Imaging of pediatric gastrostomy tube malposition: Pearls and pitfalls

Abstract

This pictorial review discusses the imaging approach to evaluate for proper placement or complications of pediatric gastrostomy tube (G-tube) placement and long-term use. G-tubes are crucial for long-term nutritional support in patients facing challenges with oral intake. The article depicts the role of imaging such as contrast radiography, fluoroscopy, ultrasound, and computed tomography scans for confirming G-tube position and evaluating complications, in addition to basic anatomical considerations and placement techniques. Complications discussed include malposition, intraperitoneal placement, buried bumper syndrome, and tube malfunction. Specific imaging techniques and checklists are provided to guide clinicians in assessing G-tube placement accurately. The latter half of the review is a comprehensive exploration of pearls and pitfalls of imaging when employed to detect complications to avoid false positives and negatives.

Key Words: Gastrostomy tube; Malposition; Pneumoperitoneum; Buried bumper syndrome; Bowel perforation; Bowel obstruction; Abscess

Core Tip: Gastrostomy tube (G-tube) complications can be evaluated using fluoroscopy or 2-view contrast radiography with positive contrast injection. Presence of intraluminal contrast with gastric contour and rugae, normal emptying into the duodenum and confirmation of balloon positioning are key indicators of appropriate positioning. Awareness of critical complications associated with G-tube helps in early recognition and better patient management. These conditions include intraperitoneal placement, bowel perforation, colonic or esophageal placement, buried bumper syndrome and local abscess.

INTRODUCTION

Enteral nutrition plays a vital role in ensuring adequate nutrition and quality of life for patients facing challenges in oral intake during and after hospitalization, offering a reliable and effective means of delivering essential nutrients directly into the gastrointestinal tract. In cases where impaired oral intake is expected to be less than four to six weeks, nasogastric tubes are often used. However, for patients with long-term needs or permanent feeding requirements, insertion of a gastrostomy tube (G-tube) is the preferred solution[1-4].

G-tube is helpful in cases of diminished oral intake or feeding aversion, especially in cases of neurologic injuries, and esophageal atresia. Additionally, children with increased nutritional requirements (such as burns, cystic fibrosis, and chronic infections) or with impaired gastrointestinal system, such as short gut syndrome, inflammatory bowel disease, and pancreatitis, also benefit from G-tube usage[3]. Feeding by a G-tube can mimic physiological feeding by utilizing bolus feeds that emulate natural eating patterns, making them suitable for patients who can tolerate periodic, larger feedings. On the other hand, G-tubes can be used when continuous feeds are necessary, particularly in cases where patients face risks such as gastroesophageal reflux disease, aspiration, or pancreatitis[2,5].

Children with an indwelling G-tube had a minor complication rate ranging from 16%-74% with skin granulomas, local site infection and dislodgement being the most frequent culprits[6,7].

A recent meta-analysis found a major complication rate in pediatric G-tubes of 3.6% with percutaneous endoscopic (PEG) showing more complications over laparoscopic insertion[8]. About half of the patients with an indwelling G-tube experience dislodgement at some point[9,10]. In addition, laparoscopically inserted G-tubes have lesser complications than image guided or endoscopically guided insertions[8,11]. This comprehensive review discusses the imaging techniques that can be used to assess G-tube positioning and complications, including radiography, fluoroscopy, ultrasound and computed tomography (CT). Specific complications, including dislodgement or advancement of the G-tube, buried bumper syndrome, and inappropriate positioning into bowel or peritoneum will be discussed in detail. It also delves further into the pearls and pitfalls of imaging to avoid raising false alarms.

DESIGN OF A G-TUBE AND PLACEMENT TECHNIQUE

The standard G-tube comprises an external portion with a disk against the skin, an internal balloon in the stomach with the tube opening into the stomach (Figure 1A). In pediatrics, a preferred alternative is the low-profile G-tube, or gastrostomy-button, which minimizes the external profile (Figure 1B). It features a small, flush-to-skin port as the primary external component, reducing the risk of dislodgment, and still utilizes an internal balloon for stabilization. This design is advantageous for pediatric patients due to its reduced risk of dislodgement, easy stoma care and better cosmetic appearance[12]. Non-availability of smaller sizes for younger patients, painful insertion requiring sedation and external leakages are some its limitations[13]. The choice between standard and low-profile G-tubes depends on clinical factors such as the patient's age, medical condition, and lifestyle considerations.

