先天性寰枢椎脱位的CT影像学分型及其临床意义

A study on a CT imaging classification of congenital atlantoaxial dislocation and its clinical significance

中文关键词:  先天性寰枢椎脱位  寰枢椎脱位CT 影像分型  手术策略  经口咽截骨改造、松解复位钢板内固定术

英文关键词:Congenital atlantoaixal dislocation  Atlantoaxial dislocation CT image classification  Surgery strategy  Transoral osteotomy, remodelling, releasing, reduction and fixation with plate

中文摘要:

  【摘要】 目的：建立一种基于CT影像特征的先天性寰枢椎脱位分型方法，探讨其对寰枢椎手术方式选择的指导价值。方法：2020年1月~2022年12月，共纳入61例先天性寰枢椎脱位患者，其中男性26例、女性35例；年龄32±12岁（6~61岁）。对61例患者的术前CT影像学特征进行分析，并根据其寰枢侧块关节及寰齿关节的畸形程度分为三种类型：A型（23例，侧块关节轻度畸形，不伴寰齿关节畸形）；B型（20例，侧块关节中度畸形，不伴寰齿关节畸形）；C型（18例，侧块关节重度畸形或伴寰齿关节畸形）。根据不同分型采用不同手术策略：A型或B型患者先行全麻下寰枢椎后路器械撑开复位内固定术，对复位效果不佳的患者增加寰枢椎后路侧块关节松解术；C型患者行经口咽前路寰枢椎截骨改造、松解复位内固定手术（transoral osteotomy，releasing，reduction and fixation with plate，TORP）。随访时间为10~18个月。记录并比较各分型患者的手术时间及出血量；术后1周复查颈椎CT及MRI，观察并测量寰枢椎脱位复位指标，计算寰枢椎脱位的整体复位率；术后3个月采用日本骨科协会（Japanese Orthopaedic Association，JOA）评分评价术后脊髓功能恢复情况，通过CT检查评价术后骨融合情况。结果：共实施全麻牵引下寰枢椎后路器械撑开复位内固定术22例（A型20例，B型2例），全麻牵引下寰枢椎后路侧块关节松解并后路器械撑开复位内固定术21例（A型3例，B型18例），实施TORP术18例（均C型）。61例患者术后1周的CT及MRI显示寰枢椎复位良好，脊髓压迫解除。术后所有患者的脊髓功能均有不同程度的改善，A型JOA评分由术前9.8±2.7分改善为术后3个月的13.9±2.8分（P<0.05）；B型JOA评分由术前9.5±2.4分改善为术后3个月的13.7±3.1分（P<0.05）；C型JOA评分由术前9.1±2.9分改善为术后3个月的13.3±2.5分（P<0.05）。A型患者术前及术后1周寰齿间隙（atlas-dens interval，ADI）为5.8±2.5mm、0.8±0.4mm，齿状突顶点距Chamberlain线的垂直距离（vertical distance from dens to Chamberlain line，VDI）为5.7±3.6mm、1.0±0.8mm，脑干延髓角（cervical medullary angle，CMA）为138.4°±12.4°、156.5°±13.3°，斜坡枢椎角（clivus axis angle，CAA）为131.6°±11.5°、149.5°±14.4°；B型术前及术后1周ADI为6.9±3.8mm、1.1±0.9mm，VDI为5.9±4.3mm、1.1±1.0mm，CMA为135.1°±15.2°、157.3°±13.2°，CAA为128.4°±13.5°、152.5°±13.4°；C型术前及术后1周ADI为7.2±3.9mm、1.2±1.5mm，VDI为8.8±5.1mm、1.5±1.8mm，CMA为132.7°±10.9°、158.2°±15.3°，CAA为124.5°±17.8°、153.8°±11.2°；各分型术后ADI、VDI、CMA和CAA值均得到显著改善（P＜0.05）。A型整体复位率84.30%，B型整体复位率82.68%，C型整体复位率81.53%，各组之间复位率比较差异无统计学意义（P>0.05）。除1例B型患者因骨融合不佳，发生螺钉松动，后实施经口咽前路翻修手术外，其余60例患者均在术后10~12个月得到了稳定的骨性融合。结论：本研究建立的关于先天性寰枢椎脱位的CT影像学分型方法，可为寰枢椎手术方式选择提出精准、可靠的指导意见。

