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

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.

Towards a standardized reporting of the impact of magnetic resonance imaging on the decision-making of thoracolumbar fractures without neurological deficit: Conceptual framework and proposed methodology

Introduction

A recent meta-analysis showed that only four prior studies have shown that magnetic resonance imaging (MRI) can change the fracture classification in 17% and treatment decisions in 22% of cases. However, previous studies showed a wide methodological variability regarding the study population, the definition of posterior ligamentous complex (PLC) injury, and outcome measures.

Research question

How can we standardize the reporting of the impact of MRI for neurologically intact patients with thoracolumbar fractures?

Material and methods

All available literature regarding the impact of MRI on thoracolumbar fracture classification or decision-making were reviewed. Estimating the impact of MRI on the TLFs' classification is an exercise of analyzing the CTs' accuracy for PLC injury against MRI as a ''Gold standard''and should follow standardized checklists such as the Standards for the Reporting of Diagnostic Accuracy Studies. Additionally, specific issues related to TLFs should be addressed.

Results

A standardized approach for reporting the impact of MRI in neurologically intact TLF patients was proposed. Regarding patient selection, restricting the inclusion of neurologically intact patients with A- and B-injuries is crucial. Image interpretation should be standardized regarding imaging protocol and appropriate criteria for PLC injury. The impact of MRI can be measured by either the rate of change in fracture classification or treatment decisions; the cons and pros of each measure is thoroughly discussed.

Discussion and conclusion

We proposed a structured methodology for examining the impact of MRI on neurologically intact patients with TLFs, focusing on appropriate patient selection, standardizing image analysis, and clinically relevant outcome measures.

How Often Would MRI Change the Thoracolumbar Fracture Classification or Decision-Making Compared to CT Alone?

STUDY DESIGN

retrospective study of consecutive patients.

OBJECTIVE

to analyze the frequency of change in Thoracolumbar fractures (TLFs) classification or decision-making after MRI compared by CT alone.

METHODS

A retrospective review of 244 consecutive patients with acute TLFs (T1-L5) presented to a single level 1 trauma center between 2014 and 2021. Three and 4 reviewers independently classified all fractures according to AOSpine and AOSpine injury severity score (TLAOSIS) by CT then MRI, respectively. Posterior ligamentous complex Injury (PLC) was diagnosed on CT and MRI by ≥ 2 positive CT findings and Black stripe discontinuity.

RESULTS

MRI changed AO classification in 25/244 patients (10.2%, P < .0001) due to an 8.2% upgrade from type A to type B and a 2% downgrade from type B to type A. The addition of MRI changed TL AOSIS among the 3 treatment recommendation groups in 35/244 (19.7%, 95% CI [14.9%-25.2%]. The best predictor of upgrade from type A to type B and downgrade from type B to type A was a single positive CT finding and the presence of only 2 CT signs as opposed to ≥3 signs, respectively (P < .0001 P = .03, respectively). Thoracic fractures showed a significantly higher reclassification rate than thoracolumbar and low lumbar (20% vs 10% and 0%, respectively, P = .07).

CONCLUSION

using appropriate CT/MRI criteria for PLC injury, MRI changed the AOSpine classification by 10% and TLAOSIS based treatment by 19.7%. The best predictors of fracture reclassification by MRI were the number of positive CT findings and fracture level.

A Proposal for a Standardized Imaging Algorithm to Improve the Accuracy and Reliability for the Diagnosis of Thoracolumbar Posterior Ligamentous Complex Injury in Computed Tomography and Magnetic Resonance Imaging

STUDY DESIGN

Systematic Literature Review.

OBJECTIVE

To propose a systematic imaging algorithm for diagnosing posterior ligamentous complex (PLC) injury in computed tomography (CT) and magnetic resonance imaging (MRI) to improve the reliability of PLC assessment.

METHODS

A systematic review was conducted following PRISMA guidelines. The Scopus database was searched from its inception until July 21, 2022, for studies evaluating CT or MRI assessment of the PLC injury following thoracolumbar trauma. The studies extracted key findings, objectives, injury definitions, and radiographic modalities.

RESULTS

Twenty-three studies were included in this systematic review, encompassing 2021 patients. Five studies evaluated the accuracy of MRI in detecting thoracolumbar PLC injury using intraoperative findings as a reference. These studies indicate that black stripe discontinuity due to supraspinous or ligamentum flavum rupture is a more specific criterion of PLC injury than high-signal intensity. Thirteen papers evaluated the accuracy or reliability of CT in detecting thoracolumbar PLC injury using MRI or intraoperative findings as a reference. The overall accuracy rate of CT in detecting PLC injury was 68-90%. Two studies evaluate the accuracy of combined CT findings, showing that ≥2 CT findings are associated with a positive predictive value of 88-91 %. Vertebral translation, facet joint malalignment, spinous process fracture, horizontal laminar fracture, and interspinous widening were independent predictors of PLC injury.

CONCLUSION

We provided a comprehensive imaging algorithm for diagnosing PLC in CT and MRI based on available literature and our experience. The algorithm will potentially improve the accuracy and reliability of PLC assessment, however it needs multicentre prospective validation.

Which Morphological Features of Facet Diastasis Predict Thoracolumbar Posterior Ligamentous Complex Injury as Defined by Magnetic Resonance Imaging?

BACKGROUND

The association of various morphological features of facet diastasis with posterior ligamentous complex (PLC) injury has not been previously described. This study aims to determine the diagnostic value of facet diastasis subtypes for diagnosing thoracolumbar PLC injury.

