ABSTRACT
<p><b>OBJECTIVE</b>To compare the stability of subaxial cervical anterior transpedicular screw(ATPS) fixation and three traditional fixations for three-column injury.</p><p><b>METHODS</b>Six specimens of cervical spine were prepared. After measurememt of the range of motion(ROM) in intact state, the specimens were made into three-column injury models. The models were reconstructed with an anterior cervical cage, and stabilized by ATPS, anterior plate(AP), anterior plate + lateral mass screw(AP+LMS) and posterior transpedicular screw(PTPS). The ROM of the models in the four states were measured, and the results of data were compared after standardization.</p><p><b>RESULTS</b>The normalized ROM of ATPS state in flexion-extension, lateral bending, axial rotation were(77.17±4.75)%, (82.00±2.61)%, (83.17±2.23)%, which were significant small than those in intact state(<0.05). The normalized ROM of AP state in flexion-extension, lateral bending, axial rotation were(119.67±7.42)%, (116.33±7.53)%, (112.67±5.99)% , which were significant larger than those in intact state(<0.05). The normalized ROM of AP in all directions were significant larger than those of ATPS(<0.05). There was no significant difference between normalized ROM of PTPS state and those of ATPS state in flexion-extension and lateral bending(>0.05). The normalized ROM of PTPS state in axial rotation was(6.83±2.48)% and was significant larger than that of ATPS state(=0.009). The normalized ROM of AP+LMS state in flexion-extension was(68.50±2.43)%, which was significant smaller than that of ATPS state(=0.003). There was no significant difference between the normalized ROM of AP+LMS state and those of ATPS state in lateral bending and axial rotation(>0.05).</p><p><b>CONCLUSIONS</b>Subaxial cervical three-column injury model reconstruction by ATPS can provide the adequate primary stability, of which biomechanics property is superior compared to AP and PTPS, and is similar to that of AP+LMS. It can be applied to the patients with no need to decompression and reduction through posterior approach.</p>
ABSTRACT
Objective To compare the initial stability between anterior transpedicular screw (ATPS) fixation,anterior plate (AP) fixation and combining anterior and posterior (CAP) fixation for subaxial cervical three-column injury.Methods Six specimens of cervical spine were prepared.After measurement of the range of motion (ROM) of the intact cervical spine,the specimens were made into models of three-column injury.After the models were simulatively reconstructed using an anterior cervical cage,they were stabilized by ATPS,AP and CAP.After the ROMs of the models in the 3 fixation states were measured,the data were normalized by standardizing them to the intact state ROM which was set at 100％.The normalized ROMs of the models in the 3 fixation states were compared.Results The normalized ROMs of AP fixation state in flexion,extension,lefi lateral bending,right lateral bending,left axial rotation and right axial rotation were 119.68±8.34％,119.63±6.74％,115.20±7.91％,117.47±7.81％,120.67±5.99％ and 112.35 ± 8.42％,respectively,significantly larger than those of the intact state (P ＜ 0.05).The normalized ROMs of the other 2 states in all directions were significantly smaller than those of the intact state (P ＜0.05).The normalized ROM of ATPS state in flexion was 87.48 ± 5.31％,significantly larger than that of CAP state (69.60 ± 2.06％) (P ＜ 0.05).There were no significant differences between the normalized ROMs of ATPS state and those of CAP state in extension (65.53 ± 4.36％ versus 67.17 ± 3.10％),in left lateral bending (82.13 ± 2.85％ versus 82.30 ±4.69％),in right lateral bending (81.78 ± 3.42％ versus 81.27 ± 2.79％),in left axial rotation (83.20 ± 2.30％ versus 82.95 ± 2.40％),or in right axial rotation (83.03 ± 1.30％ versus 83.60 ± 6.56％) (P ＞ 0.05).Conclusions In subaxial cervical three-column injury,the initial stability of ATPS fixation may be superior to that of AP fixation and similar to that of CAP fixation.We believe that ATPS can provide enough initial stability for subaxial cervical three-column injury.
ABSTRACT
In a thoracolumbar fracture, accurate diagnosis of spinal stability is necessary in deciding on appropriate treatment options and for prevention of complications that can subsequently occur. In various reports for spinal stability, rupture of the posterior ligament complex is generally accepted as a very important factor of spinal stabiliby. In cases of conservative treatment for unstable thoracolumbar fractures, the progressive kyphotic deformity can cause chronic pain and functional disability, and neurologic deterioration in severe cases. Therefore, the concept of surgical treatment for unstable thoracolumbar fracture has been well established. We report on two cases of neglected three column injury in the thoracolumbar spine, which were treated conservatively due to misdiagnosis at other hospitals, and finally underwent delayed operation in our hospital because of chronic back pain and progressive kyphotic deformity.