The Biomechanical And Clinical Research Of The Posterior Different Structure In The Stability Of The Thoracic Spine

Objective To investigate the role of the posterior different structure inthe stability of the thoracic spine.Methods The thoracic spine specimen of9cadaver from T7to T10,consisting of the sixth to ninth ribs, were used. After testing the intactspecimen, resection of the T8～9posterior stabilizers was conductedincrementally in the following manner:1) Total unilateral facentectomywith unilateral laminectomy (Group1),2) resection of the unilateralcostoverebral joint (Group2),3) resection of the posterior ligamentouscomplex with laminectomy (Group3)，4) bilateral total facetectomy (Group4),5) resection of the bilateral costoverebral joints (Group5). All specimenwere tested in six direction. Paired t-test was used as statistics analysis method.Results Total unilateral facentectomy with unilateral laminectomy didnot significantly increase the range of motion in cadaveric thoracic spines(P＞0.05), however, a large increase in the range of motion was observedafter bilateral total facetectomy (P＜0.05) and resection of the posteriorligamentous complex with laminectomy in flexion-extension (P＜0.01). Asignificant increase in the range of motion in flexion-extension, lateralbending and axial rotation was observed after bilateral resection of thecostovertebral joints (P＜0.01).Conclusion Total unilateral facentectomy with unilateral laminectomydid not significantly increase the range of motion in cadaveric thoracicspines. The facet joint plays an important role in providing stability to thethoracic spine in flexion-extension and axial rotation. The state of theposterior ligamentous complex should be assessed to evaluate the stabilityof the thoracic spine. The costovertebral joints serve as one of the mostimportant stabilizing structures to the thoracic spine in the sagittal, coronal,and transverse planes. Objective To investigate the role of the posterior different structure inthe stability of the thoracic spine using three-dimensional finite elementmethod.Methods Imaging samples of one case without spinal disease andosteoporosis, who informed content was obtained, were selected from CTdata. Using the CT data, three-dimensional finite element model of thoracicvertebrae and other structures (T7～T10) were reconstructed by Mimics,Rapidform and Abaqus softwares. The modified FE model was simulatedthe movements of thoracic vertebrae under flexion-extension, lateralbending and axial rotation respectively.Results The three-dimensional finite element model of thoracicvertebrae was confirmed reliability and efficiency, the geometric profile ofthe FE model were approximate as the specimens in vitro. Throughthree-dimensional finite element analysis, compared with in vitrobiomechanical experiment results, the intact model and the posteriordifferent structure model have consistency and the data were more reliable on the ROM for the effect in the stability of the thoracic spine.Conclusion Finite element analysis method combined with in vitrobiomechanical study, it can be the research method of the spinalpostoperative effect on the stability and which should be provide more dataand to provid more theoretical basis. Objective To investigate the effect of different length pedicle screwdivice fixation on adjacent segments in thoracic spine.Methods The thoracic spine specimen of6cadaver from T4to T11,consisting of the fifth to tenth ribs, were used. After testing the intactspecimen, subsequently in the following manner:1)Above and below usingthe two groups of pedicle screw fixation (Group1),2) Above using the twogroups and below using the one groups of pedicle screw fixation (Group2),3) Above using the one groups and below using the two groups of pediclescrew fixation (Group3)，4) Above and below using the one groups ofpedicle screw fixation (Group4). All specimen were tested in six direction.Paired t-test was used as statistics analysis method..Results The superior adjacent segments of Group1and Group2didnot significantly increase the range of motion in cadaveric thoracic spines,however, a large increase in the range of motion was observed inflexion-extension at the inferior adjacent segments (respectively，P＜0.05，P＜0.01). The superior adjacent segments of Group3and Group4did significantly increase the range of motion in cadaveric thoracic spines, asignificant increase in the range of motion in lateral bending and axialrotation was observed (P＜0.01).Conclusion The mode of above and below using the two groups ofpedicle screw fixation had the least influence at the adjacent segments thanthe other three modes in thoracic spine, the other three modes had certaindegree influence at the inferior or the superior adjacent segments inthoracic spine. Objective Our aim was to evaluate the feasibility and efficiency of theapplication of posterior transpedicular debridement with instrumentationand fusion to the treatment of over60years old patients with thoracictuberculosis.Methods15over60years old patients with Thoracic tuberculosistreated by posterior transpedicular debridement with instrumentation andfusion between August2006to November2010,7male and8female inthis study were reviewed retrospectively. Their age ranged from61to75years old (mean63.4years). The follow-up period ranged from12to51months (mean30months). The patients were evaluated based on vertebralbody loss, kyphotic angle, fusion status of affected segment, visual analogscale (VAS) pain score, and Frankel’s classification.Results A solid fusion was achieved in all15cases. No postoperativecomplications, chronic infection, sinus formation, or significant loss ofdeformity correction were noted in these patients. Moreover, VAS scorewas reduced and Frankel’s grade was recovered in all patients and therewas no recurrence of the tuberculous infection. Conclusion Posterior transpedicular debridement with instrumentationand fusion is a feasible and effective procedure in the treatment for thoracictuberculosis in patients over the age of60years.