Department of Spine Surgery, Honghui Hospital, Xi'an Jiaotong University College of Medicine, No. 76 Nanguo Road, Xi'an, 710054, Shaanxi, People's Republic of China,
Eur Spine J. 2014 May;23(5):1109-14. doi: 10.1007/s00586-014-3217-y. Epub 2014 Feb 9.
To explore the feasibility and effectiveness of C1 pedicle screw fixation in patients whose atlas vertebral artery groove (defined as the C1 pedicle) height is less than 4 mm, but with a medullary canal.
From January 2010 to January 2013, 7 patients (6 males, 1 female) with atlantoaxial instability whose C1 pedicle height was less than 4.0 mm on one or both sides were treated by C1 pedicle screw fixation at our institution. Thirteen of the 14 C1 pedicles were less than 4.0 mm in height, but all had a medullary canal. Patients were followed up at regular intervals. Postoperative computed tomography (CT) scans were performed to assess if C1 pedicle screw placement was successful. Clinical outcomes were evaluated according to postoperative complications, the American Spinal Injury Association grading system, and bone graft status.
Thirteen C1 pedicles with a height less than 4.0 mm were inserted by 13 3.5- or 4.0-mm-diameter pedicle screws, and one C1 pedicle whose height was 4.1 mm was inserted by a 4.0-mm-diameter pedicle screw. In addition, 14 pedicle screws were inserted in the axis. The mean follow-up period was 23 (range 8-38) months. No neurologic or vascular complications occurred in any of the seven patients. Postoperative CT three-dimensional reconstruction images showed that all 14 pedicle screws were inserted in the C1 pedicles without destruction of the atlas pedicle cortical bone. All patients demonstrated bony fusion 6 months postoperatively.
If there is a medullary canal in the C1 pedicle, a 3.5- or 4.0-mm-diameter pedicle screw can be safely inserted into the atlas and C1 pedicle screw fixation can be performed without any impact on fixation stability and clinical efficacy, even if the C1 pedicle height is less than 4.0 mm.
探讨高度小于 4mm 但存在椎管的枢椎椎弓根（定义为 C1 椎弓根）能否进行 C1 椎弓根螺钉固定及其可行性和有效性。
2010 年 1 月至 2013 年 1 月，本院对 7 例（6 男 1 女）单侧或双侧 C1 椎弓根高度小于 4.0mm 的寰枢椎不稳患者行 C1 椎弓根螺钉固定术。14 枚 C1 椎弓根中，有 13 枚高度小于 4.0mm，但均存在椎管。定期随访，术后行 CT 扫描评估 C1 椎弓根螺钉位置是否满意。根据术后并发症、美国脊髓损伤协会（ASIA）分级和植骨情况评估临床疗效。
13 枚高度小于 4.0mm 的 C1 椎弓根使用 3.5mm 或 4.0mm 直径的椎弓根螺钉固定，1 枚高度为 4.1mm 的 C1 椎弓根使用 4.0mm 直径的椎弓根螺钉固定，同时对枢椎也进行了椎弓根螺钉固定。平均随访时间为 23（8~38）个月。7 例患者均无神经或血管并发症发生。术后 CT 三维重建图像显示，14 枚椎弓根螺钉均位于 C1 椎弓根内，未破坏寰椎椎弓根皮质骨。所有患者术后 6 个月均获得骨性融合。
如果 C1 椎弓根存在椎管，即使 C1 椎弓根高度小于 4.0mm，也可使用 3.5mm 或 4.0mm 直径的椎弓根螺钉安全地置入寰椎和枢椎，并进行 C1 椎弓根螺钉固定，不会影响固定的稳定性和临床疗效。
