Simple and Economical Method to Create Thoracolumbar Burst Fracture in a Calf Spine Model

How does vertical laminar fracture impact the decision-making in thoracolumbar fractures? A systematic scoping review and meta-analysis

OBJECTIVE

Although vertical laminar fracture (VLF) is generally considered a severity marker for thoracolumbar fractures (TLFs), its exact role in decision-making has never been established. This scoping review aims to synthesize the research on VLF's role in the decision-making of TLFs.

METHODS

A systematic review was conducted following PRISMA guidelines. We searched PubMed, Scopus, and Web of Science from inception to  June 11, 2023, for studies examining the association of VLF in thoracolumbar fractures with dural lacerations, neurological deficits, radiographic parameters, or treatment outcomes. Additionally, experimental studies that analyze the biomechanics of burst fractures with VLF were included. The studies extracted key findings, objectives, and patient population. A meta-analysis was performed for the association of VLF with dural laceration and neurological deficit, and ORs were pooled with a 95% confidence interval (CI).

RESULTS

Twenty-eight studies were included in this systematic review, encompassing 2021 patients, and twelve were included in the meta-analysis. According to the main subject of the study, the association of VLF with a dural laceration (n = 14), neurological deficit (n = 4), radiographic parameters (n = 3), thoracolumbar fracture classification (n = 2), and treatment outcome (n = 2). Seven studies with a total of 1010 patients reported a significant association between VLF and neurological deficit (OR = 7.35, 95% CI [3.97, 14.25]; P < 0.001). The pooled OR estimates for VLF predicting dural lacerations were 7.75, 95% CI [2.41, 24.87]; P < 0.001).

CONCLUSION

VLF may have several important diagnostic and therapeutic implications in managing TLFs. VLF may help to distinguish AO type A3 from A4 fractures. VLF may help to predict preoperatively the occurrence of dural laceration, thereby choosing the optimal surgical strategy. Clinical and biomechanical data suggest VLF may be a valuable modifier to guide the decision-making in burst fractures; however, more studies are needed to confirm its prognostic importance regarding treatment outcomes.

Can Vertical Laminar Fracture Further Discriminate Fracture Severity Between Thoracolumbar AO Type A3 and A4 Fractures?

OBJECTIVE

To determine whether vertical laminar fracture (VLF) can distinguish between AO type A3 and A4 fractures.

METHODS

In a retrospective review of 111 consecutive acute thoracolumbar burst fractures, 5 reviewers independently analyzed computed tomography scans to classify fractures into A3 or A4 and to identify VLF. The following computed tomography parameters were measured: spinal canal stenosis >50%, anterior vertebral height ratio <50%, load sharing score >6, and local kyphosis >20°. We calculated the diagnostic performance of VLF in detecting A4 fracture. We compared the proportion of fractures with positive bony parameters, neurological deficit, dural tears, and surgical treatment between A3, A4 with VLF, and A4 without VLF.

RESULTS

VLF was present in 62/75 (83%) A4 fractures and 2/36 (5.5%) A3 fractures (P < 0.0001). VLF yielded a high specificity of 94% (95% confidence interval 81%-99%) and moderately high sensitivity of 83% (95% CI 72%-91%) in detecting A4 fractures. A significantly higher proportion of A4 fractures with VLF had neurological deficit (24% vs. 0, P = 0.05), spinal canal stenosis >50% (25% vs. 0, P = 0.04), and anterior vertebral height ratio <50% (24% vs. 0, P = 0.05) than A4 fractures with no VLF. Interrater and intrarater κ values for VLF and AO standard criterion were excellent (>0.85).

CONCLUSIONS

We found VLF to be highly specific, sensitive, and reliable in detecting A4 fractures. A higher proportion of A4 fractures with VLF had radiographic parameters and neurological deficit than A4 fractures with no VLF. VLF could be used as a severity modifier to further discriminate A3 and A4 fractures regarding severity and potentially guide treatment decision making.

Clinical efficacy and therapeutic value of delayed surgery in patients with symptomatic old thoracolumbar fractures

Background

To investigate the clinical efficacy and therapeutic value of posterior decompression reduction, bone grafting fusion, and internal fixation for treatment of symptomatic old thoracolumbar fractures.

Method

Retrospective analysis was conducted for 14 patients (9 men, 5 women; average age 40.1 years) with old thoracolumbar fractures who underwent posterior operation. American Spinal Injury Association (ASIA) scores were used to evaluate neurologic function. Vertebral body height, Cobb angle in the sagittal plane, spinal canal volume ratio (%) and bone graft fusion were analyzed by radiography and computed tomography on different follow-up times.

