1 INTRODUCTION
Data from the Ministry of Health show the increasing importance of obesity in the health of the population. The change in habits has made Brazil a country with fewer cases of malnutrition to the detriment of the progressive increase in cases of obesity, with the age group most affected between 45-64 years and similar distribution between men and women¹.
Public policies are gradually trying to encourage healthy habits that impact the population’s diet and lifestyle, as well as investment in drug therapies to control obesity-related comorbidities¹. However, conservative therapies have high rates of abandonment and are ineffective.
Bariatric surgery, although effective, has limited indications2, in addition to offering a risk of early and late postoperative complications3. According to the Brazilian Society of Bariatric and Metabolic Surgery, from 2012 to 2017, the number of bariatric surgeries in the country increased by 46.7%. In the midst of this scenario, this type of surgery has aroused surgeons’ interest in improving and modernizing their techniques, as well as in addressing their complications, aiming at a safer and more effective treatment4.
The most used operative techniques are gastric bypass (Roux-en-Y gastric bypass) and vertical gastrectomy (Sleeve). Gastric bypass is a mixed technique, in which the disabsorptive component is provided by the extension of the intestinal bypass. Several modifications of this technique were created in an attempt to improve weight loss and reduce the number of complications5.
Fobi and Capella proposed the placement of a silicone ring in the gastric reservoir, just above the gastrojejunal anastomosis, in order to calibrate its diameter and prevent a possible dilation that would cause weight recovery in the future. Despite the benefit, patients who underwent gastric bypass surgery with a ring may experience late complications of the technique such as food intolerance, erosion, or ring migration5. The classic treatment for complications is the surgical removal of the ring, but this approach offers great morbidity and mortality due to possible complications. However, several techniques have been developed, in order to solve the cases in a less invasive way, through endoscopic procedures, without the need for surgical reintervention6.
Among the endoscopic techniques, there is the endoscopic removal of the ring through the use of accessories (scissors), pneumatic balloon dilation, and the application of gastric stents (plastic or metallic) with peculiar and specific indications for each type of complication.
Erosion of the retaining ring is a rare complication7,8 with an incidence of 1% to 7% of patients in the postoperative period. The clinical picture can be asymptomatic as an endoscopic finding or vary from mild symptoms such as epigastric pain, nausea/vomiting, obstructive symptoms and changes in weight (recovery or excessive loss), to more serious complications such as bleeding, intra-abdominal abscess, and fistula formation9.
When less than 50% of the ring is visible through gastric light, one can use the prosthesis (metallic or plastic) for a period of one to two weeks to accelerate the erosion process, which is based on the necrosis provided by the ischemia in the gastric wall between the prosthesis and the retaining ring8.
Ring intolerance may be secondary to gastric stenosis promoted by the ring in its usual position or due to distal sliding. Stenosis can cause constrictive symptoms; the contrasted examination may show a narrowing in the region of the device and, on endoscopic examination, an insurmountable ring constriction or laborious passage of the endoscopy device is noted8.
The slip corresponds to the displacement of the prosthesis externally to the gastric pouch in a distal direction that promotes the riding on the jejunal loop, generating extrinsic compression and the consequent difficulty in emptying the gastric pouch with an incidence of less than 1%9. Such slippage can be total or partial, generating a picture with lesser or greater feeding difficulties and vomiting, respectively. The diagnosis of slippage can be performed by means of contrasted radiography observing a poor positioning of the ring in early cases, or even in the identification of late findings such as the increased diameter of the gastric pouch, hydro-aerial level, and wide anastomosis. At the endoscopic examination, dilation of the gastric pouch, gastric residue, esophagitis due to vomiting, the convergence of jejunal folds, and even mucosal prolapse to the gastric chamber.
The treatment for this condition can be carried out with the rupture of the ring by the use of a pneumatic balloon dilator or the extraction of it by the use of stents (plastic or metallic).9 The dilation mechanism aims at the rupture of the wire inside the ring by inflating the balloon used for the treatment of achalasia, which has sufficient radial force to rupture the device. Through endoscopic examination, the guidewire is passed through the efferent loop, and, with the aid of fluoroscopy, the pneumatic dilator balloon (30 mm) is positioned so that it is enclosed by the ring when it is inflated and its rupture in the ring must be accompanied by radioscopy.10
The dilation of the esophagogastric transition (TEG) and gastrojejunal anastomosis should be avoided in case of distal migration of the device since jejunum loops are not as resistant and offer a high risk of perforation for the procedure. The success rate of one study revealed 66% of the complete rupture of the ring. However, in the other 34%, clinical improvement was successful, even without rupture of the device10.
The use of a gastric prosthesis, whether plastic or metallic, may be indicated in cases of partial erosion of the band (<50%) or when there is an indication for ring extraction, but there is no migration of it to the interior of the gastric chamber8. This procedure causes progressive erosion of the ring into the lumen of the stomach, due to the ischemia caused between the prosthesis and the ring due to the compression of the stomach wall10. In the market there is no longer the manufacture of plastic stents previously used (Polyflex - Boston Scientific®), therefore, currently, metallic stents fully covered for this type of treatment are used.
Prosthesis implantation and extraction procedures are preferably performed in the operating room, under general anesthesia and with the aid of fluoroscopy. External markings with radiopaque materials can be used to facilitate the probable location of the prosthesis, which should encompass the ring in its middle portion.11 The proximal end should be located below the level of the diaphragmatic hiatus to avoid pathological gastroesophageal reflux and the distal end should be placed in the efferent loop. After a period of 10 to 15 days, the stents are extracted through the mouth with the aid of grasping forceps, and in that period more than 50% of the rings are migrated into the gastric chamber.12 If the ring is not extracted next to the prosthesis, it can be removed with grasping forceps similar to the removal of a foreign body13. However, if it is not extruded, but only apparent in the gastric chamber, it must also be removed after 30 days, with the aid of endoscopic scissors and grasping forceps.
In general, complications related to the procedure are mild, such as nausea/vomiting, abdominal pain, migration, and late stenosis in the ring region, which can be treated with balloon dilation later13. Serious complications have not yet been reported in the literature.
Despite being used to increase the restrictive effect of bariatric surgeries, the gastric containment ring is prone to complications, such as slipping and erosion and consequent side effects, such as food intolerance. One of the modalities used in the endoscopic treatment of this condition is the endoscopic extraction through the use of Stents and that configures a minimally invasive, safe and effective alternative to the detriment of the surgical treatment that is less and less used due to its higher morbidity and mortality.