OBJECTIVETo investigate the damage characteristics and biomechanical mechanisms of the thoracolumbar vertebral bursh fracture during the impact loading.

METHODSFrom September 2008 to October 2009, 10 fresh human thoracolumbar spine specimens were collected for experimental model and divided into two groups. Biomechanical static and dynamic impact strength test were performed respectively in two groups. The static and dynamic data from thoracolumbar vertebrae shock response in different loads were observated.

RESULTSThoracolumbar yield load was (5 280.00 +/- 354.2) N, yield displacement was (13.32 +/- 2.07) mm, the limit load was(6 590.00 +/- 249.20) N, ultimate displacement was (20.60 +/- 2.57) mm, load speed was 0.02 g, and the average limit load of dynamic mechanical properties of thoracic and lumbar vertebrae was (14 425.60 +/- 1101.52) N, the average reaction time load was (17.29 +/- 2.04) ms, the average of acceleration was (36.80 +/- 2.81) g, the dynamic displacement was (45.11 +/- 1.13) mm.

CONCLUSIONThoracolumbar vertebral burst fracture is a serious injury caused by the release of high-energy moment, the role of biomechanical forces are in a pattern of pulse change, thoracic and lumbar vertebrae present with the viscoelastic properties of biological materials.

Biomechanical Phenomena ; Cadaver ; Humans ; Lumbar Vertebrae ; injuries ; Spinal Fractures ; metabolism ; physiopathology ; Stress, Mechanical ; Thoracic Vertebrae ; injuries

OBJECTIVE: To explore MSCT optimal examination time for patients with unconspicuous rib fracture. METHODS: Sixty-three patients with thoracic trauma from January 2009 to June 2011 were collected. They were examined by MSCT in the first week after trauma and re-examined during eighth weeks after trauma. The number of rib which had been found fractured in the first examination was compared to that in re-examinations. RESULTS: Patients with fine rib fracture often have different diagnostic results at different examination time after trauma. There was statistical difference between the number in the first week and the third week to the fifth week. CONCLUSION MSCT could show the pathophysiological changes of rib fracture objectively in the stage between the third week and the fifth week after trauma, which is optimal examination time for the fine rib fracture.
Adult ; Aged ; Female ; Humans ; Male ; Middle Aged ; Multidetector Computed Tomography ; Pleura/pathology* ; Radiography, Thoracic/methods* ; Rib Fractures/physiopathology* ; Thoracic Injuries/physiopathology* ; Time Factors ; Wounds, Nonpenetrating/physiopathology* ; Young Adult

Adult ; Aneurysm, Dissecting ; diagnosis ; physiopathology ; Aneurysm, False ; Coronary Aneurysm ; diagnosis ; physiopathology ; Coronary Vessels ; pathology ; physiopathology ; Humans ; Male ; Myocardial Infarction ; diagnosis ; physiopathology ; Thoracic Injuries ; complications ; physiopathology ; Young Adult

We experienced a rare case of winged scapula that was caused by the rupture of the rhomboideus major and the lower trapezius muscles without any nerve injury in a 12 yr old female after she had carried a heavy backpack. Electrodiagnostic study revealed that the onset latencies, amplitudes and conduction velocities were normal in the long thoracic nerve, the spinal accessory nerve and the dorsal scapular nerve. The needle EMG findings were normal as well. An explorative operation was performed and the rupture of the rhomboideus major and lower trapezius muscles was detected. Direct surgical repair of the ruptured muscle was carried out and the deformity was corrected. The anatomical and functional restoration was satisfactorily accomplished.
Weight Lifting/injuries ; Thoracic Nerves/*injuries ; Scapula/anatomy & histology/*physiopathology ; Rupture ; Neurons/metabolism ; Muscle, Skeletal/*injuries/innervation/*pathology ; Humans ; Female ; Electromyography/*methods ; Child

OBJECTIVETo compare the influence of normal and degenerative discs on stress distribution of the thoracolumbar vertebrae under destructive load, explore the biomechanical background and clinical meaning and provide theoretical basis for clinical diagnosis and treatment.

METHODSA mechanical model of thoracolumbar motion segment of normal and degenerative discs was built with a three dimensional finite element method and three stresses of vertical compression, compressive flexion and distractive flexion were comparatively analyzed.

