Thoracolumbar burst fracture: evaluating stability

Contiguous Burst Fractures of the Lumbar Spine

Burst fractures of vertebrae are usually caused by high-energy axial compression force, mostly caused by fall from height or road traffic accidents. They frequently occur at the thoracolumbar junction mostly requiring surgery. Contiguous burst fractures involving multiple lumbar vertebrae are uncommon. This case is a male in his early 40s presented with low back pain and weakness of lower limbs following an injury sustained during a road traffic accident. Clinically, the patient had a bilateral foot drop. On radiological evaluation, he was diagnosed to have L3 and L4 burst fractures with spinal canal occlusion. He underwent posterior stabilization from L2-L5 and decompression at the L3-L4 level. At one-year follow-up, the patient was pain-free with complete neurological recovery. Contiguous lumbar spine burst fractures are very rare in occurrence. Though burst fractures are managed surgically to provide stability, the surgical approaches depend on the individual fracture pattern, degree of spinal canal occlusion, and neurological status.

Finite element study of sagittal fracture location on thoracolumbar fracture treatment

Background: Posterior internal fixation is the main method used for the treatment of thoracolumbar fractures. Fractures often occur in the upper 1/3 of the vertebral body. However, they can also occur in the middle or lower 1/3 of the vertebral body. At present, there is no report discussing the potential effects of sagittal location on instrument biomechanics or surgical strategy. The object of this study was to investigate the effect of the sagittal location of the fracture region of the vertebral body on the biomechanics of the internal fixation system and surgical strategy. Methods: A finite element model of the T11-L3 thoracolumbar segment was established based on a healthy person's CT scan. Different sagittal fracture location finite element models were created by resection of the upper 1/3, middle 1/3, and lower 1/3 of the L1 vertebral body. Three surgical strategies were utilized in this study, namely, proximal 1 level and distal 1 level (P1-D1), proximal 2 level and distal 1 level (P2-D1), and proximal 1 level and distal 2 levels (P1-D2). Nine fixation finite element models were created by combining fracture location and fixation strategies. Range of motion, von Mises stress, and stress distribution were analyzed to evaluate the effects on the instrument biomechanics and the selection of surgical strategy. Results: In all three different fixation strategies, the maximum von Mises stress location on the screw did not change with the sagittal location of the fracture site; nevertheless, the maximum von Mises stress differed. The maximum rod stress was located at the fracture site, with its value and location changed slightly. In the same fixation strategy, a limited effect of sagittal location on the range of motion was observed. P2D1 resulted in a shorter range of motion and lower screw stress for all sagittal locations of the fracture compared with the other strategies; however, rod stress was similar between strategies. Conclusion: The sagittal location of a fracture may affect the intensity and distribution of stress on the fixation system but does not influence the selection of surgical strategy.

Radiographic Outcomes of Conservative and Operative Treatment in Isolated L1 Fractures

Background and Objectives: The adequate therapy of thoracolumbar fractures in the elderly population is still controversially discussed. The aim of this study was to evaluate and compare the results of conservatively and surgically treated younger (≤60a) and elderly patients (>60a) with fractures of L1. Materials and Methods: Patients (231) with isolated L1 fractures were included and treated at the University Clinic of Orthopedics and Trauma Surgery, Division of Trauma Surgery, Medical University of Vienna, during the observation period of 2012–2018. Results: Conservative treatment led to a significant increase in the vertebral and bi-segmental kyphosis angle in both age groups (young vertebral: p = 0.007; young bi-segmental: p = 0.044; old vertebral: p = 0.0001; old bis-segmental: p = 0.0001). A significant reduction in the vertebral angle in both age groups was achieved after operative treatment (young: p = 0.003, old: p = 0.007). The bi-segmental angle did not significantly improve after surgery in both age groups (≤60a: p = 0.07; >60a: p = 1.0). Conclusions: The study shows that conservative treatment does not seem to be sufficient for a correction of radiological parameters in young and elderly patients. In contrast, operative treatment led to a significant improvement of the vertebral kyphosis angle, without changing the bi-segmental kyphosis angle. These results suggest a greater benefit from operative treatment in patients ≤ 60a than in older patients.

