Neurological deficit and canal compromise in thoracolumbar and lumbar burst fractures

Does Magnetic Resonance Imaging Predict Neurological Deficit in Patients with Traumatic Lower Lumbar Fractures?

STUDY DESIGN

A retrospective cohort study.

PURPOSE

This study aimed to understand the role of magnetic resonance imaging (MRI) in predicting neurological deficits in traumatic lower lumbar fractures (LLFs; L3-L5).

OVERVIEW OF LITERATURE

Despite studies on the radiological risk factors for neurological deficits in thoracolumbar fractures, very few have focused on LLFs. Moreover, the potential utility of MRI in LLFs has not been evaluated.

METHODS

In total, 108 patients who underwent surgery for traumatic LLFs between January 2010 and January 2020 were reviewed to obtain their demographic details, injury level, and neurology status at the time of presentation (American Spinal Injury Association [ASIA] grade). Preoperative computed tomography scans were used to measure parameters such as anterior vertebral body height, posterior vertebral body height, loss of vertebral body height, local kyphosis, retropulsion of fracture fragment, interpedicular distance, canal compromise, sagittal transverse ratio, and presence of vertical lamina fracture. MRI was used to measure the canal encroachment ratio (CER), cross-sectional area of the thecal sac (CSAT), and presence of an epidural hematoma.

RESULTS

Of the 108 patients, 9 (8.3%) had ASIA A, 4 (3.7%) had ASIA B, 17 (15.7%) had ASIA C, 21 (19.4%) had ASIA D, and 57 (52.9%) had ASIA E neurology upon admission. The Thoracolumbar Injury Classification and Severity score (p =0.000), CER (p =0.050), and CSAT (p =0.019) were found to be independently associated with neurological deficits on the multivariate analysis. The receiver operating characteristic curves showed that only CER (area under the curve [AUC], 0.926; 95% confidence interval [CI], 0.860-0.968) and CSAT (AUC, 0.963; 95% CI, 0.908-0.990) had good discriminatory ability, with the optimal cutoff of 50% and 65.3 mm2, respectively.

CONCLUSIONS

Based on the results, the optimal cutoff values of CER >50% and CSAT >65.3 mm2 can predict the incidence of neurological deficits in LLFs.

Posterior unilateral small fenestration of lamina combined with a custom-made Y-shaped fracture reduction device for the treatment of severe thoracolumbar burst fracture: a prospective comparative study

BACKGROUND

The purpose was to evaluate the clinical effect of a custom-made Y-shaped fracture fragment reduction device and to assist in posterior unilateral small fenestration of lamina to reduce the fracture fragments.

METHODS

In this study, 40 patients were assigned to one of two groups: the traditional reduction device group (TRG) or the Y-shaped reduction device group (YRG). All patients underwent posterior unilateral small fenestration of the lamina and direct decompression through the spinal canal. And the operation time (OT), intraoperative bleeding (IB), preoperative, postoperative, and final follow-up data on the spinal stenosis rate (SSR), Cobb angle, the anterior compression ratio of injured vertebrae (ACRIV), and ASIA neurological function grade were compared between the two groups.

RESULT

There were no complications, including vascular and nerve injury, serious postoperative infection, internal fixation fracture, or loosening, for any of the patients. And the average follow-up time of the two groups was 14.2 months, the average operation time of the TRG was 236.6 min, and the average intraoperative blood loss was 357.20 ml. Moreover, the average operation time of the YRG was 190.6 min, and the average intraoperative blood loss was 241.5 ml. There were significant differences between the two groups in terms of operation duration and intraoperative blood loss. The YRG's was lower than that of the TRG. Besides, there was no difference in SSR, Cobb angle, ACRIV, or neurological recovery between the two groups before or immediately after the operation or at the last follow-up.

CONCLUSION

The Y-shaped fracture reduction device can reduce the fracture fragments and the OT and IB stably; it also has satisfactory postoperative curative effects and clinical utility.

Percutaneous versus open posterior stabilization and decompression in AOSpine-type A3 thoracolumbar fractures with neurological deficit

BACKGROUND

This retrospective cohort study aimed to compare the clinical and radiological outcomes between two treatment strategies focusing on non-osteoporotic AOSpine-type A3 fractures of the thoracolumbar spine with neurological deficits at levels T11 to L2.