RESULTSWith vertical compression and compressive flexion loads, the thoracolumbar motion segment of the normal disc showed that the central part of the upper and lower end-plates of the vertebrae and the central part of the trabecular bone adjacent to the end-plate were loaded with the most intensive stresses, meanwhile, the postero-lateral part of the annulus fibrosus was concentrated with stresses. Degenerative disc showed that the stress distribution of the trabecular bone was relatively averaged, the stresses of the central part adjacent to the end-plate were low, while at the same time, the stresses of the peripheral part were elevated relatively. With distraction flexion load, the stresses of the cortex bone, trabecular bone, end-plate and annulus fibrosus of the thoracolumbar vertebrae of degenerative discs were low, meanwhile, the stresses of the posterior structure of the vertebral body were relatively elevated compared with that of normal discs.

CONCLUSIONSThere is difference in influence between normal and degenerative discs on the stress distribution of the thoracolumbar vertebrae with destructive load. The transferring way of load is changed after disc degeneration.

Elasticity ; Finite Element Analysis ; Humans ; Lumbar Vertebrae ; physiology ; Spinal Injuries ; physiopathology ; Stress, Mechanical ; Tensile Strength ; Thoracic Vertebrae ; physiology

OBJECTIVETo explore the effect of seawater immersion on serum osmotic pressure and electrolytes balance following chest trauma in dogs.

METHODSTwenty-five healthy adult dogs were used in the experiment. A canine model of right open pneumothorax was established by chest puncturing on all animals. Animals were divided into three groups: a control group (n=10) with chest trauma without any immersion; a seawater group (n=10) immersed in seawater after chest trauma and a normal saline group (n=5) immersed in normal saline solution following chest trauma. Blood samples were taken at different time intervals to determine plasma osmotic pressure and electrolytes. The hemodynamic changes were also recorded.

RESULTSMortality in the seawater group was much higher than that of the control group and the normal saline group. The mean survival time in the seawater group lasted only 45 minutes, while in the control group and the normal saline group the average survival time was more than 4 hours (P<0.01). One of the most important causes of death was hypernatremia and high osmolality. Severe electrolytes imbalance was observed in seawater group. Hypernatremia and high osmolality were the most significant factors of high mortality in the seawater group.

CONCLUSIONSSeawater immersion after chest trauma appears to be associated with severe electrolyte imbalance as well as high osmotic pressure. These may be the risk factors leading to fatal outcome.

Animals ; Dogs ; Hemodynamics ; Osmotic Pressure ; Risk Factors ; Seawater ; adverse effects ; Thoracic Injuries ; physiopathology ; Water-Electrolyte Balance ; physiology

OBJECTIVETo study the curative effect of postural reduction with instrumental reduction in treatment of flexion-distraction thoracolumbar fractures.

METHODSA retrospective study was performed on 43 patients with single thoracolumbar flexion-distraction fractures admitted from August 2009 to August 2011, included 28 males and 15 females with an average age of 44 years old (34 to 56 years old). All patients were treated with postural reduction with instrumental reduction. The kyphosis (Cobb angle) recovery of injured vertebral height and complication were analyzed. The visual analogue scale(VAS) and com-plications were followed up and recorded.

RESULTSThere was no difference in recovery of injured vertebral posterior height among preoperative, 1 week and 1 year after operation (P > 0.05). There were significantly difference in kyphosis (Cobb angle) and recovery of injured vertebral anterior height between preoperative and postoperative at 1 week (P < 0.05). There was no difference in kyphosis (Cobb angle) and recovery of injured vertebral anterior height between 1 week and 1 year after operation (P > 0.05). VAS significantly improved from preoperative (7.2 +/- 1.2) to (0.8 +/- 0.7) at 1 year after operation (t = 18.47, P < 0.001).

CONCLUSIONPostural reduction with instrumental reduction is effective for thoracolumbar flexion-distraction fractures and it is beneficial to the recovery of vertebral height and saggital alignment.

Adult ; Female ; Fracture Fixation, Internal ; adverse effects ; Humans ; Male ; Middle Aged ; Retrospective Studies ; Spinal Fractures ; physiopathology ; surgery ; Thoracic Vertebrae ; injuries ; physiopathology ; surgery ; Visual Analog Scale

BACKGROUNDThoracolumbar 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.

METHODSA nonlinear three-dimensional finite element model of T11-3 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.

RESULTSA 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.

CONCLUSIONSThe 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.

