When it is too difficult to remove the sac entirely a portion may be left behind.
Hunter's Operation. — In the And method the artery was tied too near the sac, where the diseased arterial wall did not allow the ligatures to hold firmly; by Hunter's method the artery is tied at some distance above the sac, where it is healthy. The sac does not collapse; the force of the circulation is simply dimin ished, allowing the sac and its contents to be absorbed.
Slight oedema of the limb is not a contra-indication for Hunter's opera tion, but the aneurism should be of slow growth. of moderate size, and the sac not inflamed. It should not be per formed in multiple aneurism. except if there are only two. and these can be operated on simultaneously.
This operation may be followed by return of pulsation in the sae. and re currence, secondary haemorrhage, in flammation and suppuration of the sac. pymmia, and septicannia.
In performing Hunter's operation it is advisable to make distal compression for a few seconds before tightening the ligature, so as to distend the sac, and to ascertain, by digital compression, that the pulsation can be entirely arrested.
A rise in the temperature of the limb is observed after the operation, accord ing to Holmes and Ashhurst. Accord ing to the majority of writers, however, the temperature first falls, rising only when the collateral circulation is estab lished.
After the operation two sets of vessels are formed for the collateral circulation: one around the point tied, the other around the aneurism.
In a very few cases the sac will be ob literated, but a narrow channel will still be left for the passage of the blood. As the aneurism itself has caused previous dilatation of the neighboring vessels, those forming the collateral circulation around the sac develop earlier in cases where two sets develop. If the aneu rism be tied near the sac, but one set of collateral vessels is formed.
Secondary aneurism, or pulsation, may occur in from a few hours to several months after consolidation and contrac tion of an aneurismal sac; but in most eases it forms about twenty-four hours after the new sac, being generally slightly higher up on the artery than the old sac. Recurrent pulsation is due to the
upper anastomotic arch allowing too much blood to flow into the artery be tween the point of ligation and the sac. Though in some cases as distinct as be fore the operation, it usually consists in a mere thrill, without bruit.
Pulsation in the sac may also be caused by too rapid collateral circulation being re-established above the sac.
Recurrent pulsation is best treated by raising the limb, compressing the sac moderately, and using cold with care. If this is unsuccessful, the artery may be tied lower down. But, if there is danger of sloughing of the sac, amputa tion should be performed in axillary or popliteal aneurism, and Antyllus's modi fied operation in cervical or inguinal aneurism. The prognosis of cases of re current pulsation is usually favorable, as it will usually disappear when the sac consolidates. (Ashhurst.) Secondary luemorrhage is most likely to take place from the seventh to the fifteenth day, and on the upper than on the lower limb, owing to the more abundant arterial anastomosis on the former. It is favored by the presence of large branches given off close to the point of ligation. Strong, well-prepared, chromicized catgut is less likely to be followed by secondary hemorrhage than silk.
If after ligation the tumor enlarges, but without pulsation, it is due to blood coining from the artery beyond the sac. The obstruction of the venous circula tion caused by this may give rise to gan grene. However, in most cases the blood coagulates, and the aneurism forms a solid fibrinous tumor.
Suppuration and sloughing of the sac after Hunter's operation may be due to recurrent pulsation from want of con solidation due to an imperfectly devel oped lower collateral circulation, or to total sudden coagulation of the blood in the sac, from complete arrest of the cir culation, from violence or handling of the tumor. Death results in about 25 per cent. of cases where the sac bursts.