Predictors of intramedullary lesion expansion rate on MR images of patients with subaxial spinal cord injury

MRI variables and peripheral inflammatory response biomarkers predict severity and prognosis in patients with acute cervical traumatic spinal cord injury

OBJECTIVE

Traumatic spinal cord injury (TSCI) stands as one of the most profoundly damaging and debilitating conditions. This study aims to explore the potential of magnetic resonance imaging (MRI) variables and peripheral inflammatory indicators as promising biomarkers. It aims to understand their significance in evaluating the severity and predicting the prognosis of TSCI. Furthermore, the study aims to ascertain whether combining these indicators could enhance the accuracy of injury assessment and predictive prognostic ability.

METHODS

A multicentre retrospective cohort study was conducted to assess the severity and prognostic value of MRI variables and peripheral inflammatory response biomarkers in patients with acute cervical TSCI. The study involved 374 patients with acute cervical TSCI drawn from the First Affiliated Hospital of Nanchang University and the Second Affiliated Hospital of Nanchang University. The severity and prognosis of patients with acute cervical TSCI were assessed using the American Spinal Injury Association Impairment Scale (AIS). The correlation between MRI variables, peripheral inflammatory response biomarkers, admission severity, and the 1-year follow-up prognosis was analysed.

RESULTS

After the initial assessment using the AIS grade system, 169 (49.2%) patients fell into the severe category for cervical TSCI (AIS A-B), while 205 (50.8%) patients were classified as non-severe cases (AIS C-E). The MRI variables (intramedullary lesion length [IMLL], Brain and Spinal Injury Centre [BASIC], maximum spinal cord compression [MSCC], and maximum canal compromise [MCC]) and inflammatory response biomarkers (white blood cells [WBCs], neutrophils, and C-reactive protein [CRP]) exhibited a consistent decrease correlating with the severity grades noted upon admission. Among the 374 patients assessed, 147 (39.3%) experienced a poor prognosis, as indicated by the AIS grade during the 1-year follow-up. MRI variables and peripheral inflammatory response biomarkers declined in correspondence with the follow-up AIS grades. Sex (p < 0.001), IMLL (p < 0.001), MSCC (p < 0.001), MCC (p < 0.001), BASIC (p < 0.001), WBC (p < 0.001), neutrophils (p < 0.001), and CRP (p < 0.001) were statistically significant in predicting poor outcomes. Through multivariate logistic regression analysis, BASIC score and CRP emerged as independent predictors of poor prognosis. Notably, the model combining the BASIC score and CRP yielded a larger area under the curve compared to models using only the BASIC score or CRP individually.

CONCLUSIONS

The BASIC score and CRP are crucial biomarkers for evaluating the severity of cervical TSCI and predicting prognosis. Their combination proved to be a more robust determinant of injury severity and a better predictor of neurological recovery.

Perfusion imaging metrics after acute traumatic spinal cord injury are associated with injury severity in rats and humans

Traumatic spinal cord injury (tSCI) causes an immediate loss of neurological function, and the prediction of recovery is difficult in the acute phase. In this study, we used contrast-enhanced ultrasound imaging to quantify intraspinal vascular disruption acutely after tSCI. In a rodent thoracic tSCI model, contrast-enhanced ultrasound revealed a perfusion area deficit that was positively correlated with injury severity and negatively correlated with hindlimb locomotor function at 8 weeks after injury. The spinal perfusion index was calculated by normalizing the contrast inflow at the injury center to the contrast inflow in the injury periphery. The spinal perfusion index decreased with increasing injury severity and positively correlated with hindlimb locomotor function at 8 weeks after injury. The feasibility of intraoperative contrast-enhanced ultrasound imaging was further tested in a cohort of 27 patients with acute tSCI of varying severity and including both motor-complete and motor-incomplete tSCIs. Both the perfusion area deficit and spinal perfusion index were different between motor-complete and motor-incomplete patients. Moreover, the perfusion area deficit and spinal perfusion index correlated with the injury severity at intake and exhibited a correlation with extent of functional recovery at 6 months. Our data suggest that intraoperative contrast-enhanced, ultrasound-derived metrics are correlated with injury severity and chronic functional outcome after tSCI. Larger clinical studies are required to better assess the reliability of the proposed contrast-enhanced ultrasound biomarkers and their prognostic capacity.

Advances and Challenges in Spinal Cord Injury Treatments

Spinal cord injury (SCI) is a debilitating condition that is associated with long-term physical and functional disability. Our understanding of the pathogenesis of SCI has evolved significantly over the past three decades. In parallel, significant advances have been made in optimizing the management of patients with SCI. Early surgical decompression, adequate bony decompression and expansile duraplasty are surgical strategies that may improve neurological and functional outcomes in patients with SCI. Furthermore, advances in the non-surgical management of SCI have been made, including optimization of hemodynamic management in the critical care setting. Several promising therapies have also been investigated in pre-clinical studies, with some being translated into clinical trials. Given the recent interest in advancing precision medicine, several investigations have been performed to delineate the role of imaging, cerebral spinal fluid (CSF) and serum biomarkers in predicting outcomes and curating individualized treatment plans for SCI patients. Finally, technological advancements in biomechanics and bioengineering have also found a role in SCI management in the form of neuromodulation and brain-computer interfaces.

Spinal cord injury: Current trends in acute management

Introduction

Traumatic spinal cord injury (tSCI) is a profoundly debilitating condition necessitating prompt intervention. However, the optimal acute treatment strategy remains a subject of debate.

Research question

The aim of this overview is to elucidate prevailing trends in the acute tSCI management.

