Introduction

The first reported percutaneous endoscopic gastrostomy (PEG) tube placement was in 1980 by Ponsky, Gauderer, and Izant in a pediatric patient. PEG tube insertion was initially reported in pediatric patients, was subsequently popularized in adults, and was later reintroduced for use in children by pediatric gastroenterologists. Although initially developed by surgeons, it is now performed at an equal or greater frequency by adult and pediatric gastroenterologists. Despite many similarities in the indications and some technical aspects of the procedure between children and adults, there are also significant differences in the indications, limitations, and technical aspects of the procedure.

Indications

In the pediatric population, PEG is appropriate in children who require a gastrostomy tube and do not require a simultaneous open abdominal procedure. PEG tubes can be considered in very young pediatric patients, including neonates, and have been successfully utilized in patients as small as 2.5 kg. PEGs can be placed for a variety of indications which include medication administration, nutritional support, gastric decompression or a combination of these reasons. It is important to recognize that PEG insertion does not predispose to development of gastroesophageal reflux. Patients who are, however, undergoing a simultaneous fundoplication, pyloroplasty or pyloromyotomy would likely not derive additional benefit from placement of a PEG tube compared to a surgical gastrostomy. PEG tube placement does not interfere with subsequent fundoplication, pyloroplasty or pyloromyotomy.

Benefits of PEG tube insertion compared to a surgical gastrostomy include reduced procedure time and cost, smaller incision, shorter length of stay, and decreased incidence of postoperative complications including wound infection, wound dehiscence, bowel obstruction, pain, atelectasis, and impaired mobility.

The decision regarding placement should be individualized based on the patient’s medical needs and requires a multidisciplinary approach.

Contraindications

There are only a few absolute contraindications to PEG tube placement. It should not be attempted in the setting of an unstable patient, uncorrectable coagulopathy, existing bleeding disorders with an INR >1.5 (normal range 0.9–1.3), elevated PTT >50 sec (normal range 23–32.4 sec) and/or platelet count <50 × 10⁹/L (normal range 150–450 10⁹/L), abdominal ascites, peritonitis, portal hypertension with gastric varices, and in a patient with a pharyngeal or esophageal obstruction. If there is any factor that interferes with successful transillumination of the gastric wall, failure to identify finger indentation performed during the procedure or if there is a suspicion that the anterior gastric wall is not opposed to the abdominal wall such as in the case of an intervening colon or other abdominal organ, PEG tube insertion should not be attempted.

Certain medical conditions require more attention and PEGs should be considered only with significantly increased caution in patients with the following clinical aspects: patients on peritoneal dialysis, scoliosis or spine abnormalities, small size, ventriculoperitoneal (VP) shunts, prior abdominal surgery, especially gastric surgery, congenital abnormalities such as situs inversus, hepatomegaly, splenomegaly or other abdominal masses, small laryngeal or tracheal size, tracheal compromise or ventilatory issues. The presence of a VP shunt or use of peritoneal dialysis prior to PEG placement is associated with a particularly poor outcome and high complication rate following placement, especially infectious complications including fungal peritonitis. As with any endoscopic procedure, the patient should be medically stable, airway protection and management are imperative, and the endoscopist should be willing to abort the procedure if the procedure is not progressing as anticipated.

Decision to proceed with PEG and preprocedure evaluation

The preprocedure evaluation varies between centers, but a thorough history and physical exam is the first step in the assessment. It is important to carefully evaluate and identify the need for an accompanying antireflux procedure and to ensure tolerance of gastric feeds prior to the procedure. Depending on the clinical scenario, additional studies including pH or impedance probe testing, modified barium swallow, and motility testing may be indicated preoperatively to determine if a simultaneous antireflux procedure is indicated.

It is a common misconception that PEG tube placement results in gastroesophageal reflux (GER). However, open gastrostomy is associated with a significantly increased risk of severe postoperative GER compared to PEG insertion (odds ratio 6–7:1). Potential contributing factors include alteration of the angle of His and reduced lower esophageal sphincter (LES) pressure by an open gastrostomy.

In our center, the standard evaluation prior to PEG includes an upper GI X‐ray to exclude malrotation and to identify if part of the stomach is located below the ribcage and therefore amenable to PEG placement. In addition, a 10‐day trial of outpatient nasogastric (NG) feeds is preferred when medically possible prior to PEG placement. If patients are unable to tolerate NG feeds this would also warrant further evaluation and consideration for an accompanying antireflux procedure.

When comparing different techniques for gastrostomy tube placement, a recent retrospective study performed in pediatric patients less than 18 years found that the open Stamm gastrostomy technique was associated with a higher rate of minor complications, including unintentional tube dislodgment, frequent emergency room visits, and need for reoperation within 30 days, compared to other techniques including PEG, fluoroscopy‐guided, laparoscopic and laparoscopic‐assisted PEG tube placement.

