Value of a rigid collar in addition to head blocks: a proof of principle study

BACKGROUND: All trauma patients with a cervical spinal column injury or with a mechanism of injury with the potential to cause cervical spinal injury should be immobilised until a spinal injury is excluded. Immobilisation of the entire patient with a rigid cervical collar, backboard, head blocks with tape or straps is recommended by the Advanced Trauma Life Support guidelines. However there is insufficient evidence to support these guidelines. OBJECTIVE: To analyse the effects on the range of motion of the addition of a rigid collar to head blocks strapped on a backboard. METHOD: The active range of motion of the cervical spine was determined by computerised digital dual inclinometry, in 10 healthy volunteers with a rigid collar, head blocks strapped on a padded spine board and a combination of both. Maximal opening of the mouth with all types of immobiliser in place was also measured. RESULTS: The addition of a rigid collar to head blocks strapped on a spine board did not result in extra immobilisation of the cervical spine. Opening of the mouth was significantly reduced in patients with a rigid collar. CONCLUSION: Based on this proof of principle study and other previous evidence of adverse effects of rigid collars, the addition of a rigid collar to head blocks is considered unnecessary and potentially dangerous. Therefore the use of this combination of cervical spine immobilisers must be reconsidered.