Chapter 27 (page 130)

The Pyloric Sphincteric Cylinder in Health and Disease

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Chapter 27 (page 130)

Gastric Ulceration

Du Plessis (l965) found the concentration of bile acid conjugates in fasting gastric aspirates to be abnormally high in cases of gastric ulceration. Capper et al. (l966) found moderate or gross reflux in 66 percent of gastric ulceration patients, while Rhodes et al (l969) and Delaney et al. (l970) mentioned an increased incidence of bile reflux in patients with gastric ulceration. Flint and Grech (l970) stated that the pylorus was incompetent in gastric ulceration and chronic alcoholic gastritis, while the results of Valenzuela and Defilippi (l976) suggested pyloric "sphincter" incompetence in gastric ulceration. Nicolai et al. (l980) found increased reflux in l8 gastric ulcer cases.

In our series (Keet l982) there were 9 cases of benign ulcer on the lesser curvature of the stomach at varying distances proximal to the sphincteric cylinder, i.e. not within the cylinder. Seven of these showed moderate reflux. In the series of Hughes et al. (l982) reflux was present in 21 of 46 patients with gastric ulcer. Although there appeared to be a higher proportion of gastric ulcer patients with reflux, the results did not reach statistical significance when compared with the other dyspeptic patients examined. The impression was that there was no direct association between the degree of reflux and the presence of peptic ulceration, according to Hughes et al. (l982). Niemela et al. (l984) found that of l9 patients with gastric ulcer in the body of the stomach, l7 had reflux. Two patients had both gastric and duodenal ulceration, both showing reflux. Twelve patients had prepyloric and antral gastric ulcers, 8 showing reflux. Of 30 patients with gastric ulceration Wolverson et al. (l984) found l7 (53 percent) to be reflux positive. Gotthard et al. (l985) examined 11 patients with prepyloric ulcer disease (i.e. with the ulcer situated within 2.0 cm of the pyloric ring); in all the intragastric concentrations of bile acid were measured over a 12 hour period. The mean bile acid concentrations in prepyloric ulcer patients were found to be significantly higher than in both controls and duodenal ulcer patients, diurnally as well as nocturnally.

Gastric ulceration is often associated with spasm of the pyloric sphincteric cylinder (Chap. 29). Spasm of the cylinder resembles a normal, partial contraction; at this stage the pyloric aperture is normally open (Chap. 13). In spasm the aperture is "fixed" in the open position. It is surmized that for this reason a high incidence of duodenogastric reflux is to be expected in gastric ulceration.

Malignant Gastric Ulceration

In our series (Keet l982) 2 malignant gastric ulcers were found. In one case, with the ulcer on the gastric lesser curvature close to the pylorus (i.e. within the sphincteric cylinder), there was moderate to marked reflux. In the second case, with the ulcer at the incisura angularis, no reflux was seen.

Sliding Hiatus Hernia with Gastro-Oesophageal Reflux

Donovan et al. (l977) noted duodenogastric reflux in 3 of 8 patients with hiatus hernia. In 10 cases of hiatus hernia Nicolai et al. (l980) found no evidence of increased reflux. In our series (Keet l982) there were 9 cases of hiatus hernia, 4 showing reflux of duodenal contents. There seems to be an association between hiatus hernia and spasm of the pyloric sphincteric cylinder; this may allow increased duodenogastric reflux and may ultimately lead to biliary oesophagitis (Chap. 32).

Combined Lesions

In the present series 7 cases had combined lesions, e.g. duodenal ulceration and hiatus hernia; most of these showed reflux. One of these cases showed a constant spasm of the pyloric sphincteric cylinder with irregular and transverse mucosal folds (Fig. 27.4). It was diagnosed radiologically and endoscopically as spasm and gastritis affecting the cylinder; in addition the duodenal bulb was deformed due to ulceration. In this case moderate to marked duodenogastric reflux occurred. Owing to the tube-like spasm of the cylinder, the pyloric aperture was neither fully open nor fully closed, but fixed in the patent position.

Pyloric Motility

Both in normal controls and in patients, duodenogastric reflux only occurred while the pyloric sphincteric cylinder was relaxed or in a state of partial contraction; it never occurred during maximal contraction of the cylinder. During relaxation of the cylinder there is absence of muscular closure of the aperture; mucosal closure may be present (Chap. 13). During partial contraction of the cylinder, occurring as a phase of cyclical contractile activity, the pyloric aperture is open (Chap. 13). Spasm of the cylinder resembles partial, physiological contraction, and is associated with patency of the aperture; it differs from a physiological contraction in that its contraction is permanent. Consequently increased duodenogastric reflux is to be expected in spasticity of the pyloric sphincteric cylinder.

The above does not imply that the phase of contraction of the sphincteric cylinder is the only factor in the pathogenesis of duodenogastric reflux.

Duodenal Motility

Both in normal subjects and in patients, duodenal peristaltic waves and "segmental" contraction waves in the third part of the duodenum appeared to be of little consequence in duodenogastric reflux (vide supra). However, in experimental studies in canines Ehrlein (l981) found that the timing between contractions of the duodenal bulb and the pyloric "sphincter" (right pyloric loop) was not perfect. Contraction maxima of the duodenal bulb often occurred slightly before or after contraction maxima of the "sphincter". Consequently the pyloric aperture was often inadequately closed during contraction of the duodenal bulb, resulting in reflux.