CT for thoracic and lumbar spine fractures: Can CT findings accurately predict posterior ligament complex injury?

Multicenter External Validation of the Accuracy of Computed Tomography Criteria for Detecting Thoracolumbar Posterior Ligamentous Complex Injury

BACKGROUND AND OBJECTIVE

Recent studies have proposed computed tomography (CT) criteria for posterior ligamentous complex (PLC) injury: disrupted if ≥2 CT findings, indeterminate if single finding, and intact if 0 CT findings. The study aims to validate the CT criteria for PLC injury externally.

METHODS

Three level 1 trauma centers enrolled 614 consecutive patients with acute thoracolumbar fractures (T1-L5) who received CT and MRI. Three reviewers from each center assessed CT for facet joint malalignment, horizontal laminar fracture, spinous process fracture, and interspinous widening and MRI for disrupted PLC, defined as black stripe discontinuity. The primary outcome is the diagnostic accuracy of CT criteria (0, 1, ≥2 findings) in detecting disrupted PLC on MRI using all CT readings. A subgroup analysis was performed for each participating center and reviewer. The inter-reader agreement on PLC status on MRI and CT criteria was assessed using Fleiss Kappa ( k ).

RESULTS

The positive predictive value for PLC injury was 0 findings 3%, single positive CT 43%, and ≥2 CT findings in 94%. The accuracy measures were consistent across various centers and reviewers. The area under the curve for ≥1 CT finding in detecting PLC injury ranged from 90% to 97%, indicating excellent discrimination for all centers. The inter-reader k on PLC status by MRI and overall CT findings was substantial ( k > 0.60).

CONCLUSION

This study externally validates the previously proposed CT criteria for PLC injury. A total of ≥2 positive CT findings or 0 CT findings can be used as criteria for a disrupted PLC (B-type injury) or intact PLC (A-type injuries), respectively, without added MRI. A single CT finding implies indeterminate PLC status and the need for further MRI assessment. The CT criteria will potentially guide MRI indications and treatment decisions for neurologically intact thoracolumbar burst fractures.

Accuracy of CT Scan for Detecting Posterior Ligamentous Complex Injury in Traumatic Thoracolumbar Fractures: A Systematic Review and Meta-Analysis

Study DesignA systematic review and meta-analysis.ObjectivesThis systematic review and meta-analysis aim to evaluate the diagnostic accuracy of CT in detecting PLC injuries in traumatic thoracolumbar fractures.MethodsA comprehensive search of PubMed/MEDLINE, Embase, and Web of Science was conducted up to January 2025. Studies were included if they examined the diagnostic validity of CT for PLC injuries compared with MRI with predefined outcomes (true/false positives/negatives). Quality assessment was performed using the QUADAS-2 tool, and statistical analysis involved bivariate binomial regression to generate summary receiver operating characteristic (SROC) curves and pooled estimates of sensitivity and specificity.ResultsEight studies involving 1440 patients were included. The pooled sensitivity and specificity of CT for PLC injury detection were 75% (95% CI: 68 to 80, P = 0.00) and 87% (95% CI: 71 to 95, P = 0.00), respectively. The area under the curve (AUC) from the SROC analysis was 0.81 (95% CI: 0.78 to 0.84), indicating fair diagnostic accuracy. Meta-regression analysis revealed that sensitivity and specificity remained consistent across advanced CT techniques, multiplanar reconstruction, and full MRI protocol, but extensive trauma, CT 16-64 or ≥128 slices, and 3.0 T MRI scanner influenced it. No significant publication bias was detected.ConclusionThis meta-analysis demonstrates that CT has fair diagnostic accuracy for detecting PLC injuries in traumatic thoracolumbar fractures, supporting its clinical utility. Future research should explore integrating advanced imaging technologies to enhance CT's diagnostic precision.

Toward Identifying and Resolving the Challenges to the Prognostic Validation of the Classifications for Thoracolumbar Burst Fractures: A Narrative Review

OBJECTIVE

To review the historical thoracolumbar burst fractures (TLBFs) classifications and discuss the probable gaps for their clinical validation.

