Biomechanical evaluations of three anterior thoracolumbar internal fixation devices / 中国组织工程研究

ABSTRACT

BACKGROUND: The anterior thoracolumbar internal fixation devices can be divided into two main categories the stick system such as kaneda,and the plate system such as Z-plate. Both categories have satisfactory biomechanical properties, but the devices of these types are all imported and so expensive that they exceed the affordability of domestic patientsBased on various anterior throacolumbar internal fixation devices and the spinal characteristics of the Chinese people, the author designed a new brand of anterior thoracolumbar internal fixation device for Chinese peopleNew Ti-plate (NTP).OBJECTIVE: Biomechanical properties of three anterior thoracolumbar internal fixation devices were compared in an attempt to provide a scientific and theoretical basis for clinical applications.DESIGN: A sampling investigation.SETTING: The Department of Orthopaedics of the Second Affiliated Hospital of Soochow University and Department of Radiology of Nantong Hongqiao Hospital.PARTICIPANTS: This study was carried out at the Biomechanical Engineering Research Institute of Shanghai University between May and August 2003. Fifteen fresh spinal samples from the healthy adults (T12-S1) were used in this study.METHODS: Fifteen spinal (T12-S1) specimens were obtained from fresh bodies to induce injuries to anterior and middle columns, which were fixed with Dunn Ⅲ, NTP and Z-plate respectively to compare the strength, rigidity, and the stability of the spine.MAIN OUTCOME MEASURES: Changes of load-straining and loaddisplacement of the three groups of specimens under the conditions of axial decompression, anteflection, post-extention, and lateral flexion.RESULTS: Fifteen fresh adult spinal specimens were involved in this study and all entered the stage of result analysis. Under the maximal load of 500 N,the average straining for Z-plate, NTP and Dunn Ⅲ was 410 uε,430 uε, 477 uε respectively. The average longitude displacement for the above three devices was 2.23 mm, 2.38 mm and 2.85 mm respectively.The thoracolumbar fracture was fixed with three anterior internal fixation devices and it was proved that Z-plate and NTP fixations were better than fixation with Dunn Ⅲ in respect of spinal strength, rigidity and stability (P ＜ 0.05), but the difference between Z-plate and NTP had no statistical significance (P ＞ 0.05).CONCLUSION: NTP and Z-plate devices are conformed to the spinal biomechanical principles and were capable of reconstructing spinal biomechanical stability effectively, and it is a preferable anterior spinal internal fixation device.