Inter-observational analysis of computed tomography parameters to predict nonobvious posterior ligament complex injury in neurologically intact patients with thoracolumbar trauma.

Introduction: Assessing the integrity of the posterior ligament complex (PLC), as a key element in the characterization of an unstable Thoracolumbar fracture (TLF), is challenging, but crucial in the choice of treatment. Research question: How to create a reproducible score using combined parameters of Computed Tomography (CT) to predict nonobvious PLC injury. How CT parameters relate with PLC status. Material and methods: Retrospective analysis of neurologically intact patients with an acute traumatic TLF, who underwent CT and Magnetic Resonance Imaging (MRI) within 72 h, in the Emergency Department of a single institution between January 2016 and 2022. Four investigators rated independently 11 parameters on CT and PLC integrity on MRI. The interrater reliability of the CT parameters was evaluated, and two risk scores were created to predict PLC injury on CT using the coefficients of the multivariate logistic regression. Results: 154 patients were included, of which 62 with PLC injury. All CT measurements had excellent or good interrater reliability. Patients with Horizontal Fracture of the lamina or pedicle (HLPF), Spinous process fracture (SPF) and Interspinous Distance Widening (IDW) were positively associated with PLC injury (p < 0.001, p < 0.001 and p = 0.045, respectively). Risk Score 2 (RS2), which included only statistically significant variables, had a total of 75.9% of correct classifications (p < 0.001), with a sensitivity of 71.0% and specificity of 78.3% to estimate PLC injury detected in the MRI. Discussion and conclusion: Standardized procedures pre-established in the CT measurement protocol were effective. Identically to early findings, those three CT measurements showed a positive relation to PLC injury, thus enhancing the conclusions of previous studies. Comparing to the reliability of the CT findings above mentioned, the score was less precise.

The Relationship Between MRI Findings of Posterior Ligamentous Complex and Lumbar Instability in Degenerative Spondylolisthesis.

Background: To determine the factors in posterior ligamentous complex indicating lumbar instability in patients diagnosed with degenerative spondylolisthesis on conventional magnetic resonance imaging (MRI). Methods: We retrospectively analyzed patients who underwent PLIF surgery for degenerative spondylolisthesis at our institution between 2018 and 2020 and who had complete eligible preoperative imaging data for review and study, including lumbar MRI and anteroposterior and flexion-extension radiographs. Results: Fifty-three patients were confirmed to have lumbar instability (Unstable Group, 44%), while sixty-seven patients (Stable Group, 56%) did not have instability on radiographs. The patients in the stable group had more advanced status of the degeneration of intervertebral disc than in the unstable group (p<0.05). The degeneration of supraspinous ligament (SSL) was more severe in the unstable group (p<0.05). Compared with the patients with rotatory instability, advanced degeneration of interspinous ligament (ISL) and SSL was observed in patients with translatory instability (p<0.05). However, there was no significant difference with regard to the height of the spinous process and the interspinous distance in patients with or without instability. Conclusion: This MRI analysis showed that abnormal segmental motion is closely associated with the pathological characteristics of supraspinal ligament. Advanced degeneration of SSL in patients with degenerative spondylolisthesis should raise the suspicion for lumbar instability and additional evaluations. The status of ISL and ligamentum flavum (LF) may not be helpful for the diagnosis of lumbar instability. Functional radiographs combined with MRI may provide valuable information when diagnosing lumbar instability in patients with mechanical back pain.

The trapeziometacarpal screw home torque mechanism as a clinical indicator of the posterior joint ligament complex integrity: A cadaveric investigation.

