The Pyloric Sphincteric Cylinder in Health and Disease

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Chapter 29 (page 144)

Gastric Ulceration Within the Pyloric Sphincteric Cylinder

Golden (l937) pointed out that the narrowing of antral gastritis and spasm, as seen on radiographs, was confined to that part of the stomach which normally exhibited antral systole and diastole, i.e. the pyloric sphincteric cylinder (Chap. 28). A similar contraction could occur in cases of prepyloric ulceration, where the ulcer was surrounded by contraction of the "fan-shaped muscle". According to Golden (l937) it had been customary to attribute "antral spasm" in these cases to the ulcer, but as the same spasm could occur in gastritis without ulceration, it was more likely that the spasm was due to the inflammatory change in the gastric wall. As pointed out above, an identical contraction might occur in cases where the ulcer was located more proximally in the stomach.

Magnus (l954) examined various features of 421 surgical resection specimens in cases of gastric ulceration. A total of 131 ulcers were located within 2.5 cm of the pylorus, 50 were situated between 2.5 to 5.0 cm from the pylorus and the remainder were located further proximally. No morphological difference was found between the ulcers in the various situations.

Raffensperger (l955) described an adult case in whom a prepyloric gastric ulcer, situated on the greater curvature 1.0 cm proximally to the pylorus, was diagnosed radiologically. Initially no associated narrowing was seen, but as the ulcer healed a prepyloric narrowing containing prominent irregular mucosal folds, became evident. Five weeks after the original diagnosis the radiographic appearance of adult hypertrophic pyloric stenosis (AHPS) was seen, and at operation the gross appearance was that of typical AHPS. Microscopically the thickening consisted solely of muscular tissue without evidence of associated oedema or inflammation. A healed gastric ulcer was also present. The condition was considered to be AHPS which had developed within five weeks around a healing, prepyloric gastric ulcer.

It has been mentioned that Johnson (l957, l965) and Johnson et al. (l964) divided gastric ulcers into three types, depending on the associated acid secretory characteristics. Prepyloric ulcers (occurring within 2.54 cm of the pylorus) and other antral ulcers (occurring to the right of the angulus but further than 2.54 cm from the pylorus) were associated with acid hypersecretion, resembled duodenal ulcers clinically, and constituted Type III gastric ulcers.

Foulk et al. (l957) stated that the "pyloric channel" was not a well-delineated anatomical entity, and that gastric landmarks and boundaries differed in their details for the radiologist, the endoscopist, the surgeon and the pathologist (Chap. 2). For that reason the literature on "pyloric and pyloric-channel" ulcers was confusing. The proximal boundary of the so-called pyloric channel was difficult to define, and the term merely described a region of the stomach near the pylorus rather than a definite anatomical entity. The length of the anatomical pyloric channel was variable, but was approximately 2.0 cm. Pyloric channel ulcers were defined as ulcers occurring between the gastroduodenal junction and an imaginary line 2.0 cm above the junction; the term pyloroduodenal ulcers was used to indicate ulcers which straddled the junction. These authors studied three groups of patients with surgically treated peptic ulcer near the pylorus. There were 35 cases with pyloric channel ulcers, 29 with pyloroduodenal and l9 with duodenal ulcers. Clinically there were no features which permitted a differentiation of pyloric channel ulcers from the other two groups.

In their description of 6 cases of AHPS, Skoryna et al. (l959) included one case in which an ulcer of the pyloric canal was associated with hypertrophy of the musculature of the canalis egestorius as described by Torgersen (l942) (Chap. 24).

Texter et al. (l959) also drew attention to the confusion which existed concerning the terminology of the distal portion of the stomach. These authors looked upon the pyloric sphincter as the muscular ring surrounding the lumen of the gastroduodenal junction, and the pyloric channel or pyloric canal as the narrow space encompassed by the ring. Ulceration of the pyloric channel consequently indicated an ulcer involving the ring. This concept of pyloric channel ulcers differed from that of Foulk et al. (l957), who would have termed these pyloroduodenal ulcers. In a clinical study of 67 cases of pyloric channel ulcers Texter et al. (l959) found that although the symptoms were not pathognomonic, they differed significantly from those of gastric ulcers occurring elsewhere in the stomach, and from those of uncomplicated duodenal ulcers.

Burge et al. (l963) described a pyloric channel syndrome occurring in association with gastric ulceration. The ulcer in these cases could be located either high on the lesser curvature or in the pyloric channel. Pathologically the pylorus and prepyloric region showed small round cell infiltration and muscle hypertrophy with fibrous replacement of muscle cells. These features were apt to cause a narrowing of the pylorus and prepyloric region.

Murray et al. (l967) described features in 47 patients who underwent operation for pyloric channel ulcers. (Comment: From the description it is clear that the pyloric channel was equated with the pyloric aperture). Preoperative radiologic examination was obtained in 42 of the patients and the diagnosis of pyloric channel disease was confirmed in 41. There was associated duodenal ulcer disease in 25 cases, while 8 patients had an associated lesser curvature gastric ulcer and 10 associated hiatus hernia. Clinically pyloric channel ulcer was frequently associated with a symptom complex called the pyloric syndrome. Dysfunction of the "antral" evacuation mechanism was noted in one half of the patients. The ulcer was usually associated with low gastric acidity, and histologically it appeared to occur in gastric mucous membrane.

Gear et al. (l97l) found gastritis associated with prepyloric ulcers to be much less severe, and also less extensive, than that associated with ulcers in the body of the stomach. In both groups of ulcers the gastritis occurred predominantly in the distal part of the stomach and along the middle of the lesser curvature. Superficial or atrophic gastritis was found to persist or even worsen after healing of the ulcer, whether the treatment was medical or surgical.

Liebermann-Meffert and Allgöwer (l977, l98l), in their study of surgical resection specimens, found that the changes in the antropyloric wall occurring in association with pyloric ulceration, were similar to those seen in gastric ulceration elsewhere in the stomach (see above); these included abnormalities of Auerbach's plexuses and the muscularis externa with replacement of contractile muscular tissue by fibrous tissue. It was thought that this might impair antropyloric motor function.

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