椎弓根螺钉系统在儿童寰枢区不稳治疗中的应用

APPLICATION OF PEDICLE SCREW INTERNAL FIXATION FOR ATLANTOAXIAL INSTABILITY OF CHILDREN

目的探讨采用椎弓根螺钉系统内固定治疗儿童寰枢区不稳的疗效。 方法2005年7月－2012年1月，收治19例寰枢区不稳患儿。男10例，女9例；年龄4～15岁，平均7.5岁。X线片、CT及MRI检查示枕颈区畸形9例，先天性齿突不连3例，齿突骨折（Ⅱ型）1例，寰枢椎横韧带断裂2例，寰枢椎骨折脱位4例；颈脊髓损伤8例，根据美国脊髓损伤协会（ASIA）分级标准：B级1例、C级2例、D级5例。其中17例经颅骨牵引或枕颌带牵引复位后行颈后路椎弓根螺钉系统固定（采用寰枢椎融合固定12例，枕颈融合固定5例）；2例牵引复位失败后行经口腔入路寰枢松解、颈后路椎弓根螺钉系统固定（寰枢椎融合固定）。 结果手术均顺利完成。手术时间平均89 min，术中出血量平均95 mL，术后引流量平均73 mL，住院时间平均14 d。19例均获随访，随访时间6～27个月，平均18.3个月。患儿寰枢椎均获满意融合；植骨均融合，融合时间3～7个月，平均4.5个月。随访期间无断钉、断棒以及寰枢椎再脱位发生。末次随访时，5例行枕颈融合固定患儿左、右侧颈椎旋转活动度（cervical range of motion，CROM）分别为（62.0 ± 5.9）°和（63.9 ± 3.8）°，与同龄正常儿童左、右侧CROM [分别为（72.3 ± 7.0）°和（74.1 ± 7.6）°]比较，差异有统计学意义（t= —3.915，P=0.018；t= —5.954，P=0.004）；14例行寰枢椎融合固定患儿左、右侧CROM分别为（70.5 ± 5.8）°和（72.7 ± 4.9）°，与同龄正常儿童左、右侧CROM比较差异无统计学意义（t= —1.417，P=0.180；t= —1.021，P=0.323）。末次随访时疼痛视觉模拟评分（VAS）为（3.5 ± 0.8）分，较术前（7.8 ± 1.1）分显著改善（t=17.267，P=0.000）。8例脊髓损伤患儿末次随访时ASIA分级： C级2例， D级1例， E级5例。 结论经颈后路椎弓根螺钉系统内固定治疗儿童寰枢区不稳可取得较好效果，能明显缓解枕颈部疼痛、活动受限、神经功能损伤等症状。

Objective To investigate the effectiveness of pedicle screw internal fixation for the atlantoaxial instability of children. Methods Between July 2005 and January 2012, 19 cases of atlantoaxial instability were treated, included 10 boys and 9 girls with an average age of 7.5 years （range, 4-15 years）. The X-ray films, CT, and MRI examinations of the cervical spine showed craniocervical malformation in 9 cases, congenital os odontoideum in 3 cases, odontoid fracture （type II） in 1 case, disruption of transverse ligament in 2 cases, atlantoaxial fracture and dislocation in 4 cases; and spinal cord injury in 8 cases, according to the American Spinal Cord Injury Association （ASIA） impairment scale, 1 case was rated as grade B, 2 as grade C, and 5 as grade D. Preoperative skull traction was performed routinely on all cases, and complete reduction was achieved in 17 cases, no reduction in 2 cases. In 17 patients who achieved complete reduction, pedicle screw internal fixation was used through posterior approach, including occipitocervical fusion and fixation in 5 cases, and atlantoaxial fusion and fixation in 12 cases; in 2 patients with no reduction, pedicle screw internal fixation was used through posterior approach （atlantoaxial fusion and fixation） after release by transoral approach. Results The operation was successfully performed in all patients. The mean operation time was 89 minutes; the mean intraoperative blood loss was 95 mL; the mean postoperative drainage volume was 73 mL; and the mean hospitalization days were 14 days. The patients were followed up 6-27 months （mean, 18.3 months）. Satisfactory atlantoaxial fusion was obtained, and bone fusion was obtained at 3-7 months after operation （mean, 4.5 months）. No breakage of screw or rods and re-dislocation occurred during follow-up. At last follow-up, the cervical range of motion （CROM） of the left and right rotation were （62.0 ± 5.9）° and （63.9 ± 3.8）° respectively in 5 patients receiving occipitocervical fusion and fixation, showing significant difference when compared with the values of normal children [（72.3 ± 7.0）° and （74.1 ± 7.6）°, respectively] at the same age （t= - 3.915, P=0.018; t= - 5.954, P=0.004）. The CROM of the left and right rotation were （70.5 ± 5.8）° and （72.7 ± 4.9）° respectively in 14 patients receiving atlantoaxial fusion and fixation, showing no significant difference when compared with normal children at the same age （t= - 1.417, P=0.180; t= - 1.021, P=0.323）. The visual analogue scale （VAS） score was significantly decreased from 7.8 ± 1.1 at pre-operation to 3.5 ± 0.8 at last follow-up （t=17.267, P=0.000）. In 8 cases having spinal cord injury, 2 cases were rated as grade C, 1 case as grade D, and 5 cases as grade E according to ASIA impairment scale. Conclusion Technique of pedicle screw internal fixation has been proven to be an effective treatment for the atlantoaxial instability of children. It plays an important part in relieving pain and limitation of the cervical region.