Comparison of Posterior Fixation Strategies for Thoracolumbar Burst Fracture: A Finite Element Study

The management of thoracolumbar (TL) burst fractures remained challenging. Due to the complex nature of the fractured vertebrae and the lack of clinical and biomechanical evidence, currently, there was still no guideline to select the optimal posterior fixation strategy for TL burst fracture. We utilized a T10-L3 TL finite element model to simulate L1 burst fracture and four surgical constructs with one- or two-level suprajacent and infrajacent instrumentation (U1L1, U1L2, U2L1, and U2L2). This study was aimed to compare the biomechanical properties and find an optimal fixation strategy for TL burst fracture in order to minimize motion in the fractured level without exerting significant burden in the construct. Our result showed that two-level infrajacent fixation (U1L2 and U2L2) resulted in greater global motion reduction ranging from 66.0 to 87.3% compared to 32.0 to 47.3% in one-level infrajacent fixation (U1L1 and U2L1). Flexion produced the largest pathological motion in the fractured level but the differences between the constructs were small, all within 0.26 deg. Comparisons in implant stress showed that U2L1 and U2L2 had an average 25.3 and 24.8% less von Mises stress in the pedicle screws compared to U1L1 and U1L2, respectively. The construct of U2L1 had better preservation of the physiological spinal motion while providing sufficient range of motion reduction at the fractured level. We suggested that U2L1 is a good alternative to the standard long-segment fixation with better preservation of physiological motion and without an increased risk of implant failure.

Minimally invasive reduction of thoracolumbar burst fracture using monoaxial percutaneous pedicle screws: Surgical technique and report of radiological outcome

PURPOSE

To describe the reduction technique of thoracolumbar burst fracture using percutaneous monoaxial screws and its radiological outcomes compared to polyaxial screws.

METHODS

All surgeries were performed by minimally invasive technique with either percutaneous monoaxial or percutaneous polyaxial screws inserted at adjacent fracture levels perpendicular to both superior end plates. Fracture reduction is achieved with adequate rod contouring and distraction maneuver. Radiological parameters were measured during preoperation, postoperation, and follow-up.

RESULTS

A total of 21 patients were included. Eleven patients were performed with monoaxial pedicle screws and 10 patients performed with polyaxial pedicle screws. Based on AO thoracolumbar classification system, 10 patients in the monoaxial group had A3 fracture type and 1 had A4. In the polyaxial group, six patients had A3 and four patients had A4. Total correction of anterior vertebral height (AVH) ratio was 0.30 ± 0.10 and 0.08 ± 0.07 in monoaxial and polyaxial groups, respectively (p < 0.001). Total correction of posterior vertebral height (PVH) ratio was 0.11 ± 0.05 and 0.02 ± 0.02 in monoaxial and polyaxial groups, respectively (p < 0.001). Monoaxial group achieved more correction of 13° (62.6%) in local kyphotic angle compared to 8.2° (48.0%) in polyaxial group. Similarly, in regional kyphotic angle, 16.5° (103.1%) in the monoaxial group and 8.1° (76.4%) in the polyaxial group were achieved.

CONCLUSIONS

Monoaxial percutaneous pedicle screws inserted at adjacent fracture levels provided significantly better fracture reduction compared to polyaxial screws in thoracolumbar fractures.

Usefulness of antero-posterior radiograph and variability of management in non-major thoracolumbar injuries: a single centre pilot study and review of literature

Background

Most adult trauma protocols suggest that where there has been a dangerous mechanism of injury or the patient exhibits abnormal physiology, CT scan is the primary radiological investigation. Other patients who may have suffered thoraco-lumbar (T-L) trauma initially have antero-posterior (AP) and lateral plain X-rays performed. Our clinical experience suggests AP views are not particularly useful in the management of these relatively low-velocity injuries. This is the first study intended to determine the contribution made by AP X-rays in these cases.

