CHANDLER, Arizona. (EGMN) – Computed tomography alone is safe for cervical spine clearance in obtunded blunt trauma patients with gross extremity movement, according to the authors of a prospective, uncontrolled study of 197 patients.
No patient had a missed cervical spinal cord injury or neurologic sequelae as a result of a missed cervical spine injury, Dr. William H. Leukhardt said at the annual meeting of the Eastern Association for the Surgery of Trauma.
Although MRI is widely used to exclude ligamentous and spinal cord injuries that computed tomography (CT) may fail to detect, the optimal method to clear the cervical spine in obtunded blunt trauma patients is not established. MRI is accurate, but is associated with increased costs and exposes unstable patients to risks during transport and acquisition, said Dr. Leukhardt, a general surgery resident with MetroHealth Medical Center in Cleveland. Indeed, the death of a patient during MRI prompted the level I trauma center to change its protocol to eliminate routine MRIs in obtunded patients with blunt trauma.
The use of CT alone in the study was also associated with earlier removal of cervical collars, fewer complications, and shorter hospital stay when compared with a previous study by the same group in a similar cohort who underwent MRI in addition to CT to clear the cervical spine (J. Trauma 2007;63:544-9).
The study launched a fiery debate at the meeting over whether the use of CT alone could put patients at risk of a catastrophic injury because of missed fractures or undiagnosed ligamentous spine injuries. Autopsies performed in 22 of the 53 overall deaths revealed no cervical spine fractures, though one patient did have an isolated C5-C6 ligament injury, a rupture of the anterior longitudinal ligament.
Invited discussant Dr. Marie Crandall, an assistant professor of surgery and preventive medicine at Northwestern University in Chicago, called the study “wildly underpowered to inform your decision to take off C-collars.” She said that at least 600 patients would be needed to find no harm with the CT-only protocol.
While acknowledging that MRIs are costly, Dr. Crandall said there are other lower-cost alternatives for the detection of ligamentous injury such as fluorographic flexion-extension studies or simply keeping patients in C-collars for 6 weeks.
“The first-year costs of the care of the spinal cord injury patient range from $200,000 to $400,000 for a quadriplegic,” she said. “You’d have to do a heck of a lot of MRIs in 1 year to equal those costs.”
The public costs associated with missing a ligamentous injury that results in quadriplegia could be enormous, she added, noting the backlash that arose last year when the U.S. Preventive Services Task Force recommended against routine mammograms for women younger than 50 years.
Dr. Leukhardt responded that the study included only patients with gross movement in all four extremities and excluded those with limited movement or neurologic deficits. A case involving para- or quadriplegia or neurologic deficits from a missed injury would be tragic, he said. “However, we have sufficient evidence from what we’ve found so far and reason to believe this is doing the most good for the most number of patients.”
Dr. John Como, the study’s principal investigator, said in an interview that it is not necessary to have MRIs performed on all patients and that the one ligamentous injury identified in the study was deemed to be a stable injury that did not require immobilization.
Dr. Leukhardt also said that the complications of MRI cannot be understated; there have been reports of increased intracranial pressure, and patients have coded during MRI when they were a long way from a critical care unit.
“I believe CT is a safe practice, and in this population it is reasonable to use MRI only in patients where it is indicated,” he said.
Dr. Samir Fakhry, an audience member, said that all cervical spine studies, including the current one, have failed to determine just how many missed injuries are acceptable to the medical community and society. “That number is out there, and it isn’t zero,” he said.
He agreed with Dr. Crandall about the danger of causing a potentially irreversible spinal injury in patients cleared by CT alone.
“We have a technology that we are betting a patient’s life on, and it’s not infallible,” said Dr. Fakhry, professor and chief of general surgery at the Medical Center of South Carolina in Charleston.
CT scans in the current study were obtained using a 16- or 64-slice scanner, and were all negative for an acute injury according to the attending radiologist. Cervical spine injury was defined by a fracture line extending on two consecutive cuts, marked prevertebral soft-tissue swelling or hematoma, malalignment not explained by degenerative changes, abnormal facets or posterior malalignment on sagittal reconstruction, and occipital condyle injury involving the craniocervical junction.
The patients had their cervical spines cleared and cervical collars removed at a mean of 3.3 days (range 0-15), significantly earlier than the 7.5 days reported in the previous study, Dr. Leukhardt said.
There was a 90% reduction in the occurrence of cervical spine decubitus ulcers, from 5.2% in the previous cohort to 0.5%. Hospital length of stay also decreased significantly from a mean of 23.4 days under the old protocol to 13.8 days. The difference in hospital stay was not attributable entirely to the change in spinal clearance protocol, but could also reflect differences in the populations not accounted for by age, gender, or injury severity, he said.
The mean age of the patients was 47.7 years in the current cohort vs. 43.9 years in the previous cohort; males composed 73% vs. 78% of the respective cohorts; and the mean Injury Severity Scores were 23.2 vs. 24.4.
Overall, 62% of the current patients were re-examined when awake and found to have no cervical spine symptoms or motor dysfunction in their extremities. A total of 13% died before reexamination, 12% were followed up by telephone or chart review, and 2% had persistent symptoms for which an MRI was negative for injury. The remaining 11% were lost to follow-up, although none of those patients contacted the hospital to report a subsequent deterioration in function, Dr. Leukhardt said.
He acknowledged that the study was limited by the lack of uniformity of longitudinal follow-up, lack of physician follow-up in some patients, and loss of some patients to follow-up.
Dr. Leukhardt and his colleagues disclosed no study sponsorship or relevant conflicts of interest.
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