BACKGROUND: To date, no clinical test provides specific objective information on the integrity of key ligamentous support of the trapeziometacarpal (TMC) joint. PURPOSE: To examine the potential of the TMC joint screw home torque mechanism (SHTM) in estimating the integrity of the posterior ligament complex in older adult population. STUDY DESIGN: Cross-sectional laboratory-based study. METHODS: Twenty cadaver hands presenting with various degrees of TMC joint degradation ranging from none to severe osteoarthritis (OA) were radiographed in multiple positions to establish their degeneration status, joint mobility, and amount of dorsal subluxation at rest and with the application of the SHTM. Comparisons and correlations between degeneration status, joint mobility, subluxation reduction and ligament status obtained from dissection were calculated. RESULTS: No significant statistical correlation was demonstrated with the subluxation reduction ratio of the SHTM and the combined ligament complex value however, a moderate negative correlation was found with dorsal central ligament injury at 21 Nm (τb = -0.46, p < 0.05) and 34 Nm (τb = -0.45, p < 0.05). A statistically significant reduction of radial subluxation of the TMC joint was observed between the subluxation at rest (M = 5.2, SD = 1.9) and subluxation with SHTM of 21 Nm (M = 4.4, SD = 2.4), t (19) = 3.2, p = 0.01, 95% CI [0.3, 1.4] and subluxation with SHTM of 34 Nm (M = 4.3, SD = 2.6), t (19) = 2.6, p = 0.02, 95% CI [0.2, 1.5]. CONCLUSION: Our results did not support the SHTM as indicator of the TMC posterior ligament complex integrity however, it demonstrated 100% stabilization effect with non-arthritic TMC population.

Biomechanical effects of iatrogenic muscle-ligaments complex damage on adjacent segments following posterior lumbar interbody fusion: A finite element analysis.

OBJECTIVE: To analyze the biomechanical effects of proximal iatrogenic muscle-ligaments complex (MLC) damage on adjacent segments following posterior lumbar interbody fusion (PLIF) by finite element (FE) analysis. METHODS: The multifidus muscle force was loaded in the validated intact lumbosacral finite element model. Based on whether undergoing PLIF or the proximal MLC damage, three models were established. Range of motion (ROM) and the maximum von Mises (VM) stress of adjacent segments were analyzed, as well as the average muscle force and work capacity in four loading directions. RESULTS: PLIF results in significant changes in ROM and stress. ROM changed significantly in the upper adjacent segment, the PLIF model changed the most in extension, and the largest change in the lower adjacent segment occurred after MLC damage. The VM stress of the upper adjacent segment occurred in extension of the PLIF model, and that of the lower adjacent segment occurred in rotation after MLC damage. In flexion, ROM, and stress of the damaged MLC fusion model were significantly increased compared with the normal and PLIF models, there was a stepwise amplification. The average muscle force comparison of three models was 5.8530, 12.3185, and 13.4670 N, respectively. The total work capacity comparison was close to that of muscle force. CONCLUSION: PLIF results in increased ROM and the VM stress of adjacent segments, the proximal MLC damage will aggravate this change. This may increase the risk of ASD and chronic low back pain. Preserving the proximal MLC reduces the biomechanical effects on adjacent segments.

Thumb carpometacarpal joint soft-tissue lesions in an asymptomatic population. An MRI study.

The purpose of this study was to evaluate the prevalence of ligament pathology around the first carpometacarpal joint in an asymptomatic population. We used a compact office-based MRI system and examined the hands of 117 healthy volunteers. We checked the competence of the anterior oblique ligament and of the posterior ligament complex on the MRI images. Our results showed that, in 82% of the study population, both ligaments could be perfectly visualized, with consistent signal from origin to insertion. Examination found signal changes indicating a damaged or torn ligament in the other cases. This study suggests that ligament pathology seen on MRI should be interpreted with caution. In symptomatic patients, pathologic images are to be interpreted in the light of the relevant clinical context. LEVEL OF EVIDENCE: III.

Assessment of Interobserver Variability for CT Scan-Based Evaluation of Posterior Ligament Complex Injury in Thoracolumbar Fractures: An International Multicenter Pilot Study.