Methods

Adults with a history of T-L trauma referred to our tertiary spinal service over 20 weeks were reviewed. Those with a CT scan performed prior to X-rays were excluded. Four spine surgeons and four neuroradiologists were independently shown lateral X-rays along with the clinical details and asked to provide a management plan. Then they were shown the AP X-rays and asked if they would like to change their advice.

Results

Fifty-two patients were identified. Thirty-four sets of supine and 40 sets of erect X-rays were included (four people only had lateral X-rays performed), yielding 1152 film views. Average patient age was 58.3 years with 30 (58%) males. Forty-five (87%) were AO type A (compression-type) fractures. Seven (13%) had been erroneously referred with a diagnosis of acute fracture, which on review was not considered to be the case. Fifty-four percent of fractures were between T11 and L2. Forty-six percent appeared osteoporotic.

In no instance did evaluation of the AP X-ray change the management plan which had been suggested following the evaluation of the lateral X-ray alone. However, there was significant variation in advice on further management between consultants.

Conclusions

Our results suggest AP X-rays do not contribute to the management of low-velocity thoraco-lumbar traumas. Larger studies are required to support these findings, but there appears to be a potential to reduce both cost and radiation exposure. More importantly, it demonstrates there is large variability in the management of such patients due to the lack of evidence-based protocols.

THORACOLUMBAR BURST FRACTURES, SHORT X LONG FIXATION: A META-ANALYSIS

ABSTRACT The number of fixed segments in the surgical treatment of thoracolumbar burst fractures remains controversial. This study aims to compare the results of short and long fixation in thoracolumbar burst fractures through a meta-analysis of studies published recently. MEDLINE and Cochrane databases were used. Randomized controlled trials and non-randomized comparative studies (prospective and retrospective) were selected. Data were analyzed with the software Review Manager. There was no statistically significant difference in the Cobb angle of preoperative kyphosis. Long fixation showed lower average measurements postoperatively (MD = 1.41; CI = 0.73-2.08; p<0.0001) and in the last follow-up (MD = 3.98; CI = 3.22-4.75; p<0.00001). The short fixation showed the highest failure rates (RD = 4.03; CI = 1.33-12.16; p=0.01) and increased loss of height of the vertebral body (MD = 1.24; CI = 0.49-1.98; p=0.001), with shorter operative time (MD = -24.54; CI = -30.16 - -18.91; p<0.00001). There was no significant difference in blood loss and clinical outcomes. The high rates of kyphosis correction loss with short fixation and the lower correction rate in the immediate postoperative period were validated. There was no significant difference in the blood loss rates because arthrodesis was performed in a short segment in the analyzed studies. The short fixation was performed in a shorter operative time, as expected. No study has shown superior clinical outcomes. The short fixation had worse rates of kyphosis correction in the immediate postoperative period, and increased loss of correction in long-term follow-up, making the long fixation an effective option in the management of this type of fracture.

Imaging features of spinal trauma: what the radiologist needs to know

Traumatic spinal fractures typically occur in a young subset of patients following a high-energy motor vehicle accident (MVA) or a fall from height. Upon recognizing the spinal injury, the radiologist should be able to describe the fracture pattern based on conventional nomenclature and to deduce the likely mechanism of injury. This will enable the provision of a more clinically relevant report and will help the radiologist to appreciate the likelihood of associated ligamentous and neurological injury. Vertebral trauma often follows a recognizable pattern based on a specific mechanism of injury. These predictable types of fracture have been referred to as the "fingerprints" of the injury.(1) This review depicts the variety of vertebral column fractures seen in a cohort of 781 patients admitted to our level 1 trauma centre over 1 year.

