Teaching Case

Elderly woman with recurrent squamocellular carcinoma of the oral cavity infiltrating the mandible, admitted to emergency department because of fever, abdominal pain and inability to pass stools. Two months earlier at another institution she underwent positioning of permanent tracheostomy and of percutaneous endoscopic gastrostomy (PEG).

A semi-erect plain radiograph (Fig. 1) was immediately obtained of the bedridden patient: a prominent right subphrenic air crescent revealed the presence of pneumoperitoneum, associated with basal lung opacities consistent with hypoventilation. Her clinical conditions rapidly worsened with altered mental state, hypotension, metabolic decompensation and oliguria.
Urgent contrast-enhanced multidetector CT (Fig. 2) confirmed pneumoperitoneum, associated with fluid-attenuation ascites. The PEG device was seen dislocated externally, with the internal bumper clearly outside the collapsed stomach and located in the anterior abdominal wall within the thickened left rectus muscle. Air was visible along the PEG migration tract. These findings were consistent with gastric perforation from PEG dislodgement (“buried bumper syndrome”).
Emergency laparotomic surgical exploration confirmed biliary ascites and gastric perforation at the PEG site, which was repaired and anchored to the abdominal wall.
Unfortunately, the patient could not recover because of her critical condition.

Since its description in 1980, percutaneous endoscopic gastrostomy (PEG) has become the preferred minimally invasive technique to provide enteral access and prevent lung aspiration in patients with normal intestinal function but unable to take oral feeding. The commonest indications for long-term nutrition support or palliation include swallowing disorders or dysphagia due to neurologic disorders (such as amyotrophic lateral sclerosis or stroke) and upper aerodigestive tract cancers undergoing chemoradiotherapy. Furthermore, PEG is increasingly adopted in patients requiring prolonged intensive care unit hospitalization [1-3].
PEG has a high technical success rate, low intrinsic morbidity and mortality, and may be easily replaced when malfunction occurs. However, PEG is associated with a non-negligible risk of complications which may result from insertion, from devices left in place for a long time, or during replacement. After the early post-procedural period, adverse events occur in 18-21% of cases and include peristomal infections, diarrhoea, leakage, and device migration/dislodgement. These complications often need urgent surgery and are associated with a significant mortality (approaching 17% of patients). A rare complication (incidence 0.3-2.4%) the “buried bumper syndrome” (BBS) refers to the tightly juxtaposed internal bumper progressively eroding into the gastric wall along the PEG tract, causing haemorrhage, difficult feeding, and abdominal pain. Endoscopically, in most cases the internal bumper is hardly seen “buried” into a large ulceration [3-6].
The PEG tube positioning and function is checked during physical examination of the device exit site at the skin, complemented by endoscopy or fluoroscopic-guided injection of contrast medium. However, only CT can provide information on the anatomical structures and abnormalities located along the PEG tract. CT easily shows the thickness and structural changes of subcutaneous fat, abdominal wall muscles and the peritoneal gap between the stomach and abdominal wall. In BBS CT allows localizing the buried internal bumper between the gastric and abdominal wall, and assessing the presence and severity of inflammation, abscess collections, extraluminal air or effusion. As this case demonstrates, CT demonstration of the buried bumper migration path allows a correct therapeutic choice including surgical, manual, or endoscopic removal. Delayed recognition and treatment are associated with severe morbidity and death [2, 6].
In conclusion, due to the increasing use of these devices for enteral feeding and palliation, clinicians and radiologist may become faced with suspected acute and long-term PEG-related complications. Prompt use of CT may prove useful to elucidate most occurrences and prevent severe consequences [5, 6].