METHODS

In total, 67 patients between 18 and 60 years of age who were treated operatively with either of the two treatment strategies were included. One treatment strategy included open posterior stabilization and decompression, whereas the other was based on percutaneous posterior stabilization and decompression via a tubular retraction system. Demographic data, surgical variables, and further parameters were assessed. Patient-reported outcomes (PROs), including the Visual Analog Scale (VAS), the Oswestry Disability Index (ODI), and the American Spinal Injury Association (ASIA) impairment score, were measured to assess functional outcomes. The regional Cobb angle (CA), the anterior height ratio of the fractured vertebrae (AHRV), and the degree of canal encroachment (DCE) were assessed. The ASIA score was used to assess neurological function recovery. The follow-up period was at least 12 months.

RESULTS

Surgical time and postoperative hospital stay were significantly shorter in the minimally invasive surgery (MIS) group. Intraoperative blood loss was significantly less in the MIS group. Regarding radiological outcome, CA and AHRV at the time of follow-up did not show a significant difference. DCE at the time of follow-up was significantly improved in the MIS group. Lower VAS scores and better ODIs were observed in the MIS group at the 6-month follow-up, but similar outcomes were observed at the 12-month follow-up. The ASIA score was similar between both groups at the 12-month follow-up.

CONCLUSIONS

Both treatment strategies are safe and effective; however, MIS could provide earlier pain relief and better functional outcomes compared with OS.

A comparative study on efficacies of posterior microscopic mini-open and open technique for thoracolumbar burst fractures with severe traumatic spinal stenosis

PURPOSE

This study compares the efficacies of minimally invasive decompression by posterior microscopic mini-open technique combined with percutaneous pedicle fixation (hereafter MOT) to traditional open surgery in patients with severe traumatic spinal canal stenosis resulting from Arbeitsgemeinschaft für Osteosynthesefragen (AO) type A3 or A4 thoracolumbar burst fractures and provides references for clinical treatment.

METHODS

In total, 133 patients with severe traumatic spinal canal stenosis caused by AO type A3 or A4 thoracolumbar burst fractures who underwent MOT (group A) or traditional open surgery (group B) were retrospectively enrolled. The demographic and radiological data of the two groups were analyzed and compared.

RESULTS

A total of 64 patients were finally recruited in this study. There were no significant differences in gender, age, follow-up time, injury mechanism, injury level, AO classification, American Spinal Injury Association (ASIA) score, visual analogue scale (VAS) score, and duration of hospital stay between the two groups (P > 0.05). After the procedures, the prevertebral height ratio (PHR), the Cobb angle, and the mid-sagittal canal diameter compression ratio (MSDCR) were significantly improved (P < 0.05) in both groups. However, group A demonstrated less intraoperative bleeding and a greater VAS score improvement postoperatively and at the last follow-up but involved a longer operation time (P < 0.05). The PHR and the Cobb angle in the two groups showed no significant difference postoperatively and at the last follow-up (P > 0.05). In contrast, a significant improvement in MSDCR was observed at the last follow-up when compared with the postoperative value (P < 0.05). However, the Cobb angle in group A was better maintained than in group B at the last follow-up (P < 0.05), while the MSDCR in group B demonstrated a greater improvement at the last follow-up than in group A (P < 0.05).

CONCLUSIONS

Both the MOT and traditional open surgery are effective treatment options for AO type A3 and A4 thoracolumbar burst fractures with severe traumatic spinal stenosis. The advantages of MOT include the minimally invasive procedure, extremely fine spinal canal decompression, less intraoperative bleeding, and significant pain relief. We suggest that MOT should be preferentially performed for AO type A3 or A4 thoracolumbar burst fractures with severe traumatic spinal stenosis.

Spinal canal invasion as a predictor of neurological deficit in traumatic vertebral burst fractures

Background:

This study correlated the extent of spinal canal compression from retropulsed traumatic burst cervical, thoracic, and lumbar spine fractures with the severity of neurological dysfunction.

Methods:

One hundred and sixty-nine patients with cervical, thoracic, or lumbar sub-axial traumatic burst fractures were seen in an emergency department from 2019 to 2021; 79.3% were men, averaging 37 years of age. The lumbar spine was most frequently involved (42%), followed by the thoracic (36.1%) and cervical (21.9%) levels. The extent of spinal canal compression was quantitated utilizing Hashimoto’s method, and correlated with patients’ extent of neurological injury based on their American Spinal Injury Association scores.