Material and Methods

We provided an overview using peer-reviewed studies.

Results

Early surgical treatment (<24h after trauma) appears beneficial compared to delayed surgery. Nonetheless, there is insufficient evidence supporting a positive influence of ultra-early surgery on neurological outcome in tSCI. Furthermore, the optimal surgical approach to decompress the spinal cord remains unclear. These uncertainties extend to a growing aging population suffering from central cord syndrome (CCS). Additionally, there is a paucity of evidence supporting the beneficial effects of strict hemodynamic management.

Discussion and Conclusion

This overview highlights the current literature on surgical timing, surgical techniques and hemodynamic management during the acute phase of tSCI. It also delves into considerations specific to the elderly population experiencing CCS.

Early surgical intervention for acute spinal cord injury: time is spine

Acute traumatic spinal cord injury (tSCI) is a devastating occurrence that significantly contributes to global morbidity and mortality. Surgical decompression with stabilization is the most effective way to minimize the damaging sequelae that follow acute tSCI. In recent years, strong evidence has emerged that supports the rationale that early surgical intervention, within 24 h following the initial injury, is associated with a better prognosis and functional outcomes. In this review, we have summarized the evidence and elaborated on the nuances of this concept. Additionally, we have reviewed further concepts that stem from "time is spine," including earlier cutoffs less than 24 h and the challenging entity of central cord syndrome, as well as the emerging concept of adequate surgical decompression. Lastly, we identify barriers to early surgical care for acute tSCI, a key aspect of spine care that needs to be globally addressed via research and policy on an urgent basis.

Delirium Risk Score in Elderly Patients with Cervical Spinal Cord Injury and/or Cervical Fracture

The number of elderly patients with cervical trauma is increasing. Such patients are considered to be at high risk for delirium, which is an acute neuropsychological disorder that reduces the patient’s capacity to interact with their environment due to impairments in cognition. This study aimed to establish a risk score that predicts delirium in elderly patients with cervical SCI and/or cervical fracture regardless of treatment type. This retrospective cohort study included 1512 patients aged ≥65 years with cervical SCI and/or cervical fracture. The risk factors for delirium according to treatment type (surgical or conservative) were calculated using multivariate logistic regression. A delirium risk score was established as the simple arithmetic sum of points assigned to variables that were significant in the multivariate analyses. Based on the statistical results, the delirium risk score was defined using six factors: old age (≥80 years), hypoalbuminemia, cervical fracture, major organ injury, dependence on pre-injury mobility, and comorbid diabetes. The score’s area under the curve for the prediction of delirium was 0.66 (p < 0.001). Although the current scoring system must be validated with an independent dataset, the system remains beneficial because it can be used after screening examinations upon hospitalization and before deciding the treatment strategy.

Predicting the Role of Preoperative Intramedullary Lesion Length and Early Decompressive Surgery in ASIA Impairment Scale Grade Improvement Following Subaxial Traumatic Cervical Spinal Cord Injury

BACKGROUND

 Traumatic cervical spinal cord injury (TCSCI) is a disabling condition with uncertain neurologic recovery. Clinical and preclinical studies have suggested early surgical decompression and other measures of neuroprotection improve neurologic outcome. We investigated the role of intramedullary lesion length (IMLL) on preoperative magnetic resonance imaging (MRI) and the effect of early cervical decompressive surgery on ASIA impairment scale (AIS) grade improvement following TCSCI.

METHODS

 In this retrospective study, we investigated 34 TCSCI patients who were admitted over a 12-year period, from January 1, 2008 to January 31, 2020. We studied the patient demographics, mode of injury, IMLL and timing of surgical decompression. The IMLL is defined as the total length of edema and contusion/hemorrhage within the cord. Short tau inversion recovery (STIR) sequences or T2-weighted MR imaging with fat saturation increases the clarity of edema and depicts abnormalities in the spinal cord. All patients included had confirmed adequate spinal cord decompression with cervical fixation and a follow-up of at least 6 months.

RESULTS

 Of the 34 patients, 16 patients were operated on within 24 hours (early surgery group) and 18 patients were operated on more than 24 hours after trauma (delayed surgery group). In the early surgery group, 13 (81.3%) patients had improvement of at least one AIS grade, whereas in the delayed surgery group, AIS grade improvement was seen in only in 8 (44.5%) patients (early vs. late surgery; odds ratio [OR] = 1.828; 95% confidence interval [CI]: 1.036-3.225). In multivariate regression analysis coefficients, the timing of surgery and intramedullary edema length on MRI were the most significant factors in improving the AIS grade following cervical SCI. Timing of surgery as a unique variance predicted AIS grade improvement significantly (p < 0.001). The mean IMLL was 41.47 mm (standard deviation [SD]: 18.35; range: 20-87 mm). IMLL was a predictor of AIS grade improvement on long-term outcome in bivariate analysis (p < 0.001). This study suggests that patients who had IMLL of less than 30 mm had a better chance of grade conversion irrespective of the timing of surgery. Patients with an IMLL of 31 to 60 mm had chances of better grade conversion after early surgery. A longer IMLL predicts lack of improvement (p < 0.05). If the IMLL is greater than 61 mm, the probability of nonconversion of AIS grade is higher, even if the patient is operated on within 24 hours of trauma.

CONCLUSION

 Surgical decompression within 24 hours of trauma and shorter preoperative IMLL are significantly associated with improved neurologic outcome, reflected by better AIS grade improvement at 6 months' follow-up. The IMLL on preoperative MRI can reliably predict outcome after 6 months. The present study suggests that patients have lesser chances of AIS grade improvement when the IMLL is ≥61 mm.

