In adults, again, absolute closure of the rectum and anus, and complete obstruction, may be the result of malignant disease, or even, very rarely, of simple organic stricture.
In such cases, where the patient is tolerably strong and yet evidently doomed from the complete obstruction, an attempt at the formation of an artificial anus is warrantable, and in many cases afford great relief, and prolongs life for months.
Without going into all the various positions proposed for such operations, I select the two most warrantable, which have borne the test of experience. These are—1. Colotomy in the left loin. This is applicable in the case of adults with rectal obstruction. 2. Colotomy in the left groin applicable in cases of imperforate anus and deficiency of rectum in infants.
1. Colotomy in the left loin, generally known by the name of Amussat's operation.—The patient is laid upon his face, a pillow placed under the abdomen, rendering the left flank prominent. A transverse incision should then be made at a level about two finger-breadths above the crest of the ilium, extending from the outer edge of the erector spinæ muscle forward for four or five inches, according to the fatness of the patient; the muscles must then be carefully divided till the transversalis fascia is exposed. It is then to be pinched up and divided, as in the operation for strangulated hernia. The muscular wall of the colon uncovered by peritoneum is then in most cases very easily recognised from its immense distension. The bowel should then be hooked up by a curved needle, two or three points at least secured to the margins of the wounds by stitches, and then the bowel should be opened by a longitudinal incision of at least an inch in length. When the distension has been great, there is generally a rush of fluid fæces, which must be provided for, special care being taken lest any get into the cavity of the peritoneum.
Fig. xxxiii. [149]
2. Colotomy in the left groin, for absence of anus and deficiency of rectum in newly born infants.—The dissections of Curling, Gosselin, and others have shown that in infants the operation of lumbar colotomy is very difficult, and its results uncertain, while it is comparatively easy to open the colon in the left groin. Huguier, again, has shown that in certain cases the colon is not to be found in the left groin, but is accessible in the right groin. This abnormality seems, as shown by Curling, to occur not oftener than once in every ten cases.
Operation.—An oblique incision from an inch and a half to two inches in length should be made in the left iliac region above Poupart's ligament, extending a little above the anterior-superior spinous process of the ilium. The fibres of the abdominal muscles should be divided on a director passed beneath them, and the peritoneum should next be cautiously opened to a sufficient extent. The colon will most likely protrude, but if small intestine appear the colon must be sought for higher up. A curved needle armed with a silk ligature should be passed lengthways through the coats of the upper part of the colon, and another inserted in the same way below, and the bowel, being drawn forwards, should then be opened by a longitudinal incision. The colon must afterwards be attached to the skin forming the margin of the wound by four sutures at the points of entry and exit of the needles.
Operation for the Removal of an Artificial Anus, in cases where the bowel is patent below.—After the operation for hernia in a case where the bowel is gangrenous, the only hope of the patient's recovery consists in the formation of adhesions between the bowel and the external wound, and the presence, for a time at least, of an artificial anus. If adhesions do form, and the patient recovers, it becomes a matter of great importance for his future comfort that the canal of the intestine should be re-established, and the fistulous opening allowed to close. This, however, is by no means easy, as even when the portion of intestine destroyed has been very small, a septum or valve remains which directs the contents of the bowel outwards, and so long as it exists is an effectual obstacle to any of the fæcal contents passing into the distal portion of the bowel. This septum or éperon is formed by the mesenteric side of the two ends of the bowel. To destroy this without causing peritonitis is the aim of the surgeon, and it is not an easy matter to accomplish. To cut it away would at once open the peritoneal cavity, so the mode of treatment now adopted in the rare cases where it is necessary is that recommended by Dupuytren. The principle of it is to destroy the éperon by pressure so gradual as to cause adhesive inflammation between the two surfaces, and thus seal up the cavity of the peritoneum, before the continuance of the same pressure shall have caused sloughing of the septum. This is managed by the gradual approximation by a screw of the blades of a pair of forceps, to which Dupuytren gave the name Enterotome. The process, which extends over days and weeks, must be carefully watched lest the inflammation go too far.
Plastic operations are occasionally required to close the opening after the passage is restored. For a good example of such an operation see Edin. Med. Journal for August 1873, in which Mr. John Duncan describes a case.