STUDY DESIGN: A multicenter, pilot study, for radiological assessment of thoracolumbar spine fractures was performed with the participation of 7 centers in Africa, Europe, Asia, and South America as a part of the AO Foundation network. OBJECTIVES: To determine the interobserver variability for computed tomography (CT) scan-based evaluation of posterior ligament complex (PLC) injury in thoracolumbar fractures. METHODS: Forty-two observers including 1 principal investigator at each participating center performed variability assessment. Each center contributed toward a total of 91 patient images with A3 or A4 thoracolumbar burst fractures (T11-L2) with or without suspected PLC injury. Pathological fractures, multilevel injuries, obvious posterior bony element injury and translation/dislocation injuries were excluded. Ten patients were randomly selected and commonly reported CT parameters indicating PLC injury, including superior inferior endplate angle, vertebral body height loss, local kyphotic deformity, interspinous distance and interpedicular distance were assessed for variability. Observer values were compared with an experienced gold rater in spinal trauma. Analysis of variability was performed for all observers, between the principal investigators and also between observers participating in each center. RESULTS: The studied parameters showed considerable variability in measurements among all observers and amongst all participating centers. The variability between the principal investigators was lower, but still substantial. The deviation of observer measurements from the gold rater were also significant for all CT parameters. CONCLUSIONS: CT-based radiological parameters previously reported to be suggestive of PLC injury showed considerable variability and magnetic resonance imaging verification of a PLC injury in all doubtful cases is suggested.

[Treatment of benign tumors in thoracic spinal canal by modified replanting posterior ligament complex applying piezoelectric osteotomy].

OBJECTIVE: To investigate the feasibility and effectiveness of modified replanting posterior ligament complex (PLC) applying piezoelectric osteotomy in the treatment of primary benign tumors in thoracic spinal canal. METHODS: The clinical data of 38 patients with primary benign tumors in thoracic spinal canal between March 2014 and March 2016 were retrospectively analyzed. There were 16 males and 22 females, aged from 21 to 72 years (mean, 47.1 years). The disease duration ranged from 6 to 57 months (mean, 32.6 months). Pathological examination showed 24 cases of schwannoma, 6 cases of meningioma, 4 cases of ependymoma, 2 cases of lipoma, and 2 cases of dermoid cyst. The lesions located in 18 cases of single segment, 15 cases of double segments, and 5 cases of three segments. The length of the tumors ranged from 0.7 to 6.5 cm. There were boundaries between the tumors and the spinal cord, cauda equina, and nerve roots. The preoperative Japanese Orthopaedic Association (JOA) score was 12.2±2.3 and the thoracic Cobb angle was (11.7±2.7)°. Modified PLC replantation and microsurgical resection were performed with piezoelectric osteotomy. Continuity of uniside supraspinal and interspinous ligaments were preserved during the operation. The PLC was exposed laterally. After removing the tumors under the microscope, the pedicled PLC was replanted in situ and fixed with bilateral micro-reconstruction titanium plate. X-ray film, CT, and MRI examinations were performed to observe spinal stability, spinal canal plasty, and tumor resection after operation. The effectiveness was evaluated by JOA score. RESULTS: The operation time was 56-142 minutes (mean, 77.1 minutes). The intraoperative blood loss was 110-370 mL (mean, 217.2 mL). The tumors were removed completely and the incisions healed well. Three cases complicated with cerebrospinal fluid leakage, and there was no complications such as spinal cord injury and infection. All the 38 patients were followed up 24-28 months (mean, 27.2 months). There was no internal fixation loosening, malposition, or other related complications. At last follow-up, X-ray films showed no sign of kyphosis and instability. CT showed no displacement of vertebral lamina and reduction of secondary spinal canal volume, and vertebral lamina healed well. MRI showed no recurrence of tumors. At last follow-up, the thoracic Cobb angle was (12.3±4.1)°, showing no significant difference when compared with preoperative value ( t=0.753, P=0.456). JOA score increased to 23.7±3.8, showing significant difference when compared with preoperative value ( t=15.960, P=0.000). Among them, 14 cases were excellent, 18 were good, 6 were fair, and the excellent and good rate was 84.2%. CONCLUSION: Modified replanting PLC applying piezoelectric osteotomy and micro-reconstruction with titanium plate for the primary benign tumors in thoracic spinal canal can reconstruct the anatomy of the spinal canal, enable patients to recover daily activities quickly. It is an effective and safe treatment.