Surgical Decompression of Traumatic Cervical Spinal Cord Injury: A Pilot Study Comparing Real-Time Intraoperative Ultrasound After Laminectomy With Postoperative MRI and CT Myelography

BACKGROUND

Decompression of the injured spinal cord confers neuroprotection. Compared with timing of surgery, verification of surgical decompression is understudied.

OBJECTIVE

To compare the judgment of cervical spinal cord decompression using real-time intraoperative ultrasound (IOUS) following laminectomy with postoperative MRI and CT myelography.

METHODS

Fifty-one patients were retrospectively reviewed. Completeness of decompression was evaluated by real-time IOUS and compared with postoperative MRI (47 cases) and CT myelography (4 cases).

RESULTS

Five cases (9.8%) underwent additional laminectomy after initial IOUS evaluation to yield a final judgment of adequate decompression using IOUS in all 51 cases (100%). Postoperative MRI/CT myelography showed adequate decompression in 43 cases (84.31%). Six cases had insufficient bony decompression, of which 3 (50%) had cerebrospinal fluid effacement at >1 level. Two cases had severe circumferential intradural swelling despite adequate bony decompression. Between groups with and without adequate decompression on postoperative MRI/CT myelography, there were significant differences for American Spinal Injury Association motor score, American Spinal Injury Association Impairment Scale grade, AO Spine injury morphology, and intramedullary lesion length (IMLL). Multivariate analysis using stepwise variable selection and logistic regression showed that preoperative IMLL was the most significant predictor of inadequate decompression on postoperative imaging (P = .024).

CONCLUSION

Patients with severe clinical injury and large IMLL were more likely to have inadequate decompression on postoperative MRI/CT myelography. IOUS can serve as a supplement to postoperative MRI/CT myelography for the assessment of spinal cord decompression. However, further investigation, additional surgeon experience, and anticipation of prolonged swelling after surgery are required.

A Systematic Review of Scoring System Based on Magnetic Resonance Imaging Parameters to Predict Outcome in Cervical Spinal Cord Injury

Background

Magnetic resonance imaging (MRI) is a potential tool for the objective assessment of spinal cord injury (SCI) because it correlates well with the spatial and temporal extension of spinal cord pathology. This study aimed to systematically identify currently available scoring system based on MRI parameters, including measurement of the spinal cord lesion length in sagittal view (intramedullary lesion length (IMLL)) and morphology of the lesion in axial view (Brain and Spinal Injury Center (BASIC) score).

Methods

A systematic search was conducted using the PubMed/MEDLINE database for English-language studies with the keywords "cervical," "spinal cord injury," "scoring system," "scoring," "classification," and "magnetic resonance imaging" to systematically identify the scoring system based on MRI parameters. The main outcomes of interest are the scoring system's inter- and intraobserver reliabilities and its predictive accuracy of neurological outcome.

Results

After assessing the full text and applying the inclusion and exclusion criteria, 13 articles were found to be eligible. The inter- and intraobserver reliabilities were rated as good until perfect for increased signal intensity (ISI), maximum canal compromise (MCC), maximum spinal cord compression (MSCC), BASIC score, cord-canal-area ratio, space available for the cord, and the compression ratio. The weighted mean difference of IML between the group with converted ASIA Impairment Scale (AIS) grade and the group without conversion is 31.79 (I² =93%, P=0.008). The percentage of agreement between the initial BASIC score of 4 with AIS grade of A at follow-up is 100%.

Conclusions

Certain MRI parameters, including IML and BASIC score, have good reliability and correlate well with neurological outcome, making them candidates for building simple and objective scoring system for cervical SCI. Level of Evidence: 2A.

Quantifying Intraparenchymal Hemorrhage after Traumatic Spinal Cord Injury: A Review of Methodology

Intraparenchymal hemorrhage (IPH) after a traumatic injury has been associated with poor neurological outcomes. Although IPH may result from the initial mechanical trauma, the blood and its breakdown products have potentially deleterious effects. Further, the degree of IPH has been correlated with injury severity and the extent of subsequent recovery. Therefore, accurate evaluation and quantification of IPH following traumatic spinal cord injury (SCI) is important to define treatments' effects on IPH progression and secondary neuronal injury. Imaging modalities, such as magnetic resonance imaging (MRI) and ultrasound (US), have been explored by researchers for the detection and quantification of IPH following SCI. Both quantitative and semiquantitative MRI and US measurements have been applied to objectively assess IPH following SCI, but the optimal methods for doing so are not well established. Studies in animal SCI models (rodent and porcine) have explored US and histological techniques in evaluating SCI and have demonstrated the potential to detect and quantify IPH. Newer techniques using machine learning algorithms (such as convolutional neural networks [CNN]) have also been studied to calculate IPH volume and have yielded promising results. Despite long-standing recognition of the potential pathological significance of IPH within the spinal cord, quantifying IPH with MRI or US is a relatively new area of research. Further studies are warranted to investigate their potential use. Here, we review the different and emerging quantitative MRI, US, and histological approaches used to detect and quantify IPH following SCI.

Assessment of acute traumatic cervical spinal cord injury using conventional magnetic resonance imaging in combination with diffusion tensor imaging-tractography: a retrospective comparative study

PURPOSE

The application of conventional magnetic resonance imaging (MRI) in combination with diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) to diagnose acute traumatic cervical SCI has not been studied. This study explores the role of MRI with DTI-DTT in the diagnosis of acute traumatic cervical spinal cord injury (SCI).

