枢椎乳突的测量及临床应用

Classification of the axial mastoid process and its clinical application

目的研究枢椎乳突的测量方法，并对枢椎乳突进行简单分型，依据其分型和临床经验改良传统进钉点，进而探究改良进钉点对经皮前路螺钉治疗齿状突骨折的临床指导意义。方法回顾性研究120例颈椎疾病患者的正中矢状位CT影像学图像，男63例，女57例；年龄31—59岁，平均41．6岁。在CT正中矢状位影像学图像上绘制并测量AB两点距离，即为枢椎乳突的高度，根据测量结果的X2.5%和X7.5%数值及临床经验找出改良进钉点。回顾性研究32例Anderson和D’Alonzo ⅡA、ⅡB、浅Ⅲ型齿状突骨折患者资料，其中15例患者使用改良进钉点行经皮前路螺钉内固定治疗（改良进钉点组），17例患者使用常规进钉点行经皮前路螺钉内固定治疗（常规进钉点组），比较两组患者手术切口长度、手术时间、出血量、透视次数及住院时间。结果AB两点距离为（3．42±0．68）mm，定义低平型乳突为AB两点距离〈3mm，略凸型乳突为AB两点距离在3～4mm，隆起型乳突为AB两点距离〉4ITlln；120例颈椎患者低平型乳突32例（26．7％），略凸型乳突57例（47．5％），隆起型乳突31例（25．8％）。改良进钉点组患者较常规进钉点组手术时间短【（31．32±2．12）US．（46．18±3．63）min]，透视次数少[（18．20±1．57）次US．（21．27±2．50）次]，出血量多[（43．22±3．17）mLUS．（31．22±3．52）mL]，差异均有统计学意义（P〈0．05）。两组患者的手术切口长度、住院时间比较差异均无统计学意义（P〉0．05）。结论根据枢椎乳突分型确定的改良进钉点对经皮前路螺钉治疗齿状突骨折具有重要的临床指导意义，大大提高了手术效率的同时，减少了术者受辐射危害的几率。

Objective To explore a simple classification of the axial mastoid process and its clinical significance in improving the traditional screw insertion in the treatment of odontoid fracture with percutaneous anterior odontoid screwing. Methods The median sagittal CT images of 120 patients with cervical dis- ease were measured. They were 63 males and 57 females, aged from 31 to 59 years （average, 41.6 years）. On their median sagittal CT images, line A was the connection of the lowest point of the anterior inferior boarder of the axis body to the vertex of the odontoid process and line B a parallel line to line A through the mastoid process. The distance between lines A and B was measured （the height of the axial mastoid process） and a complete statistical record was made to analyze the distribution and regularity of distances AB. The improved insertion points were indentified based on the above measurements （ X25~o and XTs~ ） and clinical ex- perience. We reviewed 32 patients with odontoid fracture of Anderson ＆ D＇ Alonzo type liA, liB or superficial IU. Of them 15 underwent percutaneous anterior screwing by the improved insertion points and 17 underwent percutaneous anterior screwing by the conventional insertion points. The 2 groups were compared in terms of incision length, operation time, bleeding, fluoroscopy frequency and hospital stay. Results Distance AB was 3.42 ± 0. 68 mm. The distance AB 〈 3 mm was classified as low-level mastoid process, the distance AB between 3 to 4 mm as slightly convex mastoid process, and the distance AB 〉 4 mm as convex mastoid process. Of the 120 patients, 32 （26.7%） were classified as having a low-level mastoid process, 57 （47.5%） as having a slightly convex mastoid process, and 31 （25.8 % ） as having a convex mastoid process. Compared with the conventional insertion group, the improved insertion group had significantly shorter oper- ation time （31.32 ± 2. 12 rain versus 46. 18 ± 3.63 min）, significantly lower fluoroscopy frequency （ 18.20±1.57 times versus 21.27 ± 2.50 times） but significantly greater bleeding （43.22 ± 3.17 mL versus 31.22± 3.52 mL） （ P 〈 0.05） . There were no significant differences between the 2 groups in incision length or hospital stay （ P 〉 0. 05）. ConcJusions In the treatment of odontoid fracture with per＇cutaneous anterior odontoid screwing, the screw insertion can be improved according to our classification of the axial mastoid process. Our simple classification of the axial mastoid process may lead to more efficient operation and less radiation hazard.