Cervifix内固定系统对陈旧性寰枢椎脱位的修复稳定应用

Application of Cervifix internal fixation system in the repair and fixation of old atlanto-axial dislocation

目的:评价应用Cervifix内固定系统治疗,改善脊髓功能的作用。方法:选择1999-10/2003-04解放军广州军区广州总医院骨科采用Cervifix内固定系统治疗陈旧性寰枢椎前脱位伴高位颈髓压迫症患者25例。陈旧性齿突骨折脱位12例,先天性畸形10例,类风湿性关节炎3例,均为寰枢椎前脱位。根据患者的病情分别采取不同方法,经口咽前路和后路一期减压及后路内固定6例,后路减压内固定12例,后路减压内固定后二期行前路减压7例。减压后全部病例均行Cervifix枕颈内固定,取髂骨植骨,术后佩带颈围3个月。采用日本骨科协会评分法(JOA17分,0分为严重障碍,分值越高表示功能越好)评价脊髓功能改善率。改善率=[(术后评分-术前评分)/17]×100%。采用自拟的公式评价脊髓受压改善率,改善率=[(术后矢径-术前矢径)/(拟正常矢径-术前矢径)]×100%。结果:按意向处理分析,25例均进入结果分析。①随访结果:平均随访22个月。患者枕颈不适消失,四肢麻木基本消失,感觉和肌力均有不同程度的恢复;术后日本骨科协会评分平均为14.2分,平均较术前提高6.4分,术后脊髓功能改善率为68.4%;术后脊髓减压改善率为70.2%;术后三四个月均骨性融合,无骨不连发生。②不良事件及副反应:25例无一例发生内固定折断及松脱现象。但随访时间超过2年的病例中,有6例患者发现其颈椎固定节段与未固定节段的界面出现明显的成角和轴线异常的影像学变化。术后被固定融合的枕颈及颈椎节段的活动功能均丧失,仅靠下颈椎的代偿,颈椎活动度明显受限,仅为正常活动度的1/3左右。1例发生椎动脉损伤,为先天性畸形患者,术中给予及时处理。结论:Cervifix颈椎后路内固定系统装配合理,提供螺丝钉最佳装配位置;留有植骨空间利于植骨融合;其纯钛/TAN合金材质不影响术后MRI检查,能量化术后的脊髓减压改善情况,优于枕颈CD环等内固定。但其固定节段多,影响颈椎活动度;并可加速下位颈椎的退行性变。

AIM： To evaluate the clinical application of Cervifix internal fixation system in treating old atlanto-axial dislocation and improving spinal cord function. METHODS： Twenty-five cases of old atlanto-axial dislocation with high spinal cord compression, who were treated with Cervifix internal fixation system in the Department of Orthopaedics, Guangzhou General Hospital of Guangzhou Military Area Command of Chinese PLA between October 1999 and April 2003, were selected. Of the 25 cases of anterior dislocation of atlantoaxial joint, 12 were old odontoid fracture dislocation, 10 were congenital deformity and 3 were rheumatoid arthritis. According to the condition of the patients, different methods were adopted： 6 cases were treated with transoral anterior and posterior decompression of stage Ⅰ and posterior internal fixation, 12 cases with posterior decompression and internal fixation, and 7 cases with anterior decompression after posterior decompression and internal fixation of stage Ⅱ. After decompression, all the patients received Cervifix occipitocervical internal fixation, autologous iliac bone graft, and wore neck collar for 3 month after operation. The ameliorative rate of spinal cord function was evaluated with the scoring system of Japanese Orthopaedic Association （JOA17, 0 point was taken as severe disorder, the higher the score, the better the function）, ameliorative rate =[（postoperative score-preoperative score）/17]×100%. The ameliorative rate for compression of spinal cord was evaluated with the self-designed formula, ameliorative rate =[（postoperative diameter -preoperative diameter）/（estimated normal diameter -preoperative diameter）]×100%. RESULTS： According to intention-to-treat analysis, all the 25 cases were involved in the analysis of results, ① Follow-up results： The patients were followed up averagely for 22 snonths. The symptoms of occipitoeervical discomfort disappeared, limbs＇ numbness generally diminished, sense and muscle force recovered to different extent; The average postoperative JOA score was 14.2 points, which was increased averagely by 6,4 points as compared with the preoperative one. The postoperative ameliorate of spinal cord function was 68.4%, and that of spinal cord decompression was 70.2%. Bone fusions were all observed after 3 or 4 months, no nonunion of bone occurred.② Adverse events and side effeets. Disjunction and looseness of the internal fixation occurred in none of the 25 cases. Of the patients who were followed up for more than 2 years, 6 cases found that there were obvious imaging changes of angulation and axial abnormalities on the interface of their cervical fixed and unfixed segments. After operation, the motor functions of the fixed and fused occipitocervical and cervical segments all disappeared, which were only compensated by lower cervical vertebra, the motion range of cervical vertebra was obviously restricted, it was only 1/3 of the normal one. Vertebral artery injury occurred in 1 case of congenital deformity, and timely treatments were given during the operation. CONCLUSION： Cervifix cervical posterior internal fixation system has reasonable installation, it provides screws the best installing position, itleaves grafted space which is good for the fusion of grafted bone. Its pure titanium/TAN metallic alloy material does not affect the MRI examination, and can quantify the postoperative amelioration of spinal cord decompression, so it is superior to other internal fixations of occipitocervical CD ring, etc. But it has many fixed segments, which affect the motion range of cervical vertebra, and accelerate the degeneration of lower cervical vertebra.