Abstract：
OBJECTIVE: To evaluate the feasibility of a novel method for occipitocervical fixation (OCF) through the endonasal corridor.
METHODS: Thin-cut computed tomography scans were obtained for 5 cadaveric specimens. Image segmentation was used to reconstruct 3D models of each O-C1 joint complex. Using computer-aided design software, plates were custom-designed to span each O-C1 joint, sit flush onto the bony surface, and accommodate screws. The final models were 3D-printed in titanium. For implantation, specimens were held in pin-fixation and registered to neuronavigation. A rigid 0º endoscope was used for endonasal visualization. An inverted U-shaped nasopharyngeal flap was raised to expose the occipital condyles and C1. The plates were introduced and fixed with bone screws. Computed tomography scans were obtained to assess screw accuracy and proximity to critical neurovascular structures. Screw entry points and trajectories were recorded.
RESULTS: Endonasal OCF was performed on 5 cadaveric specimens. The mean starting point for occipital condyle screws was 6.17 mm lateral and 5.38 mm rostral to the medial O-C1 joint. Mean axial and sagittal trajectories were 7.98° and 6.71°, respectively. The mean starting point for C1 screws was 16.11 mm lateral to the C1 anterior tubercle and 6.39 mm caudal to the medial O-C1 joint. Mean axial and sagittal trajectories were 10.97° and -9.91°, respectively.
CONCLUSIONS: Endonasal OCF is technically and anatomically feasible. The application of this technique may allow for same-stage endonasal decompression and fixation, offering a minimally invasive alternative to current methods of fixation and advancing surgeons\' ability to treat pathology of the craniovertebral junction. Next steps will focus on biomechanical testing.
METHODS: Thin-cut computed tomography scans were obtained for 5 cadaveric specimens. Image segmentation was used to reconstruct 3D models of each O-C1 joint complex. Using computer-aided design software, plates were custom-designed to span each O-C1 joint, sit flush onto the bony surface, and accommodate screws. The final models were 3D-printed in titanium. For implantation, specimens were held in pin-fixation and registered to neuronavigation. A rigid 0º endoscope was used for endonasal visualization. An inverted U-shaped nasopharyngeal flap was raised to expose the occipital condyles and C1. The plates were introduced and fixed with bone screws. Computed tomography scans were obtained to assess screw accuracy and proximity to critical neurovascular structures. Screw entry points and trajectories were recorded.
RESULTS: Endonasal OCF was performed on 5 cadaveric specimens. The mean starting point for occipital condyle screws was 6.17 mm lateral and 5.38 mm rostral to the medial O-C1 joint. Mean axial and sagittal trajectories were 7.98° and 6.71°, respectively. The mean starting point for C1 screws was 16.11 mm lateral to the C1 anterior tubercle and 6.39 mm caudal to the medial O-C1 joint. Mean axial and sagittal trajectories were 10.97° and -9.91°, respectively.
CONCLUSIONS: Endonasal OCF is technically and anatomically feasible. The application of this technique may allow for same-stage endonasal decompression and fixation, offering a minimally invasive alternative to current methods of fixation and advancing surgeons\' ability to treat pathology of the craniovertebral junction. Next steps will focus on biomechanical testing.
摘要：
目的：评估一种通过鼻内走廊进行枕颈固定术（OCF）的新方法的可行性。
方法：对5个尸体标本进行了薄层计算机断层扫描。使用图像分割来重建每个O-C1关节复合体的3D模型。使用计算机辅助设计软件，板是定制设计的，跨越每个O-C1接头，平齐地坐在骨质表面上，并容纳螺丝。最终的模型是在钛中3D打印的。对于植入，标本固定并注册到神经导航。使用刚性0º内窥镜进行鼻内可视化。抬起倒置的U形鼻咽皮瓣，露出枕骨髁和C1。引入板并用骨螺钉固定。获得计算机断层扫描以评估螺钉的准确性和与关键神经血管结构的接近度。记录螺钉入口点和轨迹。
结果：对5具尸体标本进行了鼻内OCF检查。枕骨髁螺钉的平均起点为外侧6.17mm，内侧O-C1关节的头端5.38mm。平均轴向和矢状轨迹分别为7.98°和6.71°，分别。C1螺钉的平均起点是C1前结节外侧16.11mm，内侧O-C1关节尾侧6.39mm。平均轴向和矢状轨迹分别为10.97°和-9.91°，分别。
结论：鼻内OCF在技术上和解剖学上是可行的。该技术的应用可以允许相同阶段的鼻内减压和固定，为目前的固定方法提供了一种微创替代方法，并提高了外科医生治疗颅骨交界处病变的能力。接下来的步骤将侧重于生物力学测试。
方法：对5个尸体标本进行了薄层计算机断层扫描。使用图像分割来重建每个O-C1关节复合体的3D模型。使用计算机辅助设计软件，板是定制设计的，跨越每个O-C1接头，平齐地坐在骨质表面上，并容纳螺丝。最终的模型是在钛中3D打印的。对于植入，标本固定并注册到神经导航。使用刚性0º内窥镜进行鼻内可视化。抬起倒置的U形鼻咽皮瓣，露出枕骨髁和C1。引入板并用骨螺钉固定。获得计算机断层扫描以评估螺钉的准确性和与关键神经血管结构的接近度。记录螺钉入口点和轨迹。
结果：对5具尸体标本进行了鼻内OCF检查。枕骨髁螺钉的平均起点为外侧6.17mm，内侧O-C1关节的头端5.38mm。平均轴向和矢状轨迹分别为7.98°和6.71°，分别。C1螺钉的平均起点是C1前结节外侧16.11mm，内侧O-C1关节尾侧6.39mm。平均轴向和矢状轨迹分别为10.97°和-9.91°，分别。
结论：鼻内OCF在技术上和解剖学上是可行的。该技术的应用可以允许相同阶段的鼻内减压和固定，为目前的固定方法提供了一种微创替代方法，并提高了外科医生治疗颅骨交界处病变的能力。接下来的步骤将侧重于生物力学测试。