Biomechanics of Prophylactic Tethering for Proximal Junctional Kyphosis: Comparison of Posterior Tether Looping Techniques.

STUDY DESIGN: Biomechanical study. OBJECTIVES: Compare effects of four spinous process (SP) tether looping methods on segmental flexion range of motion (ROM), intervertebral disc (IVD) pressures, and peak tether forces. SUMMARY OF BACKGROUND DATA: SP tethering has been gaining interest as a prophylactic technique to prevent PJK caused by ligamentous laxity in ASD corrective surgery. Several SP tether looping methods have been proposed; however, there is no consensus on appropriate technique. No study has investigated the effect of the tether looping method on segmental biomechanics. METHODS: Nine T1-T4 cadaveric motion segments were tested to 5 Nm of flexion-extension. The uppermost instrumented vertebra (UIV) was located at T3 using standard pedicle screws and fusion rods. A crosslink (CL) was placed inferior to the pedicle screws. A 5-mm polyester tether was looped under the CL at UIV and through holes drilled at the base of UIV + 1 and UIV + 2 SPs. Biomechanical measurements included flexion ROM, IVD pressure, and peak tether forces at UIV/UIV + 1 and UIV + 1/UIV + 2. An untethered test was used for baseline values. Tethered tests included one single-level (SL) method and three double-level (DL) methods: common (CM), chained (CH), and figure-8 (F8). RESULTS: SL yielded significant reductions in flexion ROM at UIV/UIV + 1 (p = .001) and in IVD pressure at UIV/UIV + 1 (p = .007). Choice of DL method had a significant effect on flexion ROM at UIV/UIV + 1 (p = .004) but not at UIV + 1/UIV + 2 (p = .14). Choice of DL method also had a significant effect on IVD pressure at UIV/UIV + 1 (p < .001) but not at UIV + 1/UIV + 2 (p = .311). CM produced the greatest reductions in flexion ROM and IVD pressure, with the lowest peak tether forces among the DL methods. CONCLUSION: Tether looping method significantly alters segmental biomechanics. Tethering with the CM method to UIV + 2 allows for reductions in loads acting on the UIV + 1 SP and posterior ligaments. LEVEL OF EVIDENCE: Level V, biomechanical study.

Treatment of benign tumors in thoracic spinal canal by modified replanting posterior ligament complex applying piezoelectric osteotomy / 中国修复重建外科杂志

