When should the common carotid artery be ligatured? How soon after the development of symptoms? This depends largely on the severity of the accident that produced the arterio-venous communication. If the blow was severe and the depth and duration of the stage of unconsciousness of a prolonged character, it may be presumed that the brain was injured. Under such circumstances early ligature of the common carotid presents an appreciable danger by reason of the development of hemiplegia on account of the further interference with the arterial supply to the brain. In such cases the patient should be confined to bed or kept quiet for not less than two months, the operation being carried out when the general condition warrants surgical interference.
In the event of early operation being imperative, periodic digital compression of the common carotid, for a few minutes at a time, may be carried out with the object of accustoming the brain to the proposed new form of circulation. In ordinary cases the sooner the common carotid is tied the better is the ultimate result.
[36] Hunterian Lectures, February 1904.
[37] It is absolutely essential that the scalp incision should lie some distance away from the outer margin of the plate. Failure to adopt this procedure impedes the healing of the wound and adds to the risk of infection.
[38] If desired, the plate may be anchored in position by means of a few small silver-plated screws.
CHAPTER VII
TUMOURS OF THE BRAIN
Tumours of the brain.
Tumours may develop in any part of the cerebrum and cerebellum, from the sheaths of the efferent nerves, from the vascular tissues, and from the membranes of the brain. Tumours arising from the bones of the skull are considered elsewhere (see [p. 325]).