In alert & stable patients with suspected neck injuries, the possibility of a significant cervical spine injury is very low . There is a wide variation among clinicians in the use of cervical spine radiography . This is due the potential for serious neurological injury with missed significant cervical spine injuries. There is a fear of medico-legal implications from missed cervical spine injuries . Due to the above mentioned reasons there is an excessive use and reliance on cervical spine radiography even in trauma centres .
There is however a very low yield from cervical spine radiographs in alert patients with blunt injury to their neck. The reported incidence of finding a significant injury on the cervical spine series is <3% [6, 7]. Although the cervical spine radiograph is a low cost procedure (£14 per 3 film series), its unnecessary excessive use can be cumulative and leads to added health care costs and burden of time to the emergency department staff. There is also an unnecessary radiation exposure to the neck.
There is confusion in the literature regarding the indications for cervical spine radiography with some authors recommending cervical spine radiographs in all patients with injuries above the clavicle [8, 9] while others advocate a selective approach [10, 11].
The 2 well known clinical decision rules available in the literature are the Canadian Cervical spine rule and the NEXUS (National Emergency X-radiography Utilisation Study) group . These rules provide guidance on cervical spine radiography utilisation in alert & stable patients with suspected neck injury. With the Canadian Cervical spine rule, patients fall into either a high or low risk of sustaining a significant cervical spine injury. To be categorised as high risk, patients either need to be >65 years, have paraesthesia to extremities or should have had a dangerous mechanism of injury. These patients have a cervical spine radiograph. If the patients do not have any risk factors, they are assessed for any low risk factors that allow safe assessment of neck movements. If any low risk factor is identified, a neck movement assessment is done. If the patient is able to actively rotate the neck 45 degrees to either side, radiographs are deferred, if not, cervical spine radiographs are done . The Canadian Cervical spine rule has been found to reduce cervical spine radiography rates and time in hard collar .
The NEXUS group advocates no cervical spine radiographs if patients satisfy 5 low risk criteria: absence of midline tenderness, normal level of alertness, no evidence of intoxication, no neurological findings and no painful distracting injuries . A comparison between the Canadian Cervical spine rule and the NEXUS showed the Canadian Cervical spine rule to be more specific and sensitive with less number of missed significant cervical spine injuries .
In our study we used the Canadian Cervical spine rule due to its better specificity & sensitivity. All our patients had cervical spine radiography and a significant reduction in radiography rates would have been found if the Canadian Cervical spine rule was applied. The 2 significant cervical spine injuries were identified by the Canadian Cervical spine rule. The results of our study do show the benefits of the Canadian Cervical spine rule in reducing cervical spine radiography rates.
The limitation of our study is that it was retrospective and the sample size was small. Compared to other studies in the literature that quote 25% reduction in radiography rates when applying the Canadian cervical spine rule, we would have had 75% reduction . This could be due to the fact that we have presumed all patients in the low risk category to have had >45° movement on either side. If these patients had neck movements assessed, some of them may have required cervical spine radiographs and therefore made the overall reduction in radiography rates may have been lesser. This is another limitation of our study as there is missing data. Even with this limitation, there would still be a good reduction in radiography rates when applying the rule. Further studies are therefore required to prospectively evaluate the utility of applying the Canadian Cervical spine rule in reducing cervical spine radiography rates.