METHODS

Thirty patients with acute traumatic cervical SCI underwent conventional MRI and DTI-DTT. Conventional MRI was used to detect the intramedullary lesion length (IMLL) and intramedullary hemorrhage length (IMHL). DTI was used to detect the spinal cord's fractional anisotropy (FA) and apparent diffusion coefficient value, and DTT detected the imaginary white matter fiber volume and the connection rates of fiber tractography (CRFT). Patients' neurological outcome was determined using the American Spinal Injury Association (ASIA) Impairment Scale (AIS) grades.

RESULTS

Patients were divided into group A (without AIS grade conversion) and group B (with AIS grade conversion). The IMLL and IMHL of group A were significantly higher than those of group B. The FA and CRFT of group A were significantly lower than those of group B. The final AIS grade was negatively correlated with the IMLL and IMHL, and positively correlated with the FA and CRFT. According to imaging features based on conventional MRI and DTI-DTT, we propose a novel classification and diagnostic procedure.

CONCLUSIONS

The combination of conventional MRI with DTI-DTT is a valid diagnostic approach for SCI. Lower IMLL and IMHL, and higher FA value and CRFT are linked to better neurological outcomes.

Correlation Analysis Between Magnetic Resonance Imaging-Based Anatomical Assessment and Behavioral Outcome in a Rat Contusion Model of Chronic Thoracic Spinal Cord Injury

Although plenty of evidences from preclinical studies have led to potential treatments for patients with spinal cord injury (SCI), the failure to translate promising preclinical findings into clinical advances has long puzzled researchers. Thus, a more reliable combination of anatomical assessment and behavioral testing is urgently needed to improve the translational worth of preclinical studies. To address this issue, the present study was designed to relate magnetic resonance imaging (MRI)-based anatomical assessment to behavioral outcome in a rat contusion model. Rats underwent contusion with three different heights to simulate various severities of SCI, and their locomotive functions were evaluated by the grid-walking test, Louisville swim scale (LSS), especially catwalk gait analysis system and basic testing, and Basso, Beattie, Bresnahan (BBB) score. The results showed that the lesion area (LA) is a better indicator for damage assessment compared with other parameters in sagittal T2-weighted MRI (T2WI). Although two samples are marked as outliers by the box plot analysis, LA correlated closely with all of the behavioral testing without ceiling effect and floor effect. Moreover, with a moderate severity of SCI in a contusion height of 25 mm, the smaller the LA of the spinal cord measured on sagittal T2WI the better the functional performance, the smaller the cavity region and glial scar, the more spared the myelin, the higher the volatility, and the thicker the bladder wall. We found that LA significantly related with behavior outcomes, which indicated that LA could be a proxy of damage assessment. The combination of sagittal T2WI and four types of behavioral testing can be used as a reliable scheme to evaluate the prognosis for preclinical studies of SCI.

The impact of surgical timing on motor level lowering in motor complete traumatic spinal cord injury patients

Patients with motor complete traumatic spinal cord injury (tSCI) have a low potential to recover ambulation. Motor level recovery, adjacent to the level of injury, could influence functional independency. This study addresses whether surgical timing influences motor level recovery in patients with sensorimotor complete (AIS A) and motor complete sensory incomplete (AIS B) tSCI. A retrospective cohort study was performed in the Netherlands in patients with motor complete tSCI (C2-L2), who consecutively underwent surgery between January 2010 and April 2020. Neurological examination was performed directly at presentation to the ER and at discharge from the rehabilitation facility. Motor level lowering, AIS grade and Upper and Lower Extremity Motor Score (UEMS and LEMS) recovery were calculated for patients who underwent early (<24h) and late (24h+) surgery. A total of 96 patients met the inclusion criteria. In the multivariate analysis late surgical decompression (24h+) was negatively associated with ≥1 motor level lowering and ≥2 AIS grade improvement (Odds Ratio (OR) 0.11 (95% CI: 0.01, 0.67) p=0.046, OR 0.06 (95% CI: 0.00, 047) p=0.030). The presence of sacral sparing (AIS B) at initial examination, and cervical level of the tSCI were associated with ≥1 motor level lowering. In addition, AOSpine C-type injuries were negatively associated with any type of neurological recovery, except motor level lowering. Although sensorimotor complete injuries as well as thoracolumbar injuries negatively influence neurological recovery, early surgical decompression (<24h) appears independently associated with enhanced neurological recovery in patients with traumatic spinal cord injury despite level and severity of injury.

MRI metrics at the epicenter of spinal cord injury are correlated with the stepping process in rhesus monkeys

Clinical evaluations of long-term outcomes in the early-stage spinal cord injury (SCI) focus on macroscopic motor performance and are limited in their prognostic precision. This study was designed to investigate the sensitivity of the magnetic resonance imaging (MRI) indexes to the data-driven gait process after SCI. Ten adult female rhesus monkeys were subjected to thoracic SCI. Kinematics-based gait examinations were performed at 1 (early stage) and 12 (chronic stage) months post-SCI. The proportion of stepping (PS) and gait stability (GS) were calculated as the outcome measures. MRI metrics, which were derived from structural imaging (spinal cord cross-sectional area, SCA) and diffusion tensor imaging (fractional anisotropy, FA; axial diffusivity, λ_//), were acquired in the early stage and compared with functional outcomes by using correlation analysis and stepwise multivariable linear regression. Residual tissue SCA at the injury epicenter and residual tissue FA/remote normal-like tissue FA were correlated with the early-stage PS and GS. The extent of lesion site λ_///residual tissue λ_// in the early stage after SCI was correlated with the chronic-stage GS. The ratios of lesion site λ_// to residual tissue λ_// and early-stage GS were predictive of the improvement in the PS at follow-up. Similarly, the ratios of lesion site λ_// to residual tissue λ_// and early-stage PS best predicted chronic GS recovery. Our findings demonstrate the predictive power of MRI combined with the early data-driven gait indexes for long-term outcomes. Such an approach may help clinicians to predict functional recovery accurately.

