Biomechanical evaluation of spinal fixation devices. Part III. Stability provided by six spinal fixation devices and interbody bone graft.
The three-dimentional stability provided by six spinal fixation devices with or without interbody bone graft has been studied in an in vitro biomechanical model using five-vertebral (T11-L3) fresh cadaveric thoracolumbar specimens. An injury was created at T12-L1 by complete transection of the posterior elements and posterior half of the intervertebral disc, leaving the anterior half of the intervertebral disc and anterior longitudinal ligament intact. The three-dimensional rotations and translations, measures of biomechanical instabilities, were determined under physiologic loads for the intact spine and the spinal constructs, ie, injured spine plus instrumentation. The tested devices were: Harrington reverse ratchet rods (HR); Luque rectangle rod (LR); Kaneda device without transverse fixator (KD); Kaneda device with transverse fixators (KT); transpedicular external fixator (EF). In addition, stability tests were performed for KT, EF, and Harrington compression rods with interbody bone graft following a corpectomy (KTB, EFB, and HCB). The constructs were more stable than the intact spine under the four loads in the following order: flexion: EFB, HCB, EF, HR, LR, KTB, and KT; extension: EFB, LR, EF, KTB, HR, and KT; lateral bending: KTB, KT, EFB, KD, EF, HCB, and HR; and axial rotation: EFB.
Abumi
K
K
Department of Orthopaedic Surgery, Hokkaido University, School of Medicine, Sapporo, Japan.
Panjabi
M M
MM
Duranceau
J
J
D001696:Biomechanical Phenomena; D016025:Bone Transplantation; D006801:Humans; D007403:Intervertebral Disc; D007593:Joint Instability / Q000503:physiopathology / Q000628:therapy*; D008161:Lumbosacral Region; D008422:Materials Testing / Q000295:instrumentation; D009984:Orthopedic Fixation Devices; D012399:Rotation; D013122:Spinal Diseases / Q000503:physiopathology / Q000628:therapy*; D013124:Spinal Injuries / Q000628:therapy; D013131:Spine / Q000503:physiopathology*; D013909:Thorax