Effects of the cervical collar on cerebrospinal fluid pressure.

We investigated the hypothesis that cervical collars might compress the internal jugular veins and raise intracranial pressure in head-injured patients. In a randomised, single-blind, crossover study of nine patients scheduled for elective spinal anaesthesia the cerebrospinal fluid pressure in the lumbar subarachnoid space was measured with and without a 'Stifneck' cervical collar applied. There was a significant elevation of cerebrospinal fluid pressure in seven of the patients studied when the cervical collar was applied (p < 0.01). This preliminary study raises the possibility that immobilisation of the cervical spine with the 'Stifneck' cervical collar may, by raising the intracranial pressure, contribute to secondary neurological injury in head-injured patients in whom intracranial compliance is already reduced.