Radiographic measurements of three iliac screws passage

Abstract

Objective To research the iliac screws placement and to supply reference data for iliac screw manufacturing,by radiographic measurements for secure placement of screws of Chinese adult ilium. Methods Measurements were made using three-dimensional computed tomographic reformations in 40 consecutive trauma patients(27 measurements in 21 males,16 to 75 years old;28 measurements in 19 females,16 to 78 years old).The parameters were the intrailiac length inner width,and cortical thickness of three different transiliac screw anchor paths aimed toward the anterior inferior iliac spine and initiated at the iliac tubercle,posterior superior iliac spine,or posterior inferior iliac spine. Results The posterior superior iliac spine-anterior inferior iliac spine path had the largest bony canal lengths, with 141 mm in male and 129 mm in female patients. Two stereotypic iliac constrictions allowed placement of 8 mm implants in male and 6-7 mm implants in female patients. Cortical thickness at that optimal extraarticular path was 5.2 mm in the male and 4.7 mm in the female patients. Conclusions Our radiographically performed morphometric study revealed that safe transiliac screw placement and iliac anchoring for lumbopelvic fixation can be optimized by using 6-8 mm screws with a length of up to 130 mm and 140 mm in female and male patients, respectively. Key words: Iliolumbar fixation; Ilium screw; Radiographic measurement