Against the odds: extraordinary recovery from complete cauda equina syndrome following L3 fracture. Time still matters

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.

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.