Monosegmental Transpedicular Fixation for Selected Patients With Thoracolumbar Burst Fractures

ArticleinJournal of spinal disorders & techniques 22(1):38-44 · March 2009with30 Reads
DOI: 10.1097/BSD.0b013e3181679ba3 · Source: PubMed
Abstract
A prospective cohort study on selected consecutive patients. To evaluate the efficacy of an innovative operative technique called monosegmental transpedicular fixation for the treatment of some thoracolumbar burst fractures. Short-segment pedicle screw instrumentation is accepted by many spinal surgeons as an acceptable technique for the treatment of thoracolumbar burst fractures. Preoperative evaluation using the spinal load-sharing makes this technique more reliable. To preserve more motion segments, some authors have advocated using monosegmental pedicle screw instrumentation (MSPI) to treat thoracolumbar fractures. However, up until now this kind of maneuver is only performed in cases of flexion distraction injuries. A cohort of 20 patients with thoracolumbar burst fractures fulfilling the inclusion criteria were prospectively submitted to surgical treatment of monosegmental transpedicular fixation plus posterior fusion. All instrumentations were performed with pedicle screws inserted bilaterally into the fractured level and 1 adjacent level, either superior or inferior depending on the locating side of the intact endplate. All patients were followed up. The preoperative radiographs, the postoperative radiographs within 1 week of operation, and the radiographs of the most recent follow-up were evaluated for kyphosis correction recorded in the Sagittal Index and Load-Sharing Classification (LSC) index. The postoperative functional outcomes were evaluated using the Frankel Performance Scale together with the Denis Pain Scale. Eighteen patients were followed up successfully with an average final follow-up of 24.7+/-8.0 months. The focal kyphotic angulations were corrected satisfactorily with the mean Sagittal Index of preoperative 16.5+/-6.6 degrees, initial postoperative 4.0+/-2.4 degrees, and latest follow-up 4.8+/-4.0 degrees. No obvious loss of correction occurred except for 2 patients who both scored 8 points on the LSC Score. Postoperatively, most patients attained both functional neurologic improvement and pain relief, and only a few complications were noted. For selected thoracolumbar burst fractures, MSPI can provide the same or better fixation and preserve more motion segments than other methods of posterior pedicle instrumentation. With preoperative evaluation using the spinal LSC system, MSPI is effective and reliable for the treatment of thoracolumbar burst fractures when properly indicated.
    • "Similar results were shown by other studies. [21][22][23][24]and hemorrhage showed recovery intermediate between above two groups. Flanders et al. [26] found that all patients with a neurological deficit had abnormal spinal cords at MRI; intramedullary hemorrhage was predictive of a complete lesion and patients with residual cord compression following reduction demonstrated greater neurological compromise than those without compression. "
    [Show abstract] [Hide abstract] ABSTRACT: Aim: The aim was to correlate the clinical profile and neurological outcome with findings of imaging modalities in acute spinal cord injury (SCI) patients. Subjects and methods: Imaging (radiographs, computed tomography [CT], and magnetic resonance imaging [MRI]) features of 25 patients of acute SCI were analyzed prospectively and correlated with clinical and neurology outcome at presentation, 3, 6 and 12 months. Results: Average initial sagittal index, Gardner's index, and regional kyphosis were 8.12 ± 3.90, 15.68 ± 4.09, 16.44 ± 2.53, respectively; and at 1-year were 4.8 ± 3.03, 12.24 ± 4.36, 12.44 ± 2.26, respectively. At presentation patients with complete SCI had significantly more compression percentage (CP) (P < 0.001), maximum canal compromise (P < 0.001), maximum spinal cord compression (P < 0.001), in comparison to incomplete SCI patients. Qualitative MRI findings; hemorrhage, cord swelling, stenosis showed a predilection toward complete SCI. Improvement in canal dimensions (P = 0.001), beck index (P = 0.008), spinal cord edema (P = 0.010) and stenosis (P = 0.001) was more significant in patients managed operatively; but it was not associated with improved neurological outcome. Cord edema was found more in incomplete SCI patients. Patients presenting with complete SCI improved neurologically to a lesser extent. Conclusions: The present study concludes that imaging modalities in spinal cord injuries have a major role in diagnosis, directing management and predicting prognosis. Imaging findings of severe kyphotic deformities, higher canal and cord compression, lesion length, hemorrhage, and cord swelling are associated with poor initial neurological status and recovery. Quantitative and qualitative parameters measured on MRI have a significant role in predicting initial severity of neurological status and outcome. Operative intervention helps in improving few of these imaging parameters, but not ultimate neurological outcome. MRI is an excellent modality to evaluate acute SCI, and MR images obtained in the acute period significantly and usefully predict neurological outcome.