Figure 1 Tube. A: Standard gastrostomy tube (G-tube); B: Low profile G-tube/ gastrostomy-button.

G-tube placement techniques vary, with options ranging from surgical procedures to less invasive methods. Surgical, laparoscopic, PEG, ultrasound-guided, and fluoroscopic interventional radiology (IR) techniques are commonly employed based on the patient's condition and medical requirements[14]. In general, laparoscopy is preferred over PEG[4]. In some cases, G-tube to gastrojejunostomy tube (GJ) conversion procedure is performed in the IR setting.

IMAGING TECHNIQUE AND OPTIMIZATION

The G-tube tract takes 2-4 weeks to mature. Thus, an early dislodgement predisposes to peritonitis and perforation and a blind attempt to reinsert the tube risks malposition. In contrast, late dislodgement can be corrected by reinsertion in the emergency department (ED) due to maturation of the tract[15]. Stenosis of a mature tract can occur if reinsertion of a dislodged G-tube is delayed (> 24 hours), increasing risk of complications. Thus, confirmatory imaging is warranted in scenarios such as reinsertion after early dislodgement, or traumatic or delayed reinsertion. Imaging can be skipped in timely reinsertion of late dislodgement or if clinical assessment ensures appropriate replacement[16,17].

Contrast abdominal radiography (radiographs performed after injection of water-soluble contrast) is the preferred initial imaging method for assessing G-tube placement. Traditionally, fluoroscopy was considered superior for evaluating G-tube complications. When using contrast radiography, both anteroposterior (AP) and lateral views are crucial for confirming proper positioning, particularly the retroperitoneal path of the GJ tube within the duodenal C-loop. However, Tompe et al[18] demonstrated that contrast radiography is equally effective in detecting tube malposition compared to fluoroscopy. Fluoroscopy may require on-site radiologist or additional personnel, is higher in both cost and radiation dose, and so should be reserved for cases with significant clinical concerns or other major complications. Despite its capability for real-time monitoring of G-tube position, these disadvantages have led to a decline in its preference.

Portable contrast abdominal radiography allows the patient to remain in the ED or inpatient unit, and thus quicker to perform. Water-soluble iodinated contrast (180-300 mgI/mL) should be used rather than barium due to the possibility of peritoneal leak or perforation.

For contrast radiography, our institutional protocol involves injecting 10 mL of contrast (reduced to 5 mL for infants under one year old). A cross-table lateral abdomen radiograph is obtained immediately, along with an AP supine radiograph (Figure 2 and Table 1).

Figure 2 Normal contrast abdominal radiography study for gastrostomy tube. A: Frontal; B: Cross table lateral post-injection radiographs show normal outlining of the gastric contour ( white arrows) and rugal folds (arrowheads). There is normal drainage of contrast into the duodenum (curved arrow). No extraluminal spillage noted; C: It is a schematic diagram depicting normal findings which should be looked at including filling defects of gastric rugae in the contrast pool (black arrow), more importantly the filling defect of the gastrostomy tube ballon, gastric contour and tracking of contrast into the duodenum (black arrowhead).

Table 1 Imaging marker checklist for gastrostomy tube contrast radiography.

Checklist for gastrostomy tube contrast radiography
Look for	Reason
Intraluminal contrast	Confirms proper flow and position
Contrast flows to dependent stomach and outlines rugal folds	Ensures tube position into the stomach
Contrast transits into duodenum	Rules out obstruction
Spherical shape of the catheter balloon	Confirm inflation
Intraperitoneal leak	Confirms perforation
Abdominal wall leak	Tube malposition
Tube wall continuity	Integrity/Breaks

Fluoroscopy can be used when clinical findings are not explained by contrast radiography findings. An initial scout view is obtained to look for tube kinking, discontinuity, or gross malposition. Subsequently, both AP and lateral views of the opacified stomach are acquired during contrast administration. The last image hold technique generally provides sufficient detail for evaluation while minimizing radiation exposure. Standard radiographic exposures can be selectively employed as needed to detect subtle contrast extravasation into the peritoneal cavity. Real-time fluoroscopy facilitates dynamic assessment of many G-tube related issues.