Results:

There was a positive correlation between the extent of cervical and thoracic spinal cord compression due to retro pulsed burst fragments and the severity of the patients’ neurological deficits, but this was not true for the lumbar spine.

Conclusion:

The extent of spinal cord compression from retropulsed cervical and thoracic traumatic burst fractures was readily correlated with the severity of patients’ neurological dysfunction. However, there was no such correlation between the extent of cauda equina compression from retropulsed lumbar burst fractures and the severity of their cauda equina syndromes.

Radiological Risk Factors for Neurological Deficits After Traumatic Mid and Low Lumbar Fractures

STUDY DESIGN

Retrospective study.

OBJECTIVE

We identified radiological risk factors for neurological deficits in mid and low lumbar spinal fractures.

SUMMARY OF BACKGROUND DATA

Although numerous studies have focused on radiological risk factors for neurological deficits in spinal cord injury or thoracolumbar junction area fractures, few have examined mid and low lumbar fractures at the cauda equina level.

METHODS

We retrospectively reviewed 71 consecutive patients who suffered acute traumatic mid and low lumbar fractures (L2-L5) corresponding to the cauda equina level, as confirmed on magnetic resonance imaging. We defined a neurological deficit as present if the patient had any sensory or motor deficit in the lower extremity or autonomic system at the initial assessment. Various computed tomography parameters of canal stenosis, vertebral body compression, sagittal alignment, interpedicular distance, and presence of vertical laminar fractures were analyzed as independent risk factors to predict neurological deficits using multivariate logistic regression analyses.

RESULTS

At the initial assessment, 31 patients had neurological deficits. Fracture level, AO fracture type, canal encroachment ratio, vertebral compression ratio, interpedicular distance ratio, and presence of a vertical laminar fracture were significantly associated with the presence of neurological deficits (all P < 0.05). Multivariate logistic regression identified fracture level, canal encroachment ratio (adjusted odds ratio [aOR] 1.072, 95% confidence interval [CI] 1.018-1.129), and vertebral compression ratio (aOR 0.884, 95% CI 0.788-0.992) as independent predictors of a neurological deficit. Receiver operating characteristic curve analyses revealed that only the canal encroachment ratio had good discriminatory ability (area under the curve 0.874, 95% CI 0.791-0.957), and the optimal cutoff was 47% (canal diameter 6.6 mm) with 90.3% sensitivity and 80% specificity.

CONCLUSION

The canal encroachment ratio was most strongly associated with neurological deficits in traumatic mid and low lumbar fractures, with an optimal cutoff of 47%.

LEVEL OF EVIDENCE

4.

Dynamics of spinal cord compression with different patterns of thoracolumbar burst fractures: Numerical simulations using finite element modelling

BACKGROUND

In thoracolumbar burst fractures, spinal cord primary injury involves a direct impact and energy transfer from bone fragments to the spinal cord. Unfortunately, imaging studies performed after the injury only depict the residual bone fragments position and pattern of spinal cord compression, with little insight on the dynamics involved during traumas. Knowledge of underlying mechanisms could be helpful in determining the severity of the primary injury, hence the extent of spinal cord damage and associated potential for recovery. Finite element models are often used to study dynamic processes, but have never been used specifically to simulate different severities of thoracolumbar burst fractures.

METHODS

Previously developed thoracolumbar spine and spinal cord finite element models were used and further validated, and representative vertebral fragments were modelled. A full factorial design was used to investigate the effects of comminution of the superior fragment, presence of an inferior fragment, fragments rotation and velocity, on maximum Von Mises stress and strain, maximum major strain, and pressure in the spinal cord.

FINDINGS

Fragment velocity clearly was the most influential factor. Fragments rotation and presence of an inferior fragment increased pressure, but rotation decreased both strains outputs. Although significant for both strains outputs, comminution of the superior fragment isn't estimated to influence outputs.

INTERPRETATION

This study is the first, to the authors' knowledge, to examine a detailed spinal cord model impacted in situ by fragments from burst fractures. This numeric model could be used in the future to comprehensively link traumatic events or imaging study characteristics to known spinal cord injuries severity and potential for recovery.

The Association between Sagittal Index, Canal Compromise, Loss of Vertebral Body Height, and Severity of Spinal Cord Injury in Thoracolumbar Burst Fractures

Aim:

Our aim was to determine whether a combination of sagittal index (SI), canal compromise (CC), and loss of vertebral body height (LVBH) is associated with the severity of neurological injury in patients with thoracolumbar burst fractures.