Results

Mean follow-up was 27.1 months (23–36 months). Of three patients with ASIA grade A, 2 had improved postoperative urination and defecation, although no classification change. Preoperative ASIA score for eight patients with incomplete injury was grade B; four patients recovered to grade C at final follow-up. Preoperative ASIA score was C in three patients, increased to D in two patients and returned to normal E in one patient. Preoperative results showed average injured vertebra height loss rate decreased from 50.4 to 8.9%; average Cobb angle on the sagittal plane recovered from 39.6 to 6.9°; and the average spinal canal volume ratio recovered from 33.8 to 5.9%. Bony fusion was achieved; local lumbago and leg pain were relieved to some extent. No patients exhibited loosening of the fracture treated by internal fixation, pseudoarthrosis, or other related serious complications.

Conclusion

Treatment of old thoracolumbar fractures by posterior decompression reduction, bone grafting fusion, and internal fixation can relieve spinal cord compression, improve neurologic function of some patients (ASIA grades B–C), effectively relieve pain, correct deformity, restore biomechanical stability, and significantly improve quality of life.

Behavior of Injured Lamina in Lumbar Burst Fractures during Reduction Maneuvers: A Biomechanical Study

STUDY DESIGN

An experimental biomechanical study.

PURPOSE

This study aims to investigate the behavior of a lamina injury in lumbar burst fractures during reduction maneuvers.

OVERVIEW OF LITERATURE

Lumbar burst fractures are frequently accompanied by a lamina fracture. Many researchers concluded that any reduction maneuver will close the fractured lamina edges and possibly crush the entrapped neural elements. This conclusion did not rely on solid biomechanical trials and was based primarily on clinical experience.

METHODS

Eighteen fresh-frozen lamb spines were randomly divided into three groups. Using the preinjury and the dropped-mass technique, a burst fracture model was developed. A central laminectomy of 5 mm of the L3 lumbar spine was created to mimic a complete type of lamina fracture. To measure the movement of the fractured laminar edges, two holes were drilled on both sides of the upper and lower regions of the lamina to allow for optic marker placement. A single specific spine movement was applied to each group: traction, flexion, and extension. Gap changes were measured by camera extensometers.

RESULTS

After traction, the average values of the upper and lower aspects of the lamina interval showed narrowing of 1.65±0.82 mm and 1.97±1.14 mm, respectively. No statistical significance was detected between the two aspects. The upper and lower regions of the lamina gap behaved differently during extension. At 10°, 20°, and 30°, the upper part of the lamina interval was widened by an average of 0.016±0.024, 0.29±0.32, and 1.73±1.45 mm, respectively, whereas the lower part was narrowed by an average of 0.023±0.012, 0.47±0.038, and 1.94±1.46 mm, respectively.

CONCLUSIONS

Neural element crushing may take place, particularly at the lower aspect of the fractured lamina gap during extension and throughout the whole lamina gap during traction. The lamina gap widens during flexion. Reduction maneuvers should be attempted after exploring the fractured lamina to prevent further neurological compromise.

Biomechanical comparison of short-segment posterior fixation including the fractured level and circumferential fixation for unstable burst fractures of the lumbar spine in a calf spine model

OBJECTIVE There has been a transition from long- to short-segment instrumentation for unstable burst fractures to preserve motion segments. Circumferential fixation allows a stable short-segment construct, but the associated morbidity and complications are high. Posterior short-segment fixation spanning one level above and below the fractured vertebra has led to clinical failures. Augmentation of this method by including the fractured level in the posterior instrumentation has given promising clinical results. The purpose of this study is to compare the biomechanical stability of short-segment posterior fixation including the fractured level (SSPI) to circumferential fixation in thoracolumbar burst fractures. METHODS An unstable burst fracture was created in 10 fresh-frozen bovine thoracolumbar spine specimens, which were grouped into a Group A and a Group B. Group A specimens were instrumented with SSPI and Group B with circumferential fixation. Biomechanical characteristics including range of motion (ROM) and load-displacement curves were recorded for the intact and instrumented specimens using Universal Testing Device and stereophotogrammetry. RESULTS In Group A, ROM in flexion, extension, lateral flexion, and axial rotation was reduced by 46.9%, 52%, 49.3%, and 45.5%, respectively, compared with 58.1%, 46.5%, 66.6%, and 32.6% in Group B. Stiffness of the construct was increased by 77.8%, 59.8%, 67.8%, and 258.9% in flexion, extension, lateral flexion, and axial rotation, respectively, in Group A compared with 80.6%, 56.1%, 82.6%, and 121.2% in Group B; no statistical difference between the two groups was observed. CONCLUSIONS SSPI has comparable stiffness to that of circumferential fixation.