Recent advances in point-of-care ultrasound have allowed use of ultrasound to replace and confirm G-tube positions in ED decreasing the need for radiography. The benefits include reduced length of stay in the ED and no radiation exposure but is dependent on operator experience and training[19]. Ultrasound is particularly effective in addressing abdominal wall concerns and evaluating fluid collections. In addition, ultrasound can be used as an imaging guidance for initial percutaneous placement of the G-tube and can be used bedside in critically ill patients[20].

CT serves as an adjunct in the assessment of G-tubes. It can be helpful in cases where the anatomy is complex or in cases where there is suspicion for injury to adjacent structures include the liver. Additionally, it can effectively assess fluid collections, abscesses, and the presence of pneumoperitoneum.

PEARLS AND PITFALLS

Pearl 1

Confirm the presence of rugal folds and normal gastric contour on both AP and lateral views to ensure proper G-tube placement. The contrast should follow the expected path outlining the stomach.

Pitfall 1

Inadvertent peritoneal placement of the G-tube can be easily missed. Contrast pooling in a dependent position can mimic contrast accumulation in the gastric fundus, leading to a false negative interpretation of appropriate placement. Carefully assess the contrast pattern and look for outlining of bowel loops, which indicates intraperitoneal placement (Figure 3). In cases of longstanding misplacement, a loculated collection may form, appearing as an abnormally shaped contrast accumulation without rugal folds.

Figure 3 Free peritoneal spillage of contrast. A: Lateral radiograph of a 1-year-old with recently exchanged tube. Injected contrast pools in the intraperitoneal cavity (arrowhead) which does not follow the stomach contour with outlining of bowel loops (arrow); B: Frontal radiograph irregular or angular margins of the injected contrast (arrow) (multiple black dots outlining the air filled stomach); C: Frontal radiograph of another 4-year-old boy demonstrates similar extrinsic outlining of bowel loops.

Intraperitoneal placement of the G-tube occurs less frequently than migration of the G-tube back into the peritoneum[21]. Alternatively, if the tract is wider than the catheter, there can be trickling of gastric contents into the peritoneal cavity. These scenarios predispose to the development of peritonitis (Figure 4). Continued feeding into the peritoneal cavity may be life threatening with rapid clinical deterioration, and immediate consultation with the referring emergency or surgical team is recommended.

Figure 4 Intraperitoneal leak via the gastrostomy tube tract, 2 month old postoperative day 1 open gastrostomy tube placement. A: Frontal abdominal radiograph with a large amount of pneumoperitoneum (black arrows); B: Frontal projection in a fluoroscopy gastrostomy tube (G-tube) study with a loculated intraperitoneal leak (outlined by white dotes). There is transit of contrast behind the G-tube ballon (star) into the peritoneal leak (arrow); C: G-tube was exchanged in interventional radiology, following which a lateral fluoroscopic image showed the narrowed distance (double arrow) between the disc and ballon with no trickling of contrast behind it.

Pearl 2

A small degree of pneumoperitoneum is expected after G-tube placement due to the inadvertent peritoneal puncture.

Pitfall 2

Maintain a high level of vigilance for excessive free air, especially along the liver or in subdiaphragmatic regions (Figure 4A). It may be dismissed as expected postoperative appearance. Looking for additional signs of peritonitis in such scenarios can help radiologists and clinicians guide further management[22].

Pearl 3

Observe the path of the contrast carefully to determine the location of the G-tube balloon and its impact on contrast flow. In normal placement, intraluminal contrast should follow the gastric contour with visualization of gastric rugae and importantly a spherical filling defect of the G-tube balloon deep to the abdominal wall within the gastric lumen suggests appropriate placement.