Three important considerations when deciding to proceed with PEG are:

• PEG tubes do not prevent aspiration in a patient with oral pharyngeal dysphagia who continues oral feedings
  
• if the stomach is completely under the ribcage, a PEG is unlikely to be successfully placed
  
• PEG tubes can be pulled out.

Technique

PEG insertion procedure

The PEG insertion is started with a thorough endoscopic inspection of the oral, esophageal, and gastric mucosa without intubation of the pyloris. Any retained secretions are suctioned to avoid intraoperative and/or postoperative aspiration. Next, the stomach is filled with air to move it up toward the abdominal wall. Excessive air insufflation which significantly flattens the gastric folds or results in visible abdominal distension should be avoided as this may distend the small bowel loops and interfere with gastric indentation. The light from a properly oriented endoscope should be directed toward the abdominal wall and clearly visible, especially in a dimmed room. At the brightest point of transillumination, finger pressure is applied. The indentation at the abdominal wall produced by palpation is seen endoscopically and the site is marked by the second physician (Figure 33.1). It should be at least 2 cm away from the costal margin as tubes placed too close to the ribs can cause significant pain. See Table 33.1 for some “tricks of the trade.”

The site is then prepped using standard technique. A snare is advanced through the biopsy channel and positioned at the proposed entry site. After the sterile prep is completed, local anesthesia is administered. The 25 G or 22 G needle attached to a syringe is advanced through the gastric wall while pulling back slightly on the syringe plunger. Safe site selection is confirmed when endoscopic visualization of the needle tip entry corresponds with air entry into the syringe. This is known as the “safe tract” technique (Figure 33.2).

Lidocaine 1% is injected while the needle is withdrawing. A 0.5–1 cm incision is made at the entry site. This incision should be sized to accommodate the diameter of PEG tube that has to be inserted. Too tight anincision increases the risk of postoperative wound infection due to compromised tissue around the PEG tube by the dilator forcefully pulled through the abdominal wall.

The needle–cannula assembly is inserted into the stomach through the incision under direct endoscopic visualization. The snare is closed around the cannula and the needle is removed. The loop‐insertion wire is passed through the cannula into the stomach. The snare is loosened from the cannula and tightened around the wire (Figure 33.3).

The wire, snare, and endoscope are removed together from the patient and the wire is removed from the snare and the scope. The insertion wire exiting the patient mouth is attached to the tapered dilated segment of the PEG tube. This is accomplished by insertion of the big loop of the insertion wire through the small loop on the PEG tube. The PEG tube is threaded through the big loop, internal bolster end first, and pulled to tighten in place. The tube is lubricated and the insertion segment of the wire at the abdominal wall is continuously pulled until, first, the dilating segment and then the tube itself exit the incision. The tube is pulled until the internal bolster sits snugly against the gastric mucosa (Figure 33.4).

This is a procedure that is best done quickly. Once the endoscopic portion of the procedure starts, it is usually accomplished by an experienced team within approximately 10 minutes. Longer procedures are associated with excessive air insufflation which makes identifying the gastric impression more difficult and may increase the risk of distending the small bowel or colon with air and therefore interposing a loop of bowel between the stomach and the anterior gastric wall, with its resultant complications. If things aren’t going well in terms of positioning, the PEG tube should not be placed. There may be something – liver, bowel, mesentery, etc. – between the trocar and the anterior gastric wall. Unless the liver has been punctured, these complications are usually self‐limiting if the angiocatheter/trocar is removed and the PEG is not placed. If significant bleeding occurs or stool is visualized at any point, surgical consultation is appropriate. When faced with a patient with atypical anatomy (cardiac surgery patients, patients with a scoliosis, etc.), the PEG may require placement in a nonstandard position (i.e., right side of the abdomen in a patient with situs inversus). The endoscopic technique should be similar to standard procedure. Avoid location selection by formula (i.e., one‐third of the distance between…). Pick the location that is best based on the individual patient’s anatomy.

There may be some resistance when the guidewire catheter knot reaches the abdominal wall. In this case, circular rotation of the guidewire with steady traction will facilitate removal of the tube. Excessive traction should be avoided especially in small, malnourished or immunocompromised patients, as there have been reports of catheters being pulled entirely through the abdominal wall.

The insertion wire is cut and external bolster is advanced over the PEG tube to a point where it is loosely touching the skin. The PEG tube is cut to a comfortable length for the caretaker. The endoscope is reinserted to confirm the proper positioning of the internal bolster against the gastric wall. The external bolster is adjusted as necessary so that proper tension is achieved. It is prudent to leave a small space between the external bolster and the skin to accommodate tissue swelling within the immediate postoperative period. A sterile dressing with betadine ointment is applied to the abdominal entry site.

The tubes can be used within 6–24 hours. Early initiation of post‐PEG insertion feedings is not associated with an increased complication rate but may be associated with higher gastric residual volumes. We typically initiate feedings with a clear liquid such as a balanced electrolyte solution prior to initiation of formula feedings. Feedings are advanced based on the individual patient’s tolerance.

