6.2 Superficial Temporal Artery Frontal Branch

In patients where the frontal branch of the superficial temporal artery is involved in the pain, it is important to cauterize it even when the main trunk of the superficial temporal artery is cauterized. The reason for this is that there are extensive anastomoses between the various terminal branches of the external carotid [4]. Blocking the main trunk alone does not necessarily ensure that the blood pressure in the frontal branch is sufficiently reduced.

The level of the frontal branch varies from patient to patient and from left to right in the same patient (Figs. 6.4 and 6.5).

The closer the frontal artery is to the outer canthus, the greater the chance, when cauterizing the artery, of damaging one of the branches of the facial nerve. In some cases a very small branch of the facial nerve is attached to the underside of the artery and can easily be missed. This may lead to permanent weakness or paralysis of part of the frontalis muscle. In these cases, great care must be taken to ensure that the facial nerve is not inadvertently cauterized. This can be avoided by, once one has grasped the artery in a mosquito forceps, turning the strength of the cautery down to a low level. At 5–10 watts, if the nerve is caught in the mosquito forceps, the cautery will cause the frontalis muscle to twitch without damaging the nerve. If the muscle doesn’t twitch, then the wattage is slowly increased. If the muscle still doesn’t twitch, then the nerve is not involved. If the muscle does twitch, then the nerve must be identified and separated from the artery before cauterization

6.3 Occipital Artery

The occipital artery, like the superficial temporal artery, branches at different levels (Figs. 6.6 and 6.7).