| Part OneBiomechanical study of single segmental pedicle instrumentation fixation in the management of thoracolumbar fracture dislocationObjective:To testify the biomechanical properties of thoracolumbar fracture dislocation treated with single segmental pedicle instrumentation.Methods:Twelve 6-to7-month-old fresh porcine cadaveric thoracolumbar spines from T11-L2 were obtained. The thoracolumbar spine specimens were carefully dissected from the surrounding muscles and soft tissues to preserve the bone and spinal ligaments prior. Fracture dislocation was made at the level of T12/13. Single segmental pedicle instrumentation, short segmental pedicle instrumentation and Adding pedicle screws at the level of a fractured vertebrae of a short-segment instrumentation were applied to restore spinal stability. Then pedicle screws were inserted in vertebral pedicle with three different methods:A:Single segmental pedicle instrumentation fixation through injured vertebra (one above and with another one at the fracture level);(SiSPI) B:Traditional short-segment pedicle screw instrumentation across injured vertebra (one above and one below the fracture level pedicle screw fixation) (TSSPI). C:Adding pedicle screws at the level of a fractured vertebrae of a short-segment instrumentation (one above and one below with another one at the fracture level) (ASSPI).Stability tests were performed on specimens in condition of intact and treated with different methods. Axial compression, range of motions (ROM) in flexion-extension, lateral bending and axial rotational stability were recorded.All of the data was analyzed by software SPSS 13.0,using variance analysis to analyze the difference, P<0.05 is statistical significance.Results:The load-displacement of intact specimen, SiSPI, TSSPI, ASSPI was 1.732 ±0.018mm,1.102±0.016mm,1.372±0.032mm,1.098±0.010mm. there is statistical significance between the intact specimen and treated with different instrumentation groups in axial-stiffness. (p<0.05).The ROM of intact specimen in flexion-extension, lateral bending was 1.72± 0.92°,2.81±0.97°,1.71±0.75° and 1.72±0.80° respectively. The ROM of SiSPI in flexion-extension, lateral bending was 0.40±0.05°,0.48±0.08°,0.77±0.11° and 0.76±0.09°. The ROM of intact was significantly higher than that of SiSPI in flexion-extension, lateral bending (p<0.01). Group SiSPI was more stable than intact group in flexion-extension, lateral bending. The torsional degree of SiSPI was 0.52± 0.11°,0.53±0.09°;and that of intact was 3.55±0.77°,3.53±0.75°. Intact group was significantly higher than that of SiSPI in axial rotation (p<0.05). The ROM of TSSPI in flexion-extension, lateral bending was 1.08±0.14°,0.97±0.11,1.05±0.19° and 1.05±0.16°.The torsional degree of TSSPI was 0.69±0.14° and 0.69±0.14°. The ROM of ASSPI in flexion-extension, lateral bending was 0.30±0.07°,0.37±0.09 0.75±0.12° and 0.74±0.08°. The torsional degree of ASSPI was 0.49±0.16° and 0.50±0.12°. The ROM TSSPI was significantly higher than that of SiSPI in flexion-extension, lateral bending and torsion (p<0.05). Group SiSPI was more stable than group TSSPI. The ROM SiSPI was significantly higher than that of ASSPI in flexion-extension, (p<0.05), Group ASSPI was more stable than group SiSPI in flexion-extension. Group SiSPI was as stable as group ASSPI in lateral bending and axial rotation (p>0.05).The SPI of SiSPI in flexion-extension, lateral bending and axial rotation was 0.89±0.05,0.89±0.08,0.96±0.11,0.96±0.09,0.97±0.11 and 0.97± 0.09,respectively. The SPI of TSSPI in flexion-extension, lateral bending and axial rotation was 0.79±0.11,0.90±0.19,0.91±0.16,0.89±0.14 and 0.88± 0.16,respectively. The SPI of ASSPI in flexion-extension, lateral bending and axial rotation was 0.92±0.07,0.91±0.09,0.97±0.12,0.97±0.08,0.98±0.16and 0.98± 0.12,respectively. Statistics show that The SPI between the group SiSPI and group TSSPI showed significant differences in flexion-extension, lateral bending and axial rotation (p<0.05). SiSPI was more stable than TSSPI in both fJexion-extension, lateral bending and axial rotation. The SPI of SiSPI was significantly higher than that of ASSPI in flexion-extension, (p<0.05), Group ASSPI was more stable than group SiSPI in flexion-extension. The SPI of SiSPI was significantly higher than that of ASSPI in flexion-extension, (p<0.05), There is no different between group SiSPI and group ASSPI in lateral bending and axial rotation (p>0.05). Group SiSPI was as stable as group ASSPI in lateral bending and axial rotation.Conclusion:1. Single segmental pedicle instrumentation(SiSPI), Traditional short-segment pedicle screw instrumentation (TSSPI) and adding pedicle screws at the level of a fractured vertebrae of a short-segment instrumentation (ASSPI)can provide instant stability with respect to the reconstruction of thoracolumbar fracture dislocation.2. Single segmental pedicle instrumentation(SiSPI) and adding pedicle screws at the level of a fractured vertebrae of a short-segment instrumentation(ASSPI) can provide more instant stability than Traditional short-segment pedicle screw instrumentation (TSSPI) with respect to the reconstruction of thoracolumbar fracture dislocation.3. Single segmental pedicle instrumentation can provide instant stability respect to the reconstruction of thoracolumbar fracture dislocation.Part twoThe clinical study of posterior intervertebral pressing single segmental