G-POEM, short for gastric peroral endoscopic myotomy, is a minimally invasive procedure that treats gastroparesis by cutting the pylorus muscle at the bottom of the stomach. The pylorus acts as a gate between your stomach and small intestine, and in people with gastroparesis, this muscle can become too tight or fail to relax properly, trapping food in the stomach. G-POEM opens that gate from the inside, without any external incisions, using an endoscope passed through the mouth.
How the Procedure Works
G-POEM belongs to a category called “third space endoscopy,” where a doctor works within the layers of the stomach wall itself rather than cutting through the skin. The entire procedure takes place through a flexible scope inserted through the mouth, similar to an upper endoscopy you might have had before.
The process follows a specific sequence. About 5 centimeters above the pylorus, the doctor injects fluid to create a small raised blister in the inner lining of the stomach. This lifts the lining away from the muscle layer beneath it, creating a working space. The doctor then makes a small opening in that blister and tunnels through the space between the lining and the muscle, advancing toward the pylorus. Once the pyloric ring is reached, the tight muscle fibers are cut. After the muscle is divided and the pylorus visibly opens wider, the tunnel entrance is sealed with small clips. The entire procedure typically takes about an hour less than traditional surgical approaches to the same problem.
Who Is a Candidate
G-POEM is specifically designed for people with refractory gastroparesis, meaning their symptoms haven’t improved enough with medications or dietary changes. The procedure targets the pylorus, so it works best when pyloric dysfunction is a significant part of the problem. Research shows that abnormally intense pyloric contractions (sometimes called pylorospasm) occur far more often in people with diabetic gastroparesis than in healthy individuals, which is one reason this group may benefit.
Before recommending G-POEM, some specialists use a balloon-based device called EndoFLIP to measure how well the pylorus stretches and opens. Others assess the motility patterns of the stomach and upper intestine. That said, no single pre-procedure test has proven reliable at predicting who will respond best. The decision typically comes down to the severity of symptoms, how much they’ve resisted other treatments, and the clinical judgment of a gastroenterologist experienced in the procedure.
Success Rates and Symptom Relief
Short-term results are encouraging. Up to 80% of patients experience meaningful symptom relief within six months, measured by standardized symptom scores that track nausea, vomiting, bloating, and early fullness. In one study, average symptom scores dropped from about 33 points before the procedure to 12 points afterward. Gastric emptying (how quickly food leaves the stomach) normalizes in roughly 40% to 70% of patients.
The results do fade somewhat over time for some people, but a significant majority still benefit years later. At one year, clinical success rates range from 56% to 70%. At the three-year mark, a recent meta-analysis found a pooled success rate of 75%, with individual studies reporting sustained benefit in 50% to 77.5% of patients at two to four years. The variation depends partly on what’s causing the gastroparesis and whether the underlying nerve or muscle damage continues to progress.
G-POEM vs. Traditional Surgery
Before G-POEM existed, the main surgical option for pyloric dysfunction in gastroparesis was pyloroplasty or pyloromyotomy, performed through open, laparoscopic, or robotic approaches. These procedures achieve the same basic goal (opening the pylorus) but require incisions through the abdominal wall.
A systematic review comparing the two approaches found that G-POEM patients went home about three days sooner on average, and the procedure itself took roughly an hour less. The shorter time under anesthesia is a practical advantage, especially for patients already dealing with nutritional deficits and other complications of gastroparesis. Both approaches show similar clinical outcomes, but the faster recovery and lack of surgical incisions make G-POEM an appealing first-line option when the expertise is available.
Risks and Complications
G-POEM has a technical success rate above 95%, meaning the procedure can almost always be completed as planned. Serious complications are uncommon. The most frequently reported issues in studies are post-procedure abdominal pain (typically self-limiting, reported in about a third of patients in one series) and pneumoperitoneum, where gas used during the procedure leaks into the abdominal cavity. Pneumoperitoneum occurred in roughly 27% of patients in the same study, but it usually resolves on its own or with a simple needle decompression. Mucosal injury, where the inner lining of the stomach is accidentally damaged during tunneling, is a risk the endoscopist actively works to avoid since it could lead to a full-thickness perforation.
Recovery and Diet After G-POEM
Hospital stays are short, often just one to two days. The recovery process at home centers largely on a careful dietary progression. For the first two weeks, you’ll eat a modified soft diet to let the tunnel site heal. After that, if you’re tolerating food well and have no new symptoms, you begin reintroducing foods one at a time.
The reintroduction follows a tiered approach. You start with one new food per day from a “first to reintroduce” category, beginning with a small amount (a couple of tablespoons) in the morning. If that goes well, you double the portion later in the day. Once that food is confirmed safe, you move on to the next one. After clearing the initial tier, you progress to a second and then a third tier of foods. If any food triggers symptoms, you pause the reintroduction and check in with your care team. The entire process of getting back to a full, unrestricted diet takes several weeks, but many patients notice a dramatic improvement in their ability to eat and keep food down well before that process is complete.
What G-POEM Cannot Do
G-POEM addresses one specific piece of the gastroparesis puzzle: the pylorus. Gastroparesis often involves broader problems with stomach motility, including weak contractions in the body of the stomach or dysfunction of the pacemaker cells (called interstitial cells of Cajal) that coordinate stomach movement. When these issues are the primary driver of symptoms, cutting the pylorus alone may not be sufficient. This is one reason some patients respond well initially but see symptoms return over time, and why some specialists recommend combining G-POEM with motility-enhancing medications for the best results.
One unique advantage of the procedure is that it allows the doctor to take a biopsy of the stomach muscle during the tunneling process. This tissue contains the pacemaker cells responsible for coordinating stomach contractions, giving clinicians a direct look at the cellular health of the stomach wall. That information can help clarify the underlying cause of gastroparesis and guide further treatment decisions.