title: Three-dimensional finite element analysis of a newly developed aliform internal fixation system for occipitocervical fusion.
abstract: For patients with occipital malformation, it is difficult to obtain reliable stability using three screws on the midline. A new aliform occipitocervical internal fixation system was designed. The occiput was fixed with 3, 7, or 11 screws, and a three-dimensional finite element model of the system was established. A compressive preload of 40N combined with a pure moment of 1.5Nm was applied to simulate normal flexion, extension, lateral bending, and axial rotation. The stress distribution across the screws on the occiput and the occipital displacement produced by the newly developed system were compared with those produced by the DePuy SUMMIT system. Compared with the SUMMIT system (control group), in the new system, the maximum stress on the occiputs fixed with 3 screws (group A) and 7 screws (group B) increased by 16.5% and 15.0%, respectively. In contrast, the maximum stress on the occiput fixed with 11 screws (group C) decreased by 15.6%. In addition, the maximum occipital displacements under extension decreased by 10.0%, 11.4%, and 11.8% in the A, B, and, C groups, respectively. Our results indicate that both group A and the control group exhibited sufficient strength and instant stability; however, group C exhibited the highest stability and the lowest maximum von Mises stress.
authors.affiliation: Southern Medical University, 1063 South Road of Jinxishatai, 510515 Guangzhou, PR China; Department of Orthopedics, Panyu Central Hospital, 8 Fuyu East Road, Southbridge Street, Panyu, Guangzhou 511400, PR China.
authors.forename: Sui-Xiang
authors.initials: SX
authors.lastname: Liao
authors.affiliation: Hospital of Orthopedics, Guangzhou General Hospital of Guangzhou Military Command, 111 Liuhua Road, Guangzhou 510010, PR China. Electronic address: jianhuawangddrr@163.com.
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Wang
authors.affiliation: Southern Medical University, 1063 South Road of Jinxishatai, 510515 Guangzhou, PR China; Department of Orthopedics, Jinjiang Municipal Hospital, 392 Xinhua Street, Jinjiang 362200, PR China.
authors.forename: Yong-Qiang
authors.initials: YQ
authors.lastname: Zheng
authors.affiliation: Southern Medical University, 1063 South Road of Jinxishatai, 510515 Guangzhou, PR China; Hospital of Orthopedics, Guangzhou General Hospital of Guangzhou Military Command, 111 Liuhua Road, Guangzhou 510010, PR China.
authors.forename: Guan
authors.initials: G
authors.lastname: Zheng
authors.affiliation: Southern Medical University, 1063 South Road of Jinxishatai, 510515 Guangzhou, PR China; Hospital of Orthopedics, Guangzhou General Hospital of Guangzhou Military Command, 111 Liuhua Road, Guangzhou 510010, PR China.
authors.forename: Ge-Jing
authors.initials: GJ
authors.lastname: Wei
authors.affiliation: Southern Medical University, 1063 South Road of Jinxishatai, 510515 Guangzhou, PR China; Hospital of Orthopedics, Guangzhou General Hospital of Guangzhou Military Command, 111 Liuhua Road, Guangzhou 510010, PR China. Electronic address: gzxiahong2@126.com.
authors.forename: Hong
authors.initials: H
authors.lastname: Xia
authors.affiliation: Department of Orthopedics, Panyu Central Hospital, 8 Fuyu East Road, Southbridge Street, Panyu, Guangzhou 511400, PR China.
authors.forename: Xiao-Hua
authors.initials: XH
authors.lastname: Chen
keywords: Biomechanics; Finite element analysis; Occipitocervical fusion surgery; Occipitocervical malformation