枕骨板障间螺钉固定枕颈融合术治疗伴寰椎枕化寰枢椎脱位的颅底凹陷症

Occipitocervical fusion by using inter -diploe screw fixation for basilar invagination associated with occipitalisation of atlas and atlantoaxial dislocation

目的：探讨应用枕骨板障间螺钉固定行枕颈融合术治疗伴寰椎枕化、寰枢椎脱位的颅底凹陷症的效果与安全性。方法：2004年1月～2012年6月收治9例伴寰椎枕化、寰枢椎脱位的颅底凹陷症患者，男6例，女3例：年龄36～58岁（45．4±7．8岁）。患者均有脊髓受压症状，术前脊髓功能JOA评分为7～12分（9．6±1．9分）。寰齿间隙（ADI）为3．5～14．2mm（8．4±3．2mm），齿状突顶部超出ChambeHain线的垂直距离（DDCL）为4．5～14．2ram（8．9±3．3mm）。脑干延髓角（CMA）为118°～152°（135．4°±11-3°），脊髓有效空间（SAC）为4．3～9．2ram（6-3±1．7mm）。所有患者术前均行改良Halo—vest支架头颅一双肩撑开牵引复位1～2周；均应用枕骨板障间螺钉-棒-椎弓根螺钉系统进行枕颈融合术。记录手术时间、手术出血量等，观察并发症发生情况。术后复查影像学评价寰枢椎脱位复位和脊髓压迫改善情况；术后每3个月复查颈椎正侧位X线片及CT扫描直至植骨融合，采用JOA评分对脊髓功能改善情况进行评价。结果：手术均顺利完成，手术时间90～195min（132．2±33．9min）；出血量80～200ml（122．2±43．4m1）。1例术后出现切口皮下感染，经局部换药伤口愈合；1例出现脑脊液漏，经局部换药、腰椎蛛网膜下腔穿刺置管引流1周后愈合。术后ADI2．5±1．5mm，DDCL0．9±1．7mm．CMA154．4°±9．2°，SAC16．3±1．98mm，与术前比较均有显著性差异（P〈0．01）。板障间螺钉位置均满意，没有螺钉穿透枕骨内板，2枚C2椎弓根钉进人横突孔，但未发生椎动脉损伤与压迫。患者均获随访，随访时间6～18个月（11．7±4．7个月），患者临床症状均较术前有明显改善，末次随访时JOA评分12～16分（14．3±1．4分）；术后3～9个月（5．0±2．1个月）植骨均获得骨性融合，无断钉、断棒及内固定松动发生。结论：应用枕骨板障间螺钉固定行枕颈融合术具有固定牢靠、操作简单、方便植骨等优点，是治疗伴寰椎枕化、寰枢椎脱位的颅底凹陷症的有效方法。

Objectives： To study the safety and reliability of oceipitocervieal fusion by using inter-diploe screw fixation for basilar invagination associated with oecipitalisation of atlas and atlantoaxial dislocation. Methods： From January 2004 to June 2012,9 patients（6 males, 3 females） were diagnosed with basilar invagination associated with oecipitalisation of atlas and atlantoaxial dislocation. The ages ranged from 36 to 58 years（45.4±7.8 years）. All the patients had symptoms of spinal medulla compression. The JOA scores of preoperation ranged from 7 to 12（9.6±1.9）. The atlas dens index（ADI）, distance from tip of dens to Chamberlain line（DDCL）, cervical medullary angle（CMA） and space available for the cord（SAC） of preoperation was 3.5- 14.2mm（8.4±3.2mm）, 4.5-14.2mm（8.9±3.3mm）, 118°-152°（135.4°±11.3°） and 4.3-9.2mm（6.3±1.7mm） respectively. All the patients received head traction by modified Halo-vest for 1-2 weeks. All cases received occipitoeervical fusion by using inter-diploe screw-rod-pedicel screw system. The operation time and blood loss were recorded, and the complications were observed after operation. The atlanto-axial dislocation and spinal cord compression were evaluated by postoperative radiography. All the patients were followed up every 3 months after surgery. Lateral X-ray and CT scan were used to evaluate bone graft fusion, and the JOA score was used to evaluate the improvement of spinal cord function. Results： All the patients underwent surgery successfully. The operation time was 90-195rain（132.2±33.9min）, and the blood loss was 80-200m1（122.2± 43.4ml）. 1 patient suffered from soft tissue infection after operation and was cured by local dressing. 1 patient with cerebrospinal fluid leakage was cured lumbar subarachnoid drainage for one week. Postoperative CT scan and MRI image showed the ADI 2.5＋1.5mm, DDCL 0.9±l.7mm, CMA 154.4°±9.2°and SAC 16.3±1.98mm, which had statistical differences compared with the preoperative ones（P〈0.05）. All the inter-diploe screws were placed well, with no screw penetrating into inner occipital plate. 2 C2 pedicle screws were found violating in- to vertebral artery foramen with no vertebral artery injury. All the cases were followed up for 6-18 months （11.7±4.7 months）, and all had neurofunetion improved more significantly than preoperation. The JOA score at last follow-up was 12-16（14.3±1.4）. Bone graft fusion was achieved in 3-9 months（5.0±2.1 months）. There was no internal fixation breakage or loosening. Conclusions： Oeeipitoeervical fusion by using inter-diploe screw-rod-pedicel screw system is an effective for basilar invagination associated with occipitalisation of atlas and atlantoaxial dislocation due to its rigid fixation, simple operation and easy bone graft.