Anatomical study of a new iliosacral screw placement in adult via CT reconstruction / 中华骨科杂志

ABSTRACT

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 rang-ing from 28 to 81,were included in this study.The mean age was(51.9±11.7)years.Based on three-dimensional(3D)CT recon-structions 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 feasi-ble 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.