Traumatic cervical spinal cord injury: relationship of MRI findings to initial neurological impairment

PURPOSE

To quantify the degree of available space for the cord and cord swelling in patients following traumatic cervical spinal cord injury (TCSCI), and to assess the relationship among the available space for the cord, cord swelling, and the severity of neurological impairment.

METHODS

This study included 91 patients. The following indexes were measured by two blinded observers: maximum cord available area (CAA_max) and maximum cord swelling area (CSA_max). The American Spinal Injury Association (ASIA) impairment scale (AIS) grades were used to evaluate the extent of neurological injury. Relationship among CAA_max, CSA_max, and initial AIS grades was assessed via univariate and multivariate analyses.

RESULTS

Patients who were AIS grade A (complete injury) demonstrated significantly greater median CAA_max and CSA_max than AIS grade C or D (incomplete injury) (P < 0.01). Multivariate analysis identified only CAA_max (OR 20.88 [95% CI 1.50-291.21]; P = 0.024) and CSA_max (OR 17.84 [95% CI 1.15-276.56]; P = 0.039) were identified as independently influencing the likelihood of complete injury at the initial assessment. The classification accuracy was best for CAA_max and CSA_max; areas under the curve were 0.8998 (95% CI 0.7881-1.0000) and 0.9167 (95% CI 0.8293-1.0000), respectively.

CONCLUSION

The present study provides a novel radiologic method for identifying the severity of TCSCI with T2-weighted MRI findings. Greater available space for the cord (CAA_max > 38%) and cord swelling (CSA_max > 29%) can be used to identify patients at risk for TCSCI and both imaging characteristics are associated with an increased likelihood of severe neurological deficits.

LEVEL OF EVIDENCE

Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.

Diagnostic Imaging in Spinal Cord Injury

In the evaluation of spinal trauma, diagnostic imaging is of paramount importance. Computed tomography (CT), flexion/extension radiographs, and MRI are complementary modalities. CT is typically obtained in the initial setting of spinal trauma and provides detailed information about osseous structures. MRI provides detailed information about structural injury to the spinal cord. Diffusion tensor imaging provides microstructural information about the integrity of the axons and myelin sheaths, but its clinical use is limited. Novel imaging techniques may be better suited for the acute clinical setting and are under development for potential future clinical use.

Characterizing Natural Recovery after Traumatic Spinal Cord Injury

The predominant tool used to predict outcomes after traumatic spinal cord injury (SCI) is the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI), in association with the American Spinal Injury Association (ASIA) Impairment Scale (AIS). These measures have evolved based on analyses of large amounts of longitudinal neurological recovery data published in numerous separate studies. This article reviews and synthesizes published data on neurological recovery from multiple sources, only utilizing data in which the sacral sparing definition was applied for determination of completeness. Conversion from a complete to incomplete injury is more common in tetraplegia than paraplegia. The majority of AIS conversion and motor recovery occurs within the first 6-9 months, with the most rapid rate of motor recovery occurring in the first three months after injury. Motor score changes, as well as recovery of motor levels, are described with the initial strength of muscles as well as the levels of the motor zone of partial preservation influencing the prognosis. Total motor recovery is greater for patients with initial AIS B than AIS A, and greater after initial AIS C than with motor complete injuries. Older age has a negative impact on neurological and functional recovery after SCI; however, the specific age (whether >50 or >65 years) and underlying reasons for this impact are unclear. Penetrating injury is more likely to lead to a classification of a neurological complete injury compared with blunt trauma and reduces the likelihood of AIS conversion at one year. There are insufficient data to support gender having a major effect on neurological recovery after SCI.

Trends in Demographics and Markers of Injury Severity in Traumatic Cervical Spinal Cord Injury

Over the past four decades, there have been progressive changes in the epidemiology of traumatic spinal cord injury (tSCI). We assessed trends in demographic and injury-related variables in traumatic cervical spinal cord injury (tCSCI) patients over an 18-year period at a single Level I trauma center. We included all magnetic resonance imaging-confirmed tCSCI patients ≥15 years of age for years 2001-2018. Among 1420 patients, 78.3% were male with a mean age 51.5 years. Etiology included falls (46.9%), motor vehicle collisions (MVCs; 34.2%), and sports injuries (10.9%). Median American Spinal Injury Association (ASIA) Motor Score (AMS) was 44, complete tCSCI was noted in 29.6% of patients, fracture dislocations were noted in 44.7%, and median intramedullary lesion length (IMLL) was 30.8 mm (complete injuries 56.3 mm and incomplete injuries 27.4 mm). Over the study period, mean age and proportion of falls increased (p < 0.001) whereas proportion attributable to MVCs and sports injuries decreased (p < 0.001). Incomplete injuries, AMS, and the proportion of patients with no fracture dislocations increased whereas complete injuries decreased significantly. IMLL declined (p = 0.17) and proportion with hematomyelia did not change significantly. In adjusted regression models, increase in age and decreases in prevalence of MVC mechanism and complete injuries over time remained statistically significant. Changes in demographic and injury-related characteristics of tCSCI patients over time may help explain the observed improvement in outcomes. Further, improved clinical outcomes and drop in IMLL may reflect improvements in initial risk assessment and pre-hospital management, advances in healthcare delivery, and preventive measures including public education.