Materials and Methods:

Seventy-four patients with thoracolumbar burst fracture undergoing instrumentation between 2010 and 2015 were analyzed retrospectively. The degree of neurological injury was determined using the American Spinal Injury Association (ASIA) scoring system. The association between the morphology of the fracture and the severity of neurological injury was analyzed.

Results:

There was a strong association between fracture morphology and the severity of neurological injury. Of the patients, 77.5% with SI ≥20°, 81.6% with CC ≥40%, and 100% with LVBH ≥50% had lesion according to ASIA. All of 7 patients with ASIA A had SI ≥20°, CC ≥40%, and LVBH ≥50%. On the other hand, 79% of the patients with ASIA E had SI <20°, 83.7% of the patients with ASIA E had CC <40%, and all of the patients with ASIA E had LVBH <50%. SI, CC, and LVBH were lower in neurologically intact patients (ASIA E), whereas they were higher in patients with neurological deficits (ASIA A, B, C, D) (P = 0.001; P < 0.01). These measurements had 100% negative predictive values and relatively high positive predictive values.

Conclusion:

SI, CC, and LVBH are significantly associated with the severity of neurological injury in patients with thoracolumbar burst fractures. The patients with SI >25°, the patients with CC >40%, and the patients with LVBH >50% are likely to have a more severe neurological injury.

[Decompression by mini-open posterior approach assisted with microscope for thoracolumbar burst fracture with severe spinal canal stenosis]

Objective

To investigate the effectiveness of posterior microscopic mini-open technique (MOT) decompression in patients with severe spinal canal stenosis resulting from thoracolumbar burst fractures.

Methods

The clinical data of 28 patients with severe spinal canal stenosis caused by thoracolumbar burst fractures, who were treated by posterior microscopic MOT, which performed unilateral or bilateral laminectomy, poking reduction, intervertebral bone graft via spinal canal, and percutaneous pedicle screw fixation between January 2014 and January 2016 were retrospectively analyzed. There were 21 males and 7 females with a mean age of 42.1 years (range, 16-61 years). The involved segments included T ₁₁ in 1 case, T ₁₂ in 4 cases, L ₁ in 14 cases, and L ₂ in 9 cases. According to AO classification, there were 19 cases of type A3, 9 of type A4. According to American Spinal Injury Association (ASIA) grading, 12 cases were grade C, 13 grade D, and 3 grade E. The time between injury and operation was 3-7 days (mean, 3.6 days). To evaluate effectiveness, the changes in the visual analogue scale (VAS), percentage of anterior height of injured vertebrae, Cobb angle, rate of spinal compromise (RSC), and ASIA grading were analyzed.

Results

All patients were performed procedures successfully. The operation time was 135-323 minutes (mean, 216.4 minutes). The intraoperative blood loss was 80-800 mL (mean, 197.7 mL). The hospitalization time was 10-25 days (mean, 12.5 days). The incisions healed primarily, without wound infection, cerebrospinal fluid leakage, or other early complications. All the 28 patients were followed up 12-24 months (mean, 16.5 months). No breakage or loosening of internal fixation occurred. All fractures healed, and the healing time was 3-12 months (mean, 6.5 months). Compared with preoperative ones, the percentage of anterior height of injured vertebrae, Cobb angle, and RSC at immediate after operation and at last follow-up and the VAS scores at 1 day after operation and at last-follow were significantly improved ( P<0.05). There was no significant difference in the percentage of anterior height of injured vertebrae and Cobb angle between at immediate after operation and at last follow-up ( P>0.05). But the RSC at immediate after operation and VSA score at 1 day after operation were significantly improved when compared with those at last follow-up ( P<0.05). The ASIA grading at last follow-up was 1 case of grade C, 14 grade D, and 13 grade E, which was significantly improved when compared with preoperative ones ( Z=3.860, P=0.000).

Conclusion

MOT is an effective and minimal invasive treatment for thoracolumbar AO type A3 and A4 burst fractures with severe spinal canal stenosis, and it is beneficial to early rehabilitation for patients.

