Barrey C, Cotton F, Jund J, Mertens P, Perrin G
Department of Neurosurgery, Hôpital neurochirurgical P. Wertheimer, 59 boulevard Pinel, 69394, Lyon, France.
Surg Radiol Anat. 2003 Nov-Dec;25(5-6):354-60. doi: 10.1007/s00276-003-0163-5. Epub 2003 Sep 3.
The purpose of this study was first to assess the feasibility of C7 transpedicular screwing with a morphological study and secondly to evaluate the safety of such a surgical technique when guided only by posterior landmarks. Eighteen C7 vertebrae, harvested from fresh human cadavers, were included in this study. First the morphometry of C7 pedicle was performed on computed tomography with multiplanar reconstructions. Results of this quantitative anatomy were compared with the literature data. Secondly 30 pedicle screws, whose placement was guided only by anatomical features on the posterior face of the dorsal arch, were inserted in 15 C7 vertebrae. A second computed tomographic examination was done after the surgical procedure to check the screw placement in both planes. The average pedicular width was 6+/-1.2 mm and the average height was 5.8+/-1.1 mm. The pedicle angulation in the transverse plane was 33.3 degrees +/-6.6 degrees, the pedicle angulation in the sagittal plane was 4.3 degrees +/-4.5 degrees downward with reference to the lower endplate of C7. The average distance from the entry point of transpedicular screwing to the anterior cortex of the vertebral body was 29+/-3 mm. Concerning the safety of transpedicular screwing, 63% of screws were found entirely inside the pedicle without any violation of the pedicle cortex. Most of pedicle violations were observed in the transverse plane. No grade II violation of the pedicle was observed. Dimensions of the C7 pedicle are amply compatible with transpedicular fixation using 3.5 mm screws. Such a surgical technique seems to be an interesting option when posterior fixation of C7 is required. Nevertheless morphological guidelines appeared not to be sufficient to ensure safe transpedicular screwing. Laminoforaminotomy is strongly recommended, although it has not been evaluated in this study.
本研究的目的首先是通过形态学研究评估C7经椎弓根螺钉固定的可行性，其次是评估仅以后方标志为引导的这种手术技术的安全性。本研究纳入了从新鲜人体尸体获取的18个C7椎体。首先，在具有多平面重建功能的计算机断层扫描上对C7椎弓根进行形态测量。将这一定量解剖学结果与文献数据进行比较。其次，在15个C7椎体中插入30枚椎弓根螺钉，其置入仅以背侧弓后表面的解剖特征为引导。手术后进行第二次计算机断层扫描检查，以检查螺钉在两个平面内的置入情况。椎弓根平均宽度为6±1.2毫米，平均高度为5.8±1.1毫米。椎弓根在横平面的角度为33.3度±6.6度，在矢状平面相对于C7下端板向下的角度为4.3度±4.5度。经椎弓根螺钉置入点到椎体前皮质的平均距离为29±3毫米。关于经椎弓根螺钉固定的安全性，发现63%的螺钉完全位于椎弓根内，未侵犯任何椎弓根皮质。大多数椎弓根侵犯发生在横平面。未观察到II级椎弓根侵犯。C7椎弓根的尺寸与使用3.5毫米螺钉的经椎弓根固定完全兼容。当需要对C7进行后路固定时，这种手术技术似乎是一个有趣的选择。然而，形态学指南似乎不足以确保安全地进行经椎弓根螺钉固定。尽管本研究未对其进行评估，但强烈建议进行椎板间孔切开术。
