Are “Normal” Multidetector Computed Tomographic Scans Sufficient to Allow Collar Removal in the Trauma Patient?

Abstract

Background Controversy continues as to the most safe and reliable method for clearing the cervical spine (C-spine) in a trauma patient who is rendered unable to participate in a clinical examination. Although magnetic resonance imaging (MRI) is the most sensitive test to detect soft-tissue injuries, it is impractical for routine use in every patient largely because of its cost and time of acquiescence. Recent studies have advocated the sole use of multidetector computed tomographic (MDCT) scans of the C-spine to decide if cervical collar immobilization can be discontinued. The current investigation retrospectively reviewed a series of MDCT scans obtained after an acute traumatic event that were used to direct treatment in the emergency department (ED) or intensive care unit. Methods Seven-hundred and eight trauma patients consecutively admitted to the ED between June 2001 and July 2006 underwent a computed tomographic scan of their C-spine as part of an institutional protocol. We identified 91 patients with MDCT scans that were officially recorded as adequate and negative by an attending ED radiologist who had also undergone an MRI during the same trauma admission period. Retrospectively, two fellowship-trained spine surgeons independently reviewed these MDCT studies to address the following questions: (1) Is the study adequate? (2) Is it suggestive of an acute injury? (3) Is there sufficient information to safely recommend collar removal? Institutional Review Board approval was obtained before the images were reviewed. Neither clinical examination findings nor MRI readings were made available to the surgeon evaluators. Results Both spine surgeons agreed that 76 of the 91 studies (84%) were adequate to evaluate for possible C-spine injuries. Seven of 91 MDCT scans (8%) were deemed inadequate by both surgeons (95% confidence interval, 2.3–13.1). Reasons for inadequacy included motion artifact, insufficient visualization of the cervical-thoracic or occipital-cervical junctions, incomplete reconstructive views, or poor quality. Three of the adequate MDCT scans had fractures that were identified by both of the spine surgeons; 4 additional fractures and 15 findings suspicious for instability were identified by at least one of the surgeons. Ultimately, 22 of 91 MDCT scans read as adequate and normal by attending radiologists were deemed suspicious for abnormality by the spine surgeons. Of these 22 cases, the official MRI reading was positive for a trauma-related abnormality in 17 cases. Conclusions C-spine clearance of patients without the ability participate in a clinical examination remains difficult. A multidisciplinary, algorithmic approach generally yields the most consistent results. However, our data highlight that reliance on a single imaging modality may lead to missed diagnosis of C-spine injuries. These data suggest that early involvement of the spine service for radiographic clearance may help identify occult injuries or suspicious findings necessitating further evaluation.

Anterior Atlantodental and Posterior Atlantodental Intervals on Plain Radiography, Multidetector CT, and MRI

“…MRI can also reveal isolated ligamentous injury, spinal cord contusion, and complex injuries of the occipitoatlantal joint capsule and craniocervical ligaments (16)(17)(18)(19). However, MRI does not permit close cardiovascular monitoring and ventilation support of the traumatized patients during data acquisition (17). Although the actual measurement of the AADI and PADI is inconsequential in MRI, the relation of PADI not exceeding 13 mm (11).…”

“…Recently, the multidetector CT (MDCT) scan has replaced plain radiography as the primary radiological examination type in emergency situations in many hospitals, including our institution. It has been considered the standard modality for the diagnosis of cervical spine injuries (15)(16)(17)(18)(19)(20). More recent studies have claimed that the MRI should be used for complete cervical clearance in all blunt trauma patients (16)(17)(18)(19) A 180-mm field of view (FOV), 512 × 512 matrix, 120 kVp, and 100 mAs were routinely used.…”

Unstable Multi-Level Ligamentous Injury of the Cervical Spine in an Adolescent

“…Certain literature has suggested that further imaging modalities are not required for identifying significant injuries and that there is no role for additional MRI imaging in a patient with no abnormal neurological symptoms, including in paediatric patients [12,13]. Alternative literature has however demonstrated that CT scans can miss significant soft tissue/ ligamentous/ discal injuries that require subsequent treatment [14,15]. This case clearly highlights this issue and the role of MRI.…”

Clearing the cervical spine in Plato's cave

“…Armed with reams of literature to support their position, many physicians maintain that the true injury status of the cervical spine may be known after a single negative computed tomography (CT) study [2][3][4]. Others claim that true absence of injury can only be assured once an adjunct magnetic resonance imaging (MRI) scan has been performed and confirmed as negative for trauma, especially to the soft-tissue stabilizers of the spine [2,4,5]. Advocates of the ''CT-alone'' methodology counter that MRI is an ''overly-sensitive instrument'' and that ''injuries'' identified on MRI after a negative CT study are in truth clinically insignificant and will not alter management [3].…”

“…Because of the fact that most of the studies reporting on algorithms for cervical spine evaluation are retrospective in nature [2][3][4][5], or reliant on experiences from single institutions, there naturally exists a strong potential for bias that will interfere with an examiner's capacity to accurately characterize the diagnostic validity of CT imaging. Although CT is known to be very sensitive for osseous injuries, the question at hand involves the study's specificity (eg, its ability to be truly negative in the absence of injury) and its negative predictive value (NPV, eg, what is the false negative rate for CT imaging?).…”