Patient Care

CT Scans Reliable Determinants of Blunt Trauma


 

NEW YORK - CT scans identify all clinically significant cervical spine injuries in intoxicated patients with blunt trauma, according to a new study.

"I don't think any of the results were particularly surprising to any of us who regularly do trauma care, but what I do think is remarkable about them is that they dispel several long-held myths about the c-spine, intoxicated patients, and the clearance process," Dr. Matthew J. Martin from Legacy Emanuel Medical Center, Portland, Oregon told Reuters Health.

"I think it again confirms that modern CT scan is highly reliable for identifying significant c-spine injuries, but also that the majority of so called 'intoxicated' patients are examinable enough to determine whether the collar can be removed (when combined with the CT scan)," he said.

Up to half of trauma patients are intoxicated, making clearance of the cervical spine a commonly encountered dilemma with both medical and medicolegal implications. Most guidelines indicate that the cervical spine should not be cleared in such patients, resulting in prolonged immobilization or additional imaging even in the face of a normal CT scan.

Dr. Martin's team examined cervical spine clearance practices for intoxicated trauma patients, examined the reliability of cervical spine CT scans for identifying clinically significant injuries (CSIs), and looked for CSIs that might have been missed by CT scans.

Among 1,429 patients who had an alcohol or drug screen performed, 44.2% were intoxicated, the researchers report in JAMA Surgery, online June 15.

Cervical spine injuries were identified in 11.3% of the sober group, 8.1% of the alcohol-intoxicated group, and 12.0% of the drug-intoxicated group.

CT scans yielded negative predictive values of 99.2% for all injuries and 99.8% for unstable injuries. There were five false-negative CT scans, including four central cord syndromes without associated fractures and one potentially unstable injury in a drug-intoxicated patient who presented with clear quadriplegia on examination.

Half of the intoxicated patients were admitted with continued cervical spine immobilization only on the basis of their intoxication. There were no missed CSIs in this group, and all patients were discharged without evidence of an injury or neurologic deficit. They underwent cervical spine immobilization for an average of 15.1 hours, about four times the average time to cervical spine clearance among sober patients (3.7 hours).

"The finding of how long we are keeping these patients in a c-collar based solely on intoxication should raise some eyebrows, and identifies an easy target for process improvement," Dr. Martin said.

"Cervical collars and immobilization are not therapeutic for the vast majority of c-spine injuries; they are really only to prevent inadvertent motion of an unstable c-spine injury," Dr. Martin said. "This is exceedingly rare in a patient who presents with no gross motor deficit, and a high quality CT scan will identify these unstable injuries very reliably. In addition, there are multiple adverse effects of prolonged immobilization, and even of getting an MRI."

"When these are factored in, I think the risk:benefit analysis falls squarely on the side of early clearance based on CT scan," he concluded.

"A key point is that this should be done by experts who are familiar with not only the global concept (the collar can be removed with a negative CT scan), but also the finer points where you could potentially cause harm, or where you should not remove the collar," Dr. Martin added. "This is where a very clear written protocol comes into play and reduces variation or errors that could cause patient harm."

"The results of this study suggest that it is unnecessary to delay cervical spine clearance until intoxicated patients are sober or until magnetic resonance imaging is performed," write Dr. Olubode A. Olufajo and Dr. Ali Salim from Brigham and Women's Hospital, Boston, in a related editorial. "However, caution must be taken in making conclusions based on these data."

"Although the authors conducted the study at an institution with high-quality CT technology and well-trained radiologists, they still recorded a false-negative CT report consistent with a misread," they note. "With the higher potential for this nature of error in lower-resourced settings, it becomes important to compare the costs and benefits of early removal of cervical collars."

They wonder, "With our knowledge that intoxicated patients form up to half of the population of trauma patients, is it really safe to risk irreversible injuries in 1% of the population to save a few hours in cervical clearance times?"

Dr. Stephen Asha from the University of New South Wales in Sydney, Australia, who has reported on various aspects of cervical spine imaging, told Reuters Health by email, "I think this study confirms what clinical experience as well as much of the more recent studies on cervical spine CT scanning tells us, which is that if there is nothing abnormal detected on a new generation, multi-slice CT, then the neck can be cleared."

"Of course there were a few missed injuries, but this needs to be put into context: no one just does a test in isolation, it is always combined with a clinical assessment, and a consideration the mechanism of injury," said Dr. Asha, who was not involved in the new work. "In this case there were five injuries not apparent on the CT scan, but all had obvious spinal cord injury on clinical examination before the CT was done, so these injuries were never going to be missed in a real clinical setting."

"MRI use should be carefully considered because the problem with MRI is that it can be over-sensitive, demonstrating abnormal signal suggesting ligamentous injury in patient who simply have a ligamentous 'strain,'" Dr. Asha explained. "The false-positive results then lead to further periods of inappropriate immobilization and testing, with the accompanying costs, inconvenience, and complications."

"In patients in whom the clinical assessment raises no concerns for injury, then a normal CT should herald the end of investigations," he said. "MRI should be reserved for those where the clinical assessment is abnormal or where the CT is abnormal and further evaluation for ligamentous or spinal injury is required."

Dr. Asha concluded, "If the clinical exam is not concerning and the CT is normal, then clear the neck."

SOURCE: http://bit.ly/28MxHxA and http://bit.ly/28MxHO5

JAMA Surg 2016.

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