数字化三维重建模拟后路枕骨髁螺钉置钉

Digital 3D simulation study on posterior occipital condyle screw fixation

中文关键词:  数字化  枕骨髁  枕骨髁螺钉  枕颈融合  内固定

英文关键词:Ddigital  Occipital condyle  Occipital condyle screw  Occipitocervical fusion

中文摘要:

  【摘要】 目的：利用数字化三维重建技术测量枕骨髁螺钉的最佳置钉参数，探讨后路枕骨髁螺钉置入的安全性及各置钉参数间的相关性。方法：选取50例枕颈部形态正常者的上颈椎螺旋CT扫描图像，男25例，女25例，年龄25~60岁（38.5±7.6岁）。排除骨折脱位、感染、肿瘤、畸形及退行性变，将数据导入Mimics软件，对枕骨及寰椎进行三维CT重建，模拟置入直径3.5mm的枕骨髁螺钉，测量枕骨髁长、宽、高、进钉点至枕骨内侧缘和颅底部的距离，并通过3-matic软件测量枕骨髁螺钉进钉长度、头倾角、内倾角及与枕骨切线间的切线角，比较枕骨髁解剖学参数与螺钉置钉参数间的差异。结果：共模拟置入100枚枕骨髁螺钉，三维模型大体观察均无舌下神经管、寰枕关节面和枕骨髁内外侧壁的损伤。男、女枕骨髁解剖学参数及螺钉进钉点参数、置钉后枕骨髁螺钉置钉参数左右两侧比较均无统计学差异（P＞0.05）。男性枕骨髁解剖学长、宽、高、进钉点距枕髁内侧缘水平距离及距颅底垂直距离分别为22.00±1.67mm、11.27±1.21mm、10.72±1.13mm、5.37±0.10mm及2.95±0.47mm，女性分别为21.07±1.43mm、10.64±0.81mm、9.62±0.95mm、5.05±0.10mm及3.04±0.48mm，女性枕骨髁长、宽、高及进钉点距枕髁内侧缘水平距离均显著性小于男性（P＜0.05），进钉点距颅底垂直距离与男性无统计学差异（P＞0.05）；置钉后男性头倾角、颅底切线角、内倾角及进钉长度分别为3.90°±2.01°、12.45°±4.73°、28.15°±4.53°、22.47±1.48mm，女性分别4.19°±2.01°、11.25°±4.61°、30.00°±4.70°、21.59±1.62mm，女性进钉长度较男性短（P＜0.05），头倾角、颅底切线角及内倾角男女性无统计学差异（P＞0.05）。头倾角与切线角间存在正相关性（r=0.519，P＜0.05），与其余置钉参数间无相关性（P＞0.05）。结论：国人女性枕骨髁解剖学参数与男性存在差异，枕骨髁三维重建下模拟螺钉置入显示男女性枕骨髁均可安全容纳螺钉置入固定，理论上切线角可结合进钉点及内倾角指导枕骨髁螺钉的安全置入。

英文摘要:

  【Abstract】 Objectives: To measure the best parameters for placing occipital condyle screw in posterior approach, and to discuss the safety of surgical procedure and the correlation among parameters by using digital 3D reconstruction technology. Methods: Fifty cases with occipital spiral CT data were randomly selected from the normal outpatients which meant no fracture, dislocation, infection, cancer, deformity or degeneration, including 25 males and 25 females with the age ranging from 25 to 60 years(average, 38.5±7.6 years). Then the obtained CT data were input into Mimics to reconstruct occipital bone and atlas. 3.5mm occipital condyle screw was simulated placing, the length, width and height of occipital condyle were measured, then the distances from the nailing point to the medial edge of occipital condyle and to the basis cranii were calculated. After that, the length, cranial angle, medial angle and tangent angle between nail and occipital tangent were measured by 3-matic. Results: A total of 100 occipital condyle screws were simulated to place, and there was no injury on hypoglossal canal, atlas joint surface, the medial or lateral wall of occipital condyle in 3D model. Left and right occipital condyle anatomical parameters, nailing point parameters and simulation nailing setting parameters were slightly different, but there was no statistical significance(P>0.05). The anatomical parameters of length, width and height of male occipital condyle, the horizontal distance from the nailing point to medial occipital condyle, and the vertical distance from the nailing point to the basis cranii of male were 22.00±1.67mm, 11.27±1.21mm, 10.72±1.13mm, 5.37±0.10mm and 2.95±0.47mm respectively, while those parameters of female were 21.07±1.43mm, 10.64±0.81mm, 9.62±0.95mm, 5.05±0.10mm, and 3.04±0.48mm respectively. The anatomical parameters of length, width and height of female occipital condyle, and the horizontal distance from the nailing point to medial occipital condyle of female were smaller than those of male obviously(P<0.05), but it showed no statistical significance in the parameter of vertical distance from nailing point to basis cranii between male and female(P>0.05). The cranial angulation, tangent angulation, medial angulation and nailing length measured after simulation nailing setting in male were 3.90°±2.01°, 12.45°±4.73°, 28.15°±4.53°, 22.47±1.48mm, which were 4.19°±2.01°, 11.25°±4.61°, 30.00°±4.70°, 21.59±1.62mm in female respectively, the nailing length of female was shorter than that of male(P<0.05), but there was no statistical significance in cranial angulation, tangent angulation or medial angulation between male and female(P>0.05). There was positive correlation between cranial angulation and tangent angulation(r=0.519, P<0.05), and there was no correlation of cranial angulation with the rest parameters of simulation nailing setting. Conclusions: The anatomical parameters of occipital condyle of female were smaller than those of male, screws can be safely placed in the occipital condyle under 3D reconstruction redardless of gender. Tangent angulation combine with nailing point and medial angulation can assist in safe placement of occipital condyle screws in theory.