Thoracolumbar Burst Fractures

Thoracolumbar burst fractures are high-energy vertebral injuries, which commonly can be treated nonoperatively. Consideration of the injury pattern, extent of comminution, neurological status, and integrity of the posterior ligamentous complex may help determine whether operative management is appropriate. Several classification systems are contingent upon these factors to assist with clinical decision-making. A multitude of operative procedures have been shown to have good radiographic and clinical outcomes with extended follow-up, and treatment choice should be based on the individual's clinical and radiographic presentation.

Acute Thoracolumbar Spinal Cord Injury: Relationship of Cord Compression to Neurological Outcome

BACKGROUND

Spinal cord injury in the cervical spine is commonly accompanied by cord compression and urgent surgical decompression may improve neurological recovery. However, the extent of spinal cord compression and its relationship to neurological recovery following traumatic thoracolumbar spinal cord injury is unclear. The purpose of this study was to quantify maximum cord compression following thoracolumbar spinal cord injury and to assess the relationship among cord compression, cord swelling, and eventual clinical outcome.

METHODS

The medical records of patients who were 15 to 70 years of age, were admitted with a traumatic thoracolumbar spinal cord injury (T1 to L1), and underwent a spinal surgical procedure were examined. Patients with penetrating injuries and multitrauma were excluded. Maximal osseous canal compromise and maximal spinal cord compression were measured on preoperative mid-sagittal computed tomography (CT) scans and T2-weighted magnetic resonance imaging (MRI) by observers blinded to patient outcome. The American Spinal Injury Association (ASIA) Impairment Scale (AIS) grades from acute hospital admission (≤24 hours of injury) and rehabilitation discharge were used to measure clinical outcome. Relationships among spinal cord compression, canal compromise, and initial and final AIS grades were assessed via univariate and multivariate analyses.

RESULTS

Fifty-three patients with thoracolumbar spinal cord injury were included in this study. The overall mean maximal spinal cord compression (and standard deviation) was 40% ± 21%. There was a significant relationship between median spinal cord compression and final AIS grade, with grade-A patients (complete injury) exhibiting greater compression than grade-C and D patients (incomplete injury) (p < 0.05). Multivariate logistic regression identified mean spinal cord compression as independently influencing the likelihood of complete spinal cord injury (p < 0.01).

CONCLUSIONS

Traumatic thoracolumbar spinal cord injury is commonly accompanied by substantial cord compression. Greater cord compression is associated with an increased likelihood of severe neurological deficits (complete injury) following thoracolumbar spinal cord injury.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Analysis of stress application at the thoracolumbar junction and influence of vertebral body collapse on the spinal cord and cauda equina

The thoracolumbar junction comprises the spinal cord, nerve roots and the cauda equina, exhibiting unique anatomical features that may give rise to a diverse array of symptoms under conditions of injury, thus complicating the diagnosis of compressive disorders. The present study aimed to examine varying degrees and forms of compression at this level of the spinal cord using a two-dimensional model to calculate the relationship of these variables to injury. The degree of compression was expressed as a percentage of the spinal canal that was occupied. Results were compared with findings from clinical observations to assess the validity of the model. Analysis revealed that higher levels of compression/spinal canal occupation are associated with the presence of neurological symptoms. This finding was consistent with clinical data. Results of the present analysis warrant further research involving evaluation of compression with respect to other parameters, such as blood flow, as well as more anatomically accurate three-dimensional analysis.

[Rationale and complications of the anterior-lateral extrapleural retroperitoneal approach for unstable thoracolumbar fractures: Experience in 86 consecutive patients]

OBJECTIVES

To describe the rationale, pros and cons, and complications of the anterior-lateral extrapleural retroperitoneal approach for unstable (TLICS>4) thoracolumbar fractures.

PATIENTS AND METHODS

Clinical and radiological data and outcomes from a cohort treated surgically via said approach were retrospectively reviewed. All patients were operated on exclusively by 5 neurosurgeons trained in spine surgery.

RESULTS

Between June 1999 and December 2015, 86 patients underwent surgery (median age 42years, most common level: L1). Approximately 32.5% presented with a preoperative neurological defect. After surgery (mean duration: 275minutes), 75.6% presented with no neurological sequelae and only one-third required blood transfusion. Median postoperative stay was 7days. Correction of kyphosis was considered adequate and suboptimal but acceptable in 91% and 9% of the patients, respectively. Complications occurred in 36 patients, the majority being transient. We observed failure of the construct in 2 cases (collapse of an expandable cage and extrusion of a locking screw). No infections, vascular or visceral lesions, permanent neurological worsening or mortality occurred during hospitalisation. One patient ultimately needed additional posterior fixation due to persistence of pain. Median follow-up was 252days (27.9% was lost to follow-up).