Objective: To investigate the feasibility and effectiveness of modified replanting posterior ligament complex (PLC) applying piezoelectric osteotomy in the treatment of primary benign tumors in thoracic spinal canal. Methods: The clinical data of 38 patients with primary benign tumors in thoracic spinal canal between March 2014 and March 2016 were retrospectively analyzed. There were 16 males and 22 females, aged from 21 to 72 years (mean, 47.1 years). The disease duration ranged from 6 to 57 months (mean, 32.6 months). Pathological examination showed 24 cases of schwannoma, 6 cases of meningioma, 4 cases of ependymoma, 2 cases of lipoma, and 2 cases of dermoid cyst. The lesions located in 18 cases of single segment, 15 cases of double segments, and 5 cases of three segments. The length of the tumors ranged from 0.7 to 6.5 cm. There were boundaries between the tumors and the spinal cord, cauda equina, and nerve roots. The preoperative Japanese Orthopaedic Association (JOA) score was 12.2±2.3 and the thoracic Cobb angle was (11.7±2.7)°. Modified PLC replantation and microsurgical resection were performed with piezoelectric osteotomy. Continuity of uniside supraspinal and interspinous ligaments were preserved during the operation. The PLC was exposed laterally. After removing the tumors under the microscope, the pedicled PLC was replanted in situ and fixed with bilateral micro-reconstruction titanium plate. X-ray film, CT, and MRI examinations were performed to observe spinal stability, spinal canal plasty, and tumor resection after operation. The effectiveness was evaluated by JOA score. Results: The operation time was 56-142 minutes (mean, 77.1 minutes). The intraoperative blood loss was 110-370 mL (mean, 217.2 mL). The tumors were removed completely and the incisions healed well. Three cases complicated with cerebrospinal fluid leakage, and there was no complications such as spinal cord injury and infection. All the 38 patients were followed up 24-28 months (mean, 27.2 months). There was no internal fixation loosening, malposition, or other related complications. At last follow-up, X-ray films showed no sign of kyphosis and instability. CT showed no displacement of vertebral lamina and reduction of secondary spinal canal volume, and vertebral lamina healed well. MRI showed no recurrence of tumors. At last follow-up, the thoracic Cobb angle was (12.3±4.1)°, showing no significant difference when compared with preoperative value ( t=0.753, P=0.456). JOA score increased to 23.7±3.8, showing significant difference when compared with preoperative value ( t=15.960, P=0.000). Among them, 14 cases were excellent, 18 were good, 6 were fair, and the excellent and good rate was 84.2%. Conclusion: Modified replanting PLC applying piezoelectric osteotomy and micro-reconstruction with titanium plate for the primary benign tumors in thoracic spinal canal can reconstruct the anatomy of the spinal canal, enable patients to recover daily activities quickly. It is an effective and safe treatment.

CT for thoracic and lumbar spine fractures: Can CT findings accurately predict posterior ligament complex injury?

PURPOSE: This study aims to determine whether secondary CT findings can predict posterior ligament complex (PLC) injury in patients with acute thoracic (T) or lumbar (L) spine fractures. METHODS: This is a retrospective study of 105 patients with acute thoracic and lumbar spine fractures on CT, with MRI as the reference standard for PLC injury. Three readers graded CT for facet joint alignment (FJA), widening (FJW), pedicle or lamina fracture (PLF), spinous fracture (SPF), interspinous widening (ISW), vertebral translation (VBT), and posterior endplate fracture (PEF). Univariate and multivariate logistic regression analyses were performed separately for each reader to test for associations between CT and PLC injury, and diagnostic performance of CT was calculated. RESULTS: Fifty-three of 105 patients had PLC injury by MRI. Statistically significant predictors of PLC injury were VBT, PLF, ISW, and SPF. Using these four CT findings, odds of PLC injury ranged from 3.8 to 5.6 for one positive finding, but increased to 13.6-25.1 for two or more. At least one positive CT finding was found to yield average sensitivity of 82% and specificity 59%, while two or more yielded sensitivity 46% and specificity 88%. CONCLUSION: While no individual CT finding is sufficiently accurate to diagnose or exclude PLC injury, greater the number of positive CT findings (VBT, PLF, ISW, and SPF), the higher the odds of PLC injury. The presence of a single abnormal CT finding may warrant confirmatory MRI for PLC injury, while two or more CT findings may have adequate specificity to avoid need for MRI prior to surgical intervention. These slides can be retrieved under Electronic Supplementary Material.

Using the "ligamentum flavum gap" to identify originally missed type B vertebral fractures.

