单侧枢椎椎板螺钉在椎动脉变异的上颈椎不稳中的临床应用

目的：探讨后路寰椎侧块螺钉联合单侧枢椎椎板螺钉＋对侧枢椎椎弓根螺钉固定、自体双皮质骨加压植骨融合术治疗上颈椎不稳伴椎动脉变异的临床疗效。方法：2008年6月至2012年12月，行后路寰椎侧块螺钉联合单侧枢椎椎板螺钉＋对侧枢椎椎弓根螺钉固定、自体双皮质骨加压植骨融合术12例，男8例，女4例，年龄16—77岁，平均47．5岁。术前患者枕颈部活动受限伴或不伴疼痛，VAS评分0-7分，平均3．50±2．71；椎动脉造影或颈椎CTA示单侧椎动脉明显狭窄。观察术中有无神经及血管损伤；术后7d内行X线和CT检查，了解内固定位置；术后随访观察有无内固定松动、断裂失败并发症、复位丢失，以及植骨融合率等。结果：12例单侧枢椎椎板螺钉固定，术中未发生神经和椎动脉损伤。患者颈部VAS评分0．92±0．90，较术前明显减轻（P=0．01）。术后x线示12例患者颈椎序列恢复良好，CT示1例枢椎椎板腹侧皮质侵犯，余位置均良好。12例患者均获得随访，时间6个月～3年；未见内固定松动、断裂和复位丢失等并发症；术后6个月12例均骨性融合。结论：后路寰椎侧块螺钉联合单侧枢椎椎板螺钉＋对侧枢椎椎弓根螺钉固定、自体双皮质骨加压植骨融合术，既避免了传统螺钉固定椎动脉损伤的同时，又克服了部分病例双侧枢椎椎板螺钉时植骨床的不足，在保证良好力学稳定的情况下，可以取得良好的骨性融合率。单侧枢椎椎板螺钉可以作为一种安全有效的补充固定措施应用于椎动脉变异的上颈椎不稳患者中。

Clinical application of unilateral axis translaminar screws in upper cervical instability with vertebral artery variations

Objective: To investigate the clinical outcomes of the posterior C_1,2 screw-rod combined with C₂ unilateral translaminar screw and contralateral pedicle screw fixation and autogenous bicortical iliac crest graft fusion in treating upper cervical instability with vertebral artery variations. Methods: From June 2008 to December 2012,the clinical data of 12 patients with upper cervical instability underwent C₁ lateral mass screws-C₂ unilateral laminar and contralateral pedicle screws fixation combined with autogenous bicortical iliac crest graft fusion were analyzed retrospectively. There were 8 males and 4 females with a mean age of 47.5 years (ranged,16 to 77 years). Patients suffered from occipitocervical activity limitation of motion with pain or not,VAS was 0-7 points with an average of (3.50±2.71) points. Unilateral vertebral artery hypoplasia was demonstrated by vertebral arteriography (VAG) or CTA in all patients. Cervical X-ray and CT scans were done within 7 days after surgery in order to confirm internal fixation position. Internal fixation loosening and breakage,reduction losing,bone fusion ratio were observed during follow-up. Results: No nerves and vertebral artery injuries occurred during operation. Cervical pain obviously decreased and VAS was (0.92±0.90) points. Cervical alignment of 12 patients had well-recovered by X-ray while Atlantoaxial ventral lamina cortex of 1 case was encroached by CT scan without neurological symptom. All patients were followed up for 6 months to 3 years,no internal fixation loosening and breakage,reduction losing were found. All patients obtained bone fusion in 6-12 months after operation. Conclusion: Posterior C₁ lateral mass screws-C₂ unilateral laminar and contralateral pedicle screws fixation combined with autogenous bicortical iliac crest graft fusion can achieve biomechanical stability and raise the successful rate of bone fusion,while avoiding the risk of vertebral artery injury and overcoming the insufficient of bone fusion during bilateral laminar screws placement as well. Posterior C₁ lateral mass screws fixation is a safe and effective additional method in treating upper cervical instability with vertebral artery variations.