CONCLUSIONS

The extrapleural extraperitoneal approach provides solid anterior reconstruction, allows wide decompression of the spinal canal, and permits adequate and long-lasting correction of kyphosis. The rates of infection, construct failure, need for reoperation and vascular or visceral lesions are minimal.

Analysis of the independent risk factors of neurologic deficit after thoracolumbar burst fracture

Background

The objective of this study is to identify the independent risk factors of neurologic deficit after thoracolumbar burst fracture. Traumatic fractures of the thoracolumbar spine are the most common type of spinal column fractures. Many studies have attempted to determine whether neurologic deficit in such fractures is related to spinal canal stenosis or other parameters observed on axial computed tomography. However, this relationship remains controversial.

Methods

A review of the clinical data and axial computed tomography (CT) for 105 patients was performed. Neurologic deficit was classified according to the American Spinal Injury Association (ASIA) classification. Various preoperative CT parameters, including vertebral body compression, canal stenosis, sagittal alignment, and fragment reverse, were analyzed using ordinal logistic regression analysis.

Results

Arbeitsgemeinschaft für Osteosynthesefragen (AO) classification, canal volume, transverse canal diameter, median sagittal diameter, Cobb angle, compression ratio of the sagittal diameter, compression ratio of the cross-sectional area, and compression ratios of the anterior vertebral height (AVH), middle vertebral height (MVH), and posterior vertebral height (PVH) were significantly associated with severity of nerve injury (P < 0.05). However, flip angle and rotation angle of bony fragments were unrelated to severity of nerve damage. Multivariate logistic regression identified AO classification, compression ratio of median sagittal diameter, anterior vertebral compression ratio, and distance from the posterior margin to the vertebral body above to be independent variables associated with neurologic deficit.

Conclusions

The four CT parameters most strongly associated with neurologic deficit in thoracolumbar burst fractures are AO classification, compression ratio of median sagittal diameter, anterior vertebral compression ratio, and distance from the posterior margin to the vertebral body above.

TREATMENT OF UNSTABLE THORACOLUMBAR FRACTURES IN PEDIATRIC PATIENTS

Objective:To analyze the characteristics of unstable thoracolumbar fractures in the pediatric population.Methods:A retrospective cross-sectional study was conducted with pediatric patients (0 to 15 years) who presented with unstable thoracolumbar fracture with or without neurological damage. Twenty-four operated patients were analyzed: 13 male and 11 female.Results:Falls from height are the most common cause, being the thoracolumbar junction the anatomical site most frequently injured.Conclusion:The thoracolumbar fractures are rare in the pediatric population, as well as post-surgical instrumentation structural deformities.

Posterior indirect reduction and pedicle screw fixation without laminectomy for Denis type B thoracolumbar burst fractures with incomplete neurologic deficit

Purpose

The aim of this study is to evaluate the efficacy of posterior indirect reduction and pedicle screw fixation without laminectomy for the treatment of Denis type B thoracolumbar burst fractures with incomplete neurologic deficit.

Methods

From March 2008 to May 2012, 36 consecutive patients of Denis type B thoracolumbar burst with incomplete neurologic deficit were enrolled. All of the patients accepted the treatments of posterior indirect reduction and pedicle screw fixation without laminectomy. Clinical and radiologic outcomes were assessed preoperatively and postoperatively.

Results

Operations were performed in a relatively short time without massive hemorrhage. Their neurologic functions were improved by at least one Frankel grade. The average score of American Spinal Injury Association (ASIA) motor increased from 25.4 ± 10.8 to 42.1 ± 10.5, and the recovery rate of the ASIA score was also increased. The pain level was relieved for all the patients. The local kyphosis angle was reduced from 25.9° ± 3.4° to 6.9° ± 2.2° (P <0.05) and remained 7.9° ± 2.0° (P > 0.05) at the latest follow-up. After the operation, the mean vertebral canal diameter increased from 5.5 ± 1.3 to 11.1 ± 2.2 mm (P < 0.05) and the mean canal stenosis index increased from 32.9 ± 7.8 to 84.8 ± 7.3 % (P < 0.05). There were no serious complications and fixation failures during follow-up.