Consideration should be given to aborting the procedure if any of the following are identified or occur: failure to identify good gastric impression, excess angiocatheter length without seeing the tip in the stomach, air bubbling in the needle syringe without seeing the tip in the stomach, gastric varices or significant ulceration, identification of fecal matter at any point during the procedure.

Postprocedure management

Once the tract has healed, the PEG tube can be replaced by a regular gastrostomy tube or button. We usually wait at least two months to allow the tract to mature completely, although replacement of PEG tubes following accidental dislodgment has been reported within two weeks.

There are two methods of PEG replacement: by traction or endoscopy. A traction removal is stressful for the patient and associated with some degree of pain and small risk of complications, including gastric tear and extravasation. If this method is chosen, oral midazolam with Tylenol® and good lubrication of the gastrostomy tract are very useful. In our practice, we prefer an endoscopic technique. Once the PEG tube is cut externally just above the skin, the internal bumper with the stump is retrieved using alligator forceps or a small snare. We do not cut the bumper and allow it to pass, as intestinal obstruction, impaction, perforation, and migration into the esophagus with subsequent tracheoesophageal fistula and other complications have been reported with cut and unretrieved bumpers.

The procedure is finished by confirmation of the replacement tube in the stomach. Absence of the replacement tube within the stomach is alarming for possible penetration into the abdominal cavity or the intestinal loop between the abdominal wall and stomach. Surgical consultation is warranted at this point.

If a low‐profile gastrostomy device has been chosen for PEG tube replacement, the length of the tract is measured. Gastrostomy buttons are available in a variety of lengths (0.8–6.5 cm) and diameters (12–24 Fr), depending on the brand. Once a gastrostomy button is in place, it requires replacement every 4–6 months. With time, the size of the device, especially the length, should be adjusted according to the patient weight and corresponding lengthening of the gastrostomy track to avoid gastric ulcerations and/or buried bumper syndrome. This is especially important if there is rapid early weight gain in patients undergoing PEGs for malnourishment.

Complications

Complications of PEG can be minor, major, early or late. Rates in the literature vary greatly in the range of 4–44%, but generally in the lower portion of the range, between 10% and 15%. Major complications can occur in 1–10% of cases within 6–12 months of PEG placement. Many are preventable with appropriate antibiotic prophylaxis, good endoscopic/percutaneous technique, and recognition by the performing physicians that things are not going well with a decision to abort the procedure and proceed with an open gastrostomy. Sometimes complications are unavoidable due to patient anatomy or underlying disease and this should be discussed with parents prior to the endoscopic procedure.

Reported minor complications which can become major complications include cellulitis, uncomplicated pneumoperitoneum, tube defects/disconnection, GER, granulation tissue at the insertion site, and pain at the insertion site. Reported major complications include gastrocolic fistula, gastroileal fistula, gastrocoloileal cutaneous fistula, intrahepatic placement, duodenal hematoma, complicated pneumoperitoneum, aspiration, peritonitis, catheter complications including migration, buried bumper syndrome (Figure 33.5), partial gastric separation, catheter/bumper impaction if not retrieved, intussusception secondary to catheter migration, VP shunt infection, gastric or bowel perforation, gastric or bowel volvulus, and death.

Late complications include gastrocolic fistula, gastroileal fistula, catheter migration/buried bumper syndrome/partial gastric separation, gastric ulceration, cellulitis, fasciitis, gastric or bowel perforation, catheter migration or other catheter‐related complications, bronchoesophageal fistula (following catheter removal), and aortic perforation (following cut‐and‐pass technique). PEG tubes in children are not associated with a higher rate of subsequent revision when compared to surgically placed open gastrostomy tubes if tube revisions due to unrecognized bowel perforation at initial PEG placement are excluded.

When comparing minor versus major complication rates in pediatric patients following PEG placement, Fortunato et al. reported minor complications in 4% of children prior to hospital discharge and 20% after hospital discharge. The most common minor postoperative complication reported was wound infection. Major complications occurred in less than 1% of subjects which include gastric separation and gastrocolonic fistula.

A recent “in press” article reporting NICU bedside placement of PEG in 106 neonates reported a total complication rate of 8.4%, of which 1.8% were major complications. The major complications in that study included one case of migration of the PEG tube bumper and one case of dislodgment. This review concluded that bedside PEG placement was safe in appropriately selected neonates.

Once enteral access is no longer required, the gastrostomy tube or button can be removed and the gastrostomy site can be allowed to close on its own over a period of several weeks. In 5–30% of cases a chronic gastrocutaneous fistula remains patent, particularly in patients with longer duration of gastrostomy tube use. In this circumstance we have utilized either endoscopic clipping, fibrin glue injection or surgical closure to close the tube site.