经口咽截骨松解及钢板内固定术治疗难复性寰枢椎脱位

Treating irreducible atlantoaxial dislocation by transoral bony deformity osteotomy and releasing combined with plate fixation

中文关键词:  难复性寰枢椎脱位  颅底凹陷症  经口咽截骨松解钢板内固定术  疗效

英文关键词:Irriducible atlantoaxial dislocation  Basilar invagination  Transoral osteotomy releasing and plate fixation  Curative effect

中文摘要:

  【摘要】 目的：探讨应用经口咽截骨松解及钢板内固定术治疗难复性寰枢椎脱位（irreducible atlantoaixal dislocation，IAAD）的方法与疗效。方法：回顾性分析2015年3月~2018年12月我院应用经口咽截骨、松解及钢板内固定术治疗合并骨性阻挡因素的IAAD的213例患者资料。包括陈旧性齿状突骨折合并寰枢椎脱位15例，游离齿状突合并寰枢椎脱位5例，颅底凹陷症合并寰枢椎脱位193例。患者出现临床症状到手术的时间6个月~3年，平均1.5年。将影响IAAD骨性因素区分为两型8类：A1型（枢椎上关节面的斜坡化），118例（55.4%），178侧（41.8%）；A2型（侧块关节唇样增生），19例（8.9%），31侧（7.3%）；A3型（侧块关节球窝畸形），15例（7.1%），21侧（4.9%）；A4型（侧块关节垂直交锁畸形），13例（6.1%），20侧（4.7%）；A5型（寰枢侧块关节点状融合），6例（2.8%），9侧（2.1%）；B1型（寰齿间隙增生骨痂），30例（14.1%）；B2型（钩状齿突畸形），5例（2.3%）；B3型（肥大齿状突畸形），7例（3.3%）。所有患者行经口咽软组织松解，并将阻碍复位的骨性因素实施截骨，利用侧块关节撑开与撬拨技术将IAAD转化为可复性寰枢椎脱位，最终实施侧块关节间植骨和钢板固定。在术前、术后的颈椎中矢状面重建CT片上测量寰齿间隙（atlas-dens interval，ADI）、齿状突顶点距离Chamberlain线的垂直距离（vertical distance from odontoid process to Chamberlain′s line，DOCL）与斜坡枢椎角（clivus axis angle，CAA），在术前、术后的MRI片上测量脑干颈髓角（cervical medullary angle，CMA），记录术前及术后半年时的日本骨科协会（Japanese Othopaedic Association，JOA）评分。结果：213例患者手术顺利，手术时间148±38min，出血量150±35ml。术后患者肢体麻木、无力及走路不稳症状均有不同程度改善，头痛、颈痛症状有明显缓解。术前ADI为6.5±3.2mm，术后改善为2.5±1.5mm（P<0.05）。术前DOCL为10.3±4.8mm，术后改善为3.3±2.1mm（P<0.05）。术前CMA为115°±25°，术后158°±21°（P<0.05）；术前CAA为101°±28°，术后141°±10°（P<0.05）。随访时间15~24个月（18±13个月），JOA评分由术前9.3±2.8分改善为术后半年的13.9±2.5分（P<0.05）。实施钢板固定置钉时，有3枚逆向椎弓根螺钉偏向内侧进入椎动脉孔，均为非优势侧，未造成严重后果。除1例患者因骨质疏松出现螺钉松动外，其余病例均在术后半年~1年获得了骨性融合。术后1周出现切口感染1例，立即予以清创，取出钢板，改后路固定，术后2年随访愈合良好。结论：除软组织因素外，骨性阻挡是影响寰枢椎复位的重要因素，经口咽截骨松解及钢板内固定术是处理有骨性阻挡因素的IAAD的一种有效手段。

英文摘要:

  【Abstract】 Objectives: To investigate a novel method for treating irreducible atlantoaixal dislocation (IAAD) by transoral bony deformity osteotomy and releasing combined with plate fixation. Methods: A retrospective analysis was conducted on the data of 213 consecutive patients diagnosed as IAAD associated with bony obstruction factors, who underwent a novel method by transoral bony deformity osteotomy and releasing combined with plate fixation from March 2015 to December 2018 in our hospital. There were 15 cases of old odontoid fractures with atlantoaxial dislocation, 5 cases of free odontoids with atlantoaxial dislocation, and 193 cases of basilar invagination (BI) with atlantoaxial dislocation. The period from the onset of clinical symptoms to surgery was 6 months to 3 years, averaged 1.5 years. The skeletal factors affecting IAAD were categorized into two types and 8 subgroups: type A1 [clivus of superior articular facet of axis in 118 cases (55.4%) with 178 sides (41.8%)], type A2 [labial hyperosteogeny of lateral mass joint in 19 cases (8.9%) with 31 sides (7.3%)], and type A3 [lateral mass joint ball and socket deformity in 15 cases (7.1%) with 21 sides (4.9%)], type A4 [lateral mass joint vertical interlocking deformity, 13 cases (6.1%) with 20 sides (4.7%)] and type A5 [dot like bone fusion between lateral mass joints in 6 cases (2.8%) with 9 sides(2.1%)]; and type B1 (bony structures hindering reduction between the atlas-dens gap in 30 cases, 14.1%), type B2 (5 cases of uncinate odontoid deformity, 2.3%), and type B3 (7 cases of hypertrophic odontoid deformity, 3.3%). After soft tissue releasing, the bony structures were eliminated by osteotomy and remodeling to transform the irreducible atlantoaxial dislocation (IAAD) into reducible type, which was fixed with plate after bone implantation between the lateral mass joints. The atlas-dens interval(ADI), vertical distance fromodontoid process to Chamberlain′s line(DOCL) and the clivus axis angle(CAA) were measured on CT films of the mid-sagittal reconstruction of the cervical spine before and after operation. The cervical medulla angle(CMA) was measured on the MRI film before and after operation, and the Japanese Orthopaedic Association(JOA) scores were recorded before operation and at half-year follow-up. Results: Of the 213 patients, the average operation time was 148±38min and the intra operative blood loss was 150±35ml. After operation, the symptoms of numbness, weakness and walking instability were improved to varying degrees, and the symptoms of headache and neck pain were alleviated significantly. The average preoperative ADI was 6.5±3.2mm, and the postoperative ADI was improved to 2.5±1.5mm on average(P<0.05). The average value of VDI before operation was 10.3±4.8mm, and was improved to 3.3±2.1mm postoperatively(P<0.05). The average preoperative CMA was 115°±25°, and the postoperative CMA was 158°±21°(P<0.05); the preoperative CAA averaged 101°±28°, and the postoperative CAA was 141°±10°(P<0.05). The follow-up time was 18±13 months and the JOA score improved from 9.3±2.8 preoperatively to 13.9±2.5 half year after operation(P<0.05). During the process of plate fixation, 3 reverse pedicle screws entered the vertebral artery foramen inwardly, all of which were on non-dominant sides and did not cause serious consequences. In this group of cases, excepted 1 patient experienced screw loosening due to osteoporosis, the rest achieved bone fusion within half a year to 1 year after operation. One case of incision infection occurred 1 week after operation. The wound was immediately debrided, the steel plate was removed, and the posterior fixation was adopted. The follow-up at 2 years after operation showed the wound healed well. Conclusions: In addition to soft tissue factors, bone obstruction is an important factor affecting atlantoaxial reduction. Transoral bony deformity osteotomy and releasing combined with plate fixation is effective in dealing with IAAD with bone obstruction factors.