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.

Diagnostic Value of Various Morphological Features of Horizontal and Vertical Laminar Fractures for Posterior Ligamentous Complex Injury of the Thoracolumbar Spine as Defined by Magnetic Resonance Imaging

OBJECTIVE

To determine diagnostic value of morphological features of horizontal laminar fracture (HLF) and vertical laminar fracture (VLF) for diagnosis of posterior ligamentous complex (PLC) injury.

METHODS

This retrospective review comprised 271 consecutive patients with acute thoracolumbar fractures presenting to a Level 1 trauma center between January 2014 and January 2021. Two reviewers evaluated computed tomography and magnetic resonance imaging. VLFs were subclassified based on length and depth of lamina involved, as follows: type 1, full-length complete; type 2, full-length incomplete; type 3, partial-length complete or incomplete. HLFs were subclassified as follows: bilateral versus unilateral, displaced >2 mm versus nondisplaced, and lamina-only versus laminar and pedicle. We examined the diagnostic accuracy and the univariate and multivariate associations of laminar fracture subtypes with PLC injury as defined by black stripe discontinuity.

RESULTS

Bilateral HLFs, laminar and pedicle fractures, displaced HLFs, and type 1 VLFs yielded a high positive predictive value for PLC injury (95%, 91%, 100%, and 86%, respectively). Type 2 and 3 VLFs did not show significant univariate associations with PLC injury. Bilateral HLFs, laminar and pedicle fractures, and displaced HLFs showed independent associations with PLC injury (adjusted odds ratio = 13.6, 8.4, 6, and 10.3, respectively; P < 0.002). Type 1 VLFs did not show a significant association with PLC (adjusted odds ratio = 10.3; P = 0.06).

CONCLUSIONS

Bilateral HLFs, laminar and pedicle fractures, and displaced HLFs, but not any VLF subtypes, were independently associated with PLC injury. These findings may improve the reliability of PLC assessment by computed tomography.