SUMMARY OF BACKGROUND DATA

Despite multiple classification schemes, the treatment decisions for TLBFs in neurologically intact patients remain controversial. There are gaps between the current classifications and their predictive validation.

METHODS

A narrative literature review.

RESULTS

The potential barriers to establishing the predictive value of the current classifications of TLBFs could be connected to validation studies' flaws such as nonvalidated outcome measures and challenges of randomization. It could also be related to limited interobserver reliability in diagnosing A3/A4 fractures. Finally, it might be attributed to the inability to incorporate all prognostic variables, such as computed tomography (CT) parameters, patient-related factors, and traumatic disc injury, may result in failed validation.

CONCLUSION

AOSpine Patient and Clinical Reported Outcome Spine Trauma (PROST) and a recently proposed natural experiment observational study hold promise for mitigating methodological challenges. A structured approach for distinguishing A3/A4 fractures and standardized CT criteria for PLC injury is critical to improving reliability. Finally, a treatment algorithm incorporating all potential prognostic variables, independent of the morphologic classification, may improve the predictive value of the classification. Machine learning techniques could be helpful in this context.

Traumatic thoracic spine fracture: can we predict when MRI would modify the fracture classification or decision-making compared to CT alone?

PURPOSE

To determine the impact of magnetic resonance imaging (MRI) on fracture classification for thoracic spine fractures (TSFs) compared to computed tomography (CT) alone.

METHODS

This study was a retrospective review of 63 consecutive patients with TSFs who underwent CT and MRI within ten days of injury. Three reviewers classified all fractures according to the AOSpine Classification and the Thoracolumbar AOSpine Injury severity score (TLAOSIS). Posterior ligamentous complex (PLC) injury on MRI was defined by "black stripe discontinuity" and on 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 TLAOSIS ≤ 5 and ≥ 6 was compared between CT and MRI. Classification and regression trees were used to create a series of predictive models for the probability of PLC injury in AO type A fractures.

RESULTS

AO classification using CT was as follows: type A in 35 patients (55%), type B in 18 patients (29%), and type C in 10 patients (16%). Thirty-three patients (52%) had a TLAOSIS ≤5, while the remaining 30 (48%) had TLAOSI ≥6. The addition of MRI after CT upgraded type A to type B fractures in 10 patients (16%) and changed TL AOSIS from ≤5 to ≥6 in 8 cases (12.8%). Type A fractures with load sharing score (LSC) ≥6 had a 60% chance of upgrading to type B, while LSC <6 had a 12.5% chance of upgrading to type B.

CONCLUSIONS

CT yielded (89%) accuracy in diagnosing PLC injury in TSFs. The addition of MRI after CT substantially changed the AO classification or TLAOISS, compared to CT alone, thus suggesting an added value of MRI for PLC assessment for TSFs classification.

Inter-observational analysis of computed tomography parameters to predict nonobvious posterior ligament complex injury in neurologically intact patients with thoracolumbar trauma

Introduction

Assessing the integrity of the posterior ligament complex (PLC), as a key element in the characterization of an unstable Thoracolumbar fracture (TLF), is challenging, but crucial in the choice of treatment.

Research question

How to create a reproducible score using combined parameters of Computed Tomography (CT) to predict nonobvious PLC injury. How CT parameters relate with PLC status.

Material and methods

Retrospective analysis of neurologically intact patients with an acute traumatic TLF, who underwent CT and Magnetic Resonance Imaging (MRI) within 72 h, in the Emergency Department of a single institution between January 2016 and 2022. Four investigators rated independently 11 parameters on CT and PLC integrity on MRI. The interrater reliability of the CT parameters was evaluated, and two risk scores were created to predict PLC injury on CT using the coefficients of the multivariate logistic regression.

