Why Is a Partial Gastrectomy Necessary for Peptic Ulcers? Can't We Remove Less of the Stomach?

When peptic ulcers—whether gastric or duodenal—fail to respond to standard medical treatments, or when complications such as pyloric obstruction, gastric perforation, or gastrointestinal bleeding occur, a partial gastrectomy often becomes the most effective treatment option. This is especially true in cases where there is suspicion of malignancy, such as in refractory ulcers. A partial gastrectomy involves removing approximately two-thirds of the distal stomach, also known as a distal subtotal gastrectomy. But why exactly is it necessary to remove such a large portion? Could removing less of the stomach be just as effective? These are common questions patients often ask, and to understand the reasoning, it's important to explore the anatomy and function of the stomach.

Understanding the Anatomy of the Stomach

The stomach is located in the upper left quadrant of the abdomen and is divided into several key anatomical regions. It has two openings—the upper esophageal opening known as the cardia, and the lower pyloric opening connecting to the duodenum. The lesser curvature forms the upper border of the stomach, while the greater curvature forms the lower border. The stomach is further classified into four main regions: the cardia, fundus, body, and pylorus. The pylorus itself is divided into the pyloric antrum (or gastric antrum) on the left and the pyloric canal on the right. The junction between the body and antrum along the lesser curvature is called the angular notch. Each of these areas has different types of gastric glands and performs distinct physiological functions.

Key Physiological Functions of the Stomach

The stomach performs several essential physiological functions, including:

Storage: It acts as a reservoir for ingested food.
Digestion: Through gastric motility and the secretion of hydrochloric acid and pepsin, the stomach initiates mechanical and chemical digestion—often referred to as the first stage of digestion.
Transport: It moves partially digested food into the duodenum and jejunum for further breakdown and nutrient absorption.
Defense: The gastric mucosa, along with gastric acid, immunoglobulins like IgA and IgG, and lymphatic tissue, protects against pathogens and harmful substances.
Secretion: The stomach produces key substances such as hydrochloric acid, pepsin, gastrin, motilin, and somatostatin. Among these, hydrochloric acid and pepsin play crucial roles in protein digestion.

The Role of Gastric Secretions in Ulcer Formation

Hydrochloric acid is primarily secreted by parietal cells in the gastric mucosa. Excessive acid production, combined with pepsin activity, can erode the stomach lining, leading to ulceration. This mechanism is central to the development of both gastric and duodenal ulcers. Additionally, in recent years, Helicobacter pylori, a conditionally pathogenic bacterium, has been identified as a significant contributor to mucosal damage, further exacerbating ulcer formation.

Why the Distal Two-Thirds of the Stomach Must Be Removed

Most of the acid-producing parietal cells are concentrated in the distal two-thirds of the stomach. Moreover, the gastric antrum contains G cells that secrete gastrin, which stimulates acid production through neurohumoral pathways. Importantly, the vast majority of gastric and duodenal ulcers occur in this distal region.

Therefore, removing this portion of the stomach during a partial gastrectomy serves multiple therapeutic purposes:

Reduces Acid Secretion: By removing the majority of parietal cells, gastric acid production is significantly decreased, eliminating the primary cause of ulcer formation.
Eliminates Gastrin Production: Removing the G cells in the antrum reduces gastrin levels, which in turn lowers acid secretion.
Removes Ulcer Sites: The procedure removes the area most prone to ulcers, thereby preventing complications such as bleeding, perforation, obstruction, and malignant transformation.

What Happens If Less of the Stomach Is Removed?

If the resection is limited—removing only half or a smaller portion of the stomach—there may be significant residual parietal cells. This can lead to recurrent ulcers in the remaining stomach or at the surgical anastomosis site, a condition known as anastomotic ulcer. In such cases, persistent symptoms and complications may indicate surgical failure. Therefore, removing at least two-thirds of the stomach is crucial for long-term success.

Impact on Digestive Function After Surgery

While a partial gastrectomy does alter the stomach's anatomy, its impact on digestion is generally temporary. Patients are advised to eat small, frequent meals—about 4 to 5 times per day—and gradually transition from a liquid diet to semi-solid and then regular food. Over time, typically within a year, the remaining stomach adapts and expands to nearly its original capacity, allowing for a return to near-normal digestive function. Thus, concerns about long-term digestive impairment after a partial gastrectomy are largely unfounded.