EXPERIMENTAL STUDY OF RE-ESTABLISHMENT OF PERIPHERIAL BLOOD FLOW AFTER LIGATION OF EXTERNAL CAROTID ARTERY

Ligation of the external carotid artery is not infrequent operation now, and every surgeon today has performed or has had been acquainted with the surgery of this vessel.It is commonly believed that the peripherial blood flow after the ligation of external carotid artery is reduced or ceased for a long time, but concerning this, only a few experiments about reestablishment of the blood flow after the ligation have been made.Therefore, the re-establishment of blood flow was observed in man by using a plethysmograph and sphygmo-manometer and by using the three dimensional cast model of the blood vessel in the dog.1) Re-establishment of the blood flowThe plethysmograph at the ear lobe showed that in 11 of the 18 cases (61%) the blood flow was recovered in 5 days, that is, in 4 of 11 immediately after the ligation, 3 in 1 day, 1 in 3 days, 3 in 5 days. And also immediately after the ligation low but regular waves were noted.2) Blood pressureBlood pressure of the external carotid artery was messured befor and after the ligation in 4 cases in man and 6 cases in dog, and arterial pressure was maintained on the same level as venous pressure.3) AnastomosisThree dimensional cast model in dogs showed the most important channel of collateral circulation to the external carotid artery were the external ophthalmic artery and middle meningial artery and following this the free communication between the external carotid arteries of both sides and the vertebral artery into the occipital artery. Moreover, the route of the ophthalmic artery to the external ophthalmic artery and the ethmoidal artery to the external ophthalmic artery were recognized, but it is thought that the route does not contribute to the blood flow because of its narrowness.Results.The re-establishment of the blood flow was much earlier than it was thought and the arterial pressure was maintained on the same level as the venous pressure, so one should not rely too much on the ligation of the external carorid artery for control of hemorrhage.