Conclusion

Denis type B thoracolumbar burst fractures with incomplete neurologic deficit can be effectively treated by posterior indirect reduction and pedicle screw fixation without laminectomy.

Posterior fixation including the fractured vertebra for severe unstable thoracolumbar fractures

BACKGROUND CONTEXT

Traditional short-segment fixation of unstable thoracolumbar injuries can be associated with progressive kyphosis and implant failure. Load sharing classification (LSC) recommends supplemental anterior reconstruction for fractures of score 7 or greater. Posterior fixation including the fractured vertebra (PFFV) has biomechanical advantages over conventional short-segment fixation. However, its efficacy in severe thoracolumbar injuries (LSC≥7) has not been studied.

PURPOSE

To study the clinical, functional, and radiologic results of PFFV for severe, unstable thoracolumbar injuries (LSC≥7) at a minimum of 2 years.

STUDY DESIGN

A retrospective review of case records.

PATIENT SAMPLE

Thirty-two patients with an unstable burst fracture of LSC≥7 treated with PFFV were included.

OUTCOME MEASURES

They included clinical outcomes: American Spinal Injury Association grade, visual analog scale (VAS), Oswestry Disability Index (ODI); and radiologic measures: segmental kyphosis angle, vertebral wedge angle, and percentage loss of anterior and posterior vertebral height.

METHODS

Thirty-two patients with LSC≥7 who had undergone PFFV, with a minimum follow-up of 2 years were studied for demographic, injury, and surgical details. Clinical and radiologic outcomes were measured before surgery and at 6, 12, and 24 months postoperatively. The presence of screw breakage, screw pullout, peri-implant loosening, and rod breakage were considered as criteria for implant failure.

RESULTS

None of the patients had postoperative implant failure at the final follow-up. The mean preoperative kyphosis angle was 22.9°±7.6°. This improved significantly to 9.2°±6.6° after surgery (p=.000). There was a loss of mean 2.4° (mean kyphosis angle of 11.6°±6.3°) at the final follow-up. The mean preoperative wedge angle was 23.0°±8.1°. This was corrected to 9.7°±6.2° (p=.000). There was a loss of kyphosis (mean 1.2°) in the follow-up period. The mean anterior and posterior vertebral height also showed significant improvements postoperatively, which were maintained at the final follow-up. The mean ODI and VAS scores at the end of 2 years were 17.5% and 1.6, respectively.

CONCLUSIONS

Reduction of unstable thoracolumbar injuries even with LSC≥7 can be achieved and maintained with the use of short-segment pedicle screw fixation including the fractured vertebra, avoiding the need for anterior reconstruction. In the current era of evolving concepts of fracture fixation, the relevance of LSC in the management of unstable burst fractures is questionable.

Traumatic thoracolumbar spine injuries: what the spine surgeon wants to know

The Thoracolumbar Injury Classification and Severity Score (TLICS) is a scoring and classification system developed by the Spine Trauma Study Group in response to the recognition that previous classification systems have limited prognostic value and generally do not suggest treatment pathways. The TLICS provides a spine injury severity score based on three components: injury morphology, integrity of the posterior ligamentous complex (PLC), and neurologic status of the patient. A numerical score is calculated for each category, with a lower point value assigned to a less severe or less urgent injury and a higher point value assigned to a more severe injury requiring urgent management. The total score helps guide decision making about surgical versus nonsurgical management. The TLICS also emphasizes the importance of magnetic resonance imaging in evaluating PLC injury and acknowledges that the primary driver of surgical intervention is the patient's neurologic status. Knowledge of PLC anatomy and its significance is essential in recognizing unstable injuries. Signs of PLC injury at computed tomography include interspinous distance widening, facet joint widening, spinous process fracture, and vertebral subluxation or dislocation. Familiarity with the TLICS will help radiologists who interpret spine trauma imaging studies to effectively communicate findings to spine trauma surgeons. The complete article is available online .

