Esophageal stent fracture: Case report and review of the literature

Exploring the potential of intermetallic alloys as implantable biomaterials: A comprehensive review

This review delves into the utilization of intermetallic alloys (IMAs) as advanced biomaterials for medical implants, scrutinizing their conceptual framework, fabrication challenges, and diverse manufacturing techniques such as casting, powder metallurgy, and additive manufacturing. Manufacturing techniques such as casting, powder metallurgy, additive manufacturing, and injection molding are discussed, with specific emphasis on achieving optimal grain sizes, surface roughness, and mechanical properties. Post-treatment methods aimed at refining surface quality, dimensional precision, and mechanical properties of IMAs are explored, including the use of heat treatments to enhance biocompatibility and corrosion resistance. The review presents an in-depth examination of IMAs-based implantable biomaterials, covering lab-scale developments and commercial-scale implants. Specific IMAs such as Nickel Titanium, Titanium Aluminides, Iron Aluminides, Magnesium-based IMAs, Zirconium-based IMAs, and High-entropy alloys (HEAs) are highlighted, with detailed discussions on their mechanical properties, including strength, elastic modulus, and corrosion resistance. Future directions are outlined, with an emphasis on the anticipated growth in the orthopedic devices market and the role of IMAs in meeting this demand. The potential of porous IMAs in orthopedics is explored, with emphasis on achieving optimal pore sizes and distributions for enhanced osseointegration. The review concludes by highlighting the ongoing need for research and development efforts in IMAs technologies, including advancements in design and fabrication techniques.

Spontaneous Endoscopic Esophageal Stent Fracture Post-endoscopic Placement: A Case Report

Endoscopic esophageal stent (EES) placement is an important tool for the non-operative management of esophageal pathologies. A rare and infrequently reported complication of EES placement is stent fracture and subsequent migration of the broken fragments. We report a rare case of a spontaneous EES fracture from Pakistan four weeks following its placement for esophageal perforation management, and an uneventful endoscopic retrieval of the fractured stent pieces. The recommended guidelines from available, albeit limited, research literature are also discussed as part of this case report.

Small Bowel Obstruction Secondary to Migration of a Fractured Esophageal Stent

Esophageal stent placement is commonly indicated for the management of inoperable esophageal malignancies, benign strictures, and esophageal perforations including Boerhaave's syndrome. We present a case of a 74-year-old female, who presented with small bowel obstruction secondary to a migrated esophageal stent, which was placed 20 weeks previously for Boerhaave's syndrome. She was surgically managed with laparotomy and retrieval of the fractured stent with local resection of the small bowel, followed by primary anastomosis.

Inversion technique under fluoroscopy for removal of self-expanding nitinol esophageal stent after long-term placement: review of 107 consecutive cases

BACKGROUND

Removal of self-expanding esophageal metal stents that have been implanted for a long time can be difficult and risky.

PURPOSE

In this paper, we describe the use of the "inversion technique" under fluoroscopy for removal of self-expandable nitinol esophageal stents that have been placed for long periods and evaluate the effectiveness and safety of the method.

METHODS

Retrospective analysis of patients who underwent removal of self-expanding nitinol esophageal stents by the inversion technique under fluoroscopy at our center. Demographic characteristics, type of esophageal stents, stent retention time, reasons for stent removal, and related complications were collected from the case records and analyzed.

RESULTS

A total of 112 metal esophageal stents (62 fully covered esophageal stents and 50 partially covered esophageal stents) were extracted from the 107 patients included in the study. Indications for stent implantation were malignant esophageal stenosis (27 patients), benign esophageal stenosis (42 patients), and esophageal fistula (38 patients). Median duration of stent retention was 77 days (29-727 days). All stents were removed successfully without major complications such as esophageal rupture, massive hemorrhage, asphyxia, or cardiorespiratory arrest.

CONCLUSION

Inversion technique under fluoroscopy appears to be a safe, effective, and quick procedure for removal of self-expanding nitinol esophageal stent after long-term placement.