    Full-text · Article · Sep 2015
    • "Seventy-six patients were treated by AA, [19,252627 175 were treated by PSSF2829303132 and 36 were treated by PMF. [33,34] The regression analysis for the whole database revealed that the model with LFU kyphotic angle regressed on fracture level (dummy variable) had no explanatory power. The simple linear regression of LFU kyphotic angle on surgical treatment, a dummy variable, indicated that the patients treated by PSSF developed a post-surgical kyphotic angle 8.51° more severe than those treated by AA. "
    Full-text · Article · Jan 2015
    • "There are several posterior surgical techniques currently employed to treat thoracolumbar burst fractures, and a large number of biomechanical studies suggest that reinforcement with a fracture-level screw combination can help to improve the biomechanical stability [7,8,10,12]. Clinical evidence suggests that reinforcement with a fracture-level screw combination can help to provide better kyphosis correction and that the reinforcement offers immediate spinal stability, more effectively restores fractured vertebral height, and allows earlier ambulation in patients with thoracolumbar burst fracture [7,9,11], but no studies have compared the von Mises stresses of the internal fixation devices among different short segment pedicle screw fixation techniques using pedicle fixation at the level of the fracture, especially the mono-segment pedicle screw fixation and intermediate unilateral pedicle screw fixation techniques13141516. In this study, we investigated the biomechanical comparison of the four posterior short segment pedicle screw fixation techniques used in thoracolumbar burst fractures. "
    [Show abstract] [Hide abstract] ABSTRACT: Objective To compare the von Mises stresses of the internal fixation devices among different short segment pedicle screw fixation techniques to treat thoracic 12 vertebral fractures, especially the mono-segment pedicle screw fixation and intermediate unilateral pedicle screw fixation techniques. Methods Finite element methods were utilised to investigate the biomechanical comparison of the four posterior short segment pedicle screw fixation techniques (S4+2: traditional short-segment 4 pedicle screw fixation [SPSF]; M4+2: mono-segment pedicle screw fixation; I6+2: intermediate bilateral pedicle screw fixation; and I5+2: intermediate unilateral pedicle screw fixation). Results The range of motion (ROM) in flexion, axial rotation, and lateral bending was the smallest in the I6+2 fixation model, followed by the I5+2 and S4+2 fixation models, but lateral bending was the largest in the M4+2 fixation model. The maximal stress of the upper pedicle screw is larger than the lower pedicle screw in S4+2 and M4+2. The largest maximal von Mises stress was observed in the upper pedicle screw in the S4+2 and M4+2 fixation models and in the lower pedicle screw in the I6+2 and I5+2 fixation models. The values of the largest maximal von Mises stress of the pedicle screws and rods during all states of motion were 263.1 MPa and 304.5 MPa in the S4+2 fixation model, 291.6 MPa and 340.5 MPa in the M4+2 fixation model, 182.9 MPa and 263.2 MPa in the I6+2 fixation model, and 269.3 MPa and 383.7 MPa in the I5+2 fixation model, respectively. Comparing the stress between different spinal loadings, the maximal von Mises stress of the implants were observed in flexion in all implanted models. Conclusion Additional bilateral pedicle screws at the level of the fracture to SPSF may result in a stiffer construct and less von Mises stress for pedicle screws and rods. The largest maximal von Mises stress of the pedicle screws during all states of motion were observed in the mono-segment pedicle screw fixation technique.
    Full-text · Article · Jun 2014
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