Melvin T. Alexander

Optimization of Selection for Nonoperative Management of Blunt Splenic Injury: Comparison of MDCT Grading Systems

OBJECTIVE The purpose of this study was to compare the usefulness of two CT grading systems of blunt splenic trauma in predicting which patients need surgery or angioembolization. MATERIALS AND METHODS Four hundred patients in hemodynamically stable condition admitted with blunt splenic injury were included in the study. All patients underwent contrast-enhanced MDCT. Grade of splenic injury was prospectively assigned according to the American Association for the Surgery of Trauma (AAST) splenic injury scale. Patients were treated with surgical intervention, splenic arteriography with or without embolization, or observation alone. All MDCT images were retrospectively reviewed and regraded according to a novel grading system that specifically incorporates the findings of active bleeding or splenic vascular injury, including pseudoaneurysm and arteriovenous fistula. Receiver operating characteristics curves were generated with both grading systems for all splenic interventions, and statistical analyses were performed. RESULTS The area under the ROC curves for the new splenic grading system for splenic arteriography, surgery, and both interventions exceeded 80%. The area under the curve for the new splenic grading system was greater than that for the AAST injury scale for all interventions. Differences were found to be statistically significant for splenic arteriography (p = 0.0036) and the combination of arteriography and surgery (p = 0.0006). CONCLUSION The proposed CT grading system is better than the AAST system for predicting which patients with blunt splenic trauma need arteriography or splenic intervention.

Dynamics of subdural hygroma following decompressive craniectomy: a comparative study

OBJECT This retrospective comparative cohort study was aimed at discovering the risk factors associated with subdural hygroma (SDG) following decompressive craniectomy (DC) to relieve intracranial hypertension in severe head injury. METHODS Sixty-eight of 104 patients who had undergone DC during a 48-month period and survived > 30 days were eligible for this study. To assess the dynamics of subdural fluid collections, the authors compared CT scanning data from and the characteristics of 39 patients who had SDGs with the data in 29 patients who did not have hygromas. Variables significant in the appearance, evolution, and resolution of this complication were analyzed in a 36-week longitudinal study. RESULTS The earliest imaging evidence of SDG was seen during the 1st week after DC. The SDG volume peaked between Weeks 3 and 4 post-DC and was gradually resolved by the 17th week. Among the mechanisms of injury, motor vehicle accidents were most often linked to the development of an SDG after DC (p < 0.0007), and falls were least often associated (p < 0.005). Moreover, patients with diffuse brain injury were more prone to this complication (p < 0.0299) than those with an evacuated mass (p < 0.0001). There were no statistically significant differences between patients with and without hygromas in terms of age, sex, Glasgow Coma Scale score, intraventricular and subarachnoid hemorrhage, levels of intracranial pressure and cerebral perfusion pressure, timing of decompression, and the need for CSF diversion. More than 90% of the SDGs were ipsilateral to the side of the craniectomy, and 3 (8%) of 39 SDGs showed evidence of internal bleeding at approximately 8 weeks postinjury. Surgical evacuation was needed in 4 patients with SDGs. CONCLUSIONS High dynamic accidents and patients with diffuse injury were more prone to SDGs. Close to 8% of SDGs converted themselves into subdural hematomas at approximately 2 months postinjury. Although SDGs developed in 39 (approximately 60%) of 68 post-DC patients, surgical evacuation was needed in only 4.

Optimizing Trauma Multidetector CT Protocol for Blunt Splenic Injury: Need for Arterial and Portal Venous Phase Scans

PURPOSE To retrospectively compare the diagnostic performance of arterial, portal venous, and dual-phase computed tomography (CT) for blunt traumatic splenic injury. MATERIALS AND METHODS Informed consent was waived for this institutional review board-approved, HIPAA-compliant study. Retrospective record review identified 120 blunt trauma patients (87 male [72.5%] 33 female [27.5%]; age range, 18-94 years) who had undergone dual-phase abdominal CT within 5 years, including 30 without splenic injury, 30 with parenchymal injury only, 30 with splenic active bleeding, and 30 with intrasplenic pseudoaneurysm. Six radiologists each performed blinded review of 20 different cases, and scored the presence of pseudoaneurysm, active bleeding, parenchymal injury, and hematoma; 20 cases were interpreted by all radiologists. Data analysis included calculation of diagnostic performance measures with confidence intervals, areas under receiver operating characteristic curves, and interobserver agreement/variability. RESULTS For intrasplenic pseudoaneurysm, arterial phase imaging was more sensitive (70% [21 of 30] vs 17% [five of 30]; P < .0002) and more accurate (87% [78 of 90] vs 72% [65 of 90]; P = .0165) than portal venous phase imaging. For active bleeding, arterial phase imaging was less sensitive (70% [21 of 30] vs 93% [28 of 30]; P = .0195) and less accurate (89% [80 of 90] vs 98% [88 of 90]; P = .0168) than portal venous phase imaging. For parenchymal injury, arterial phase CT was less sensitive (76% [68 of 90] vs 93% [84 of 90]; P = .001) and less accurate (81% [nine of 120] vs 95% [114 of 120]; P = .0008) than portal venous phase CT. For all injuries, dual-phase review was equivalent to or better than single-phase review. CONCLUSION For CT evaluation of blunt splenic injury, arterial phase is superior to portal venous phase imaging for pseudoaneurysm but inferior for active bleeding and parenchymal disruption; dual-phase CT provides optimal overall performance.