Fracture of self-expandable metallic stent inserted for unresectable gastric cancer at the esophagogastric junction: successful retrieval of distal fragment by gastrotomy

Endoscopic stenting is useful for amelioration of gastrointestinal stenosis. This procedure benefits severely compromised patients who cannot afford surgery. Although the self-expandable metallic stent (SEMS) is safe, it is also associated with several complications such as perforation, migration, and fracture. Migration of a SEMS is not particularly rare; however, fracture of a SEMS is relatively rare. An 88-year-old man underwent stenting for dysphagia at another hospital. He was being treated for gastric cancer at the esophagogastric junction. After appropriate stenting, he regained his ability to eat and was discharged the hospital. Only 2 months later, however, he again lost his ability to eat and visited our hospital. Abdominal X-ray and computed tomography revealed a stent fracture. The proximal fragment was in the esophagus, and the distal fragment was in the stomach. An emergency operation involving gastrotomy and gastrostomy was performed. Open gastrotomy was performed to remove the fractured distal stent, and percutaneous tube gastrostomy was placed through the same gastric incision for nutrition support. The surgery was successful, and he was again able to eat. In this report, we discuss the occurrence of SEMS fracture within a short time periods after insertion.

Characterization of Partially Covered Self-Expandable Metallic Stents for Esophageal Cancer Treatment: In Vivo Degradation

Partially covered self-expandable metallic esophageal stent (SEMS) placement is the most frequently applied palliative treatment in esophageal cancer. Structural characterization of explanted 16 nitinol-polyurethane SEMS (the group of 6 females, 10 males, age 40-80) was performed after their removal due to dysfunction. The adverse bulk changes in the polymer structure were identified using differential scanning calorimetry (DSC), differential mechanical thermal analysis (DMTA), and attenuated total reflectance infrared spectroscopy (ATR-IR) and discussed in terms of melting point shift (9 °C), glass-transition shift (4 °C), differences in viscoelastic behavior, and systematic decrease of peaks intensities corresponding to C-H, C═O, and C-N polyurethane structural bonds. The scanning electron and confocal microscopic observations revealed all major types of surface degradation, i.e., surface cracks, peeling off of the polymer material, and surface etching. The changes in the hydrophobic polyurethane surfaces were also revealed by a significant decrease in wettability (74°) and the corresponding increase of the surface free energy (31 mJ/m²). To understand the in vivo degradation, the in vitro tests in simulated salivary and gastric fluids were performed, which mimic the environments of proximal and distal ends, respectively. It was concluded that the differences in the degradation of the proximal and distal ends of prostheses strongly depend on the physiological environment, in particular stomach content. Finally, the necessity of the in vivo tests for SEMS degradation is pointed out.

Environmental fatigue of superelastic NiTi wire with two surface finishes

Surface finish of NiTi is widely perceived to affect its biocompatibility and corrosion fatigue performance. The aim of this work was to find out, whether a carefully engineered surface oxide shows any beneficial effect over electropolished surface on the fatigue performance of superelastic NiTi wire mechanically cycled in simulated biofluid. Series of corrosion and environmental fatigue tensile tests was performed on superelastic NiTi wire with two different surface finishes frequently used in medical device industry. Open Circuit Potential reflecting the activity of chemical reactions on the surface of the wire cycled in electrochemical cell was continuously monitored during the fatigue tests. Microcracks at the surface of the fatigued NiTi wires were characterized by SEM and TEM. It was found that the carefully engineered 70 nm thick TiO₂ oxide provides the NiTi wire with similar level of protection against the static corrosion as the less than 10 nm thin natural oxide on the electropolished wire and that it does not have any positive effect on its performance in environmental fatigue tests, whatsoever. On the contrary, the wire covered by the carefully engineered 70 nm thick TiO₂ oxide displayed systematically poorer fatigue performance upon tensile cycling under specific critical loading conditions (strain amplitude <0.5% at large mean strains 1-7%).

Self-Expanding Metallic Stent Fracture in the Treatment of Malignant Biliary Obstruction

Background

Palliative therapies for malignant biliary obstruction (MBO) include choledochojejunostomy and self-expanding metallic stent (SEMS) insertion. Fractures following SEMS insertion in MBO treatment are scarce.