Dynamics of interpedicular widening in spinal burst fractures: an in vitro investigation

BACKGROUND CONTEXT

Spinal burst fractures are a significant cause of spinal instability and neurologic impairment. Although evidence suggests that the neurologic trauma arises during the dynamic phase of fracture, the biomechanics underpinning the phenomenon has yet to be fully explained. Interpedicular widening (IPW) is a distinctive feature of the fracture but, despite the association with the occurrence of neurologic deficit, little is known about its biomechanics.

PURPOSE

To provide a comprehensive in vitro study on spinal burst fracture, with special attention on the dynamics of IPW.

STUDY DESIGN

Experimental measurements in combination with computed tomography scanning were used to quantitatively investigate the biomechanics of burst fracture in a cadaveric model.

METHODS

Twelve human three-adjacent-vertebra segments were tested to induce burst fracture. Impact was delivered through a drop-weight tower, whereas IPW was continuously recorded by two displacement transducers. Computed tomography scanning aided quantifying canal occlusion (CO) and evaluating sample anatomy and fracture appearance. Two levels of energy were delivered to two groups: high energy (HE) and low energy (LE).

RESULTS

No difference was found between HE and LE in terms of the residual IPW (ie, post-fracture), maximum IPW, or CO (median 20.2%). Whereas IPW was not found to be correlated with CO, a moderate correlation was found between the maximum and the residual IPW. At the fracture onset, IPW reached a maximum median value of 15.8% in approximately 20 to 25 milliseconds. After the transient phase, the pedicles were recoiled to a median residual IPW of 4.9%.

CONCLUSIONS

Our study provides for the first time insight on how IPW actually evolves during the fracture onset. In addition, our results may help shedding more light on the mechanical initiation of the fracture.

Anterior versus posterior approach for treatment of thoracolumbar burst fractures: a meta-analysis

PURPOSE

To critically review and summarize the literature comparing the results of surgery via an anterior approach and that via a posterior approach for the treatment of thoracolumbar burst fractures to identify the better approach.

METHODS

In this meta-analysis, we conducted electronic searches of MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials and other databases using the search terms "thoracolumbar fractures", "anterior", "posterior", "controlled clinical trials". Relevant journals or conference proceedings were also searched manually. Data extraction and quality assessment were in accordance with Cochrane Collaboration guidelines. The analysis was performed on individual patient data from all the trials that met the selection criteria. Sensitivity analysis was performed when there was significant heterogeneity. Results were expressed as risk difference for dichotomous outcomes and mean difference for continuous outcomes with 95 % confidence interval.

RESULTS

Four randomized clinical trials and three controlled clinical trials comparing the results of the anterior versus posterior approach in the treatment of thoracolumbar burst fractures were retrieved; these studies included 179 and 152 patients in the anterior and posterior approach groups, respectively. There were no differences in terms of neurological recovery, return to work, complications and Cobb angle between the two groups. The anterior approach was associated with longer operative time, greater blood loss and higher cost than the posterior approach.

CONCLUSIONS

The posterior approach may be more effective than the anterior approach. However, more high-quality, randomized controlled trials are required to compare these approaches and guide clinical decision-making. Level of Evidence Level II, therapeutic study. See the Guidelines for Authors for a complete description of level of evidence.

Reference data for interpreting widening between spinous processes in the lumbar spine

BACKGROUND CONTEXT

Traumatic injury to the lumbar spine is evaluated and treated based on the perceived stability of the spine. Recent classification schemes have established the importance of evaluating the posterior ligamentous complex (PLC) to fully comprehend stability. There are a variety of techniques to evaluate the PLC, including assessment of interspinous distance. However reference data to define normal widening are poorly developed.

PURPOSE

Define normal interspinous widening in the lumbar spine.

STUDY DESIGN

Biomechanical and observational. To establish reference data for asymptomatic population and use the reference data to suggest criteria for routine clinical practice to be validated in future studies.

