基于数字化技术建立距骨颈骨折螺钉固定安全通道的研究

 目的 探讨距骨颈骨折螺钉自距骨内侧壁安全固定时螺钉安全通道的建立。方法 限定志愿者年龄20~60岁,男性身高165~185 cm,女性身高155~175 cm,体质指数(BMI)< 25,既往踝、足部无骨折病史,非重体力劳动及长期站立工作者,X线片证实无关节退行性改变等。共获得男性33名,年龄21~59岁,平均43.7岁,身高168~184 cm,平均176.0 cm;女性22名,年龄22~60岁,平均43.2岁,身高158~172 cm,平均165.4 cm。对所有志愿者的踝部及足部进行CT扫描,将重建层厚为0.75 mm的图像数据以DICOM格式存入光盘,使用SuperImage^TM Orthopedics Edition1.1软件对图像进行显示和三维重建。测量距骨颈和跗骨管的高度,建立螺钉进入跗骨管的模型;模拟螺钉自距骨内侧壁远端中1/3和下1/3两点置入,并沿两条不同的方向走行,测量螺钉的最大长度及角度;最后使用SPSS 13.0软件对以上数据进行比较分析。 结果 获得距骨颈和跗骨管的高度值,同性别左右侧的差异无统计学意义;男性距骨颈和跗骨管高度均大于女性;获得螺钉自距骨颈穿出进入跗骨管的模型;获得以距骨内侧壁远端中1/3和下1/3为入点、自不同方向置入时螺钉的长度值和角度值;以距骨内侧壁远端中1/3为入点时螺钉固定的夹角较以距骨内侧壁远端下1/3为入点时明显更大;;计算出螺钉不同固定方向的长度、角度的安全范围。 结论 螺钉固定时应避免对距骨血运造成进一步破坏;距骨内侧壁中1/3是螺钉固定的良好入点;计算机数字化技术与距骨颈骨折内固定方式相结合可以提高手术安全性和可行性。

Study on secure tunnel in the fixation of talar neck fracture based on digital technology

Objective To investigate the establishment of secure tunnel in fixation for the talar neck fracture when screws were fixed from the medial wall of talus. Methods The age of volunteers was limited from 20 to 60 years old, and the height of male volunteers was from 165 to 185 centimeters, while the female volunteers’ height was from 155 to 175 centimeters. The body mass index (BMI) was less than 25. The volunteers who were not heavy manual workers or standing working for long time had no history of ankle or foot fractures, and there were no evidence of degeneration changes in ankle joints according to X-ray. At last there were 33 males in this study with an average age of 43.7 (21-59) years and an average height of 176.0 (168-184) centimeters. There were 22 females with an average age of 43.2 (22-60) years and an average height of 165.4 (158-172) centimeters. After the volunteers’ ankle joints and feet were scanned by CT, the reconstructed images were stored in CD and the slice thickness was 0.75 millimeters. The SuperImage^TM Orthopedics Edition1.1 software was used to display the images and perform three dimensional reconstruction. The height of talar neck and the height of tarsal canal were measured. The models that screws passing into tarsal canals were built. The maximal length and angle that screws were inserted in the middle 1/3 and in the inferior 1/3 of medial wall of talus and run along to two directions were measured. At last, the data were analyzed with SPSS 13.0 software. Results The height of talar neck and tarsal canal had no significant difference between left side and right side in the same gender. The height of male talar neck was greater than the female’s. The models of screws passing into tarsal canals was gained. The length and angle in different insert points and different directions of screw fixation were also gained. When the screws were inserted from the middle 1/3 of the medial wall of talus, the angle of screw fixation was much wider than that when the screws were inserted from the inferior 1/3 of the medial wall of talus. At last, the safe range of the length and angel of screw fixation was calculated. Conclusion Damage of the blood of talus during internal fixation should be avoided. The middle 1/3 of the medial wall of talus is the most favourable choice to the fixation. Combining the digital technology with internal fixation for talar neck fracture could promote the operation’s security and feasibility.