Pitfall 3

Misinterpreting the location of the G-tube balloon and its impact on contrast flow can lead to misdiagnosis and delayed management of complications. If the balloon migrates distally to the pylorus, it causes gastric outlet obstruction, and the gastric contour appears expanded with an air-fluid level and relative loss of rugal folds (Figure 5). This clinically presents vomiting and feeding intolerance. If the balloon is in the proximal duodenum, contrast only outlines the duodenal C-loop, and the stomach may not be visualized (Figure 6). Rarely, the G-tube balloon in the duodenum may also cause biliary or pancreatic drainage obstruction. Thus, visualization of gastric contour ensures proper G-tube placement and function. Contrast emptying from the stomach into the duodenum can be a normal supportive finding.

Figure 5 Gastric outlet obstruction secondary to gastrostomy tube ballon. A: Frontal; B: Lateral. A 2 year old presented with increased abdominal distension, gagging and reflux from gastrostomy tube (G-tube). Portable radiographs, frontal and lateral after contrast administration revealed retention of contrast in an overdistended stomach (arrowhead) with the G-tube balloon in the distal stomach (arrow). Obstruction was later relieved after the balloon (arrow) was deflated and the tube was exchanged.

Figure 6 Malposition of G-port of gastrojejunostomy tube into the duodenum. A 20 year old male with increased abdominal distension and bilious output from G-port of gastrojejunostomy tube. A: Frontal radiograph shows that the G-port (black arrow) has migrated into the right upper quadrant from its ideal location in the left upper quadrant suggesting peripyloric position. The G-port should be in the left upper quadrant; B: Oblique post injection radiograph demonstrated intraluminal opacification of the duodenum (arrow) without opacification of the stomach (arrowhead) confirming a migrated G-port balloon into the pylorus or proximal duodenum.

Buried bumper syndrome involves abnormal positioning of the inflated ballon into the gastric or abdominal wall. Contrast radiography will demonstrate normal gastric contour albeit without a round filling defect from the balloon. In addition, a deformed balloon may also be seen in the anterior abdominal wall on contrast radiography (Figure 7E).

Figure 7 Buried bumper syndrome. A 5-year-old kid presented with drainage and pain at the gastrostomy tube (G-tube) site. A and B: Contrast abdominal radiography shows contrast filling the stomach and small bowel without extravasation. However, the balloon is not well seen; C: A local site ultrasound revealed G-tube balloon in the anterior abdominal wall along the tract outside of the stomach; D: A follow up fluoroscopy shows delineation of the inflated balloon which lies in the anterior abdominal wall (curved arrow); E: A different case demonstrates a deformed G-tube balloon (arrowhead) in the anterior abdominal wall.

Pearl 4

Due to the frequent imaging encounters in patients with G/GJ tubes, establishing a standardized approach for assessing tube placement is essential. Regardless of the imaging modality or clinical reason for the study, the visualized portion of the G/GJ tube should be carefully evaluated on every image.

When using contrast radiography, both AP and lateral views are crucial for confirming proper positioning, particularly the retroperitoneal path of the GJ tube within the duodenal C-loop. Comparing current images with prior studies helps identify any subtle changes or deviations from the baseline tube position. This practice is especially valuable when reviewing studies where the G/GJ tube is incidentally visualized and might not trigger an automatic comparison by Picture Archiving and Communication Systems, such as scoliosis radiographs. By consistently implementing these steps, radiologists can ensure a thorough evaluation of G/GJ tube placement and promptly identify potential complications, ultimately optimizing patient care.

Pitfall 4

Patients with G/GJ tubes often undergo numerous imaging studies using various modalities (radiography, fluoroscopy, CT) for a range of clinical indications. While the G/GJ tube may be incidentally visualized within the field of view, meticulous evaluation of its positioning and course is frequently overlooked. This oversight can lead to missed complications such as tube malposition or migration, resulting in delayed diagnosis and management. For instance, a retracted GJ tube into the stomach presents as vomiting and feed intolerance since the feeds administered via the jejunostomy port are emerging into the stomach (Figure 8)[13].

