髂骶螺钉固定模式的解剖学研究

Anatomical study of a new iliosacral screw placement in adult via CT reconstruction

目的 对髂骶螺钉内固定系统钉道各参数进行CT测量,探讨髂骶螺钉固定的可行性及安全性。方法 选取2016年8 至12月收治的腰椎病变患者50例,男、女各25例,年龄28~81岁,平均（51.9±11.7）岁。行骨盆螺旋CT薄层扫描及三维重建,采用Light Speed工作站模拟理想的髂骶螺钉钉道。前后旋转三维骨盆图像,于S1椎弓根所在的长轴上得到最佳的髂骶螺钉钉道所在的平面（最宽和最长的骶骨横断面）,在此平面画出一条理想的髂骶螺钉通道。测量参数包括连接器相关参数（内收角、头倾角、S1椎弓根宽度、埋入深度和连接器进钉点与皮肤的垂直距离）及髂骶螺钉相关参数（外展角、尾倾角、髂骨内钉道长度、骶骨内钉道长度、髂骶钉道最大长度和髂骶螺钉进钉点与皮肤的距离）。结果 所有研究对象左、右侧均成功建立1条理想的髂骶螺钉置入通道,该钉道由外向内穿过髂骨和骶髂关节至骶骨内。髂骶骨连接器相关参数方面,男性内收角、头倾角、S1椎弓根宽度、埋入深度和连接器进钉点与皮肤的垂直距离分别平均为28.5°±6.3°,27.9°±5.6°,（22.5±2.4） mm,（18.8±3.1） mm和（52.8±8.4） mm;女性分别为26.9°±5.7°,25.8°±7.2°,（20.4±2.2） mm,（16.9±2.5） mm和（56.3±7.4） mm。其中男性S1椎弓根宽度较女性更宽,埋入深度较女性更深,而女性连接器进钉点与皮肤的垂直距离较男性更深,差异均有统计学意义。髂骶螺钉相关参数方面,男性外展角、尾倾角、髂骨内钉道长度、骶骨内钉道长度、髂骶钉道最大长度、髂骶螺钉进钉点与皮肤的距离分别为61.5°±6.6°、16.4°±3.2°、（16.6±2.8） mm、（73.0±5.7）mm、（96.8±5.5） mm、（65.0±11.9） mm;女性分别为63.1°±5.7°、16.1°±4.8°、（15.1±2.4） mm、（74.0±6.4）mm、（96.8±5.4）mm、（68.0±11.4） mm。其中男性髂骨内钉道长度较女性更长,差异有统计学意义。结论 临床应用髂骶螺钉内固定系统具有可行性,但要注意S1椎弓根宽度、连接器进钉点的位置、埋入深度以及性别间的差异等;术前骨盆CT三维重建及钉道模拟有助于术中髂骶螺钉的准确置入。

Objective To investigate the feasibility and safety of a novel iliosacral screw placement in adult pelvis by computed tomography（CT）. Methods All of 50 adults with normal pelvis, including 25 males and 25 females with the age ranging from 28 to 81, were included in this study. The mean age was （51.9±; 11.7） years. Based on three-dimensional（3D） CT reconstructions of these specimens, virtual iliosacral screw channel was identified and measured. The virtual iliosacral screw channel holding the greatest width and length of osseous channel was measured by rotating the 3D pelvis. Measurements of the determined channels including connector-related parameters （divergent angle, cephalad angle, S1 pedicle width, embedding depth and skin distance） and iliosacral-screw related parameters （convergent angle, caudal angle, iliac length, sacral length, max-length and skin distance）. Results There was a virtual channel going through the ilium as well as iliosacral joint and into the sacral in either side of each specimen. The connector-related parameters in males included divergent angle, cephalad angle, S1 pedicle width, embedding depth and skin distance, and they were 28.5°±; 6.3°, 27.9°±; 5.6°, （22.5±; 2.4） mm, （18.8±; 3.1） mm and （52.8±; 8.4） mm, respectively. In females, they were 26.9°±; 5.7°, 25.8°±; 7.2°, （20.4±; 2.2） mm, （16.9±; 2.5） mm and （56.3±; 7.4） mm, respectively. The S1 pedicle width and embedding depth in males were higher than that of females, while the skin distance in females was higher than that of males. The iliosacral-screw related parameters in males included convergent angle, caudal angle, iliac length, sacral length, max-length and skin distance, and they were 61.5°±; 6.6°, 16.4°±; 3.2°, （16.6±; 2.8） mm, （73.0±; 5.7） mm,（96.8±; 5.5） mm and （65.0±; 11.9） mm, respectively. In females, they were 63.1°±; 5.7°, 16.1°±; 4.8°, （15.1±; 2.4） mm, （74.0±; 6.4） mm,（96.8±; 5.4） mm and （68.0±; 11.4） mm. The iliac length in males was higher than that of females. Conclusion It is safe and feasible to place iliosacral screw when performing spino-pelvic fixation. Preoperative CT imaging and 3D reconstructions may help to determine correct anchoring point and screw channel individually.