BACKGROUND: Spine fractures may involve the ligamentum flavum (LF). Here, we utilized the "ligamentum flavum gap," defined by the discontinuity of the LF at the level of a vertebral fracture, to document a vertebral fracture. METHODS: Utilizing X-rays, computed tomography (CT), and magnetic resonance (MR) studies, 10 patients with type B vertebral fractures were diagnosed with the ligamentum flavum gap (LFG: discontinuity of the LF) at the fracture levels. The fractures were located in 2 patients in the cervical and 8 in the thoracolumbar spine. RESULTS: All 10 patients with vertebral fractures had complained of axial pain. Four also showed progressive thoracic kyphosis. Notably, all demonstrated a loss of continuity in the LF at the level of fracture "ligamentum flavum gap." T2-weighted and short tau inversion recovery (STIR) MR sagittal studies were best at locating LFG at the level of a fracture. CONCLUSION: Here, we identified best on sagittal T2 and STIR-weighted MR studies 10 patients for whom discontinuity of the ligamentum flavum (LFG) correlated with the location of type B vertebral fractures.

Effects of Preserving Posterior Ligament Complex on Biomechanical Properties of the Adjacent Segments after Lumbar Decompression and Fusion / 医用生物力学

Objective To compare the effects of preserving the posterior ligament complex (PLC) with torque loading and displacement loading on the biomechanical properties of the adjacent segments after lumbar decompression and fusion. Methods Six fresh male cadaver lumbar specimens of T12-S2 were tested in the sequence of intact, L4-5 laminotomy (preserving the PLC) with fixation and L4-5 laminectomy (destructing the PLC) with fixation, by applying both displacement loading and torque loading, respectively. Ranges-of-motions (ROMs) of the adjacent segments were measured under a noncontact photographic recording system. Results In displacement-loading mode, the flexion ROM in laminectomy group was significantly higher than that in laminotomy group, and no obvious ROM differences were found in the laminectomy and laminotomy groups under extension, lateral bending, and rotation movement. Conclusions Torque loading and displacement loading have different biomechanical effects on the adjacent segments after lumbar decompression and fusion. Compared with the laminotomy method, in which the PLC is preserved, the laminectomy method in which PLC structures are damaged can obviously lead to an increment of flexion ROMs at the adjacent segments, and also increase the ROMs of the adjacent segments under extension, lateral bending, and rotation movements, which might increase the risk of further instability of the fused adjacent segments.

Another diagnostic tool in thoracolumbar posterior ligament complex injury: interspinous distance ratio.

PURPOSE: The increased interspinous distance ratio (ISDR) at the fracture site in plain X-ray is useful as an indicator of injury of the posterior ligament complex in thoracolumbar fractures. METHODS: 154 patients of thoracolumbar junctional fracture (T12, L1, L2) were subjects for this study. The sensitivity, specificity, accuracy of MRI was measured by comparing the surgery findings for the two analysis groups: one in which indeterminate cases were included in the intact group and another in which the indeterminate cases were included in the ruptured group. Sensitivity, specificity, accuracy of ISDR (measured in lateral decubitus X-ray) were measured after dividing patients into 3 groups (110, 120, 130 % increased). RESULTS: MRI's sensitivity, specificity and accuracy were 70.8, 100, and 80.5 %, respectively, when the indeterminate was assumed to have intact PLC. After assuming the indeterminate to have ruptured PLC, sensitivity, specificity and accuracy were 99.1, 52.4, and 85.7 %, respectively. In 53 cases with indeterminate MRI reading, sensitivity, specificity and accuracy were 81.2, 76.2, and 79.2 % %, respectively. CONCLUSION: In this study, in cases where it was difficult to make a diagnosis of the injury in the posterior ligament complex, based on the interspinous distance ratio (ISDR) of 120 % measured in plain X-ray in a lateral decubitus position, the sensitivity was 81.3 %, the specificity was 76.2 %, and the accuracy was 79.2 %. Therefore, measuring the ISDR will be helpful in determining whether surgical treatment is required in patients with thoracolumbar injury.

