The Study Of Endoscopically Placed Procedure Of Metallic Stents For Malignant Gastric Outlet Obstruction

[Objective] Covered or uncovered self-expanding metallic stents have been proved to be an easy, safe and effective device for palliation of esophageal malignant obstruction and esophagorespiratory fistula. However, there was neither standard therapeutic methord nor mature experience in endoscopically placed procedure and stent selection during endoscopic stenting on the parts of alimentary canal except esophagus and biliary tract. Surgical gastrojejunostomy is the only way of treatment for malignant outlet obstruction (GOO) in the past. Unfortunately this intervention can be association with significant morbidity and mortality. Self-expanding metallic stents designed for the biliary tract, such as the Gianturco-Rosch Z-stent and the Wallstent have been reported to provide effective treatment for the GI tract with minimal morbidity. Endoscopic stenting can be as a alternative at present, although the stents are small-caliber lumens and the result of the treatment have been limited. We wanted to conduct a prospective study to determine the technical feasibility and clinical outcomes of using of an improved-designed self-expanding metal stents by non-TTS (stent placement no need pass through the endoscopic channel) to treat malignant GOO. These stents. as having larger caliber lumens, have the more advantage than the ones placed by TTS. Owing to the sharp ends of stent, it usually caused the membrane lesion, hemorrhage and perforation previously when positioned on the location such as gastric pylorus, duodenum and colon. This is the reason why the metallic stents were only applied for malignant esophageal obstruction. At present, self-expanding metallic stent can be positioned at any place of GI that could be covered by gastroscope and colonoscope as the modification of the stents hasundergone in its manufacture and the length of the delivery system have been increased. However, as the delivered distance of stent is extended, the clinical technique such as stent introduce, stent release and the location of stent placement as well as intervention complication will be made further exploration. The aim of our study is to evaluate the technical feasibility and clinical effectiveness of endoscopic stenting in the treatment of gastric outlet obstruction caused by gastric cancer, in order to establish a new endoscopic therapy.[ Methods 1 42 patients with gastric cancer complicated gastropyloric obstruction have been selected as our subjects. The procedure of our subject's selection as follow: during conventional endoscopy, the patients with gastric cancer diagnosed by gastroscope underwent endoscopic biopsy, the final diagnosis of gastric cancer was obtained by means of histopathologic examination. In all of 42 patients, the gastric cancer was considered inoperable because of its extensive growth and the presence of distance metastases according to the result of careful physical examination. Surgical treatment was refused by the patients or the members of their family. Gastropyloric obstruction was diagnosed by gastroscopy and was graded on a scale of 0 to 4 before stent placement. All the patients selected as our subjects were first dilated with pyloric dilation balloon catheter on the obstructive site. After balloon dilation, the stricture site was studied with endoscope in order to choose appropriate length and diameter of metallic stents. Then stent placement was performed endoscopically. All the patients were kept in hospital for one week after the procedure of stent placement. During this period, the symptoms such as nausea, vomiting and patient's diet were conscientiously recorded and laboratory test, EKG and abdominal fluoroscopy were provided for every one. After the patients were discharged, further follow-up in each one was based on clinical examination in the outpatient department at least for 12 weeks. While obstructive symptoms appeared or the migration of stent have been found by x-ray, endoscopy was performed immediately.[Results] We attempted to place a metallic stent in 42 patients withinoperable gastric or gastroduodenal malignant obstruction. Before stent placement, obstructive site had been dilated by pyloric dilation balloon catheter with a maximum inflated diameter of 1.5cm. The position of the balloon was adjusted endoscopically. The balloon was then expanded manually with dilute contrast medium and dilated the site open about 1.5cm in diameter. Implantation of the self-expandable metallic stent was achieved in 40 patients and the percentage of technically successful rate was about 95.2%. At the beginning of the therapeutic period, in 5 patients, at first, the stents in the delivery systems could not be released. Two of these 5 patients, the delivery systems were retracted and the covered stents were exchanged with naked ones and then were released smoothly. The other 3 patients were treated using knitted nitinol stent insertion for gastric outlet stenoses. In the early phase of this study, two patients had failure of stent placements because we could not advanced the introducer-stent set through pyloric site into the duodenum duo to loop formation of the delivery system in the fundus of the stomach. A follow-up study was available in 34 patients for more than 12 weeks. Five of 40 patients died 4, 5 and 10 weeks after stent placement. 32 patients were able to ingest at least soft food and there were no vomiting in aii of them. The percentage of clinically successful rate was 76.2%. No major complications except migration of stents occurred, such as bleeding, perforation and pressure ulceration from the ends of the stents. Stent migration occurred in 2 patients during a follow-up of 3 weeks after stent placement. The stent migrated upward completely in one patient and removed by using a loop-snare technique, in another, the stent migrated downward into small intestine and was extracted during gastrectomy one weeks later.[Conclusion] A simple, nonsurgical method to palliate intractable vomiting and the inability to eat would be important advance in the management of inoperable malignant gastroduodenal obstructions. Different types of covered or uncovered expandable metallic stents have been reported to provide effective treatment alternatives with minimal morbidity in patients with benign or malignant gastroduodenal obstruction. However, per oral placement of metallic stents ing astro duodenal obstructions by using the currently available introducer was considered extremely difficult because of the acute angularity of the gastric antrum to the esophageal axis. Our prospective study found that endoscopic treatment of malignant GOO with the self-expanding metallic stents is a safe and effective alterative to surgery. Our deployment facilitate accurate and safe stem insertion. The slim and flexible delivery systems permits stent placements into the angulated lumen of the gastrointestinal tract with prior dilation of the stenoses. The large diameter of these stents allows patients to eat regular food and perhaps prevents early occlusion as a result of tumor ingrowth. With our experience, we found that placement of a metallic stent was associated with minimal morbidity, allowing us to discharge patients shortly after stenting. In conclusion, our initial experience with use of the self-expanding metallic stents to treat patients with malignant GOO is favorable. Endoscopic stenting is technically feasible and safe . efficacious and minimally invasive means for palliation of patients with inoperable malignant GOO. The operation procedure is simple and easy, and the successful rate is so high that it is worth while application and dissemination clinically.