PROCEDURE OF THE DAY
Percutaneous Endoscopic Gastrostomy
A percutaneous endoscopic gastrostomy (PEG) is an endoscopic procedure for placing a tube into the stomach. It involves placing a tube into the stomach through the abdominal wall. It is an alternative to surgical gastrostomy. PEG tubes may also be extended into the small bowel. The procedure does not require a general anesthetic, although mild sedation is typically used.
The procedure is performed in order to place a gastric feeding tube as a long-term means of providing nutrition to patients who cannot productively take food orally. PEG administration of enteral feeds is the most commonly used method of nutritional support for patients in the community. Many stroke patients, for example, are at risk of aspiration pneumonia due to poor control over the swallowing muscles; some will benefit from a PEG performed to maintain nutrition. PEGs may also be inserted to decompress the stomach in cases of gastric volvulus.
Gastrostomy may be indicated in numerous situations, usually those in which normal or nutrition (or nasogastric) feeding is impossible. The causes for these situations may be neurological (e.g. stroke), anatomical (e.g. cleft lip and palate during the process of correction) or other (e.g. radiation therapy for tumors in head & neck region).
In certain situations, the indication for PEG placement is more debatable. In advanced dementia, studies show that PEG placement does not in fact prolong life. Indeed, work has been done to inform doctors and healthcare staff of the perceived futility of the treatment.
A gastrostomy may also be placed to decompress the stomach contents in a patient with a malignant bowel obstruction. This is referred to as a "venting PEG" and is placed to prevent and manage nausea and vomiting.
A gastrostomy can also be used to treat volvulus of the stomach, where the stomach twists along one of its axes. The tube (or multiple tubes) is used for gastropexy, or adhering the stomach to the abdominal wall, preventing twisting of the stomach.
Two major techniques for placing PEGs have been described in the literature.
The Ponsky or Bard-Ponsky pull technique involves performing a gastroscopy to evaluate the anatomy of the stomach. The anterior stomach wall is identified and techniques are used to ensure that there is no organ between the wall and the skin:
* digital pressure is applied to the abdominal wall, which can be seen indenting the anterior gastric wall by the endoscopist.
* transillumination: the light emitted from the endoscope within the stomach can be seen through the abdominal wall.
* a small (21G, 40mm) needle is passed into the stomach before the larger cannula is passed.
An angiocath is used to puncture the abdominal wall through a small incision, and a soft guidewire is inserted through this and pulled out of the mouth. The feeding tube is attached to the guidewire and pulled through the mouth out of the incision.
The Russell introducer technique involves a gastroscopy to evaluate the anatomy. The Seldinger technique is used to place a wire into the stomach, and a series of dilators are used to increase the size of the gastrostomy. The tube is then pushed in over the wire.
As with the case of other types of feeding tubes, care must be made to place PEGs into an appropriate population. The following are contraindications to PEG use:
* Inability to perform an esophagogastroduodenoscopy
* Uncorrected coagulopathy
* Untreatable (loculated) massive ascites
* Bowel obstruction (unless the PEG is sited to provide drainage)
* Massive ascites
* Gastric mucosal abnormalities: large gastric varices, portal hypertensive gastropathy
* Previous abdominal surgery, including previous partial gastrectomy: increased risk of organs interposed between gastric wall and abdominal wall
* Morbid obesity: difficuties in locating stomach position by digital indentation of stomach and transillumination
* Gastric wall neoplasm
* Abdominal wall infection: increased risk of infection of PEG site
* Cellulitis (infection of the skin) around the gastrostomy site
* Gastric ulcer either at the site of the button or on the opposite wall of the stomach ("kissing ulcer")
* Perforation of bowel (most commonly transverse colon) leading to peritonitis
* Puncture of the left lobe of the liver leading to liver capsule pain
* Gastrocolic fistula: this may be suspected if diarrhoea appears a short time after feeding. In this case, the feed goes direct from stomach to colon (usually transverse colon)
* Gastric separation
* "Buried bumper syndrome" (the gastric part of the tube migrates into the gastric wall)
Removal of PEG tubes
* PEG tube no longer required (recovery of swallow after stroke or surgery for laryngeal cancer)
* Persistent infection of PEG site
* Failure, breakage or deterioration of PEG tube (a new tube can be sited along the existing track)
* "Buried bumper syndrome"
PEG tubes with fixed "bumpers" are removed endoscopically. The PEG tube is pushed into the stomach so that part of the tube is visible behind the bumper. An endoscopy snare is then passed through the endoscope, and passed over the bumper so that the tube adjacent to the bumper is grasped. The external part of the tube is then cut, and the tube is withdrawn into the stomach, and then pulled up into the oesophagus and removed through the mouth. The PEG site heals without intervention.
PEG tubes with a deflatable bumper can be removed simply by pulling the PEG tube out through the abdominal wall once the bumper has been deflated (traction removable PEG tubes or "button" PEG tubes).
The first percutaneous endoscopic gastrostomies were performed at the Cleveland Clinic in children.