METHODS

We retrospectively reviewed 337 consecutive patients with acute thoracolumbar fractures who had computed tomography (CT) and magnetic resonance imaging (MRI) within 10 days of injury. Three and 5 reviewers evaluated MRI and CT images, respectively. Facet diastasis was subclassified as follows: Dislocated, no articular surface apposition; subluxed, incomplete articular surface apposition; and facet fracture articular process fractures which may be displaced ≥2 mm or otherwise undisplaced, facet joint widening (FJW) ≥ 3 mm. We examined the diagnostic accuracy and the multivariate associations of facet diastasis subtypes with PLC injury in MRI.

RESULTS

Facet dislocation, subluxation, and displaced facet fracture yielded a high positive predictive value (PPV) for PLC injury (96%, 88%, and 94%, respectively). In contrast, undisplaced facet fracture and FJW yielded a moderate PPV for PLC injury (78%, and 45%, respectively). Facet dislocation, subluxation, and displaced facet fracture showed independent associations with PLC injury (adjusted odds ratio [AOR] = 38.4, 17.1, 13.4, respectively; P < 0.05). Undisplaced facet fracture and FJW were not associated with PLC injury (AOR = 3.9 [95% confidence interval, 0.49-38.4], P = 0.20) and (AOR = 1.94 [95% confidence interval, 0.48-7.13]; P = 0.20; P = 0.33), respectively.

CONCLUSIONS

Facet dislocation, subluxation, and displaced facet fracture, but not undisplaced facet fracture or FJW, were independently associated with PLC injury. Therefore, we propose to define facet diastasis as a surrogate marker of PLC injury in MRI based on these morphologies.

The association between vertical laminar fracture and recurrent kyphosis after implant removal of Thoracolumbar burst fracture: a retrospective study

BACKGROUND

Surgeons often encounter recurrent kyphosis of Cobb angle following thoracolumbar burst fracture surgery. Some factors affecting postoperative correction loss have been studied in previous studies, but few have examined the relationship between laminar fractures and postoperative loss of correction.

METHODS

The clinical data of 86 patients with thoracolumbar burst fracture who met the inclusion criteria and were admitted to our Department of Spine Surgery between 2013 and 2020 was retrospectively analyzed. To examine the association between laminar fracturs and postoperative correction loss, demographic and radiographic characteristics of the two groups were analyzed.

RESULTS

The presence or absence of laminar fractures was statistically different between the two groups (P < 0.05). Binary logistic regression analysis showed that laminar fractures and preoperative Cobb were statistically significant in the two groups. There were statistically significant differences in the degree of injury of laminar fractures in the coronal plane between the two groups (P < 0.05).

CONCLUSION

This study investigated that the presence or absence of laminar fractures and preoperative Cobb contribute to loss of correction after thoracolumbar burst fracture surgery. There was a statistically significant difference between full-length and partial-length laminar fractures on the loss of postoperative correction of thoracolumbar burst fractures with laminar fractures.

Injury of the thoracolumbar posterior ligamentous complex : a bibliometric literature review

OBJECTIVE

This bibliometric review of literature on posterior ligamentous complex (PLC) injury in thoracolumbar (TL) trauma aims to guide future research.

METHODS

We conducted a keyword-based search from January 2000 to September 2021 using the Scopus database. Relevant publications were analyzed for the year of publication, authorship, publishing journals, institution and country of origin, subject matter, and article type. In addition, content analysis of clinical articles was performed, analyzing for sample size, study design (retrospective vs. prospective), single vs. multicenter, and level of evidence.

RESULTS

262 publications have been published in 61 journals by 537 authors, 162 institutions, and 29 countries. Thomas Jefferson University, the University of Calgary, and the University of Toronto have the largest number of publications related to PLC injury. The United States, Canada, and China were the most frequent contributors in terms of the number of publications. Spine was the most prolific and top-cited Journal, while Vaccaro A.R. was the most prolific author. The most cited publication was the Thoracolumbar Injury Classification and Severity Score (TLICS) classification by Vaccaro et al. in 2005. Most of the publications have been case studies, with diagnostic accuracy being the most frequently discussed topic. The sample size for a large portion of the case series was less than 50. The majority of case series were retrospective studies conducted at a single center.

CONCLUSION

Our review provides an extensive list of the most historically significant spinal imaging articles, acknowledging the key contributions made to the advancement of this research area.

Traumatic low lumbar fractures: How often MRI changes the fracture classification or clinical decision-making compared to CT alone?

PURPOSE

To determine the impact of magnetic resonance imaging (MRI) on fracture classification for low lumbar fractures (LLFs) compared to CT alone.

METHODS

This study was a retrospective review of 41 consecutive patients with LLFs who underwent CT and MRI within 10 days of injury. Three reviewers classified all fractures according to AOSpine Classification and the Thoracolumbar Injury Classification (TLISS). Posterior ligamentous complex (PLC) injury in MRI was defined by black stripe discontinuity and in CT by the presence of: vertebral body translation, facet joint malalignment, horizontal laminar or spinous process fracture, and interspinous widening. The proportion of patients with AO type A/B/C and with TLISS < 5 and ≥ 5 was compared between CT and MRI. We examined the overall accuracy and individual CT findings for PLC injury.

RESULTS

AO classification using CT was: AO type A in 26 patients (61%), type B in 7 patients (17%), and type C in 8 patients (22%). Seventeen patients (41%) had a TLISS ≥ 5 while 24 (59%) had TLISS < 5. The addition of MRI after CT changed the AO classification in only 2 patients (4.9%, 95% CI (0.6-16.5%) due to upgrade of type A to type B or vice versa, but did not change TLISS from < 5 to ≥ 5 [p< 0.0001; 95% CI (0.59, 0.77)].

CONCLUSIONS

CT was highly accurate (95%) for diagnosis of PLC injury in LLFs. Addition of MRI after CT did not change the AO classification or TLISS, compared to CT alone, thus suggesting limited additional value of MRI for PLC assessment or fracture classification.

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.