METHODS

Interspinous distances were measured from lateral lumbar X-rays of 157 asymptomatic volunteers. Measurements from the asymptomatic population were used to define normal limits and create a simple screening tool for clinical use. Distances were calculated from the relative position of landmarks at each intervertebral level. The distances were normalized to the anterior-posterior width of the superior end plate of L3. The change in interspinous process distance from flexion to extension was calculated, and the change in interspinous widening between flexion and extension with respect to widening at the adjacent levels was also calculated.

RESULTS

Seven hundred seventy-two thoracolumbar levels were available for analysis. The observed interspinous motion was slightly more than the interlaminar motion. However, the tips of the spinous processes were more difficult to identify in some images, so the interlaminar line distances were considered more reliable. Significant difference in interlaminar distances was not found between levels. The upper limit (UL) of normal spacing measured between the interlaminar lines was approximately 85% of the L3 end plate width at all levels except L5-S1, which was 105%. The UL of normal for interlaminar displacements between flexion and extension was 30% of the L3 end plate width at L1-L2 to L4-L5 and 40% at L5-S1.

CONCLUSIONS

This study provides normative data and methods that can be used in developing guidelines to objectively assess interspinous process widening. Simple rules can be applied to quickly assess interspinous widening. Additional research is required to validate these guidelines. A simple measurement such as spinous process widening is unlikely to be proven as an isolated clinically effective screening test but combining that with other patient evaluation's screening modalities may prove to be a sensitive evaluation protocol for the screening of injuries to the PLC.

Spine trauma

Spinal fractures represent 3% to 6% of all skeletal injuries. Spine trauma is a complex diagnostic area in which the radiological assessment is crucial. Plain radiography is often used as the initial diagnostic modality. However, stabilization of the acutely injured spine is a primary concern. In this respect, computed tomography (CT) is vastly superior to plain film in terms of speed and accuracy. In many trauma centers, CT has replaced plain film as the primary modality for evaluation of spinal trauma. Magnetic resonance imaging is not indicated for all cases of spinal trauma but provides detailed information about soft tissue structures including the intervertebral disc, the ligaments, the epidural space, the blood vessels, and the spinal cord. MR imaging provides information on these structures not obtained from other modalities. Patients with spinal cord injury may suffer devastating long-term neurologic deficits, so prompt and efficient spinal imaging guidelines are necessary in all trauma centers.

Is there a way to diagnose spinal instability in acute burst fractures by performing ultrasound?

The aim of this study is to examine the predictive value of ultrasound diagnostics for the assessment of traumatic lesions of the posterior ligament complex (PLC) in burst fractures of the thoracolumbar spine. This was a prospective validating cohort study. Judgment about instability and treatment of burst fractures depends on the condition of the PLC. There have been some studies describing underdiagnosis of PLC injuries due to classification problems in ligamentary distraction type fractures. The gold standard for assessing these lesions is magnetic resonance imaging (MRI). Even then, there are often limits in contemporary operational availability and technical limitations of MRI. Ultrasound was described being an alternative. In a prospective study, 54 levels of 18 patients with acute burst fractures of the thoracic and lumbar spine have been examined by ultrasound and additional MRI scans preoperatively. The condition (intact vs. ruptured) of supraspinous ligament (SSL) and the interspinous ligament has been assessed for the ligaments separately. Hematoma below the SSL has also been evaluated as an indirect sign of an injured PLC. In all the patients the primary performed operative treatment was a posterior spinal instrumentation. Postoperatively the blinded results of the ultrasound procedures have been matched against intraoperative and MRI findings. Assessments of all target structures have been contributed to the calculation of the sensitivity and specificity of ultrasound. A total of 18 patients, 14 males and 4 females, with acute burst fractures have been qualified for inclusion in the study. The patients' mean age was 43.4 years. Comparing intraoperative findings with preoperatively performed investigations, ultrasound archived a sensitivity of 0.99 and a specificity of 0.75 (P < 0.05) to detect traumatic lesions to the PLC. As hypothesized the obtained predictive value using ultrasound correlates closely with intraoperative findings. Anyway MRI still seems to be the superior diagnostic method for examining the PLC. However, ultrasound can be considered to be an adequate alternative method in cases with contraindications for MRI such as ferromagnetic side effects, claustrophobia, availability or emergency diagnostics in multiple injuries.

