Xu R, Ebraheim N A, Klausner T, Yeasting R A
Department of Orthopaedic Surgery, Medical College of Ohio, Toledo 43699, USA.
J Spinal Disord. 1998 Jun;11(3):237-40.
Twelve adult embalmed cadaveric cervical spines were used to modify the traditional Magerl technique for screw placement in the lower cervical spine. The starting point for the drill bit was 2 mm inferior to the inferiormost edge of the superior facet and 1-2 mm medial to the posterior midline of the lateral mass. The orientation of the drill bit was parallel to the superior facet in the sagittal plane, and 25-30 degrees lateral in the transverse plane. After drilling, we made direct measurements of the screw path length between the dorsal and ventral cortexes of the lateral mass and screw-path angles in both the sagittal and transverse planes. The results showed the mean screw-path length for all levels ranged from 11 to 15 mm with the smallest value at C7. The mean sagittal and transverse angles of the screw path ranged from 41 to 43 degrees and from 26 to 28 degrees. Penetration of the superior facet was found in three (2.5%) cases. Possible spinal nerve violation was seen in 13 (10.8%) cases if the drill bit was excessively overpenetrated. This study suggested that our modified Magerl technique for lateral mass screw placement be as high as possible without impinging on the facet joint, and drilling be as cranial and lateral as possible to leave the superior articular process as high and lateral as possible. This may further decrease the incidence of spinal nerve injury. Careful drilling and tapping technique is recommended to avoid overpenetration.
使用12具经过防腐处理的成人尸体颈椎来改良传统的Magerl技术，用于下颈椎螺钉置入。钻头的起始点位于上关节突最下缘下方2毫米处，以及侧块后中线内侧1 - 2毫米处。钻头在矢状面的方向与上关节突平行，在横断面的方向为向外侧25 - 30度。钻孔后，我们直接测量了侧块背侧和腹侧皮质之间的螺钉路径长度以及矢状面和横断面的螺钉路径角度。结果显示，所有节段的平均螺钉路径长度在11至15毫米之间，C7处的值最小。螺钉路径的平均矢状角和横断角分别为41至43度和26至28度。发现有3例（2.5%）出现上关节突穿透。如果钻头过度穿透，在13例（10.8%）病例中可见可能的脊神经损伤。本研究表明，我们改良的用于侧块螺钉置入的Magerl技术应尽可能高，同时不影响关节突关节，钻孔应尽可能向头侧和外侧进行，以使上关节突尽可能高和外侧。这可能会进一步降低脊神经损伤的发生率。建议采用仔细的钻孔和攻丝技术以避免过度穿透。