Efficacy of Ultra-Early (< 12 h), Early (12-24 h), and Late (>24-138.5 h) Surgery with Magnetic Resonance Imaging-Confirmed Decompression in American Spinal Injury Association Impairment Scale Grades A, B, and C Cervical Spinal Cord Injury

In cervical traumatic spinal cord injury (TSCI), the therapeutic effect of timing of surgery on neurological recovery remains uncertain. Additionally, the relationship between extent of decompression, imaging biomarker evidence of injury severity, and outcome is incompletely understood. We investigated the effect of timing of decompression on long-term neurological outcome in patients with complete spinal cord decompression confirmed on postoperative magnetic resonance imaging (MRI). American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade conversion was determined in 72 AIS grades A, B, and C patients 6 months after confirmed decompression. Thirty-two patients underwent decompressive surgery ultra-early (< 12 h), 25 underwent decompressive surgery early (12-24 h), and 15 underwent decompressive surgery late (> 24-138.5 h) after injury. Age, gender, injury mechanism, intramedullary lesion length (IMLL) on MRI, admission ASIA motor score, and surgical technique were not statistically different among groups. Motor complete patients (p = 0.009) and those with fracture dislocations (p = 0.01) tended to be operated on earlier. Improvement of one grade or more was present in 55.6% of AIS grade A, 60.9% of AIS grade B, and 86.4% of AIS grade C patients. Admission AIS motor score (p = 0.0004) and pre-operative IMLL (p = 0.00001) were the strongest predictors of neurological outcome. AIS grade improvement occurred in 65.6%, 60%, and 80% of patients who underwent decompression ultra-early, early, and late, respectively (p = 0.424). Multiple regression analysis revealed that IMLL was the only significant variable predictive of AIS grade conversion to a better grade (odds ratio, 0.908; confidence interval [CI], 0.862-0.957; p < 0.001). We conclude that in patients with post-operative MRI confirmation of complete decompression following cervical TSCI, pre-operative IMLL, not the timing of surgery, determines long-term neurological outcome.

Influence of Preoperative Magnetic Resonance Imaging on Surgical Decision Making for Patients with Acute Traumatic Cervical Spinal Cord Injury: A Survey Among Experienced Spine Surgeons

OBJECTIVE

Early decompression after acute spinal cord injury (SCI) is recommended. Acute care is crucial, but optimal management is unclear. The aim of this study was to investigate the role of preoperative magnetic resonance imaging (MRI) in addition to computed tomography (CT) in surgical decision making for acute cervical SCI.

METHODS

All patients with cervical SCI between 2008 and 2016 who had preoperative CT and MRI (n = 63) at the Trauma Center Murnau, Germany, were included. We administered a survey to 10 experienced spine surgeons (5 neurosurgeons, 5 trauma surgeons) regarding the surgical management. First, the surgeons were shown clinical information and CT scans. Two months later, the survey was repeated with additional MRI. Corresponding percentages of change and agreement were obtained for each rater and survey item. Finally, results from both parts of the survey were compared with the definitive treatment option (i.e., real-world decision).

RESULTS

MRI modified surgical timing in a median of 41% of patients (interquartile range 38%-56%). In almost every fifth patient (17%), no surgery would have been indicated with CT alone. The advocated surgical approach was changed in almost half of patients (median 48%, interquartile range 33%-49%). Surgically addressed levels were changed in a median of 57% of patients (interquartile range 56%-60%). MRI led to higher agreement with the real-world decision concerning addressed levels (median 35% vs. 73%), timing (median 51% vs. 57%), and approach (median 44% vs. 65%).

CONCLUSIONS

Preoperative MRI influenced surgical decision making substantially in our cohort and has become a new standard for patients with cervical SCI in our institution if medically possible.

AOSpine Subaxial Cervical Spine Injury Classification System: The Relationship Between Injury Morphology, Admission Injury Severity, and Long-Term Neurologic Outcome

OBJECTIVE

The AOSpine Subaxial Cervical Spine Injury Classification System was introduced to improve communication, clinical management, and research. Here, the system was studied in relation to injury severity along with admission and long term neurologic follow-up.

METHODS

A retrospective study was performed in subaxial cervical spine injury patients. Morphology was classified using the AOSpine Subaxial Cervical Spine Injury Classification System. Six major morphology subtypes were selected for analysis. The American Spinal Injury Association (ASIA) motor and Abbreviated Injury Severity (AIS) scores were recorded at admission and at follow-up >6 months. Admission intramedullary lesion length (IMLL) on MRI was recorded.

RESULTS

In all, 82 patients met criteria for analysis. The mean follow-up time was 11 months (range, 6-33 months). The were 36 patients with morphology subtypes A0, 4 with A1/A2, 9 with A3/A4, 8 with B2, 11 with B3, and 14 with C. The A1/2 subtype had the least severe injuries on admission. The C and A3/A4 subtypes had the most severe injuries. The subtype C had the lowest ASIA Motor Score (AMS) and second highest percentage of complete injuries. A3/A4 patients had the highest percentage of complete injuries on admission. At follow-up, A3/A4 patients had the lowest AMS, and 33% of patients continued to have complete injuries. C subtype injuries all converted to AIS incomplete injuries on follow-up (P = 0.04). IMLL was found to be significantly different compared across multiple morphologic subtypes. Surgical management for each morphology subtype was reported.

