Medicine
Pathophysiology of Gastric Volvulus and Surgical Decompression
Quick fact
Gastric volvulus presents with the classic Borchardt triad—severe epigastric pain, retching without vomiting, and inability to pass a nasogastric tube—and can be fatal within hours if decompression is delayed.
Why this is interesting
The stomach normally stays put, but what happens when it flips upside down inside your chest? A twist no bigger than a knot can cut off its blood supply and turn a simple meal into a surgical emergency.
Read the full explanation
Understanding Pathophysiology of Gastric Volvulus and Surgical Decompression
Imagine the stomach as a soft, collapsible sac with two ends: the esophagus enters at the top, and the duodenum exits at the bottom. Normally, it is anchored in place by several ligaments that keep it in the upper abdomen. Gastric volvulus occurs when the stomach rotates on itself, much like a twist in a water balloon. This rotation can be along its long axis (organoaxial), causing it to flip from side to side, or along its short axis (mesenteroaxial), causing it to fold backwards. The twist can be partial or complete, but even a partial twist can kink the stomach like a hose, blocking both the entrance and the exit. This leads to a closed-loop obstruction: gas and fluid accumulate inside, distending the stomach. At the same time, the twist can squeeze the blood vessels that run along the stomach's wall and mesentery, especially the splenic artery and vein. When blood flow is cut off, the stomach wall starts to become ischemic—starved of oxygen—and if left untreated, it can progress to necrosis and perforation. Because the stomach is hollow and relatively movable, it is especially susceptible to twisting when its normal anchors are loose or absent.
A deeper explanation
The underlying mechanism is a combination of mechanical rotation and vascular compromise. The stomach is held in place by four major ligaments: the gastrohepatic, gastrocolic, gastrosplenic, and gastrophrenic ligaments. When these are lax or disrupted—often due to a diaphragmatic hernia, trauma, or congenital absence—the stomach gains abnormal mobility. A twist can then occur, and the severity depends on the axis and degree of rotation. Organoaxial volvulus, the most common type, rotates the stomach around an axis connecting the gastroesophageal junction and the pylorus, causing the greater curvature to move upward and the stomach to invert. Mesenteroaxial volvulus rotates around an axis perpendicular to that, causing the antrum to move upward and the fundus to move downward. In either case, the twist creates a mechanical obstruction at the cardia and pylorus, preventing food and gas from passing. The closed loop distends, and the intragastric pressure rises, which further compromises venous drainage—leading to congestion and edema. Arterial inflow is also reduced, especially in the left gastric artery and gastroepiploic vessels, leading to ischemia. Ischemia triggers an inflammatory cascade, and if not relieved within hours, the stomach wall becomes necrotic. The danger is not just obstruction but also the risk of gastric perforation, which can spill gastric contents into the peritoneal cavity causing peritonitis and septic shock. Surgical decompression is the definitive treatment: it involves emergency reduction of the volvulus—untwisting the stomach—followed by fixation (gastropexy) to anchor it to the abdominal wall or diaphragm to prevent recurrence. In cases where necrosis has already developed, the affected portion is resected (partial gastrectomy). The goal is to relieve the obstruction and restore blood flow as quickly as possible to prevent irreversible damage. Understanding this pathophysiology is crucial because the clinical presentation can be misleading, and delay in surgical intervention can be fatal.