Nine issues about clinical application of thoracolumbar injury classification and severity score / 中华创伤骨科杂志

Spinal fractures are a big challenge to orthopedists.Thoracolumbar Injury Classification and Severity Score (TLICS),a newly developed evaluation system for thoracolumbar fractures,has proved to be valid and reliable in the last decade.However,there have still been many problems in the clinical application of TLICS in China.We discussed nine issues about the clinical application of TLICS in this article,hoping to promote better understanding and application of TLICS in Chinese spinal surgeons in their daily practice.

Nine issues about clinical application of thoracolumbar injury classification and severity score / 中华创伤骨科杂志

Spinal fractures are a big challenge to orthopedists.Thoracolumbar Injury Classification and Severity Score (TLICS),a newly developed evaluation system for thoracolumbar fractures,has proved to be valid and reliable in the last decade.However,there have still been many problems in the clinical application of TLICS in China.We discussed nine issues about the clinical application of TLICS in this article,hoping to promote better understanding and application of TLICS in Chinese spinal surgeons in their daily practice.

Association study on classification,injury score, kyphosis deformity and nerve function injury of thoracolumbar fracture / 重庆医学

Objective To investigate the association between the lumbar vertebral fracture damage degree with the fracture classification,injury score,kyphosis deformity and nerve function injury.Methods According to the damage degree of posterior lig ament complex(PLC),the patients were divided into the PLC intact group and PLC injury group.Its relationship with PLC injury was researched by evaluating the fracture classification,injury score and nerve function injury situation in the two groups.Results The LCS score and TLICS score in the PLC injury group were (7.1±0.8) points and (8.2±0.6) points,which were higher than (5.7±0.5) points and (4.6±0.7) points in the PLC intact group.The Denis score in the PLC injury group was more serious.The Cobb angle in the PLC injury group was 29°,and which in the PLC intact group was 19°.The proportion of nerve function insufficiency in the PLC injury group was 89％,while which in the PLC intact group was only 60 ％.Conclusion The thoracolumbar vertebral fracture is closely related with PLC.PLC damage degree is positively correlated with the fracture classification,injury score,kyphosis deformity and nerve function injury degree.

Creating reproducible thoracolumbar burst fractures in human specimens: an in vitro experiment.

OBJECT: The treatment of traumatic burst fractures unaccompanied by neurological impairment remains controversial and ranges from conservative management to 360° fusion. Because of the heterogeneity of fracture types, classification systems, and treatment options, comparative biomechanical studies might help to improve our knowledge. The aim of the current study was to create a standardized fracture model to investigate burst fractures in a multisegmental setting. METHODS: A total of 28 thoracolumbar fresh-frozen human cadaveric spines were used. The spines were dissected into segments (T11-L3). The T-11 and L-3 vertebral bodies were embedded in Technovit 3040 (cold-curing resin for surface testing and impressions). To simulate high energy, a metallic drop tower was designed. Stress risers were used to ensure comparable fractures. CT scans were acquired before and after fracture. All fractures were classified using the AO/OTA classification. RESULTS: The preparation and embedding of the spine segments worked well. No repositioning or second embedding of the specimen, even after fracture, was required. It was possible to create single burst fractures at the L-1 level in all 28 spine segments. Among the 28 fractures there were 16 incomplete burst fractures (Type A3.1), 8 burst-split fractures (Type A3.2), and 4 complete burst fractures (Type A3.3). The differences before and after fracture for stiffness and for anterior, posterior, and central heights were all significant (p < 0.05). CONCLUSIONS: The ability to create reproducible burst fractures of a single vertebral body in a thoracolumbar spine segment may serve as a basis for future biomechanical studies that will provide better understanding of mechanical properties or fixation techniques.