CONCLUSION

The AOSpine Subaxial Cervical Spine Injury Classification System successfully associated injury morphology with IMLL along with admission and long-term neurologic function and recovery.

Extent of Spinal Cord Decompression in Motor Complete (American Spinal Injury Association Impairment Scale Grades A and B) Traumatic Spinal Cord Injury Patients: Post-Operative Magnetic Resonance Imaging Analysis of Standard Operative Approaches

Although decompressive surgery following traumatic spinal cord injury (TSCI) is recommended, adequate surgical decompression is rarely verified via imaging. We utilized magnetic resonance imaging (MRI) to analyze the rate of spinal cord decompression after surgery. Pre-operative (within 8 h of injury) and post-operative (within 48 h of injury) MRI images of 184 motor complete patients (American Spinal Injury Association Impairment Scale [AIS] grade A = 119, AIS grade B = 65) were reviewed to verify spinal cord decompression. Decompression was defined as the presence of a patent subarachnoid space around a swollen spinal cord. Of the 184 patients, 100 (54.3%) underwent anterior cervical discectomy and fusion (ACDF), and 53 of them also underwent laminectomy. Of the 184 patients, 55 (29.9%) underwent anterior cervical corpectomy and fusion (ACCF), with (26 patients) or without (29 patients) laminectomy. Twenty-nine patients (16%) underwent stand-alone laminectomy. Decompression was verified in 121 patients (66%). The rates of decompression in patients who underwent ACDF and ACCF without laminectomy were 46.8% and 58.6%, respectively. Among these patients, performing a laminectomy increased the rate of decompression (72% and 73.1% of patients, respectively). Twenty-five of 29 (86.2%) patients who underwent a stand-alone laminectomy were found to be successfully decompressed. The rates of decompression among patients who underwent laminectomy at one, two, three, four, or five levels were 58.3%, 68%, 78%, 80%, and 100%, respectively (p < 0.001). In multi-variate logistic regression analysis, only laminectomy was significantly associated with successful decompression (odds ratio 4.85; 95% confidence interval 2.2-10.6; p < 0.001). In motor complete TSCI patients, performing a laminectomy significantly increased the rate of successful spinal cord decompression, independent of whether anterior surgery was performed.

Correlation of magnetic resonance diffusion tensor imaging parameters with American Spinal Injury Association score for prognostication and long-term outcomes

OBJECTIVE

Conventional MRI is routinely used to demonstrate the anatomical site of spinal cord injury (SCI). However, quantitative and qualitative imaging parameters have limited use in predicting neurological outcomes. Currently, there are no reliable neuroimaging biomarkers to predict short- and long-term outcome after SCI.

METHODS

A prospective cohort of 23 patients with SCI (19 with cervical SCI [CSCI] and 4 with thoracic SCI [TSCI]) treated between 2007 and 2014 was included in the study. The American Spinal Injury Association (ASIA) score was determined at the time of arrival and at 1-year follow-up. Only 15 patients (12 with CSCI and 3 with TSCI) had 1-year follow-up. Whole-cord fractional anisotropy (FA) was determined at C1–2, following which C1–2 was divided into upper, middle, and lower segments and the corresponding FA value at each of these segments was calculated. Correlation analysis was performed between FA and ASIA score at time of arrival and 1-year follow-up.

RESULTS

Correlation analysis showed a positive but nonsignificant correlation (p = 0.095) between FA and ASIA score for all patients (CSCI and TCSI) at the time of arrival. Additional regression analysis consisting of only patients with CSCI showed a significant correlation (p = 0.008) between FA and ASIA score at time of arrival as well as at 1-year follow-up (p = 0.025). Furthermore, in case of patients with CSCI, a significant correlation between FA value at each of the segments (upper, middle, and lower) of C1–2 and ASIA score at time of arrival was found (p = 0.017, p = 0.015, and p = 0.002, respectively).

CONCLUSIONS

In patients with CSCI, the measurement of diffusion anisotropy of the high cervical cord (C1–2) correlates significantly with injury severity and long-term follow-up. However, this correlation is not seen in patients with TSCI. Therefore, FA can be used as an imaging biomarker for evaluating neural injury and monitoring recovery in patients with CSCI.

Impact of Admission Imaging Findings on Neurological Outcomes in Acute Cervical Traumatic Spinal Cord Injury

Variable and unpredictable spontaneous recovery can occur after acute cervical traumatic spinal cord injury (tSCI). Despite the critical clinical and interventional trial planning implications of this tSCI feature, baseline measures to predict neurologic recovery accurately are not well defined. In this study, we used data derived from 99 consecutive patients (78 male, 21 female) with acute cervical tSCIs to assess the sensitivity and specificity of various clinical and radiological factors in predicting recovery at one year after injury. Categorical magnetic resonance imaging parameters included maximum canal compromise (MCC), maximum spinal cord compression (MSCC), longitudinal length of intramedullary lesion (IML), Brain and Spinal Injury Center (BASIC) score, and a novel derived Combined Axial and Sagittal Score (CASS). Logistic regression analysis of the area under the receiver operating characteristic curve (AUC) was applied to assess the differential predictive value of individual imaging markers. Admission American Spinal Injury Association Impairment Scale (AIS) grade, presence of a spinal fracture, and central cord syndrome were predictive of AIS conversion at one year. Both BASIC and IML were stronger predictors of AIS conversion compared with MCC and MSCC (p = 0.0002 and p = 0.04). The BASIC score demonstrated the highest overall predictive value for AIS conversion at one year (AUC 0.94). We conclude that admission intrinsic cord signal findings are robust predictive surrogate markers of neurologic recovery after cervical tSCI. Direct comparison of imaging parameters in this cohort of patients indicates that the BASIC score is the single best acute predictor of the likelihood of AIS conversion.

