颅脊交界疾患经口手术的枕寰枢置钉策略

Screw placement strategy of transoral occipitoatlantoaxial instrumentation for craniocervical junction diseases

中文关键词:  颅脊交界疾患  寰枢关节  经口手术  置钉策略

英文关键词:Craniocervical junction disease  Atlantoaxial joints  Transoral surgery  Screw placement strategy

中文摘要:

  【摘要】 目的：探讨颅脊交界疾患经口手术枕寰枢螺钉固定的置钉策略。方法：2010年1月～2010年12月，30例颅脊交界疾患病例（包括寰枢椎脱位12例，颅底凹陷症15例和先天性颅脊交界畸形3例）均采用第三代经口寰枢椎复位钢板（transoral atlantoaxial reduction plate-Ⅲ，TARP-Ⅲ）内固定植骨融合手术进行治疗。患者术前均有颈部不适和不同程度的肢体麻木、无力等高位脊髓受压表现，影像学检查均存在脊髓腹侧受压。按美国脊髓损伤协会（American Spinal Injury Association，ASIA）分级：C级5例，D级25例。ASIA运动评分为42～96分，平均77.2±14.4分。所有病例均通过计算机辅助设计快速成型（computer aided design and rapid prototype，CAD-RP）技术制作颅脊交界区的1∶1三维模型实物，13例复杂病例术前在模型实物上模拟手术进钉。枕寰枢螺钉的选择主要采用四种方法：A，C0/C1融合者（存在先天性寰椎枕骨化畸形的患者）采用寰椎侧块枕骨髁融合体螺钉；B，C0/C1未融合者（C1侧块完整的患者）采用寰椎侧块螺钉；C，无颅底凹陷且枢椎椎弓根发育正常的患者采用枢椎经口逆向椎弓根螺钉；D，存在颅底凹陷或虽无颅底凹陷但枢椎椎弓根发育狭小或存在椎动脉高跨等无法置入椎弓根螺钉的患者，采用枢椎经口逆向关节突螺钉。本组颅底凹陷症患者TARP-Ⅲ内固定时采用AC或AD的螺钉组合，寰枢椎脱位和先天性颅脊交界畸形患者采用BC或BD的螺钉组合，从而形成TARP固定的4种螺钉组合方式：AC、AD、BC或BD。随访观察治疗效果。结果：30例患者术后颈部局部症状和肢体麻木无力症状均不同程度改善，无感染、神经血管损伤、钉板松脱等并发症发生，2例术后有短暂头晕，术后2周～1个月自愈。术后影像学检查内固定位置满意，脊髓压迫均彻底解除。术后25例ASIA分级D级患者中的8例改善至E级，其余17例分级无变化，但术后运动评分改善至87～100分（96.4±4.2分）；5例C级患者均改善至D级。术后随访3～12个月，平均7.2个月，所有病例均获骨性融合，30例计120枚螺钉（包括寰椎侧块枕骨髁融合体螺钉30枚，寰椎侧块螺钉30枚，枢椎经口逆向椎弓根螺钉16枚和枢椎经口逆向关节突螺钉44枚）均位置理想。结论：不同的颅脊交界疾患病例行经口入路手术时，应选择不同的螺钉固定方法，通过枕寰枢螺钉的多种组合方式，可达到使TARP坚强固定寰枢关节的作用。

英文摘要:

  【Abstract】 Objectives: To study the screw placement strategy of transoral occipitoatlantoaxial instrumentation for craniocervical junction diseases. Methods: 30 patients with craniocervical disease (including 12 atlantoaxial dislocation, 15 basilar invagination, and 3 congenital deformity of craniocervical junction) were treated surgically with transoral atlantoaxial reduction plate-Ⅲ(TARP-Ⅲ) from January to December of 2010. All the patients presented with neck pain and extremity weakness and numbness in different degrees. Preoperative imaging of all cases showed the obvious ventral spinal cord compression. According to ASIA score, 5 cases were in grade C and 25 were in grade D. The motorscore was averagely 77.2±14.4(range, 42-96). Three-dimensional craniocervical models of all cases were established according to the technique of CAD-RP with the proportion of 1∶1. Preoperational screw-insertion simulation was performed on the models of 13 cases. 4 techniques of screw placement for transoral occipitoatlantoaxial internal fixation were adopted as follows: A, C1 lateral mass/occipital condyle complex screw(indicated for C0/C1 fusion); B, lateral mass screw of C1 (indicated for C0/C1 non-fusion); C, transoral transpedicular screw of C2(indicated for normal pedicle without basilar invagination); D, transoral articular mass screw of C2(indicated for basilar invagination, slim pedicle of C2, or elevatus vertebral artery of C2, etc.). The screw combination of AC or AD was chosen based on the presence of basilar invagination, that of BC or BD was chosen based on atlantoaxial dislocation or congenital craniocervical malformation. As a result, the combination of the screw placement for TARP fixation included: AC, AD, BC, and BD. Results: All 30 cases had neck pain and extremity weakness and numbness improved to some degree after operation. Infection, neurological or vascular injury, or screw-loosening was not noted. Some cases presented with light dizziness, which was resolved 2-4 weeks later maturely. Postoperative imaging showed the ideal position of internal fixation and complete decompression. 8 cases had neurofuntion improved from D to E according to ASIA standard; while the other 17 cases remained unchanged, but their motor scores increased to 96.4±4.2(range, 87-100). 5 cases had ASIA score improved from C to D. During an average follow-up of 7.2 months, all cases obtained bony fusion, and all 120 screws(including 30 in C1 lateral mass/occipital condyle complex screw, 30 in lateral mass screw of C1, 16 in transoral transpedicular screw of C2, and 44 in transoral articular mass screw of C2) were in good position. Conclusions： For craniocervical junction diseases necessitating transoral procedure, the screw placement should be decided individually. Multiple combinations of the occipitoatlantoaxial screws are available.