fixation treatment of thoracolumbar fracture dislocationBackground:Thoracolumbar fracture dislocation belongs to unstable type fracture damaging three columns at the same time. Except bony structure damage in centrum, lamina, pedicle, and pines, thoracolumbar fracture dislocation often merges ligament, intervertebral disc and nerve tissue injury. Currently, it is still controversy about urgical procedure. Anterior approach operation can rebuild well anterior support, but is difficult for restoration and obtain firmly fixation. Traditional posterior four pins across segmental restoration and fixation technology cannot satisfy fracture and dislocation vertebral reset, and may appear excessive distraction. In recent years, most scholars adopted three centrums six pins restoration and fixation including the injured vertebra and obtained satisfactory effect. By using the calf specimens to simulate single segmental pedicle screw fixation through injured vertebra and traditional short-segment pedicle screw fixation across injured vertebra in treating thoracolumbar fracture, studies confirmed that there was no significant difference in the stability of reconstructed spine between two methods. Since spin could be located in injured vertebra, does it necessary to fix the inferior normal vertebral body? Or fix and fusion another normal intervertebral disc? We adopted single segmental pedicle screw fixation through injured vertebra on patients with thoracolumbar fracture dislocation, and found its curative effect was satisfactory. This study investigated the clinical efficacy of posterior intervertebral pressing single segmental fixation, traditional across injured vertebra and three centrums six pins restoration and fixation including the injured vertebra on treating thoracolumbar vertebral fracture dislocation.ObjectiveThoracolumbar fracture dislocation often appears bony structure damage in centrum, lamina, pedicle, and spines. This study investigated the clinical efficacy of screwing through injured vertebra, posterior intervertebral pressing, single segmental fixation, traditional across injured vertebra and three centrums six pins restoration and fixation including the injured vertebra on treating thoracolumbar vertebral fracture dislocation.Methods26 patients with thoracolumbar fracture dislocation received surgical treatment between June 2010 and June 2014 were enrolled in Jinan central hospital affiliated to Shandong University. According to the surgical strategy the patients is divided into three groups. Group A:received single segmental pedicle screw fixation through injured vertebra; Group B:traditional short-segment pedicle screw fixation across injured vertebra; Group C:three centrums six pins restoration and fixation including the injured vertebra.All patients received posterior open reduction, vertebra canal open window decompression pedicle screw fixation in 12 days after injury.Midline incision was performed on patients with prone position. Spine, interspinal ligament, and supraspinal ligament structure were reserved. The operation operating procedure included decompression, restoration, nailing and fixation, fusion. All cases received posterolateral fusion.All patients walked in one week after surgery under the brace support.26 patients received more than 12 months follow-up, with mean time as 22.3 months.Perioperative indicators were observed. To compare the operation time, intraoperative blood loss, incision length, and complications. Nerve function recovery, injured vertebral leading edge height ratio, Cobb angle, dislocation rate, and injured spinal canal occupation rate were compared before surgery, one week after surgery, and the last follow-up.All data were analyzed by SPSS 13.0 software. Measurement data was presented as ± s and calculated by t-test. Enumeration data was tested by Kruskal-Wallis test.ResultsNeurological function evaluation:ASIA score at last follow-up in all groups increased significantly compared before surgery (P<0.05), while no obvious different was observed between groups A, groups B and group C (P>0.05).Single segmental pedicle screw fixation group showed obviously better performance in operation time, intraoperative blood loss, incision length, and complications than cross segment pedicle screw fixation group and three centrums six pins restoration and fixation including the injured vertebra group(P<0.05). whereas no complication was observed in single segment group.No statistical difference was found in preoperative injured vertebral leading edge height ratio, Cobb angle, dislocation rate, and injured spinal canal occupation rate (P>0.05). All three groups showed significantly improved imaging indicators after surgery (P<0.05). During the last follow-up, injured vertebral leading edge height ratio was similar between three groups (P>0.05). Group A was better in Cobb angle, dislocation rate, and injured spinal canal occupation rate than group B and group C (P<0.05)ConclusionSingle segmental pedicle screw fixation through injured vertebra, traditional short-segment pedicle screw fixation across injured vertebra and three centrums six pins restoration and fixation including the injured vertebra can recover the clinical function of thoracolumbar vertebral fracture dislocation, while the former showed better general efficacy than the others. |
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