Relationship Between Morphological Abnormalities And Spinal Cord Lesion In Thoracolumbar Burst Fracture And Therapeutic Effect Of Operation

Background:The thoraco-lumbar spine locates between the thoracic spine whose activity is limited by the thorax and lumbar spine whose activity is larger so that the stress often concentrate here and cause injuries in this region.Burst fractures account for approximately 45% of all thoracolumbar fractures and 30%～60% of them cause a neurologic deficit.One characteristic of burst fracture is the bone fragment retropulsed into the spine canal.Nowadays,the researches about the burst fracture are focused in two areas:First,where is the bone fragment from,the mechanism of nerve injury,the relationship between the injury of spinal structure and that of spinal cord;Secondly,how does the internal fixation through anterior or posterior make the bone fragment reduce,the role of different internal fixation in reconstructing spinal stability and avoiding later neurologic deficit.In clinical work,the computed tomography imaging and plain radiography often tell significant signs after the patients are hospitalized due to the thoraco-lumbar burst fracture including significant spinal canal narrowing by characteristic retropulsed fragments, increased interpediculate distance and kyphosis angle.These signs are always considered as the necessity for operation and that they exactly cause the nerve injury and affect its recovery.There are debates for how to manage the thoraco-lumbar burst fracture:One viewpoint holds that if the posterior structure keeps intact,a non-operation treatment should be taken because the bone fragments can be absorbed spontaneously;Nowadays,transpedicle screw system through posterior method is widely used for operation.It make the bone fragment reduced by the posterior longitudinal ligament and structures around it.Objective: To investigate the relationship between spinal cord deficit in thoracolumbar brust fractures and morphological abnormalities including stenosis of spinal canal and kyphosis angle;To evaluate the effective of transpedicle screw system through posterior method in recover the height of the vertebrae,the kyphosis angle,nerver function and degree of stenosis.Method:Ninety-nine patients with thorcolumbar burst fractures who were treated in the China-Japan Union Hospital were retrospectively reviewed,including 71 males,28females.The average age is 37.The causes include 57 fall,24 raod accident,12 smash,6 others. We calculate the stenotic ratio of spinal canal based on the area,and measure the kyphosis angle according to Cobb,and record the modified ASIA scoring of motor function of lower extremities;Of these ninety-nine cases,ninety-six patients were undertaken operation through posterior method.We measured the vertebral anterior and posterior height, stenotic ratio of spinal canal,kyphosis angle,nerve function before and after operation.Results: There was no significant difference (P＞0.05) of the stenotic ratio of spinal canal and the kyphosis angle among the patients of different ASIA scales.After operation,the anterior height of the injuried vertebrae is (91.4±10.0)%, the posterior height of the injuried vertebrae is(96.7±4.4)%,Cobb's angle is (-2.0±5.6)°, stenotic ratio of spinal canal is (14.6±13.8)%,the score of nerve function is (1.5±1.6),there is significant difference (Ｐ<0.05)of these data according to the ones before operation.Conclusion: The severity of spinal cord injuries in thoracolumbar burst fractures in not predicted according to the percentage of spinal canal stenosis or the degree of kyphosis induced by thoracolumbar burst fractures; Operation using tanspedicle screw system through posterior method is effective in ameliorating the sequence of spine and the function of spinal cord.It can indirect reduce the retropuled fragment effectively.