椎板后壁部分刮除辅助透视行颈椎弓根钻孔

目的探索椎板后壁部分刮除辅助透视行下颈椎椎弓根钻孔的可行性。方法3具新鲜尸体下颈椎的30例椎弓根，透视确定椎弓根轴线所在高度，将此高度侧块与椎板后壁交界内外侧各5mm范围内的皮质骨去除，刮除其下松质骨，先暴露出内侧的椎板前壁，后紧贴椎板前壁向外侧刮除，找到椎弓根入口。根据内倾角确定入口外侧骨质去除范围，以椎弓根内壁为参照，透视确定上倾角，行髓腔钻孔。CT扫描明确钻孔准确性。结果1例髓腔消失，放弃钻孔；27例钻孔准确；2例髓腔〈3mm，椎弓根外壁向外侧移位，但〈2mm。结论椎板后壁部分刮除辅助透视行下颈椎椎弓根髓腔钻孔效果满意。

Posterior cortex of lamina partially removed under the guidance of fluoroscopy for cervical pedicle canal drilling: a preliminary study on isolated fresh frozen samples

Objective To evaluate the feasibility of manipulation method of posterior cortex of lamina partially removed under the guidance of fluoroscopy (PCRF) for subaxial cervical pedicle canal drilling. Methods Thirty subaxial cervical pedicles from 3 fresh frozen cervical columns were selected for the PCRF manipulation. After confirming the pedicle axis'projection height at the posterior surface of lateral mass by fluoroscopy, the cortex and cancellous bone 5 mm medial and lateral to the sagittal boundary separating the lateral mass from lamina were removed to expose anterior cortex of lamina medial to pedicle entry firstly following moving laterally to find pedicce entry. Appropriate bones lateral and posterior to pedicce entry were removed then for ideal medial inclination of pedicle canal drilling. A 3mm-diameter pedicle probe was introduced to drill hole along the pedicle medullary canal by feeling inner surface of inter cortex of pedicle under the guidance of fluoroscopy to guide sagittal angle. CT scanning with multiplanar reconstruction was then done to provide vivid and persuading images to confirm the accuracy of pedicle drilling. Results One pedicle was excluded from the study because of its occluded medullary canal, CT scanning showed integrities of superior, medial,inferior and lateral cortexes of pedicle were preserved and trajectory paths satisfied in 27 pedicles while lateral cortexes of the remaining 2 ones were broken and moved laterally but within 2 mm for small inner transverse diameter(<3 mm). Conclusion PCRF could provide satisfactory accuracy for subaxial cervical pedicle canal drilling on isolated samples.