Digital anatomic study on sacral lateral mass screw for sacral fracture
10.3760/cma.j.issn.1001-8050.2019.10.011
- VernacularTitle: 骶骨侧块螺钉治疗骶骨骨折的数字解剖学研究
- Author:
Zhongbao XU
1
;
Futing ZHAO
2
;
Lifang LUO
3
;
Yiqi DENG
4
;
Wenchuang FAN
5
;
Weidong MU
6
Author Information
1. Department of Orthopedic Surgery, Liaocheng People's Hospital, Liaocheng 252000, China
2. Department of Orthopedic Surgery, Qingyun People's Hospital, Dezhou 253700, China
3. Department of Orthopedic Surgery, Lichuan People's Hospital, Lichuan 445400, China
4. Department of Spinal Surgery, Shanxian Central Hospital, Heze 274300, China
5. Department of Orthopedic Surgery, Yantai Mountain Hospital, Yantai 264000, China
6. Department of Traumatic Orthopedics, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250000, China
- Publication Type:Journal Article
- Keywords:
Sacrum;
Computer-aided design;
Models, anatomic;
Bone screws
- From:
Chinese Journal of Trauma
2019;35(10):930-935
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the anatomical features of the safe zone for sacral lateral mass screw placement and find the safe trajectory, so as to provide reference for clinical application.
Methods:The three-dimensional computed tomography scan materials of sacrococcygeal vertebrae in 60 patients admitted to the Liaocheng People's Hospital of Shandong Province were analyzed by Mimics software to establish three-dimensional models. There were 33 males and 27 females, aged 25-78 years, with an average age of 45.7 years. After the safe zone was separated from sacral lateral mass model, a maximum cylinder was placed into the safe zone according to its anatomical feature. The cylinder was established as safe trajectory. Anatomical data were measured, including the length and diameter of screw trajectory, the distance between the entry point and the middle jaw, and adjacent upper and lower foramen, as well as the intersection angle between the screw direction and sagittal plane, between the screw direction and the adjacent upper end plate.
Results:The restriction factor of screw size on S1, S2 lateral mass was transverse diameter, while the restriction factor on S3, S4 was the distance between adjacent intervertebral foramen. The maximal length of screw from S1 to S4 was 30 mm, 35 mm, 30 mm, 14 mm respectively, while the maximal diameter was 12 mm, 9 mm, 5 mm, 5 mm respectively. The best entry point of S1 mass screw was lateral to the zygopophysis. The best entry point of S2-S4 mass screw was located at the midpoint of a line connecting the lateral edge of adjacent posterior sacral foramen approximately about 2 cm from median sacral crest. The leaning angles of screw was increased successively, and the sagittal plane was slightly inclined. There were significant differences between male and female groups in the leaning angle in S2 [male: (35.8±1.2)°, female: (37.9±3.7)°] and the distance between entry point and median sacral crest [male: (20.5±1.0)mm, female: (19.1±1.4)mm](P<0.05), while there was no significant difference in other parameters (P>0.05).
Conclusions:Cylindrical bony channel which is feasible for screw placement can be found in the lateral mass of sacrum. Individualized measurement can provide reference for application of lateral mass screw.
