Placement of conventional and expandable stents for malignant esophageal stenoses

Esophageal Stenting: How I Do It

Endoscopic esophageal stent placement is an effective palliative treatment for malignant strictures and has also been successfully used for benign indications, including esophageal refractory strictures and iatrogenic leaks and perforations. Despite several decades of evolution and the wide variety of esophageal stents available to choose from, an ideal stent that is both effective and without adverse events such as stent migration, tissue ingrowth, or pressure necrosis has yet to be developed. This paper is an overview of how this evolution happened, and it also addresses the characteristics of some of the currently available stents, like their material and construction, delivery device, radial and axial force pattern, covering and size which may help to understand and avoid the occurrence of adverse events. The insertion delivery systems and techniques of placement of an esophageal self-expandable metal stent are reviewed, as well as some tips and tricks regarding placement and management of adverse events.

Techniques and principles of endoscopic treatment of benign gastrointestinal strictures

PURPOSE OF REVIEW

The fundamental goal of treating any stenosis is luminal enlargement to ameliorate the underlying obstructive symptoms. Symptoms depend on the etiology and the site of the stricture and may include dysphagia, nausea and vomiting, abdominal pain, obstipation, or frank bowel obstruction. This article compares the various current technologies available for the treatment of gastrointestinal stenoses with regard to ease and site of application, patient tolerance, safety and efficacy data, and cost-benefit ratio.

RECENT FINDINGS

Recent studies indicate that gastrointestinal dilation and stenting have evolved to a point at which in many if not most situations they can be the first line therapy and potentially the final therapy needed to treat the underlying condition.

SUMMARY

Following techniques and principles in the management of gastrointestinal strictures would allow for the well tolerated and effective treatment of most patients with the tools currently available today.

Auxetic oesophageal stents: structure and mechanical properties

Oesophageal cancer is the ninth leading cause of malignant cancer death and its prognosis remains poor, ranking as the sixth most frequent cause of death in the world. This research work aims to adopt an Auxetic (rotating-squares) geometry device, that had previously been examined theoretically and analysed by Grima and Evans (J Mater Sci Lett 19(17):1563-1565, 2000), to produce a novel Auxetic oesophageal stent and stent-grafts relevant to the palliative treatment of oesophageal cancer and also for the prevention of dysphagia. This paper discusses the manufacture of a small diameter Auxetic oesophageal stent and stent-graft. The oral deployment of such an Auxetic stent would be simplest if a commercial balloon dilatational catheter was used as this obviates the need for an expensive dedicated delivery system. A novel manufacturing route was employed in this research to develop both Auxetic films and Auxetic oesophageal stents, which ranged from conventional subtractive techniques to a new additive manufacturing method. Polyurethane was selected as a material for the fabrication of Auxetic films and Auxetic oesophageal stents because of its good biocompatibility and non-toxicological properties. The Auxetic films were later used for the fabrication of seamed Auxetic oesophageal stents. The flexible polyurethane tubular grafts were also attached to the inner luminal side of the seamless Auxetic oesophageal stents, in order to prevent tumour in-growth. Scanning electron microscopy was used to conduct surface morphology study by using different Auxetic specimens developed from different conventional and new additive manufacturing techniques. Tensile testing of the Auxetic films was performed to characterise their mechanical properties. The stent expansion tests of the Auxetic stents were done to analyse the longitudinal extension and radial expansion of the Auxetic stent at a range of radial pressures applied by the balloon catheter, and to also identify the pressure values where the Auxetic stent fails. Finite element models of both Auxetic film and Auxetic stent were developed, and the results were compared with experimental results with a good agreement. The tensile testing of the Auxetic polyurethane films revealed that the Poisson's ratio of the sample ranged between -0.87 and -0.963 at different uniaxial tensile load values. From the stent expansion test, it was found that the Auxetic oesophageal stent radially expanded from 0.5 to 5.73 mm and longitudinally extended from 0.15 to 1.83 mm at a range of applied pressure increments (0.5-2.7 bar) from the balloon catheter.

Self-expanding plastic stent to palliate symptomatic tissue in/overgrowth after self-expanding metal stent placement for esophageal cancer

Self-expanding metal stents (SEMS) are used to treat obstructive malignancies of the esophagus or esophagogastric junction; however, a potential complication is recurrent dysphagia because of tissue in/overgrowth. The placement of a second SEMS is one strategy to re-establish patency of the esophageal lumen. We evaluated the safety and efficacy of an alternative and likely less costly approach: placing a self-expanding plastic stent (SEPS) to manage relapsing dysphagia in patients previously treated with a partially covered SEMS. From December 2007 to January 2009, 13 patients previously treated with a SEMS for malignant dysphagia underwent treatment by inserting a SEPS to palliate relapsing dysphagia, as a result of tissue in/overgrowth. Stenosis was located in the upper esophagus in one patient, in the middle in four patients, and in the lower esophagus in eight patients. Clinical evaluation was performed at the time of stent placement, after 1 week, and then, monthly until death. The SEPS was successfully placed in a single treatment session for all patients. No preliminary dilation was required, and no further treatment was necessary for any patient. Before stenting, the median dysphagia score was 4 (range 3-4), and 1 week later the score was 0 for all patients. The resolution of dysphagia persisted until patient death (from tumor progression). The mean survival after the SEPS insertion was 4 months (range 3-8). This case series supports the use of a SEPS to palliate dysphagia from tissue in/overgrowth of a SEMS. Future clinical trials with larger patient samples are warranted.