Adult ; Biomechanical Phenomena ; Finite Element Analysis ; Humans ; Lumbar Vertebrae ; injuries ; Male ; Models, Biological ; Spinal Canal ; Spinal Fractures ; physiopathology ; Stress, Mechanical ; Thoracic Vertebrae ; injuries

BACKGROUNDPosterior pedicle screw device is widely used in treatment of thoracolumbar burst fractures. As the clinical operation is not based upon quantitative data of adjustments, the results are not optimal. At present, no study has assessed the associations between the device adjustments and the restoration of stiffness. We investigated the biomechanical effects that adjustments of a pedicle screw device had on the burst fracture, and explored an optimal adjustment.

METHODSBurst fractures were produced at L1 vertebra in 24 fresh calf spines (T12-L3). The specimens were divided into four groups at random. Pedicle screw devices were attached to T13 and L2. Four device adjustments, consisting of distraction and extension, were applied. Adjustment 1 was pure 6° extension, adjustment 2 was pure 5 mm distraction, adjustment 3 was 6° extension followed by 5 mm distraction, and adjustment 4 was 5 mm distraction followed by 6° extension. The effect of each adjustment on the stiffness restoration, anatomical reduction, and neural decompression for the burst fractures was analyzed and evaluated.

RESULTSPure extension (Group 1) produced the closest segment height and the least restoration of the canal to the intact. Pure distraction (Group 2) restored stiffness most, but with only 60% stiffness of the intact value, and lost the segmental angle most to the intact. The combination of extension-distraction (Group 3 and Group 4) produced the maximum reduction of the anatomy and restoration of the canal in the burst fracture, and the least stiffness restoration. The sequence of extension and distraction did not affect stiffness restoration, anatomical reduction, and neural decompression.

CONCLUSIONSThe device adjustments affected stiffness restoration, anatomical reduction, and neural decompression. The combined extension-distraction adjustment may be the most suitable considering the anatomical reduction and neural decompression, but the stiffness decreased the most; it should be considered to reconstruct L1 vertebra.

Animals ; Biomechanical Phenomena ; Cattle ; Female ; Fracture Fixation, Internal ; instrumentation ; Lumbar Vertebrae ; injuries ; surgery ; Male ; Spinal Fractures ; physiopathology ; surgery ; Thoracic Vertebrae ; injuries ; surgery

OBJECTIVETo explore the therapeutic effects of percutaneous vertebroplasty with Genex combined with pedical screw fixation in the treatment of thoracolumbar burst fractures.

METHODSFrom February 2007 to October 2009, 38 patients with thoracolumbar burst fractures were treated with percutaneous vertebroplasty with Genex and pedical screw fixation. There were 25 males and 13 females, with a mean age of 42 years old (ranged, 30 to 68 years). The cause of injuries included road accident of 9 cases,crush injury of 7 cases,crash of 21 cases and others of 1 case. The fractures were classified according to Denis classification: 6 cases of type A, 22 cases of type B, 7 cases of type C and 3 cases of type D. Functional assessment of nerves was assessed according to ASIA criteria: 4 cases of type A,7 cases of type B, 10 cases of type C, 6 cases of type D and 11 cases of type E. Therapeutic effects were assessed by imaging and ASIA standard.

RESULTSAll the patients were followed up, and the duration ranged from 6 months to 34 months,with a mean period of 16.5 months. The results were observed after 1 week by X-ray inspection that vertebrate column array of all patients were restored to normal, anterior height of centrum restored to (98.50 +/- 2.17)%, posterior height of centrum for (98.87 +/- 1.82)%; and Cobb angle of injured vertebra decreased to average of (1.63 +/- 2.15) degree; the stenosis rate restored to (1.45 +/- 3.47)%. By X-ray inspection, it was observed that the vertebral height kept good at 6 months after operation, and the bone density almostly normal. By CT scanning, it was observed that bone defects of vertebrae disappeared, and restored to normal bony tissue. The nerve function restored 1 to 2 grades 6 months after operation.

CONCLUSIONArtificial bone of Genex applied in vertebral body-plasty has good biocompatibility, strong bone inducibility, no complications, little loss of vertebrae height and Cobb angle, and satisfactory results in the near future.

Adult ; Aged ; Female ; Follow-Up Studies ; Fractures, Bone ; diagnostic imaging ; physiopathology ; surgery ; Humans ; Lumbosacral Region ; diagnostic imaging ; injuries ; physiopathology ; surgery ; Male ; Middle Aged ; Skin ; Thoracic Injuries ; diagnostic imaging ; physiopathology ; surgery ; Tomography, X-Ray Computed ; Vertebroplasty ; instrumentation