The retrospective analysis of posterior short-segment pedicle instrumentation without fusion for thoracolumbar burst fracture with neurological deficit

This study aims to investigate the efficacy of posterior short-segment pedicle instrumentation without fusion in curing thoracolumbar burst fracture. All of the 53 patients were treated with short-segment pedicle instrumentation and laminectomy without fusion, and the restoration of retropulsed bone fragments was conducted by a novel custom-designed repositor (RRBF). The mean operation time and blood loss during surgery were analyzed; the radiological index and neurological status were compared before and after the operation. The mean operation time was 93 min (range: 62-110 min) and the mean intraoperative blood loss was 452 mL in all cases. The average canal encroachment was 50.04% and 10.92% prior to the surgery and at last followup, respectively (P < 0.01). The preoperative kyphotic angle was 17.2 degree (± 6.87 degrees), whereas it decreased to 8.42 degree (± 4.99 degrees) at last followup (P < 0.01). Besides, the mean vertebral body height increased from 40.15% (± 9.40%) before surgery to 72.34% (± 12.32%) at last followup (P < 0.01). 45 patients showed 1-2 grades improvement in Frankel's scale at last followup. This technique allows for satisfactory canal clearance and restoration of vertebral body height and kyphotic angle, and it may promote the recovery of neurological function. However, further research is still necessary to confirm the efficacy of this treatment.

Finite element study of the mechanical response in spinal cord during the thoracolumbar burst fracture

Background

The mechanical response of the spinal cord during burst fracture was seldom quantitatively addressed and only few studies look into the internal strain of the white and grey matters within the spinal cord during thoracolumbar burst fracture (TLBF). The aim of the study is to investigate the mechanical response of the spinal cord during TLBF and correlate the percent canal compromise (PCC) with the strain in the spinal cord.

Methodology/Principal Findings

A three-dimensional (3D) finite element (FE) model of human T12-L1 spinal cord with visco-elastic property was generated based on the transverse sections images of spinal cord, and the model was validated against published literatures under static uniaxial tension and compression. With the validated model, a TLBF simulation was performed to compute the mechanical strain in the spinal cord with the PCC. Linear regressions between PCC and strain in the spinal cord show that at the initial stage, with the PCC at 20%, and 45%, the corresponding mechanical strains in ventral grey, dorsal grey, ventral white, dorsal white matters were 0.06, 0.04, 0.12, 0.06, and increased to 0.14, 0.12, 0.23, and 0.13, respectively. At the recoiled stage, when the PCC was decreased from 45% to 20%, the corresponding strains were reduced to 0.03, 0.02, 0.04 and 0.03. The strain was correlated well with PCC.

Conclusions/Significance

The simulation shows that the strain in the spinal cord correlated well with the PCC, and the mechanical strains in the ventral regions are higher than those in the dorsal regions of spinal cord tissue during burst fracture, suggesting that the ventral regions of the spinal cord may susceptible to injury than the dorsal regions.

Analysis of the risk factors for severity of neurologic status in 216 patients with thoracolumbar and lumbar burst fractures

STUDY DESIGN

A retrospective, consecutive case series.

OBJECTIVE

To determine the risk factors that have a significant correlation with the severity of neurologic impairment in thoracolumbar and lumbar burst fractures.

SUMMARY OF BACKGROUND DATA

The correlation between spinal canal stenosis due to bony fragments and the severity of neurologic deficits in thoracolumbar and lumbar burst fractures remains controversial. Moreover, there have so far been no reports in the literature in which the risk factors (spinal canal stenosis and the disruption of posterior ligamentous complex) causing a severe neurologic deficit were analyzed using a multiple logistic regression model.

METHODS

A review of the clinical data (neurologic impairments on admission and a finding of posterior ligamentous complex disruption at the time of operation), axial computed tomography, and plain lateral radiography of 216 patients in thoracolumbar (T11-L1) and lumbar (L2-L5) burst fractures was performed. The factors related to neurologic impairments were analyzed using a multiple logistic regression model.

RESULTS

In all cases, both the spinal canal stenosis (P < 0.01) and disruption of posterior ligamentous complex (P < 0.01) were significant risk factors. Interestingly, these two risk factors varied according to the injury levels: at thoracic level, the spinal canal stenosis (P < 0.01); at the first lumbar spine, the disruption of the posterior ligamentous complex (P < 0.01); and at the lumbar spine below L2, both of the spinal canal stenosis (P < 0.01) and the disruption of posterior ligamentous complex (P < 0.05) were significant risk factors, respectively.

CONCLUSION

In the patients with thoracolumbar and lumbar burst fractures, the significance of the two important risk factors related to clinical results, namely, the stenosis ratio of spinal canal and the disruption of posterior ligamentous complex, were found to vary depending on the level of injury.