The subcutaneous cellular tissue and the tendon of the external oblique may then be divided freely in the same line. Then at some one point or other (generally easiest below), the internal oblique and transversalis muscles must be cautiously scraped through with the aid of the forceps, till the transversalis fascia is reached; they may then be freely divided by a probe-pointed bistoury (guarded by the finger pushed up below the muscles) to the required extent. The muscles being held aside by flat copper spatulæ, the fascia transversalis must be carefully scratched through near the crest of the ilium, and thus the operator will be enabled to push the peritoneum inwards, and by the forefinger will easily recognise the pulsation of the artery lying on the soft brim of the pelvis.
A branch of the circumflex iliac artery will very likely be cut in dissecting through the muscles, and must be secured, as also any branches of the epigastric which may be divided in the incisions through the abdominal wall (ut supra, p. 5).
The operator should then, by pressing the peritoneum and its contents gently inwards, endeavour to see the vessel; if, from the depth of the pelvis, this cannot be done, the sense of touch will be in most cases sufficient to enable him to isolate the artery by the point of his finger-nail, or by the blunt aneurism-needle, from the vein. The ligature should be passed from the inner side to avoid including the vein, and thus there will be less chance of wounding the peritoneum from the convexity of the needle being applied to it. If possible, the genito-crural nerve should not be included in the ligature, but probably such an accident would do no great harm.
It is of much more consequence to avoid injuring the peritoneum. This is sometimes very difficult, from the adhesions which are set up between the peritoneum, the artery, and especially the aneurism, as the result of pressure and inflammation. The accident of wounding the peritoneum has happened to Keate, Tait, Post, and others, and in some cases with perfect impunity. However, the peritoneum should be displaced as little as possible from its cellular connections, as such displacement increases the risk of diffuse inflammation of that membrane; and the vessel itself should be raised and disturbed as little as possible, lest destruction of the vasa vasorum cause ulceration of the weak coats and secondary hæmorrhage.
The operation from below (Plate I. fig. 4), Sir Astley Cooper's, is thus described by Mr. Hodgson:—"A semilunar incision is made through the integuments in the direction of the fibres of the aponeurosis of the external oblique muscle. One extremity of the incision will be situated near the spine of the ilium; the other will terminate a little above the inner margin of the abdominal ring. The aponeurosis of the external oblique muscles will be exposed, and is to be divided throughout the extent, and in the direction of the external wound. The flap which is thus formed being raised, the spermatic cord will be seen passing under the margin of the internal oblique and transverse muscles. The opening in the fascia which lines the transverse muscle through which the spermatic cord passes, is situated in the mid space between the anterior superior spine of the ilium and the symphysis pubis. The epigastric artery runs precisely along the inner margin of this opening, beneath which the external iliac artery is situated. If the finger therefore be passed under the spermatic cord through this opening in the fascia, it will come in immediate contact with the artery which lies on the outside of the external iliac vein. The artery and vein are connected by dense cellular tissue, which must be separated to allow of the ligature being passed round the former."
In comparing the two methods of operating, we find that while the latter is in some respects easier, and the vessel in it lies more superficial, it has certain disadvantages which more than counterbalance its advantages. Thus, first, the epigastric artery is very likely to be wounded. It may be said, Well, if so, the ends can be tied; but this tying is sometimes very difficult; and, as shown in Dupuytren's case of this accident, involves considerable interference with the peritoneum, and a possibly fatal peritonitis. Besides this, by cutting the epigastric you destroy an important agent which would have carried on the anastomosing circulation, and thus greatly increase the risk of gangrene. By this method, also, the artery is exposed too near to the seat of disease; and if found to be enlarged and involved in the aneurism, considerable difficulty may be experienced in reaching the upper part of the vessel. Again, ligature of the lower third or half of the vessel, which this method implies, is dangerous from the occasional high origin of the circumflex or epigastric, or both, rendering the formation of a clot much more difficult, and secondary hæmorrhage much more likely.
The circumflex iliac vein must also be remembered, as it crosses the artery from within outwards in the lower end of it, just before it goes under Poupart's ligament.
However, the method may occasionally vary with the individual case. In every case of ligature of the great vessels of the abdomen, the bowels should be carefully evacuated before the operation, and the bladder emptied. A properly managed position, with the shoulders raised and the knees semiflexed, will greatly facilitate the gaining access to the vessel.
In sewing up the wounds in the abdominal walls, advantage will be gained by putting in a certain number of stitches so deeply as to include the whole thickness of the muscles, and in the intervals between these deep ones to insert others less deeply, so as accurately to approximate the edges of the skin. This will both facilitate union and also render the occurrence of hernia less probable. This latter accident did occur in a case, otherwise successful, in which Mr. Kirby tied the external iliac.
Both external iliacs have been tied in the same patient with success, on at least two occasions, once by Arendt, with an interval of only eight days between the operations; and a second time by Tait, at an interval of rather more than eleven months.
This operation is in the great majority of cases performed for femoral aneurism, and naturally secondary hæmorrhage is a too frequent result. Wounds of these great vessels generally result in so rapid death from hæmorrhage as to give no time for surgical interference. One case, however, is recorded, in which the external iliac was cut in a lad of seventeen by an accidental stab, and in which Drs. Layraud and Durand, who were almost instantly on the spot, succeeded in stopping the bleeding by compresses, till Velpeau arrived, who tied the vessel above with perfect success.
Of the first twenty-two cases collected by Hodgson, fifteen recovered—a mortality of 31.81 per cent.; and of 153 in Norris's collection, including Cutter's cases, forty-seven died—a mortality of only 32.5 per cent.,—a very satisfactory result, considering the size of the vessel and the importance of its relations.