Unrecognized or undertreated CS injury can lead to devastating consequences including quadriplegia, yet despite extensive study, there is still no consensus on the exact method of CS clearance after trauma . CT scans have become the standard of care in evaluating the CS in those for whom imaging is required . Providers face a dilemma when the CT scan shows no acute injury, but the clinical exam is unreliable, or the patient has persistent cervicalgia. There is considerable debate regarding the need for MRI to clear the CS in this situation. If we could identify a subset of trauma patients at lower risk for occult unstable CS injuries that clinicians would be more comfortable clearing both clinically and based on CT, we could potentially conserve resources and spare these patients the morbidity of prolonged immobilization.
GLF is a mechanism that is both very common and low force. GLF resulted in 2.1 million ED visits in the US in patients older than 65, a figure 10 times greater than that of motor vehicle crashes. 1 in 3 geriatric patients suffers a GLF each year . GLF are most common among the elderly. Patients in a recent study of spinal fractures due to falls from standing had an average age of 76.6 . In a study of GLF, one must consider not only the mechanism, but also the special characteristics of the typical elderly trauma patient when assessing a protocol for CS clearance.
While the forces involved in GLF are lower than those of MVC, the mechanism is not innocuous. Our data show that the Injury Severity Score (ISS) is significantly lower for GLF versus other types of trauma at 9.93 versus 12.19, but an ISS of nearly 10 still represents clinically important injury. The percent of patients with a CS injury was only slightly lower, with an absolute difference of just 1.2%. The incidence of fracture and cord injury were higher for GLF, and the incidence of central cord syndrome was over twice as high. This is consistent with other reports. In a study of ground level falls recorded in the National Trauma Data Bank, Spaniolas et al found a median ISS of 8 and a mortality of 3.2%. The mortality among those over 70 was 4.4% versus 1.6% for younger patients . Hall et al found an incidence of 229/1408 spine fractures due to falls from standing height. 140 of these were cervical. 43/229 (18.7%) of the spine fracture patients died . This shows that GLF is not a benign mechanism. The force of a ground level fall is sufficient to inflict serious injury, especially for older patients.
GLF patients may not always have a reliable clinical exam. Our group included 811 patients (23.1%) with GCS<15. In standard clinical practice, CS clearance would be delayed for most if not all of them. For the overall trauma population, there is disagreement regarding whether a high-quality CT scan is sufficient to rule out unstable CS injury in the absence of a reliable clinical exam, or in a patient with cervicalgia. Some studies show that a negative CT is sufficient. Inaba et al performed a multi-institutional prospective trial of 10,276 patients who could not be cleared clinically due to unreliable exam, CS tenderness, or neurologic symptoms. There were 3 false negative CT scans, which yielded an NPV of 99.97% for clinically significant injuries. These 3 patients had acute neurologic deficits, thus the combination of normal neurologic exam and negative CT resulted in an NPV of 100% .
In a systematic review forming the basis of the 2015 Eastern Trauma Association guidelines for the clearance of the CS in obtunded patients, 1017 obtunded patients in 5 studies showed no neurologic change after collar removal based on negative CT. 1718 patients in 11 studies showed 161 (9%) stable injuries with no unstable CS injury. NPV was 91% for stable, and 100% for unstable injuries found on subsequent MRI and clinical follow up. The authors considered the risk of false positive MRI results leading to unnecessary treatment, risk of transport and time outside ICU, and the cost of MRI in formulating their conditional recommendation to remove the c-collar after a negative high-quality CT. The authors acknowledge that this policy may lead to a “non-zero rate of neurologic deterioration” .
Other studies show a higher false negative rate for CT CS evaluation in trauma. A literature review by Malhotra in 2017 showed 4/3370 obtunded patients with unstable CS injury after negative CT versus 10/1387 alert, awake patients . A subsequent study by the same author analyzed 1080 trauma patients who received a CT and then a follow up MRI within 48 hours. Of 712 patients with a negative CT, 149 had positive findings on MRI, 97 of which were ligamentous and cervical fascial injuries. 65 of the 149 had experienced a fall from standing. 1 out of 65 injuries was unstable. CT had a 98.5% NPV, and 0.42% of patients had a change in management due to MRI findings .
False negative evaluation can be reduced by more testing, but the increased sensitivity comes with a cost. More evidence has accumulated documenting the harm of extended CS work-up and precautions. Peck showed that c-collars in the elderly are associated with pressure sores, elevated intracranial pressure, respiratory compromise, swallowing difficulty, delirium, and difficulty with mobility . Dunham et al conducted a literature review of comatose blunt trauma patients with negative CS CT scans. They found a risk of 2.5% of CS instability. However, they also found risks of 26.2% of ICU complications of prolonged c-collar use, 9.3–14.6% of secondary brain injury during MRI transport and 20.6% risk of aspiration during MRI scanning . Bedrest in trauma patients has been associated with complications of immobility such as muscle weakness, pressure ulcers and deep vein thrombosis . There are financial costs as well. A 2021 study showed that the average cost of negative MRI plus waiting time following negative CT was 4628 dollars . The risk of missing an unstable injury must be balanced against the cost and risk of immobilization and further workup.
Despite an increasing number of studies demonstrating safety, there is still widespread resistance to clearing the CS based on CT. These results may help explain why. Although neurologic deficit identified all patients needing urgent surgery in this study, patients do not always have an accurate neurologic exam. If one of these patients had been obtunded enough to mask the neurologic deficit, clearing the CS based on CT without obtaining an MRI would have missed the injury.