Fluoroscopically-guided indirect posterior reduction and fixation of thoracolumbar burst fractures without fusion

This article presents an evaluation of fluoroscopy for indirect, posterior reduction and fixation of thoracolumbar burst fractures. A prospective study of 25 patients with thoracolumbar burst fractures who underwent C-arm machine-guided posterior indirect reduction and short segment fixation without fusion is described. No laminotomies were performed. All patients had a mean follow-up of 30.4 months. At postoperative review, the average anterior and posterior vertebral heights were corrected from 57.9% to 99.0% and 89.0% to 99.5%, respectively. The Cobb angle was corrected from 18.4 degrees to 0.17 degrees . The canal compromise ratio was improved from 35.2% to 8.6%. In all 25 cases, neurological status was intact at last follow-up. Fluoroscopy guidance is an effective method to accomplish indirect reduction and fixation. Reduction was confirmed on lateral fluoroscopic views by looking for a "one-line sign," which is the reconstitution of the posterior border of the vertebral body.

Low thoracic and lumbar burst fractures: radiographic and functional outcomes

Twenty patients with thoracolumbar burst fractures (type A3 in the classification of Magerl et al.) were studied prospectively for the evaluation of clinical, radiographic and functional results. The patients were submitted to surgical treatment by posterior arthrodesis, posterior fixation and autologous transpedicular graft. The patients were followed up for 2 years after surgery and assessed on the basis of clinical (pain, neurologic deficit, postoperative infection), radiographic (load sharing classification, Farcy s sagittal index of the fractured segment, relation between traumatic vertebral body height and the adjacent vertebrae (compression percentage), height of the intervertebral disk proximal and distal to the fractured vertebra, rupture or loosening of the implants) and functional (return to work, SF-36) criteria. Two patients presented a marked loss of correction and required the placement of an anterior support graft. Pain assessment revealed that eight patients (44%) had no pain; four (22%) had occasional pain, three (17%) moderate pain, and three (17%) severe pain. According to the classification of Frankel et al., 17 patients persisted as Frankel E and one patient presented improvement of one degree, becoming Frankel D. The mean value of Farcy s sagittal index of the injured vertebral segment was 20.67 degrees +/- 6.15 degrees (range 8 degrees -32 degrees ) during the preoperative period, 11.22 degrees +/- 8.09 degrees (range -5 degrees to 21 degrees ) during the immediate postoperative period, and 14.22 degrees +/- 7.37 degrees (range 3 degrees -25 degrees ) at late evaluation. There was a statistically significant difference between the immediate postoperative values and the preoperative and late postoperative values. The compression percentage of the fractured vertebral body ranged from 9.1 to 60 (mean 28.81 +/- 11.51) during the preoperative period, from 0 to 60 (mean: 15.59 +/- 14.49) during the immediate postoperative period, and from 8 to 60 (mean: 25.9 +/- 13.02) at late evaluation. There was a statistically significant difference between the preoperative and postoperative values and between the postoperative and late postoperative values. The height of the proximal intervertebral disk ranged from 6 to 14 mm (mean 8.44 +/- 2.66) during the preoperative period, from 6 to 15 mm (mean 10 +/- 2.30) during the immediate postoperative period, and from 0 to 11 mm (mean 7.22 +/- 2.55) during the late postoperative period. A significant difference was observed between the immediate postoperative values and the preoperative and late postoperative values. The height of the intervertebral disk distal to the fractured vertebra ranged from 7 to 16 mm (mean 9.94 +/- 2.64) during the preoperative period, from 5 to 18 mm (mean 11.61 +/- 3.29) during the immediate postoperative period, and from 2 to 14 mm (mean 9.72 +/- 3.17) during the late postoperative period. There was a significant difference between the immediate postoperative values and the preoperative and late postoperative values. Except for the height of the intervertebral disk proximal to the fractured vertebra, no correlation was detected between the clinical, functional and radiologic results. The results observed in the present study indicate that other, still incompletely defined parameters influence the functional result of thoracolumbar burst fractures.