Endoscopic treatment of thoracic esophageal anastomotic leaks by using silicone-covered, self-expanding polyester stents

BACKGROUND

Surgery, as well as conservative treatment, in patients with clinically apparent intrathoracic esophageal anastomotic leaks often is associated with poor results and carries a high morbidity and mortality. The successful treatment of esophageal anastomotic insufficiencies and perforations when using covered, self-expanding metallic stents is described.

METHODS

The feasibility and the outcome of endoscopic treatment of intrathoracic anastomotic leakages when using silicone-covered self-expanding polyester stents were investigated. Twelve consecutive patients presented with clinically apparent intrathoracic esophageal anastomotic leak caused by resection of an epiphrenic diverticulum (n = 1), esophagectomy for esophageal cancer (n = 9), or gastrectomy for gastric cancer (n = 2), were endoscopically treated in our department. The extent of the dehiscences ranged from about 20% to 70% of the anastomotic circumference. After endoscopic lavage and debridement of the leakage at 2-day intervals (mean duration, 8.6 days), a large-diameter polyester stent (Polyflex; proximal/distal diameters 25/21 mm) was placed to seal the leakage. Simultaneously, the periesophageal mediastinum was drained by chest drains.

OBSERVATIONS

All 12 patients were successfully treated endoscopically without the need for reoperation. A complete closure of the leakage was obtained in 11 of 12 patients after stent removal (median time to stent retrieval, 4 weeks, range 2-8 weeks). In one patient, a persistent leak was sealed endoscopically after stent removal by using 3 clips. Distal stent migration was obtained in two patients.

CONCLUSIONS

The placement of silicone-covered self-expanding polyester stents seems to be a successful minimally invasive treatment option for clinically apparent intrathoracic esophageal anastomotic leaks.

Temporary stenting of acquired benign tracheoesophageal fistulas in critically ill ventilated patients

BACKGROUND

To evaluate the use of esophageal stents for temporary sealing of acquired benign tracheoesophageal fistulas developed in critically ill, ventilated patients.

METHODS

This is a retrospective analysis (1992-2003) of the data of 12 mechanically ventilated patients - six of them after major or multiple trauma - being intubated for a median of 30 days before they develop an acquired benign tracheoesophageal fistula. Five of them were in sepsis. Two types of stents were used: the Wilson-Cook esophageal balloon plastic stent in the first four cases and the Ultraflex covered self-expandable stent in the remaining eight. The total procedure was performed at bedside in the intensive care unit, with no special need for supplementary anesthesia or fluoroscopic control.

RESULTS

Stent implantation was technically successful in all patients and fistula occlusion was achieved in every case. There was no stent migration and fistulas remained sealed until death or upon decision for removal. Nine patients died between 5 days and 2 months after stent placement, as a result of their diseases. Three patients were referred for fistula surgical repair 33, 36, and 43 days after stent placement. Before surgery the stents were easily removed under direct vision.

CONCLUSION

Temporary closure of an acquired tracheoesophageal fistula developed in critically ill ventilated patients is an easy, bedside-applicable, safe, and effective palliative procedure, with no complications or mortality.

Use of self-expandable metallic stents in benign GI diseases

BACKGROUND

The self-expandable metallic stent is of proven benefit in patients with malignant disease; however, its use in patients with benign disease is not well established. There are few data available regarding long-term complications and outcomes with use of self-expandable metallic stents in benign disease and virtually none regarding attempted removal once the acute problem is resolved.

METHODS

Thirteen patients who had a self-expandable metallic stent placed for benign GI disorders were included in a retrospective analysis. Data collected included patient demographics, indication for procedure, type of stent used, complications, and patient outcomes.

RESULTS

Thirteen patients (7 women, 6 men; mean age 67 years, range 34-84 years) had one or more self-expandable metallic stents placed for benign disease and were followed for a mean of 3.4 years (3 weeks to 10 years). Of the 13 patients, 8 had esophageal stents, 4 biliary stents, and 1 had dual stents placed in the pancreaticobiliary tree. Complications developed in 8 (62%) patients; 4 (31%) ultimately died, either from the primary disease process (3) or from stent-related complications (1).

CONCLUSIONS

Self-expandable metallic stent placement is effective treatment for benign esophageal leaks, providing the stent can be removed. It also may be used in either the esophagus or biliary tree in patients who are poor candidates for surgery and short expected survival. However, a self-expandable metallic stent should not be placed in a patient with a benign GI disorder who has a significant life expectancy and is a good candidate for surgery.