Effect of multiple ligations of the external carotid artery and its branches on blood flow in the internal maxillary artery in dogs.

PURPOSE

The effect of occlusion of the external carotid system on blood flow of the internal maxillary artery was investigated in 16 dogs.

METHODS

The external carotid system was occluded by ligation or clamping at different levels separately or simultaneously and the blood flow of the internal maxillary artery was measured with an electromagnetic flowmeter before and after each occlusion.

RESULTS

The ligation of the external carotid artery below (low ligation) and above (high ligation) the origin of the occipital, lingual, and facial arteries reduced the blood flow by 61.1% and 71.5%, respectively. Low ligation together with ligation of the lingual artery reduced the blood flow by 73.5%. Multiple ligations (high and low ligations combined with ligations of the occipital, lingual, and facial arteries) reduced the blood flow by 81.8%. The internal maxillary artery was sectioned after the multiple ligations, and retrograde flow from the distal segment was studied. The flow was only a trace and could not be measured with the flowmeter. Total blood loss from both ends almost equaled the blood flow of the proximal segment, 18.2% of normal.

CONCLUSIONS

Multiple occlusion appears to be the most effective treatment for hemorrhage from the initial part of the internal maxillary artery.