术前三维CT理想钉道测量辅助置入经皮骶髂螺钉

目的探讨术前三维CT理想钉道测量在经皮骶髂螺钉置入中的临床价值。方法 15例骨盆后环损伤行CT三维重建后,在三维图像上设计骶髂螺钉的理想钉道(进钉点为髂前上棘与髂后上棘连线的中后1/3处,通过S1椎弓根中轴线)。在出口位及入口位上,测量理想钉道的进钉角度(∠A、∠B)。术中C臂机射线投照方向与术前三维图像测量时的位置保持一致,参照所测角度置入克氏针,并测量术中C臂机图像上克氏针进针角度(∠a、∠b),然后置入螺钉。按Mears复位标准评价骨折复位情况;根据CT图像判断螺钉的穿透情况;采用Majeed功能评分进行临床评价。结果 15例患者术前在三维图像的骨盆出口位及入口位上理想钉道进钉角度(∠A、∠B)分别为1°~19°(7.9°±5.8°)、1°~9°(5.6°±2.8°),术中在C臂机透视下骨盆出口位及入口位上测量克氏针进钉角度(∠a、∠b)分别为1°~21°(8.4°±4.9°)、1°~15°(6.9°±4.5°),两者间差异无统计学意义(P0.05)。共置入18枚螺钉。15例均获随防,时间5~35(14.2±5.1)个月。无医源性血管、神经损伤,无螺钉断裂发生。Mears标准评价骨折复位情况:解剖复位8例,满意复位7例。根据CT图像判断螺钉的穿透情况:0级16枚,1级2枚,无2、3级穿透。Majeed功能评分:优10例,良4例,可1例。结论通过三维CT测量获得理想钉道在出口及入口位上的进钉角度,结合术中C臂机透视个体化进钉能够保证经皮置入骶髂螺钉的准确性。

Screw canal measurement using three-dimensional CT image reconstruction during percuta-neous sacroiliac screw placement

Objective To discuss the value of the ideal screw canal measurement using three-dimensional CT image reconstruction preoperation during percutaneous sacroiliac screw placement. Methods There were 15 patients with the pelvic posterior ring injuries. The thin-section CT scanning and three-dimensional image reconstruction were per-formed. The idea screw canal of sacroiliac screw was simulated on three-dimensional CT image reconstruction, which the entry point was located at the posterior-middle 1/3 point of the line between anterior superior lilac spine and pos-terior superior iliac spine and was projected through the S1 pedicle central axis. The angles of the nail canal formed on the out-let and in-let views （∠A,∠B） were measured ,and the parameters were recorded. The position of C-arm fluoroscopy in operation was in accord with the position of pelvic three-dimensinal CT image preoperation. According to the measured parameters, the K-wire was implanted, the angles which the K-wires formed on the C-arm graphics （∠a,∠b） were measured, then the sacroiliac cannulated screw was implanted. The postoperative X-ray films were e-valuated according to the Mears reduction standard. The postoperative CT scans were performed in order to determine the location of the sacroiliac screw. The postoperative functions were scored following the Majeed criteria. Results The average angle which the nail canal formed on the out-let and in-let views of the pelvic three-dimensional CT ima-ges （∠A,∠B） were 7. 9° ± 5. 8°（range 1°-19°）,as well as 5. 6° ± 2. 8°（range 1°-9°）,the angles which the K-wires formed on the C-arm graphics （∠a,∠b） were 8. 4° ± 4. 9°（range 1° -21°）,as well as 6. 9° ± 4. 5°（range 1°-15°）,there was no significant difference between two groups（P＞0. 05）. 15 patients had 18 screws placement. All the patients were followed up for 5-35 （14. 2 ± 5. 1） months. All fractures were healed,with no nerve or blood vessel complication and no screw fracture wa