Figure 8 Retraction of gastrojejunostomy tube into the stomach identified incidentally on scoliosis radiographs. A: Frontal; B: Lateral spine radiographs. They show retraction and coiling of the gastrojejunostomy tube (arrows) into the stomach without a retroperitoneal course; C: Frontal abdominal radiographs of the same patient 10 days prior demonstrates gastrostomy tube coursing normally along the C-loop of the duodenum (arrowhead).

Pearl 5

Maintaining vigilance for any discontinuity and the potential accumulation of injected contrast into the abdominal wall is essential, as these are indicative of tube wall breaks. Additionally, associated soft tissue swelling in the area can serve as a subtle indicator of complications.

Pitfall 5

The continuity of the G/GJ tube, especially within the abdominal wall, is frequently overlooked due to increased soft tissue density and peripheral location on images. This oversight can lead to missed tube wall breaks and associated complications, delaying appropriate management.

Clinical presentation of G/GJ tube discontinuity varies depending on the location of the breach. When the tube wall break occurs within the skin and abdominal wall, it often leads to dermatitis and cutaneous breakdown. This can further predispose the patient to infection and abscess formation (Figure 9). If the breach is located within the peritoneum, more severe complications such as peritonitis, abscess formation, and sepsis can arise.

Figure 9 A 16 year old with malfunctioning gastrojejunostomy tube and leakage at stoma. A: Lateral radiograph depicts a focal discontinuity in the gastrojejunostomy tube, just adjacent to the disc (long arrow); B: Frontal radiographs, pre contrast injection; C: Frontal radiographs, post contrast injection. They depict pooling of contrast at the entry site (short arrow) with no luminal opacification of a jejunal loop. Distal block of the tube could also be an underlying cause leading to tube breakage.

Importantly, a leak may also indicate the possibility of a distal obstruction within the G/GJ tube. Another potential complication is a rupture of the jejunal port into the stomach, which can manifest as increased vomiting and feed intolerance.

To definitively diagnose a leak and guide further management, contrast injection under fluoroscopic guidance can be employed. This allows for direct visualization of the leak site and assessment of the extent of the issue.

Pearl 6

Continued symptoms or high suspicion of abnormal G-tube positioning warrants further imaging beyond initial contrast radiographs. For instance, in Buried Bumper syndrome, ultrasound or CT can clearly demonstrate the G-tube balloon embedded within the abdominal wall rather than the gastric lumen, as illustrated in Figure 10.

Figure 10  Local site infection. A 19 year old girl whose gastrostomy button (G-button) was changed at home with presents with a new tube discomfort and swelling. Patient did not follow up regularly since initial G-button placement. There was interval growth of body habitus. A computed tomography was performed on presentation which shows extensive abdominal wall inflammation and inward bowing of abdominal wall (arrow), likely sequela of buried bumper syndrome and leakage of feeds into abdominal wall.

Pitfall 6

Over-reliance on contrast radiography when there's a high suspicion of G-tube malposition, such as Buried Bumper syndrome. Standard contrast radiographs may appear deceptively normal, with contrast filling the stomach and small bowel without obvious extravasation (Figure 7A and B). This is because the contrast follows the gastric contours and rugae, but the buried balloon doesn't create a filling defect. Depending on the G-tube tip location, contrast extravasation into the peritoneal cavity may occur (Figure 7D), but again, the key finding of the absent balloon filling defect can be easily missed.

Pearl 7

On lateral contrast radiographs, an increased distance between the external bolster and the internal retention balloon should raise suspicion for bowel interposition between the abdominal wall and the stomach. CT imaging can definitively confirm this finding.

