Treatment of Thoracolumbar Vertebrate Fracture by Transpedicular Morselized Bone Grafting in Vertebrae for Spinal Fusion and Pedicle Screw Fixation

To enhance the fusion of graft bone in thoracolumbar vertebrae and minimize the postoperative loss of correction, short-segment pedicle screw fixation was reinforced with posterior moselizee bone grafting in vertebrae for spinal fusion in patients with thoracrolumbar vertebrate fractures. Seventy patients with thoracrolumbar vertebrate fractures were treated by short-segment pedicle screw fixation and were randomly divided into two groups. Fractures in group A （n=20） were rein-forced with posterior morselized bone grafting in vertebrae for spinal fusion, while patients group B （n=50） did not receive the morselized bone grafting for bone fusion. The two groups were compared in terms of kyphotic deformity, anterior vertebral height, instrument failure and neurological functions after the treatment. Frankel grading system was used for the evaluation of neurological evaluation and Denis scoring scale was employed for pain assessment. The results showed that the kyphosis correction was achieved in both group A and group B （group A： 6.4 degree; group B： 5.4 degree）/At the end of follow-up, kyphosis correction was maintained in group A but lost in group B （P=0.0001）. Postoperatively, greater anterior height was achieved in group A than in group B （P〈0.01）. During follow-up study, anterior vertebral height was maintained only in Group A （P〈0.001）. Both group A and group B showed good Denis pain scores （P1 and P2） but group A outdid group B in terms of control of severe and constant pain （P4 and P5）. By Frankel criteria, the changes in neurological functions in group A was better than those of group B （P〈0.001）. It is concluded that reinforcement of short-segment pedicle fixation with morselized bone grafting for the treatment of patients with thoracolumbar vertebrae fracture could achieve and maintain kyphosis correction, and it may also increase and maintain anterior vertebral height. Morselized bone grafting in vertebrae offers immediate spinal stability in patients with thoracolumbar vertebrate fractures, decreases the instrument failure and provides better postoperative pain control than without the morselized bone grafting.

IMAGING DIAGNOSIS OF THORACOLUMBAR BURST FRACTURES

Objective To review imaging use in the diagnosis of thoracolumbar burst fractures and to determine the diagnostic va-lue of different imaging methods. Methods One hundred and fourteen patients with 120 thoracolumbar burst fractures were retrospectively reviewed. Pl-ain radiographs were available in all cases; CT scans and MRI were obtained in 96 and 74 cases, respectively. Results A total of 27 burst fractures were misdiagnosed as other types of fractures on radiographs alone, and accounted for 22.5% of all fractures. The results indicated that plain radiographs often fail to delineate the pathological features of thor-acolumbar burst fractures, leading to delay in diagnosis. Conclusion In regard to thoracolumbar injury diagnosis, burst fractures should be differentiated from compression frac-tures. CT should be routinely indicated and MRI examination, when necessary, may be simultaneously considered.

Formative mechanism of intracanal fracture fragments in thoracolumbar burst fractures： a finite element study

Background Thoracolumbar burst fracture is a common clinical injury, and the fracture mechanism is still controversial. The aim of this research was to study the formation of intracanal fracture fragments in thoracolumbar burst fractures and to provide information for the prevention of thoracolumbar bursts fractures and reduction of damage to the nervous system. Methods A nonlinear three-dimensional finite element model of T11-L3 segments was established, and the injury processes of thoracolumbar bursts were simulated. The intact finite element model and the finite element model after the superior articular were impacted by 100 J of energy in different directions. The distribution and variation of stress in the superior posterior region of the L1 vertebral body were analyzed. Abaqus 6.9 explicit dynamic solver was used as finite element software in calculations. Results A three-dimensional nonlinear finite element model of the thoracolumbar spine was created. In the intact model, stress was concentrated in the superior posterior region of the L1 vertebral body. The stress peak was a maximum for the extension impact load and a minimum for the flexion impact load. The stress peak and contact force in the facet joint had close correlation with time. The stress peak disappeared after excision of the superior articular process. Conclusions The three-dimensional nonlinear finite element model was suitable for dynamic analysis. The contact force in the facet joint, which can be transferred to the superior posterior vertebral body, may explain the spinal canal fragment in thoracolumbar burst fractures.

Early posterior spinal canal decompression and circumferential reconstruction of rotationally unstable thoracolumbar burst fractures with neurological deficit

Background Among the various treatments of neurologically involved unstable thoracolumbar burst fractures,the combination of anterior and posterior instrumentation provides the most stable reconstruction.However,the use of both approaches on a trauma patient may increase the morbidity.This study is a retrospective matched cohort study to evaluate the advantages of a single stage posterior approach for spinal canal decompression in combination with circumferential reconstruction by comparing the clinical and radiographic results.Methods From March 2005 to September 2009,patients with matched type spinal fracture,ages at surgery,and involved levels in our institute underwent either a single stage posterior approach （group one,n=12） or traditional combined approach （group two,n=14） for spinal canal decompression and circumferential reconstruction were reviewed.Pre-and post-operative X-ray films were reviewed and changes in Cobb angle of thoracolumbar spine were documented.Intra-operative,post-operative,and general complications were registered.Results The mean follow-up was （27.7±9.6） months （range,14 to 56 months） in group one and （29.2±7.4） months （range,20 to 60 months） in group two （P 〉0.05）.The mean operation time was 214 minutes （range,186-327 minutes） in group one and 284 minutes （range,219-423 minutes） in group two （P 〈0.05）.The average volume of intraoperative blood loss was 1856 ml （range,1250-3480 ml） in group one and 2453 ml （range,1600-3680 ml） in group two （P 〈0.05）.There was no statistical difference between the groups one and two in average vertebral body height loss at the injured level and the average Cobb angle in sagittal plane before and immediately after surgery.Postoperatively,there was an epidural hematoma in one patient in group one and two patients in group two.Bony union after stabilization was obtained in all patients,without loosening or breakage of screws.Loss of correction （5°） was seen in 1 patient in group one at the 6th month owing to the subsidence of the Titanium mesh cages into the vertebra.In group two,totally four patients suffered respiratory-related complication,including pneumonia in two,severe atelectasis in one and pleural effusions in one.Importantly,there were no intraoperative or postoperative deaths in any group.All patients with incomplete neurologic deficits improved at least 1 Frankel grade.Conclusion Single-stage posterior vertebra resection in combination with circumferential reconstruction is a new option to manage severe thoracolumbar burst fractures.

Single-cell RNA Sequencing Reveals Thoracolumbar Vertebra Heterogeneity and Rib-genesis in Pigs

Development of thoracolumbar vertebra(TLV)and rib primordium(RP)is a common evolutionary feature across vertebrates,although whole-organism analysis of the expression dynamics of TLV-and RP-related genes has been lacking.Here,we investigated the single-cell transcriptome landscape of thoracic vertebra(TV),lumbar vertebra(LV),and RP cells from a pig embryo at 27 days post-fertilization(dpf)and identified six cell types with distinct gene expression signatures.In-depth dissection of the gene expression dynamics and RNA velocity revealed a coupled process of osteogenesis and angiogenesis during TLV and RP development.Further analysis of cell type-specific and strand-specific expression uncovered the extremely high level of HOXA103′-UTR sequence specific to osteoblasts of LV cells,which may function as anti-HOXA10-antisense by counteracting the HOXA10-antisense effect to determine TLV transition.Thus,this work provides a valuable resource for understanding embryonic osteogenesis and angiogenesis underlying vertebrate TLV and RP development at the cell type-specific resolution,which serves as a comprehensive view on the transcriptional profile of animal embryo development.