Correlation of MR Diffusion Tensor Imaging Parameters with ASIA Motor Scores in Hemorrhagic and Nonhemorrhagic Acute Spinal Cord Injury

This study investigated correlations between American Spinal Injury Association (ASIA) clinical injury motor scores in patients with traumatic cervical cord injury and magnetic resonance (MR) diffusion tensor imaging (DTI) parameters. Conventional imaging and DTI were performed to evaluate 25 patients (age, 39.7±13.9 years; 4 women, 21 men) with blunt spinal cord injury and 11 volunteers (age, 31.5±10.7 years; 3 women, 8 men). Cord contusions were hemorrhagic (HC) in 13 and non-hemorrhagic (NHC) in 12 patients. The spinal cord was divided into three regions to account for spatial and pathological variation in DTI parameters. Comparisons of regional and injury site mean diffusivity (MD), fractional anisotropy (FA), radial diffusivity ( λ(⊥)), and longitudinal diffusivity ( λ(‖)) were made with control subjects. ASIA motor scores were correlated with DTI using linear regression analysis. HC and NHC patients showed significant reduction (p<0.001) in MD and λ(‖) in all three regions. At the injury site, significant decreases in FA and λ(‖) were seen for both injury groups (p<0.001). λ(⊥) values were significantly increased only for patients with NHC (p<0.05). Significant reduction in FA and λ(‖) (p<0.0001) was observed at the whole cord level between the injured (NH and NHC) and control groups. Within the NHC group, strong correlations were observed between ASIA motor scores and average MD, FA, λ(⊥), and λ(‖) at the injury site. However, no correlation was observed within the HC group between any of the DTI parameters and ASIA motor scores. DTI parameters reflect the severity of spinal cord injury and correlate well with ASIA motor scores in patients with NHC.

Predictors of outcome in acute traumatic central cord syndrome due to spinal stenosis.

OBJECT the objective of this study was to elucidate the relationship between admission demographic data, validated injury severity measures on imaging studies, and clinical indicators on the American Spinal Injury Association (ASIA) motor score, Functional Independence Measure (FIM), manual dexterity, and dysesthetic pain at least 12 months after surgery for acute traumatic central cord syndrome (ATCCS) due to spinal stenosis. METHODS over a 100-month period (January 2000 to April 2008), of 211 patients treated for ATCCS, 59 cases were due to spinal stenosis, and these patients underwent surgical decompression. Five of these patients died, 2 were lost to follow-up, 10 were not eligible for the study, and the remaining 42 were followed for at least 12 months. RESULTS in the cohort of 42 patients, mean age was 58.3 years, 83% of the patients were men, and 52.4% of the accidents were due to falls. Mean admission ASIA motor score was 63.8 (upper extremities score, 25.8 and lower extremities score, 39.8), the spinal cord was most frequently compressed at skeletal segments C3-4 and C4-5 (71%), mean midsagittal diameter at the point of maximum compression was 5.6 mm, maximum canal compromise (MCC) was 50.5%, maximum spinal cord compression was 16.5%, and length of parenchymal damage on T2-weighted MR imaging was 29.4 mm. Time after injury until surgery was within 24 hours in 9 patients, 24-48 hours in 10 patients, and more than 48 hours in 23 patients. At the 1-year follow-up, the mean ASIA motor score was 94.1 (upper extremities score, 45.7 and lower extremities score, 47.6), FIM was 111.1, manual dexterity was 64.4% of baseline, and pain level was 3.5. Stepwise regression analysis of 10 independent variables indicated significant relationships between ASIA motor score at follow-up and admission ASIA motor score (p = 0.003), MCC (p = 0.02), and midsagittal diameter (p = 0.02); FIM and admission ASIA motor score (p = 0.03), MCC (p = 0.02), and age (p = 0.02); manual dexterity and admission ASIA motor score (p = 0.0002) and length of parenchymal damage on T2-weighted MR imaging (p = 0.002); and pain level and age (p = 0.02) and length of parenchymal lesion on T2-weighted MR imaging (p = 0.04). CONCLUSIONS the main indicators of long-term ASIA motor score, FIM, manual dexterity, and dysesthetic pain were admission ASIA motor score, midsagittal diameter, MCC, length of parenchymal damage on T2-weighted MR imaging, and age, but different domains of outcome were determined by different predictors.

