THE object of the present communication is to report three cases of aneurysm of the innominate trunk, all treated by surgical methods. In one case the innominate, common carotid, and subclavian trunks were tied simultaneously close up to the aneurysmal sac. This is the first clear record of such an operation being carried out with success. In the second case the three trunks were ligatured and the sac excised. Extirpation of an aneurysm of the innominate trunk has been reported on only one occasion previously. In the third case, in which a fatal termination eventually ensued, the aneurysm had been treated by lesser measures than ligation of the three trunks in the first instance, and it is of particular interest as illustrating the probability of recurrence of pulsation in the aneurysm under these circumstances.Aneurysm of the innominate artery is not common, comprising, as it does, only about 3 per cent of the total cases. It is, however, a site of peculiar interest to the surgeon, especially when the dilatation affects the termination of the vessel. Under such circumstances it presents a problem more difficult than does ordinary peripheral aneurysm, and is certainly without the hopelessness of aneurysm of the aorta. The possibility of the sac being adherent to the manubrium sterni and other structures, the risk of attempting its exposure, the problem of cerebral and brachial complications following ligature, all call for careful consideration, and contribute to making each individual case a fascinating study.That the treatment of innominate aneurysm is within the province of surgery is shown by the successful results gained in seven of the last ten cases reported. The striking fact is that the terrain now apparently so secure was won by the surgeon only after continued effort in the face of the most disheartening experiences throughout the nineteenth century and in the early days of the present one. A table is given below summarizing the records of aneurysms of the innominate trunk in which surgical treatment has been adopted. Although the innominate artery has been ligatured on over seventy occasions, it is evident that in the great majority of cases the operation was done for conditions other than aneurysm of that vessel itself. Failure to appreciate this distinction has resulted in great confusion in the literature, both in regard to the frequency of innominate aneurysm and also the efficacy of the various forms of treatment. Indeed, in a recent publication it is assumed that all ligations of the innominate trunk were performed for the treatment of innominate aneurysms, and the mortality of the condition was estimated on this basis. Though the number of cases is small, the table is helpful in indicating the comparative benefits conferred by the different surgical procedures.