Results

154 patients were included, of which 62 with PLC injury. All CT measurements had excellent or good interrater reliability. Patients with Horizontal Fracture of the lamina or pedicle (HLPF), Spinous process fracture (SPF) and Interspinous Distance Widening (IDW) were positively associated with PLC injury (p < 0.001, p < 0.001 and p = 0.045, respectively). Risk Score 2 (RS2), which included only statistically significant variables, had a total of 75.9% of correct classifications (p < 0.001), with a sensitivity of 71.0% and specificity of 78.3% to estimate PLC injury detected in the MRI.

Discussion and conclusion

Standardized procedures pre-established in the CT measurement protocol were effective. Identically to early findings, those three CT measurements showed a positive relation to PLC injury, thus enhancing the conclusions of previous studies. Comparing to the reliability of the CT findings above mentioned, the score was less precise.

Thoracic and Lumbar Spine Injury: Evidence-Based Diagnosis, Management, and Outcomes

BACKGROUND

Traumatic thoracolumbar spine injuries are associated with significant morbidity and mortality. Targeted for non-spine specialist trauma surgeons, this systematic scoping review aimed to examine literature for up-to-date evidence on presentation, management, and outcomes of thoracolumbar spine injuries in adult trauma patients.

METHODS

This review was reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. We searched four bibliographic databases: PubMed, EMBASE, Web of Science, and the Cochrane Library. Eligible studies included experimental, observational, and evidence-synthesis articles evaluating patients with thoracic, lumbar, or thoracolumbar spine injury, published in English between January 1, 2010 and January 31, 2021. Studies which focused on animals, cadavers, cohorts with N <30, and pediatric cohorts (age <18 years old), as well as case studies, abstracts, and commentaries were excluded.

RESULTS

A total of 2501 studies were screened, of which 326 unique studies were fully text reviewed and twelve aspects of injury management were identified and discussed: injury patterns, determination of injury status and imaging options, considerations in management, and patient quality of life. We found: (1) imaging is a necessary diagnostic tool, (2) no consensus exists for preferred injury characterization scoring systems, (3) operative management should be considered for unstable fractures, decompression, and deformity, and (4) certain patients experience significant burden following injury.

DISCUSSION

In this systematic scoping review, we present the most up-to-date information regarding the management of traumatic thoracolumbar spine injuries. This allows non-specialist trauma surgeons to become more familiar with thoracolumbar spine injuries in trauma patients and provides a framework for their management.

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.

The Influence of Comminution and Posterior Ligamentous Complex Integrity on Treatment Decision Making in Thoracolumbar Burst Fractures Without Neurologic Deficit?

STUDY DESIGN

A prospective study.

OBJECTIVE

to evaluate the impact of vertebral body comminution and Posterior Ligamentous Complex (PLC) integrity on the treatment recommendations of thoracolumbar fractures among an expert panel of 22 spine surgeons.

METHODS

A review of 183 prospectively collected thoracolumbar burst fracture computed tomography (CT) scans by an expert panel of 22 trauma spine surgeons to assess vertebral body comminution and PLC integrity. This study is a sub-study of a prospective observational study of thoracolumbar burst fractures (Spine TL A3/A4). Each expert was asked to grade the degree of comminution and certainty about the PLC disruption from 0 to 100, with 0 representing the intact vertebral body or intact PLC and 100 representing complete comminution or complete PLC disruption, respectively.

RESULTS

≥45% comminution had a 74% chance of having surgery recommended, while <25% comminution had an 86.3% chance of non-surgical treatment. A comminution from 25 to 45% had a 57% chance of non-surgical management. ≥55% PLC injury certainity had a 97% chance of having surgery, and ≥45-55% PLC injury certainty had a 65%. <20% PLC injury had a 64% chance of having non-operative treatment. A 20 to 45% PLC injury certainity had a 56% chance of non-surgical management. There was fair inter-rater agreement on the degree of comminution (ICC .57 [95% CI 0.52-.63]) and the PLC integrity (ICC .42 [95% CI 0.37-.48]).