MDCT diagnosis of penetrating diaphragm injury.

The purpose of the study was to determine the diagnostic sensitivity and specificity of multidetector CT (MDCT) in detection of diaphragmatic injury following penetrating trauma. Chest and abdominal CT examinations performed preoperatively in 136 patients after penetrating trauma to the torso with injury trajectory in close proximity to the diaphragm were reviewed by radiologists unaware of surgical findings. Signs associated with diaphragmatic injuries in penetrating trauma were noted. These signs were correlated with surgical diagnoses, and their sensitivity and specificity in assisting the diagnosis were calculated. CT confirmed diaphragmatic injury in 41 of 47 injuries (sensitivity, 87.2%), and an intact diaphragm in 71 of 98 patients (specificity, 72.4%). The overall accuracy of MDCT was 77%. The most accurate sign helping the diagnosis was contiguous injury on either side of the diaphragm in single-entry penetrating trauma (sensitivity, 88%; specificity, 82%). Thus MDCT has high sensitivity and good specificity in detecting penetrating diaphragmatic injuries.

Predictors of pulmonary complications in blunt traumatic spinal cord injury

OBJECT Pulmonary complications are the most common acute systemic adverse events following spinal cord injury (SCI), and contribute to morbidity, mortality, and increased length of hospital stay (LOS). Identification of factors associated with pulmonary complications would be of value in prevention and acute care management. Predictors of pulmonary complications after SCI and their effect on neurological recovery were prospectively studied between 2005 and 2009 at the 9 hospitals in the North American Clinical Trials Network (NACTN). METHODS The authors sought to address 2 specific aims: 1) define and analyze the predictors of moderate and severe pulmonary complications following SCI; and 2) investigate whether pulmonary complications negatively affected the American Spinal Injury Association (ASIA) Impairment Scale conversion rate of patients with SCI. The NACTN registry of the demographic data, neurological findings, imaging studies, and acute hospitalization duration of patients with SCI was used to analyze the incidence and severity of pulmonary complications in 109 patients with early MR imaging and long-term follow-up (mean 9.5 months). Univariate and Bayesian logistic regression analyses were used to analyze the data. RESULTS In this study, 86 patients were male, and the mean age was 43 years. The causes of injury were motor vehicle accidents and falls in 80 patients. The SCI segmental level was in the cervical, thoracic, and conus medullaris regions in 87, 14, and 8 patients, respectively. Sixty-four patients were neurologically motor complete at the time of admission. The authors encountered 87 complications in 51 patients: ventilator-dependent respiratory failure (26); pneumonia (25); pleural effusion (17); acute lung injury (6); lobar collapse (4); pneumothorax (4); pulmonary embolism (2); hemothorax (2), and mucus plug (1). Univariate analysis indicated associations between pulmonary complications and younger age, sports injuries, ASIA Impairment Scale grade, ascending neurological level, and lesion length on the MRI studies at admission. Bayesian logistic regression indicated a significant relationship between pulmonary complications and ASIA Impairment Scale Grades A (p = 0.0002) and B (p = 0.04) at admission. Pulmonary complications did not affect long-term conversion of ASIA Impairment Scale grades. CONCLUSIONS The ASIA Impairment Scale grade was the fundamental clinical entity predicting pulmonary complications. Although pulmonary complications significantly increased LOS, they did not increase mortality rates and did not adversely affect the rate of conversion to a better ASIA Impairment Scale grade in patients with SCI. Maximum canal compromise, maximum spinal cord compression, and Acute Physiology and Chronic Health Evaluation-II score had no relationship to pulmonary complications.

Deaths among Drivers and Right-Front Passengers in Frontal Collisions: Redesigned Air Bags Relative to First-Generation Air Bags