Anterior spinal column augmentation with injectable bone cements

A vertebral fracture, whether originating from osteoporosis or trauma, can be the cause of pain, disability, deformation and neurological deficit. The treatment of vertebral compression fractures has, for many years until the advent of vertebroplasty, consisted of bedrest and analgesics. Vertebroplasty is a percutaneous technique during which bone cement is injected in a vertebral body to provide immediate pain relief by stabilization. Inflatable bone tamps can, prior to the injection of cement, be used to create a void in the vertebral body, in which case the technique is known as balloon vertebroplasty (or kyphoplasty). The chance of extracorporal cement leakage is smaller for balloon vertebroplasty than for vertebroplasty. Some authors also claim to have gained some correction in vertebral body height or angulation. Both interventions can be used for several indications, including osteoporotic compression fractures and osteolytic lesions of the vertebral body such as myeloma, hemangioma or metastasis, and also for traumatic burst fractures in combination with pedicle screw instrumentation. Polymethyl methacrylate cement is the bone void filler that is used most frequently, although the application of calcium phosphate cements has been studied widely in vitro, in vivo and also in small-scale clinical series. The clinical results of (balloon-) vertebroplasty are favorable with 85-95% of all patients experiencing immediate and long-lasting relief of pain. Serious complications are relatively rare but include neurological deficit and pulmonary embolism. In this paper, both vertebroplasty and balloon vertebroplasty and their respective indications, techniques and results are described in relation with the application and limitations of permanent and resorbable injectable bone cements.

Diagnostic accuracy of magnetic resonance imaging for detecting posterior ligamentous complex injury associated with thoracic and lumbar fractures

OBJECT

The posterior ligamentous complex (PLC) in the thoracic and lumbar spine is one of the region's important stabilizers. The precise diagnosis of PLC injury is required to evaluate the instability of the injured spine; however, the accuracy of magnetic resonance (MR) imaging for diagnosing PLC injury has remained unclear. In this study, the authors compared preoperative MR imaging findings with direct intraoperative observation of PLC injury, clarifying the former's diagnostic accuracy regarding detection of PLC injury associated with the thoracic and lumbar fractures.

METHODS

Data obtained in 35 patients who sustained thoracic or lumbar injuries were reviewed. There were 17 burst fractures, six flexion-distraction injuries, and 12 fracture dislocations. Each patient underwent MR imaging examination within 3 weeks of injury. Three radiologists independently evaluated sagittal MR images in a blinded fashion. The PLC-related information was retrospectively collected from each operative record. The diagnostic accuracy of MR imaging was analyzed by comparing imaging-documented intraoperative findings. The PLC injuries were detected in 23 patients (65.7%) by direct observation during posterior spinal procedures. The diagnostic accuracy of MR imaging in detecting injury of the supraspinous ligament (SSL) and interspinous ligament (ISL) was 90.5 and 94.3%, respectively. The specificity of T1-weighted MR imaging alone for depicting the SSL was significantly greater than T2-weighted imaging alone (p < 0.05). The overall mean kappa coefficient for MR imaging findings of PLC injury was 0.803, which indicated excellent interobserver reliability; that for ISL (0.915) was significantly greater than that for SSL (0.69) (p < 0.05).

CONCLUSIONS

This study clarified a high diagnostic accuracy and interobserver reliability of MR imaging for PLC injury. The precise diagnosis of PLC injury is essential to determine the mechanical instability of the injured thoracic and lumbar spine, especially in differentiating unstable (three-column) burst fractures from the relatively stable (two-column) type. The authors conclude that MR imaging is a powerful diagnostic tool to evaluate PLC injury associated with thoracic and lumbar fractures.