脱及侧块关节融合作为分型修正指标，制定侧块关节分型。观察组中寰枢椎侧块关节冠状面倾角在对照组95％置信区间（confidence interval，CI）上限外，则视为冠状面倾斜；矢状面倾斜角在对照组95％CI外，则视为矢状面倾斜。根据侧块关节冠、矢状面倾斜分型：观察组中双侧侧块关节均无冠状面、矢状面倾斜，则为Ⅰ型；单侧或双侧侧块关节矢状面倾斜，无冠状面倾斜，则为Ⅱ型；单侧或双侧侧块关节冠状面倾斜，无矢状面倾斜，则为Ⅲ型;单侧或双侧侧块关节同时存在冠、矢状面倾斜，或者双侧侧块关节分别为冠状面倾斜和矢状面倾斜，则为Ⅳ型。根据侧块关节融合与滑脱情况进行分型修正：不伴侧块关节融合F0，侧块关节前缘或后缘小面积量骨性融合为F1，侧块关节大面融合为F2；不伴滑脱为D0，伴冠、矢状面部分滑脱为D1，完全滑脱或伴侧块关节绞锁为D2。通过术中全麻下颅骨牵引评估观察组患者复位难易，统计不可复型患者在侧块关节各分型中的分布情况，分析分型与复位难易相关性。结果：对照组30例中60侧侧块关节冠、矢状面倾角分别为25.4°±4.1°和2.4°±5.8°。观察组冠状面倾斜角95％CI为17.2°~33.6°，矢状面倾斜角95％CI为-9.2°~14.0°。观察组115例患者寰枢椎侧块关节分型：Ⅰ型22例（19.1％），Ⅱ型59例（51.3％），Ⅲ型8例（7.0％），Ⅳ型26例（22.6％）。Ⅰ型中伴D1患者7例，伴F1、F2、D2 0例；Ⅱ型中伴F1 1例，F2 2例，D1 42例，D2 2例；Ⅲ型中伴F1 1例，D1 5例，伴F2、D2 0例；Ⅳ型中伴F1 1例，F2 1例，D1 18例，D2 3例。Ⅰ型2 2例中不可复型患者2例（9.1％），Ⅱ型23例（39.0％），Ⅲ型3例（37.5％），Ⅳ型12例（46.2％）。观察组115例患者牵引下评估为不可复型40例。Ⅰ型不可复型患者占比显著低于Ⅱ与Ⅳ型患者，具有统计学差异（P＜0.05）。伴F1、F2及D2共11例均为不可复型。伴D1患者中不可复型患者占比显著高于D0，具有统计学差异（P＜0.05）。结论：根据颅底凹陷症伴寰枢椎脱位患者寰枢椎侧块关节的三维CT影像学特征提出寰枢椎侧块关节分型，有助于术前评估颅底凹陷症复位难易，对伴寰枢椎脱位的颅底凹陷症患者的手术决策具有重要指导作用。

英文摘要:

  【Abstract】 Objectives: To analyze the three-dimensional CT imaging of craniocervical junction area in patients with basilar invagination with atlantoaxial dislocation, to propose the classification of the lateral atlantoaxial joints, and to explore its significance for the determination of surgical strategy. Methods: Retrospective analysis of patients with basilar invagination admitted to our hospital from June 2010 to June 2018, among which 115 patients were included as observation group (24 males, 91 females, aged from 12 to 74 years, mean age 46.7±12.8 years). 30 volunteers without occipitocervical lesions, matched by age and sex, were selected as control group (6 males and 24 females, aged from 14 to 76 years, mean age 45.8±9.4 years). The imaging data of the two groups were collected and the obliquity of the lateral atlantoaxial joint in coronal plane and sagittal plane was measured using three-dimensional CT. The obliquity in sagittal plane in the observation group outside of 95% CI of the control group was regared as sagittal tilting. And the obliquity in coronal plane outside of upper limit of 95% CI of the control group was regared as coronal tilting. Classification was made according to the obliquity of coronal and sagittal planes: type Ⅰ- no obliquity in both sagittal plane and coronal plane of the bilateral lateral atlantoaxial joint in the observation group; type Ⅱ-the obliquity was found in sagittal plane of unilateral or bilateral lateral atlantoaxial joint in the observation group; type Ⅲ-the obliquity was found in coronal plane of unilateral or bilateral lateral atlantoaxial joint in the observation group; type Ⅳ-the obliquity was found in sagittal and coronal plane in unilateral or bilateral lateral atlantoaxial joint, or the sagittal and coronal obliquity was found in bilateral lateral atlantoaxial joint respectively. The classification was modified according to the fusion and slippage of the lateral atlantoaxial joint: F0 is defined as no lateral mass joint fusion, F1 for small area bone fusion of anterior or posterior edge of lateral mass joint, and F2 for large area fusion of lateral mass joint; D0 for no slippage, D1 for coronal and sagittal partial slippage, D2 for complete slippage or joint interlocking. Reducibility of patients of observation group were evaluated under intraoperative traction, and the distribution of the irreducible patients in each type of lateral mass joint was assessed. The correlation between the types and the reducibility was analyzed. Results: The obliquity in coronal plane and sagittal plane of 60 lateral mass joints of 30 volunteers in the control group were 25.4°±4.1° and 2.4°±5.8°, respectively. The 95% CI of the obliquity in coronal plane in control group was 17.2°-33.6° (the obliquity in coronal plane in the observation group was greater than 33.6°, which was regarded as coronal tilt). The 95% CI of the obliquity in coronal plane in control group was -9.2°-14.0° (the obliquity in sagittal plane in the observation group less than -9.2° or gather than 14.0°, which was regarded as sagittal tilt). 115 Patients in the observation group were classified into 4 types: 22 cases (19.1%) as type Ⅰ, 59 cases (51.3%) as typeⅡ, 8 cases (7.0%) as type Ⅲ, and 26 cases (22.6%) as type Ⅳ. In type Ⅰ, there were 7 cases with D1 and no case with F1, F2 and D1. In TypeⅡ, 1 case with F1, 2 cases with F2, 42 with D1, 2 with D2. In Type Ⅲ, 1 with F1, 5 with D1, and no case with F2 and D2. In Type Ⅳ, 1 with F1, 1 with F2, 18 with D1, 3 with D2. Among the 40 patients with irreducible atlantoaxial dislocation, 2(9.1%)were type Ⅰ, 23(39.0%) were type Ⅱ, 3(37.5%) were type Ⅲ and 12(46.2%) were type Ⅳ. 40 patients of observation group were evaluated as irreducible under intraoperative traction. The percentage of irreducible type in type Ⅰ patientswas significantly lower than that of type Ⅱ patients and type Ⅳ patients(P<0.05). 11 cases with F1, F2 or D2 were irreducible. The percentage of irreducible type in patients with D1 or D2 was significantly higher than that of D0(P<0.05). Conclusions: The classification of lateral atlantoaxial joints in patients with basilar invagination based on imaging features of three-dimensional CT of lateral atlantoaxial joints is helpful to evaluate the reducibility before operation. It is also important to guide the intraoperative operation of lateral atlantoaxial joints.