CONCLUSION

The study concludes that vetebral comminution and PLC integrity are major dterminant in decision making of thoracolumbar fractures without neurological deficit. However, more objective, reliable, and accurate methods of assessment of these variables are warranted.

Predictive Algorithm for Surgery Recommendation in Thoracolumbar Burst Fractures Without Neurological Deficits

STUDY DESIGN

Predictive algorithm via decision tree.

OBJECTIVES

Artificial intelligence (AI) remain an emerging field and have not previously been used to guide therapeutic decision making in thoracolumbar burst fractures. Building such models may reduce the variability in treatment recommendations. The goal of this study was to build a mathematical prediction rule based upon radiographic variables to guide treatment decisions.

METHODS

Twenty-two surgeons from the AO Knowledge Forum Trauma reviewed 183 cases from the Spine TL A3/A4 prospective study (classification, degree of certainty of posterior ligamentous complex (PLC) injury, use of M1 modifier, degree of comminution, treatment recommendation). Reviewers' regions were classified as Europe, North/South America and Asia. Classification and regression trees were used to create models that would predict the treatment recommendation based upon radiographic variables. We applied the decision tree model which accounts for the possibility of non-normal distributions of data. Cross-validation technique as used to validate the multivariable analyses.

RESULTS

The accuracy of the model was excellent at 82.4%. Variables included in the algorithm were certainty of PLC injury (%), degree of comminution (%), the use of M1 modifier and geographical regions. The algorithm showed that if a patient has a certainty of PLC injury over 57.5%, then there is a 97.0% chance of receiving surgery. If certainty of PLC injury was low and comminution was above 37.5%, a patient had 74.2% chance of receiving surgery in Europe and Asia vs 22.7% chance in North/South America. Throughout the algorithm, the use of the M1 modifier increased the probability of receiving surgery by 21.4% on average.

CONCLUSION

This study presents a predictive analytic algorithm to guide decision-making in the treatment of thoracolumbar burst fractures without neurological deficits. PLC injury assessment over 57.5% was highly predictive of receiving surgery (97.0%). A high degree of comminution resulted in a higher chance of receiving surgery in Europe or Asia vs North/South America. Future studies could include clinical and other variables to enhance predictive ability or use machine learning for outcomes prediction in thoracolumbar burst fractures.

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.

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.

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.

Analysis of the Combined Computed Tomography Findings Improves the Accuracy of Computed Tomography for Detecting Posterior Ligamentous Complex Injury of the Thoracolumbar Spine as Defined by Magnetic Resonance Imaging

OBJECTIVE

To determine the diagnostic accuracy of combined computed tomography (CT) findings for detecting posterior ligamentous complex (PLC) injury in thoracolumbar fractures using magnetic resonance imaging as a reference.

METHODS

A retrospective review of 263 consecutive patients with thoracolumbar fractures who underwent CT and magnetic resonance imaging within 10 days of injury. Two reviewers evaluated CT for the following findings: facet joint malalignment, facet joint widening, horizontal laminar fracture, spinous process fracture, and interspinous widening. We examined the independent association of CT findings with PLC injury before combining the CT findings to calculate the diagnostic accuracy: sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), and positive and negative likelihood ratios. PLC injury was defined by black stripe discontinuity caused by supraspinous or ligamentum flavum rupture.

RESULTS

Facet joint malalignment, spinous process fracture, horizontal laminar fracture, and interspinous widening were independently associated with PLC injury (adjusted odds ratio range, 4.4e17.4). A single positive CT finding yielded a PPV of 31% and NPV of 66% for PLC injury. Two or more CT findings yielded a PPV of 91% for PLC injury. A negative CT for all the 4 CT sings had a 94% NPV for PLC injury.

CONCLUSIONS

Two or more CT findings provided the best combination to confirm PLC injury; thus, this combination could be used as a criterion for injured PLC. A single CT finding lacks sufficient predictive value to confirm or rule out PLC injury. A negative CT for the 4 CT findings provided the highest sensitivity for PLC injuries.