The stomach is frequently affected by ulcers, which occur most often on the posterior wall toward the lesser curvature, but may occur at any part, and which also very frequently affect the pylorus and duodenum. Such ulcers may be chronic, and beyond causing occasional haemorrhage by involving some of the larger vessels in the mucous or submucous coats, may not call for surgical interference. In healing they frequently cause considerable contraction, which, when situated in the body of the stomach, may give rise to an hour-glass deformity, or, when situated over the pylorus, may cause pyloric obstruction. In other cases the ulcer may be very acute, and rapidly proceed to perforation, and if this occurs on the anterior 'surface, general peritonitis is set up. Where, however, the ulcer is situated in its more usual site on the posterior wall, adhesions generally form, which tend to limit the process, and even if rupture does occur, the contents are discharged into the lesser sac, to reach which it is generally best to lift forward the transverse colon, and perforate the transverse mesocolon.
Adhesions may take place between the stomach and other abdominal organs or diaphragm. The former may lead, if the ulcer progress, to involvement of some large vessel, even apart from those of the stomach, such as the splenic artery or portal vein, and cause death from hemorrhage. The latter may occasion septic affections of the pleurae or pericardium, the septic matter traversing the lymphatics which penetrate the diaphragm, and sometimes the lungs or even the heart may become affected. Adhesions, by limiting the general spread of septic infection, may give rise to a localized abscess. In this way subphrenic abscesses may arise between the stomach and left lobe of the liver below and diaphragm above, or an abscess may arise between stomach and liver.
Carcinoma most frequently affects the pyloric region, and, as a rule, is not palpable until so far advanced as to render radical operation impossible. Where carcinoma affects the oesophagus, the operation of gastrostomy is frequently performed, a portion of stomach being drawn up through the rectus muscle, and sutured to the skin. After the wound has healed the stomach is opened, a tube passed in, and the patient fed through it. The rectus abdominis acts as a sphincter, preventing ejection of food, and to enhance this effect the portion of stomach is generally bent at an angle as it comes through the rectus, and is finally brought out to a new small skin incision over the margin of the ribs, the first wound being stitched up. Gastrotoniy, or simple incision of the stomach, may be required for treatment of an ulcer, removal of a foreign body, etc. Gastrectomy consists of the removal of a portion or the whole of the stomach. Even the latter operation has been repeatedly successful.
Wounds of the stomach, particularly if inflicted when it is distended with food, generally cause profound collapse and death, with general acute peritonitis from escape of the contents. Where, however, the stomach is empty, and where the wound is of a punctured nature, as from a rifle-bullet, the patient may, once he gets over the preliminary shock, make an uninterrupted recovery. It is supposed that in such cases the mucous membrane projects and forms a plug, closing the wound.
The pyloric valve, by means of its sphincter muscle, controls the passage of food from the stomach into the intestine, preventing, as a rule, the passage of food until after the peptic digestion has taken place. It is apparently irritated by very acid stomach contents, at such times becoming almost entirely closed, and, at the close of normal peptic digestion, it permits of the passage of food only in very small quantities at a time, so that they may be thoroughly acted on by the bilious and pancreatic juices. The valve then apparently plays an important function in the digestive process, but not infrequently it become constricted from chronic irritation, ulcerative contraction, or carcinomatous tumour, rendering operative treatment necessary. It also is occasionally constricted congenitally by a form of tumour which also causes lengthening, and is generally fatal unless promptly recognized and treated. Normally, the pylorus should admit the passage of the forefinger, but even forks and keys have been known to pass through it. Needles, when swallowed, appear to make their way through the wall of the stomach, and may eventually project through the skin.
Where the contraction of the pylorus is non-malignant, the operative treatment may consist of performing a pyloroplasty. Here a longitudinal incision is made through all the coats, the central points of the upper and lower margin of the incision are caught by forceps, and pulled apart until the wound, from being longitudinal, becomes vertical, and then the wound is sutured in the new position. Thus a long and narrow pylorus is converted into a short and wide one. The advantage of this operation is that the pyloric valve, and also the bile and pancreatic ducts, are not disturbed in their relationship to food. Forcible dilatation of the pylorus, either through an incision through the stomach wall or by invaginating the wall, is dangerous, and has been almost discarded.
In carcinoma of the pylorus the whole pylorus may be removed (pylorectomy), and the upper end of the duodenum attached to the pyloric end of the stomach, which is narrowed to fit it. For pyloric stenosis some prefer the operation of gastrojejunostomy, and, of course, this operation is called for where the pylorus is the seat of an inoperable carcinoma. The object of this operation is to make a communication between the stomach, lying above the transverse colon and mesocolon, and the jejunum lying beneath. The abdomen having been opened, the great omentum and transverse colon are turned up, and the duodenojejunal junction sought for to the left of the spine between the mesocolon and mesenteric attachment. A portion is selected, a few inches beyond the junction to which the ligament of Treitz (q.v.) forms a valuable guide, and may either be carried in front of the colon to be attached to the anterior wall of the stomach (anterior gastro - jejunostomy), or the transverse mesocolon is perforated, the posterior wall of the stomach exposed, and the junction made at this point. The latter operation is probably the better, regurgitation of food and vicious circle being less apt to be established. To obviate regurgitation, some recommend that the jejunum must be so placed that its direction of peristalsis shall correspond with that of the stomach, while others recommend that the bowel be entirely divided, the distal end being stitched to the stomach opening, and the proximal portion being opened into the distal some distance below the junction with the stomach.