Objective

To assess the clinical features of biliary stent fractures and evaluate associated factors.

Methods

One hundred fifty-six consecutive patients who underwent biliary SEMS placement for MBO treatment at Beijing Chaoyang Hospital affiliated to Capital Medical University, in 2010–2015, were evaluated retrospectively. Demographics, clinical features, stent parameters and patency times, and survival times were collected. Across the ampulla of Vater, balloon dilatation, number of stents, stent patency time, and survival time were compared between the stent and nonstent fracture groups.

Results

There were 168 biliary metallic stents inserted in 156 patients, including 144 and 12 patients with one and 2-3 stents, respectively. Pre- and/or postballoon dilation was performed in 107 patients. Stents across and above the duodenal papilla were used in 105 and 51 patients, respectively. Six cases (3.8%) with stent occlusion had stent fractures. Single- and multiple-stent fracture rates were 4/144 (2.8%) and 2/12 (16.7%), respectively. Fracture times after stent deployment were 126.8 ± 79.0 (median, 115.5) days. Stent patency times in the stent and nonstent fracture groups were 151.8 ± 67.8 (median, 160.5) days and 159.3 ± 73.6 (median, 165.5) days, respectively. Overall survival times in the stent and nonstent fracture groups were 399.7 ± 147.6 (median, 364.0) days and 283.7 ± 126.1 (median, 289.0) days, respectively.

Conclusion

Stent fractures following MBO treatment constitute a relatively rare long-term complication. Though there were no factors found to be significantly associated with SEMSs fracture, a trend could be observed towards more fractures in multistent, transpapillary, and balloon dilation groups.

A simplified technique of esophageal self-expandable metallic stent placement without fluoroscopic and endoscopic guidance for treating esophageal carcinoma

BACKGROUND/AIMS

Self-expandable metallic stent (SEMS) placement with fluoroscopic guidance is a commonly used technique to relieve obstruction in patients with esophageal carcinoma. However, it has disadvantages such as radiation exposure. SEMS placement with endoscopic guidance also has the disadvantages of causing discomfort to patients as the endoscope and SEMS assembly are simultaneously used and it needs two experts for the procedure to be performed. To overcome these disadvantages, a simplified technique for SEMS placement was developed that does not require fluoroscopic or endoscopic guidance. Our objective was to compare the efficacy and safety of this simplified technique with the conventional SEMS placement method.

MATERIALS AND METHODS

This is a retrospective study including patients with esophageal carcinoma who underwent SEMS placement for the palliation of dysphagia.

RESULTS

Sixty-two patients were placed on stents for the palliation for esophageal carcinoma, with 46 patients in the conventional technique group (group A) and 16 in the simplified technique group (group B). The duration of the procedure was considerably lesser in group B than in group A (2 min 53 s vs. 15 min 4 s, p=0.001). The technical success rate achieved in groups A and B were 97.82% and 100%, respectively. SEMS placement required two experts in the conventional technique whereas the simplified technique required only one expert.

CONCLUSION

The advantages of the simplified technique are as follows: technical ease, cost-effectiveness, no exposure to radiation, requirement of minimal manpower, and less time-consuming; these advantages make it the technique day-care procedure.

Caustic Esophageal Stenosis: A Case Report of Endoscopic Dilation With a Dynamic Stent

INTRODUCTION

The management of esophageal strictures has evolved from surgical treatment to the endoscopic dilation and, more recently, esophageal stenting.

CLINICAL CASE

We describe a case of a two-year-old boy with a double stenosis of the esophagus resulting from accidental ingestion of strong alkaline liquid. After several unsuccessful endoscopic dilations for three years and even topical mitomicin, it was decided to place a dynamic stent developed by the Digestive Surgery and Endoscopic Unit of the Bambino Gesù Hospital, Rome. The stent is a custom silicon device built coaxially on a nasogastric tube that is inserted after stricture dilations, by endoscopic guidance, and then fixed outside the nose. The device was removed after seven weeks with good clinical outcome (no dysphagia more than a year of follow-up).

CONCLUSION

This case confirms that the dynamic stent is a simple device that may avoid aggressive surgical substitution in cases of refractory strictures.