Retrieval of a self-expanding metal stent after migration and incorporation in the omental bursa, using a gastroscopic-transgastric laparoscopic rendezvous technique.

Endoscopic drainage is a widely used treatment for pancreatic pseudocysts. Drainage-related complications may be related directly to the procedure or may occur later as stents migrate or erode into adjacent structures. Migration of a self-expanding metal stent into peritoneal cavity and incorporation in the omental bursa is rare. When endoscopic retrieval fails a combined laparoscopic-endoscopic (rendezvous technique) approach offers an alternative to open surgery. We report a case of successful gastroscopic-transgastric laparoscopic removal of a stent that was dislocated into the omental bursa after a ½ year observation period.

INTRODUCTION

Endoscopic methods are among the most important and frequently employed means of treating pancreatic pseudocysts. When possible an endoscopic approach should generally be attempted in all patients with pseudocysts, and for pancreatic fluid collections endoscopic transmural drainage is the treatment of choice. If the cyst contains more than 2/3 solid material a self-expandable stent should be selected to ensure effective drainage. An additional advantage of the self-expandable metal stent is that the necrotic tissue contained within the cyst can be actively removed using an endoscope. This article discusses the unusual case of a stent that became dislodged and migrated into the omental bursa. Following this migration some time was allowed to elapse, and the gastrotomy closed completely. Since a simple endoscopic retrieval was no longer possible, a combined laparoscopic-endoscopic technique (rendezvous technique) was used instead, and the stent was successfully retrieved.

CASE REPORT

In 2013, a 49-year-old male smoker with a history of diabetes mellitus and arterial hypertension developed severe necrotizing pancreatitis. The cause was eventually determined to be choledocholithiasis. Due to persistent inflammation suggestive of cholangitis antibiotic treatment with meropenem was initiated. Imaging revealed paralytic ileus along with an expanding cystic formation near the liver hilus and pancreatic head with compression of the duodenum. A pseudocyst near the left abdominal wall with enormous but stable proportions was also found to be compressing the left colon transversum (14 cm). Due to the extreme thinness of the wall only transcutaneous drainage was possible. After accidental removal of the drain, the cyst again filled with fluid. Areas of necrosis in the corpus area developed, necessitating transgastral cystotomy and placement of a wall stent (Niti-S™ Nagi™ Stent-Taewoong-Medical Co, Seoul, South Korea, 14 mm wide, 22 mm long). Twenty-four hours later, however, the stent became dislodged and migrated into the omental bursa. An attempt at endoscopic removal the following day was unsuccessful, making the insertion of a second stent (Nagi™ fully covered Taewoong,16 mm wide, 22 mm long) necessary. Endoscopic retrograde cholangiopancreatography (ERCP) was then performed, along with papilotomy and insertion of an 8.5 Fr. 10 stent. Two weeks later, after significant clinical improvement and drainage of necrotic tissue, the second transgastric stent was removed with no complications. For technical reasons, retrieval of the migrated stent was not possible. At follow-up gastroscopy 4 weeks later the gastric wall had completely closed and hence that endoscopic localization of the stent was no longer possible. In November 2013, an ERCP was performed, during which the 8.5 Fr. pancreas stent was replaced. The pseudocysts had regressed significantly, and a computed tomography of the abdomen showed the migrated stent in the omental bursa with no direct contact to the gastric wall. In February 2014, we decided to attempt a laparoscopic-endoscopic retrieval of the displaced wall stent. In the first step, a laparoscopic cholecystectomy was performed in a typical manner. Intraoperative endoscopy demonstrated normal gastric mucosa so that a purely macroscopic localization of the stent was not possible [Figure 1]. After localization of the stent via image converter we made a targeted 3 cm incision into the posterior gastric antrum using an Endo Knife (ERBE, Germany). Due to the location of the stent deep within the omental bursa neither optical nor palpatory contact could be made, and consequently, endoscopic retrieval was not an option. In the next step, three transgastral trocars were placed. First, electrocoagulation was used to make three incisions in the anterior wall of the greater gastric curvature (two in antrum, one in fundus). Then, 3 (Applied Medical KII®, USA) 5 mm trocars were inserted [Figure 1]. The 5 mm optics permitted a good view of the posterior gastric wall. Dissection within the omental bursa was performed using two dissectors, inserted through an incision that had been made endoscopically. An image transformer also provided assistance. After localization of the stent and some blunt dissection it was possible to carefully dislodge the stent into the gastric lumen [Figure 2]. The omental bursa was then rinsed with saline solution and suctioned. No complications occurred [Figure 2]. After further inspection, the transgastral trocars were removed, and the gastric wall incisions were closed with Lahodny stitches (Ethicon, USA). Finally, we performed an endoscopic test for leaks. The postoperative clinical course was without complications, and the patient was discharged on the 6th postoperative day. At follow-up 4 weeks later, no complications were found.

Figure 1

Intraoperative gastroscopy. The gastric wall has closed, and the stent cannot be localized (a). Three Applied KII® 5 mm trocars in the stomach (b)

Figure 2

Blunt dissection near the omental bursa after incision and retrieval of the stent (a). Removal of the stent with the aid of an endoscope (b)

DISCUSSION

Currently, endoscopic ultrasound-guided drainage is a safe and effective means of treating pancreatic fluid collections.[123] Compared with surgical or percutaneous drainage it is less invasive and results in lower mortality, costs, and hospitalization times. Drainage-related complications either may be related directly to the procedure or can occur in relation to the stents themselves. Procedure-related complications include bleeding, infection, pancreatitis, or perforation. Plastic and metal stents currently demonstrate comparable rates of success in transmural drainage. The stent should not, however, be removed before complete involution of the pseudocyst or before the passage of at least 2 months. On average, 15% of stents will become accidentally dislocated, but efforts to develop technically superior stents continue. Téllez-Ávila et al., for example, report on fully covered self-expandable metal stents with an innovative anti-migration system.[4] Tarantino et al. describe a stent-in-stent combination which employs the mechanical advantages of both plastic stents and fully covered self-expandable metal stents.[5] Although these new solutions will help reduce the rate of migration, they will not eliminate it completely. In most cases of stent migration endoscopic retrieval can be performed without difficulty. In cases of extraluminal loss, however, a surgical approach is often necessary, and a minimally invasive exploration of the abdominal cavity is the approach of choice. Retrieval from the retroperitoneal space may pose a more significant challenge due to the proximity of the large vessels. When endoscopic retrieval fails a combined laparoscopic-endoscopic approach offers an alternative to open surgery. The choice of technique is likely best predicated by individual patient presentation and local expertise. With this endoscopy-laparoscopy combination (rendezvous technique) the stent can be better localized, visualized, and safely removed.