Objective. After automakers were allowed the option of using sled tests for unbelted male dummies to certify the frontal crash performance of vehicles, most frontal air bags were depowered, starting in model year 1998, to reduce deaths and serious injuries arising from air bag deployments. Concern has been expressed that depowering air bags could compromise the protection of adult occupants. This study aimed to determine the effects of changes in air bag designs on risk of death among front-seat occupants. Methods. Deaths among drivers and right-front passengers per involvement in frontal police-reported crashes during calendar years 1998–2004 were compared among vehicles with sled-certified air bags (model years 1998–2004) and first-generation air bags (model years 1994–97). Frontal crash deaths were identified from the Fatality Analysis Reporting System. National estimates of police-reported crashes were derived from the National Automotive Sampling System/General Estimates System. Sled certification status for model years 1998–2004 was ascertained from published federal data and a survey of automobile manufacturers. Passenger cars, pickup trucks, sport utility vehicles, and minivans were studied. Stratified analyses were done to compute risk ratios (RR) and 95% confidence intervals (95% CI) for driver and right-front passenger deaths by air bag generation and crash, vehicle, and driver characteristics. Results. In frontal crashes, overall RRs were 0.89 for driver deaths (95% CI = 0.74–1.08) and 0.89 for right-front passenger deaths (95% CI = 0.74–1.07) in sled-certified vehicles compared with first-generation air bag–equipped vehicles. Child right-front passengers (ages 0–4, 5–9) in vehicles with sled-certified air bags had statistically significant reductions in risk of dying in frontal collisions, including a 65% reduced risk among ages 0–4 (RR = 0.35; 95% CI = 0.21–0.60). No differences in effects of sled-certified air bags were observed between drivers ages 15–59 and 60–74 in sled-certified vehicles, both of whom had RRs slightly below 0.90 (non-significant). Among occupants killed in sled-certified vehicles, police-reported belt use was somewhat higher than in first-generation vehicles. Conclusions. No differences in risk of frontal crash deaths were observed between adult occupants with sled-certified and first-generation air bags. Consistent with reports of decreases in air bag–related deaths, this study observed significant reductions in frontal deaths among child passengers seated in the right-front position in sled-certified vehicles. Higher restraint use rates among children in sled-certified vehicles and other vehicle design changes might have contributed partially to these reductions.

Diagnostic Determinants of Craniocervical Distraction Injury in Adults

OBJECTIVE Craniocervical distraction injury is a class of injuries that involve the skull base, the atlas, and the axis. Although these injuries often are overt imaging and clinical findings, the injury can be masked during unreliable physical examinations and difficult to identify during diagnostic imaging. The goal of this study was to identify on coronal and sagittal CT multiplanar reformations precise measurements and qualitative relations between anatomic landmarks that can help in establishing the diagnosis of craniocervical distraction injury. MATERIALS AND METHODS We performed a retrospective review of the cases of 35 patients with craniocervical distraction injury admitted to our trauma center from 2000 to 2006. Two independent radiologists made several qualitative and quantitative anatomic assessments on reformatted CT images through the craniocervical junctions (skull base through C2) of the 35 patients and of 50 other patients sustaining blunt trauma who were discharged without findings of cervical spinal injury. Logistic regression, recursive partitioning, and multivariate analysis were performed in an attempt to find measurements that differentiated the groups. RESULTS Among the patients with craniocervical distraction injury, statistically significant positive correlations were found in several measurements, including midline occiput-C1 spinolaminar distance (p=0.0016), midline C1-C2 spinolaminar distance (p<0.0001), basion-dens distance (p<0.0001), sum of condylar displacement (p=0.0002), and basion-posterior axial line distance (p<0.0001). CONCLUSION Several quantitative parameters on sagittal and coronal multiplanar CT reformations can be used to differentiate patients with craniocervical distraction injury from patients without this injury.

Intramedullary lesion expansion on magnetic resonance imaging in patients with motor complete cervical spinal cord injury

OBJECT The authors performed a study to determine if lesion expansion occurs in humans during the early hours after spinal cord injury (SCI), as has been established in rodent models of SCI, and to identify factors that might predict lesion expansion. METHODS The authors studied 42 patients with acute cervical SCI and admission American Spinal Injury Association Impairment Scale Grades A (35 patients) and B (7 patients) in whom 2 consecutive MRI scans were obtained 3-134 hours after trauma. They recorded demographic data, clinical information, Injury Severity Score (ISS), admission MRI-documented spinal canal and cord characteristics, and management strategies. RESULTS The characteristics of the cohort were as follows: male/female ratio 37:5; mean age, 34.6 years; and cause of injury, motor vehicle collision, falls, and sport injuries in 40 of 42 cases. The first MRI study was performed 6.8 ±2.7 hours (mean ± SD) after injury, and the second was performed 54.5 ± 32.3 hours after injury. The rostrocaudal intramedullary length of the lesion on the first MRI scan was 59.2 ± 16.1 mm, whereas its length on the second was 88.5 ± 31.9 mm. The principal factors associated with lesion length on the first MRI study were the time between injury and imaging (p = 0.05) and the time to decompression (p = 0.03). The lesions rate of rostrocaudal intramedullary expansion in the interval between the first and second MRI was 0.9 ± 0.8 mm/hour. The principal factors associated with the rate of expansion were the maximum spinal cord compression (p = 0.03) and the mechanism of injury (p = 0.05). CONCLUSIONS Spinal cord injury in humans is characterized by lesion expansion during the hours following trauma. Lesion expansion has a positive relationship with spinal cord compression and may be mitigated by early surgical decompression. Lesion expansion may be a novel surrogate measure by which to assess therapeutic effects in surgical or drug trials.