英文摘要:

  【Abstract】 Objectives: To develop a classification method of congential atlantoaxial dislocation(CAAD) based on CT imaging features, and to investigate its guiding values for determining atlantoaxial surgery strategies. Methods: From January 2020 to December 2022， 61 patients with CAAD were included in the study，consisting of 26 males and 35 females, aged 32±12 years(6-61 years). And the patients were divided into three types based on the extent of deformity observed in atlantoaxial lateral mass joint and atlanto-odontoid joint: Type A(23 cases, mild deformity in the lateral mass joint without concurrent atlanto-odontoid joint deformity); Type B(20 cases, moderate deformity in the lateral mass joint without concurrent atlanto-odontoid joint deformity); Type C(18 cases, severe deformity in the lateral mass joint or concurrent deformity of atlanto-odontoid joint). Different surgical strategies were employed according to the distinctive classification: Type A or Type B patients underwent posterior reduction and fixation with instrumentation only with general anesthesia, after which, additional posterior atlantoaxial facet joint release was performed for patients with unsatisfactory reduction; Type C patients received transoral osteotomy, remodelling, releasing, reduction and fixation with plate(TORP). The operative time and blood loss were recorded and compared between different types of patients. The follow-up period extended from 10 to 18 months. Cervical spine CT and MRI examinations were performed at postoperative 1 week to observe and measure the reduction indicators of atlantoaxial dislocation, and overall reduction rates were calculated. At 3 months after operation, Japanese Orthopaedic Association(JOA) score was used to evalute the recovery of spinal cord function, bone fusion status was assessed through CT examinations. Results: 22 cases underwent posterior reduction and fixation with instrumentation only under general anesthesia(type A 20 cases, type B 2 cases). 21 cases received posterior reduction by release of lateral mass joint and fixation with posterior instrument(type A 3 cases，type B 18 cases). 18 cases(type C) underwent TORP operation. Postoperative CT and MRI images taken one week after the procedure exhibited well-aligned atlantoaxial joints, indicating the release of spinal cord compression in all 61 patients. During follow-up, all the patients demonstrated diverse levels of improvement in spinal cord function. For type A cases, the JOA score improved from a preoperative value of 9.8±2.7 to 13.9±2.8 at three months postoperatively(P<0.05). Type B cases exhibited an improvement in JOA score from 9.5±2.4 preoperatively to 13.7±3.1 at three months postoperatively(P<0.05). Type C cases showed an improvement from 9.1±2.9 to 13.3±2.5 over the same period(P<0.05). At preoperation and 1 week after operation, for type A, the atlas-dens interval(ADI) was 5.8±2.5mm and 0.8±0.4mm, vertical distance from dens to Chamberlain line(VDI) was 5.7±3.6mm and 1.0±0.8mm, cervical medullary angle(CMA) was 138.4°±12.4° and 156.5°±13.3°, and clivus axis angle(CAA) was 131.6°±11.5° and 149.5°±14.4°; For type B, ADI was 6.9±3.8mm and 1.1±0.9mm, VDI was 5.9±4.3mm and 1.1±1.0mm, CMA was 135.1°±15.2° and 157.3°± 13.2°, and CAA was 128.4°±13.5° and 152.5°±13.4°; For type C, ADI was 7.2±3.9mm and 1.2±1.5mm, VDI was 8.8±5.1mm and 1.5±1.8mm, CMA was 132.7°±10.9° and 158.2°±15.3°, and CAA was 124.5°±17.8° and 153.8°±11.2°; And the ADI, VDI, CMA and CAA of the three types after operation all improved significantly(P<0.05). The overall reduction rates were 84.30% for type A, 82.68% for type B, and 81.53% for type C(P>0.05). With the exception of one case of type A, which experienced screw loosening due to poor bone fusion and subsequently underwent revision surgery via the transoral approach, the remaining 60 patients all achieved stable bony fusion within 10 to 12 months postoperatively. Conclusions: The CT imaging classification method for CAAD can provide accurate and reliable guidance in the selection of surgical methods for atlantoaxial dislocation.