Intramedullary Lesion Length on Postoperative Magnetic Resonance Imaging is a Strong Predictor of ASIA Impairment Scale Grade Conversion Following Decompressive Surgery in Cervical Spinal Cord Injury

BACKGROUND

Evidence indicates that, over time, patients with spinal cord injury (SCI) improve neurologically in various degrees. We sought to further investigate indicators of grade conversion in cervical SCI.

OBJECTIVE

To detect predictors of ASIA impairment scale (AIS) grade conversion in SCI following surgical decompression.

METHODS

In a retrospective study, demographics, clinical, imaging, and surgical data from 100 consecutive patients were assessed for predictors of AIS grade conversion.

RESULTS

American Spinal Injury Association motor score was 17.1. AIS grade was A in 52%, B in 29%, and C in 19% of patients. Surgical decompression took place on an average of 17.6 h following trauma (≤12 h in 51 and >12 h in 49). Complete decompression was verified by magnetic resonance imaging (MRI) in 73 patients. Intramedullary lesion length (IMLL) on postoperative MRI measured 72.8 mm, and hemorrhage at the injury epicenter was noted in 71 patients. Grade conversion took place in 26.9% of AIS grade A patients, 65.5% of AIS grade B, and 78.9% of AIS grade C. AIS grade conversion had statistical relationship with injury severity score, admission AIS grade, extent of decompression, presence of intramedullary hemorrhage, American Spinal Injury Association motor score, and IMLL. A stepwise multiple logistic regression analysis indicated IMLL was the sole and strongest indicator of AIS grade conversion (odds ratio 0.950, 95% CI 0.931-0.969). For 1- and 10-mm increases in IMLL, the model indicates 4% and 40% decreases, respectively, in the odds of AIS grade conversion.

CONCLUSION

Compared with other surrogates, IMLL remained as the only predictor of AIS grade conversion.

Can the acute magnetic resonance imaging features reflect neurologic prognosis in patients with cervical spinal cord injury?

BACKGROUND CONTEXT

Several prognostic studies looked for an association between the degree of spinal cord injury (SCI), as depicted by primary magnetic resonance imaging (MRI) within 72 hours of injury, and neurologic outcome. It was not clearly demonstrated whether the MRI at any time correlates with neurologic prognosis.

PURPOSE

The purpose of the present study was to investigate the relationship between acute MRI features and neurologic prognosis, especially walking ability of patients with cervical spinal cord injury (CSCI). Moreover, at any point, MRI was clearly correlated with the patient's prognosis.

STUDY DESIGN

Retrospective image study.

PATIENT SAMPLE

From January 2010 to October 2015, 102 patients with CSCI were treated in our hospital. Patients who were admitted to our hospital within 3 days after injury were included in this study. The diagnosis was 78 patients for CSCI with no or minor bony injury and 24 patients for CSCI with fracture or dislocation. A total of 88 men and 14 women were recruited, and the mean patient age was 62.6 years (range, 16-86 years). Paralysis at the time of admission was graded as A in 32, B in 15, C in 42, and D in 13 patients on the basis of the American Spinal Injury Association (ASIA) impairment scale. Patients with CSCI with fracture or dislocation were treated with fixation surgery and those with CSCI with no or minor bony injury were treated conservatively. Patients were followed up for an average of 168 days (range, 25-496 days).

OUTCOME MEASURES

Neurologic evaluation was performed using the ASIA motor score and the modified Frankel grade at the time of admission and discharge.

METHODS

Magnetic resonance imaging was performed for all patients at admission. Using the MRI sagittal images, we measured the vertical diameter of intramedullary high-intensity changed area with T2-weighted images at the injured segment. We studied separately the patients divided into two groups: 0-1 day admission after injury, and 2-3 days admission after injury. We evaluated the relationship between the vertical diameter of T2 high-intensity changed area in MR images and neurologic outcome in these two groups. This study does not contain any conflict of interest.

RESULTS

In the group admitted at 0-1 day after injury, there was a relationship between the vertical diameter of T2 high-intensity area in MR image and the ASIA motor score at admission and at discharge, but correlation coefficient was low (0.3766 at admission and 0.4239 at discharge). On the other hand, in the group admitted at 2-3 days after injury, there was a significant relationship between the vertical diameter of T2 high-intensity area in MR image and the ASIA motor score at admission and at discharge, and correlation coefficient was very high (0.6840 at admission and 0.5293 at discharge). In the group admitted at 2-3 days after injury, a total of 17 patients (68%) recovered to walk with or without a cane. Receiver operating characteristic (ROC) curve analysis demonstrated that the optimal vertical diameter of T2 high-intensity area cutoffvalue for patients who were able to walk at discharge was 45.8 mm. If the vertical diameter of T2 high-intensity area cutoff value was 45 mm, there was a significant positive correlation with being able to walk at discharge (p<.0001).

CONCLUSIONS

From our study, 2-3 days after injury, a significant relationship was observed between the vertical diameter of T2 high-intensity area and the neurologic prognosis at discharge. Zero to 1 day after injury, the relationship between the vertical diameter of T2 high-intensity area and the neurologic prognosis at discharge was weak. Neurologic prognosis is more correlated with MRI after 2-3 days after the injury. If the vertical diameter of T2 high-intensity area was <45 mm, the patients were able to walk with or without a cane at discharge. T2 high-intensity changed area can reflect the neurologic prognosis in patients with CSCI.