Rehabilitation assesment of rebuit posterior ligamentous complex in the thoracolumbar fracture / 中国综合临床

Objective To study the theraputic effect of rebuilt posterior ligamentous complex in the treatment of thoracolumbar fracture.Method From 2003 to 2007,60 patients who had simple thoracolumbar fractures were treated with rebuild of posterior ligamentous complex(group A).At the same time,50 patients with the same condition were treated with ablation of posterior ligamentous complex(group B).Modify Japanese orthopedic association low back pain score(M-JOA)score and Functional Rating scales for Low Back Pain(FRS)score for lumbar function were compared between two groups perioperatively.Results Preoperative M-JOA score for lumbar function of group A was from 19 to 30 score,on average of23.83.M-JOA score of group B was from 17 to 30 score on average of 21.68.There was no significant different between group A and group B(P＞0.05).Postoperative M-JOA score for lumbar function of group A was from 8 to 12 score,on average of 9.05.M-JOA score of group B was from 9 to 14 score.on average of 11.95.There was significant difference between group A and group B(P＜0.01).Preoperative FRS score was 28.85 in group A and 26.56 in group B averagely(P＞0.05)while postoperative FRS score was 68.22(46-84)in group A and 46.87(39-65)in group B(P＜0.05).Conclusion Management with rebuild of posterior ligamentous complex for thoracolumbar fractures contributes to the improvement of the postoperative lumbar function and clinical symptoms.

Relationships between Radiological Change of Fractured Vertebrae and Posterior Ligament Complex Injury in Thoracolumbar Fracture

OBJECTIVE: To investigate the relationships between posterior ligament complex injury and plain radiographic parameters in thoracolumbar spinal fractures. METHODS: Forty patients with thoracolumbar fractures who had operated from Jan 2006 to Dec 2007 were studied. For the evaluation of stability of injured vertebrae, we used the radiographic parameters which were wedge angle, Cobb's angle, compression rate measured on the plain radiographs, and the presence of posterior ligament complex injury on MRI. RESULTS: In the compression fracture group, the compression rate was statistically significant high in the posterior ligament complex injury patient(p=0.03). In the burst fracture group, the wedge angle, Cobb's angle and the compression rate were high in the posterior ligament complex injury patient, which were all statistically significant(p=0.02, 0.01, 0.01). CONCLUSIONS: The presence of a posterior ligament complex injury is important in the treatment of the thoracolumbar spine fracture. The status of the posterior ligament complex should be integrated into future classification schemes of thoracolumbar spine fractures.

Clinical Importance of MRI in Thoracolumbar Spinal Fracture / 대한척추외과학회지

STUDY DESIGN: Retrospective radiologic assessment OBJECTIVES: To assess the clinical importance of MRI for the diagnosis of posterior spinal ligament complex injuries in thoracolumbar fractures. SUMMARY OF LITERATURE REVIEW: Evaluation of spinal instability is important in thoracolumbar fractures. When simple radiography and CT alone are performed, spinal instability may be missed, especially that involving the posterior spinal ligament complex. MATERIALS AND METHODS: Eighty-seven patients who were evaluated using simple radiography, computed tomography (CT), and magnetic resonance imaging (MRI) between March 1994 and March 2003 were included in the study. The local kyphotic angle was measured on lateral radiography, and it was then compared to the fracture pattern on MRI. Statistical analysis was performed using ANOVA. RESULTS: There was no correlation between the local kyphotic angle on radiography and fracture involvement on MRI (p=0.106). In 41 patients who were found to have involvement of the anterior column on CT, 25 had anterior column involvement, 4 had middle column involvement, and 12 had posterior column involvement on MRI. In 36 patients who were found to have involvement of the middle column on CT, 17 had involvement of the middle column and 19 had involvement of the posterior column on MRI. The fractures of the ten patients who were found to have posterior column involvement on CT were all seen on MRI. The coincidence of fracture patterns between CT and MRI, which was evaluated using Cohen's Kappa analysis, was 0.434. The sensitivity of CT compared with MRI was 0.741 in the middle column and 0.243 in the posterior column. CONCLUSIONS: Many thoracolumbar fractures are missed on both simple radiography and CT. MRI is essential for accurate diagnosis of posterior spinal ligament complex injuries, especially when there is involvement above the middle column, or when canal encroachment is seen on CT.