Clinical And Experimental Research Of Treatment Of Thoracolumbar Burst Fracture

Objective:The clinical and experimental study of the appropriate option of the treatment of thoracolumbar burst fractures.Method:1 experimental study: The adult thoracolumbar spine specimens (T11-L4) 7 were used to make vertebral L2 burst fracture model by means of Gepstein. Specimens were used anterior and posterior united fixation and posterior fixation, decompression and lumbar interbody fusion. Normal spine and two kinds of fixed Ways were compared to biomechanical stability. Testing equipment was CSS-44020 Biomechanical machine and WS-5921 strain gauge, the reverse test machine was NWS-1000C. Statistical methods were used by statistical software SPSS.16.0 of analysis of variance (One Way ANOVA) to analyze the difference. P<0.05 was significant difference.2 Clinical study: 30 cases of thoracolumbar and lumbar burst fractures were studied retrospectively to observe the complications such as bone fusion, nerve recovery, correction loss, lower back pain effects and adjacent vertebral disc degeneration. Cases in this group were treated an effective decompression, lumbar interbody fusion, 25 cases were posterior fixed, anterior decompression and fusion, which including five cases only of the upper vertebral disc injury and try a short section fusion, to minimize the approach of disc degeneration, and the other five cases (denis type-B burst fractures, bone stations kyphosis sagittal spinal canal diameter of less than 50%)were posterior fixed alone, laminectomy decompression and removal of vertebral injured disc in the upper bone, interbody fusion, to avoid the anterior approach of complex, time-consuming, many unfavorable factors such as hemorrhage.Results:1 experimental study: The load - strain relationship: At maximum load 500 N, the average strain of normal spine with axial compression was 257.29με.; The average strain of anterior and posterior fixed spine was 190.29με, the average strain of posterior lumbar decompression and bone graft intervertebral fusion group was 261.5με. Between bone graft intervertebral fusion and normal group there was no significant differences (P> 0. 05), and between bone graft intervertebral fusion and anterior and posterior united fixed group there was significant differences (P< 0. 05).The strain was smaller the spine was more stable, anterior and posterior united fixed group was the most stable, and posterior lumbar decompression and bone graft intervertebral fusion group had the same stability as the normal spine. Load - displacement relationship: As normally, the greater displacement the spine was more unstable. At maximum load 500 N, the average vertical displacement of normal spine of L1-L3 was 2.44 mm, the anterior and posterior fixed spine was 2.24mm and the posterior lumbar decompression and bone graft intervertebral fusion spine was2.68mm. 3 groups showed no significant difference (P>0.05), so the posterior decompression and fusion fixation can be achieved the same stability with normal or anterior and posterior fixed spine. At the same twist angle 4°, the torque of the spine bigger the ability of anti-reverse stronger. The average torque of normal spine was 5.47N.m; the anterior and posterior united fixation group was 4.12N.m, the posterior decompression and interbody fusion was 4.63N.m, three groups showed no significant difference (P>0.05).2 Clinical study : 30 cases were followed up from September 2004 to December 2008。The shortest period was 7 months and the longest period was 5o months. The average period of follow-up was 33.4 months. The interbody vertebral fusion of the 25cases who were followed up successfully was achieved. 1 case who was followed up 8 months sustained thoracic 12 vertebral burst fracture associated complete paralysis was still complete paralysis. Another one who was followed up 29 months sustained thoracic 12 vertebral burst fracture was paralysis only below ankle joint. The rest patients with nerve injury were achieved Frankel 2 class or above recovery.4 cases L2 fracture and 1 case L4 fracture and dislocation were treated posterior lumbar decompression and bone graft intervertebral fusion. All cases were followed up, the shortest period was 3 months and the longest period was 7 months. The average period of follow-up was 5.2 months. All cases showed the results of strong spine bony fusion, satisfactory reduction rate without reduction lost, various differences of nerve functional improvement, no recurrence of low back pain and no fixation break.Conclusions: (1) Thoracolumber burst fractures were unstable and neurologic deficit often occurs. Therefore, surgery is necessary. (2)Dural laceration and cauda equina injury because of compression by fracture pieces were strongly suspected in the cases of lumber burst fractures associated with laminar fractures in CT scan, posterior decompression and reconstruction by pedicle screw system should be employed as soon as possible. (3)The experiment showed that anterior and posterior united fixation and the posterior decompression, fixation and intervertebral fusion spine can be met or exceeded the stability of normal spine. (4)The critical way to maintain spinal permanent stability was anterior interbody fusion whereas the intact discs were preserved as possible as you can.