Pitfall 7

Failure to meticulously assess the G-tube course for interposed bowel loops during image interpretation. The presence of other pathology should not distract from scrutinizing G-tube positioning. Anatomically, the transverse colon's anterior location predisposes it to perforation during G-tube placement. While this can present acutely with severe pain and/or pneumoperitoneum, it may also be asymptomatic[23]. Lateral contrast radiographs may reveal the increased bolster-balloon distance, but CT provides superior clarity and should be employed when suspicion is high. Additionally, be aware of the potential for gastrocolic fistula formation, presenting with diarrhea after G-tube exchange[21]. Fluoroscopy can demonstrate the fistulous tract and/or colonic haustral markings (Figure 11). Delayed G-tube tip retraction into the colon can also manifest as diarrhea and halitosis[21] Less commonly, the G-tube may also be placed into the stomach through the liver or the small bowel (Figure 12)[24].

Figure 11  Colonic gastrostomy tube placement. A 1 month old, postoperative day 5, with a thick brown and bilious output around gastrostomy tube. A and B: Injected contrast demonstrates intraluminal opacification of the transverse colon, descending colon, and rectum (arrowheads) indicating colonic tube placement.

Figure 12  Abnormal gastrostomy tube placement into the bowel loops. A 16 year old male post operative day 4 percutaneous endoscopic gastrostomy. A and B: Axial sections of the computed tomography abdomen depict the gastrostomy tube transversing the dilated small bowel (arrow) and decompressed transverse colon (arrowhead). Findings were confirmed intraoperatively along with a volvulus.

OTHER COMPLICATIONS

A rare complication associated with GJ tubes is esophageal migration because of longer length compared to G-tubes. Patients often present with vomiting and symptoms similar to gastroesophageal reflux. A radiograph without injected contrast into the GJ tube is typically sufficient to establish this analogous position since the tube will course cephalad into the esophagus (Figure 13).

Figure 13  Esophageal malposition of the gastrojejunostomy tube. An 8-year-old female with vomiting and balloon visualized in mouth. Due to respiratory concerns, the balloon was deflated and tubing pulled back prior to imaging. A: Abdomen; B: Lateral radiograph of the chest. Anteroposterior radiograph of the abdomen and lateral radiograph of the chest show that the jejunal tubing is in the esophagus (arrows) and gastric tubing (arrowhead) is coiled in a distended stomach.

Patients with an infection at the G-tube site typically exhibit symptoms such as pain, swelling, and redness. Ultrasound is a preferred modality whenever superficial abdominal wall infections are suspected while CT is preferred for intra-abdominal abscesses. CT may also be a better choice if the patient has a large body habitus which limits penetration of an ultrasound beam. Ultrasound imaging of cellulitis usually has hyperechoic subcutaneous fat locules separated by hypoechoic fluid. Abscesses, on the contrary, are seen as localized hypoechoic to isoechoic fluid collections with peripheral hyperemia[25]. Both abscesses and granulation tissue can appear hypoechoic on ultrasound, but clinical differentiation is possible. An abscess typically shows posterior acoustic enhancement on ultrasound, which on gentle compression demonstrates movement of the fluid component of an abscess (Figure 14)[26]. An abscess is associated with local swelling, tenderness, purulent discharge, and fever, while granulation tissue appears as pink, cauliflower-like tissue that may exhibit bleeding[13].

Figure 14  Local abscess. A 9 year old with gastrostomy tube (G-tube) site swelling. Ultrasound shows a complex fluid collection/abscess in the subcutaneous soft tissues. The gastric wall (long arrow) and G-tube balloon (short arrow) are well seen without evidence of intraperitoneal fluid or air.

A G-tube can be prone to blockage as a result of chronic repeated use or administering dry/incompatible materials such as crushed tablets[27]. In this scenario, flushing or replacement of the tube helps in majority of the cases. If that fails, fluoroscopic evaluation should be considered to exclude the possibility of a malpositioned tube.

CONCLUSION

In conclusion, this review underscores the critical role of imaging in confirming the proper placement of pediatric G-tubes and assessing for complications. The choice of imaging modality in evaluating G-tubes depends on the clinical scenario and level of concern. The article provides a review of the available modalities and indication for each, tips for image optimization, and checklist for thorough assessment. Recognizing these complications early is essential for timely intervention and improved patient outcomes.