Expandable stents for benign esophageal disease

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.

Biodegradable esophageal stents for the treatment of refractory benign esophageal strictures

This review attempts to present the available evidence regarding the use of biodegradable stents in refractory benign esophageal strictures, especially highlighting their impact on clinical success and complications. A comprehensive literature search was conducted in PubMed, using the terms "biodegradable" and "benign"; evidence from cohort and comparative studies, as well as data from one pooled analysis and one meta-analysis are presented. In summary, the results from these studies indicate that the effectiveness of biodegradable stents ranges from more than one third to a quarter of cases, fairly similar to other types of stents used for the same indication. However, their implementation may reduce the need for re-intervention during follow up. Biodegradable stents also seem to reduce the need for additional types of endoscopic therapeutic modalities, mostly balloon or bougie dilations. Results from pooled data are consistent, showing moderate efficacy along with a higher complication rate. Nonetheless, the validity of these results is questionable, given the heterogeneity of the studies included. Finally, adverse events may occur at a higher rate but are most often minor. The lack of high-quality studies with sufficient patient numbers mandates further studies, preferably randomized, to elucidate the exact role of biodegradable stents in the treatment of refractory benign esophageal strictures.

Esophageal leiomyoma in a dog causing esophageal distension and treated by transcardial placement of a self-expanding, covered, nitinol esophageal stent

CASE DESCRIPTION A 10-year-old spayed female Rottweiler was referred for evaluation because of a 2-month history of regurgitation and weight loss, despite no apparent change in appetite. The dog had received antiemetic and antacid treatment, without improvement. CLINICAL FINDINGS Physical examination revealed a low body condition score (2/5), but other findings were unremarkable. Diffuse, global esophageal dilatation was noted on plain thoracic radiographs, and normal motility was confirmed through videofluoroscopic evaluation of swallowing. Transhepatic ultrasonographic and CT examination revealed a circumferential, intraparietal lesion in the distal portion of the esophagus causing distal esophageal or cardial subobstruction and no metastases. Incisional biopsy of the lesion was performed, and findings of histologic examination supported a diagnosis of esophageal leiomyoma. TREATMENT AND OUTCOME In view of numerous possible complications associated with esophageal surgery, the decision was made to palliatively treat the dog by transcardial placement of a self-expanding, covered, nitinol esophageal stent under endoscopic guidance. Two weeks after stent placement, radiography revealed complete migration of the stent into the gastric lumen. Gastrotomy was performed, and the stent was replaced and fixed in place. Twenty-four months after initial stent placement, the dog had a healthy body condition and remained free of previous clinical signs. CLINICAL RELEVANCE Diffuse benign muscular neoplasia should be considered as a differential diagnosis for acquired esophageal dilatation in adult and elderly dogs. In the dog of this report, transcardial stent placement resulted in resolution of the clinical signs, with no apparent adverse effect on digestive function. The described procedure could be beneficial for nonsurgical treatment of benign esophageal tumors in dogs.

Surface modification of esophageal stent materials by a polyethylenimine layer aiming at anti-cancer function

Esophageal cancer is difficult to cure globally and possesses high mortality rate, and it is generally accepted that palliative care such as stent implantation is the main therapy method for esophageal cancer in later period. However, the restenosis caused by tumor cells and inflammatory cells seriously interferes the stent clinical application and limits its long-term services. To solve this problem, series of drug delivery stents were developed and proven rather effective in the early stage of implantation, but more serious restenosis occurred after the drug delivery was over, which endangered the patients' life. Therefore, endowing the esophageal stent continuous anti-cancer function become an ideal strategy for inhibiting the restenosis. In this contribution, the functional layer composed of polydopamine (PDA) and Poly-ethylenimine (PEI) with series of molecular weights (MW, 1.8 × 10³, 1 × 10⁴, 2.5 × 10⁴ and 7 × 10⁴ Da) were fabricated onto the esophageal stent material 317L stainless steel (317L SS) surface. The surface characterization including amine quantitative, atomic force microscopy (AFM) and water contact angle measurement indicated successful preparation of the PDA/PEI layer. The Eca109 cells culture results proved that the PDA/PEI layers significantly improve Eca109 cells apoptosis and necrosis, suggesting excellent anti-cancer function. In addition, we also found that the anti-cancer function of the PDA/PEI layers was positively correlated to the immobilized PEIs' MW. All the results demonstrated the potential application of the PDA/PEI layers on the surface modification of esophageal stent for continuous anti-cancer function. It is generally accepted that the restenosis caused by tumor cells seriously interferes the esophageal stent clinical application. Thus, endowing the esophageal stent continuous anti-cancer function is the ideal strategy for inhibiting the restenosis. In this work, we fabricated functional layers composed of polydopamine (PDA) and Poly-ethylenimine (PEI) with series of molecular weights (MW, 1.8 × 10³, 1 × 10⁴, 2.5 × 10⁴ and 7 × 10⁴ Da) onto the esophageal stent material 317L stainless steel (317L SS) surface to inhibit the tumor cells growth, and this function was related to the PEIs' molecular weights. The functional PDA/PEI layers were expected potentially applied for surface modification of esophageal stent materials.

History of the Use of Esophageal Stent in Management of Dysphagia and Its Improvement Over the Years

The art and science of using stents to treat dysphagia and seal fistula, leaks and perforations has been evolving. Lessons learnt from the deficiencies of previous models led to several improvements making stent deployment easier, and with some designs, it was also possible to remove the stents if needed. With these improvements, besides malignant dysphagia, newer indications for using stents emerged. Unfortunately, despite several decades of evolution, as yet, there is no perfect stent that "fits all." This article is an overview of how this evolution process happened and where we are currently with using stents to manage patients with dysphagia and with other esophageal disorders.

Endoscopic and Abdominal Management of Complete Benign Esophageal Obstruction

Benign esophageal strictures leading to complete esophageal occlusion are well known. In the pre-endoscopic era, such cases required surgery, but over the last decade, various novel endoscopic techniques have been developed to prevent morbidity and mortality. A 37-year-old man presented after 1 year of dysphagia and weight loss, and was found to have complete esophageal obstruction, not allowing even passage of guidewire. We used a combination antegrade endoscopic abdominal procedures to deploy a stent, obviating the need for surgery. His symptoms improved dramatically, and the stent was successfully removed 12 weeks later. He is now swallowing normally and has gained significant weight.

Stent-in-stent technique for removal of embedded partially covered self-expanding metal stents

BACKGROUND

Removal of embedded partially covered self-expanding metal stents (PCSEMS) is associated with an increased risk of adverse events compared with removal of fully covered self-expanding stents (FCSES) due to tissue ingrowth. Successful removal of embedded PCSEMS has been described by the stent-in-stent (SIS) technique.

AIMS

To report the first US experience from three high-volume quaternary care centers on the safety and efficacy of the SIS technique for removal of embedded PCSEMS.

METHODS

Retrospective study of outcomes for consecutive patients who underwent the SIS for removal of embedded PCSEMS over a 5-year period.

RESULTS

Twenty-seven embedded PCSEMS were successfully removed using the SIS technique (100 %) from 25 patients (11 males), median age 65 (range 37-80). All stents were successfully removed in one endoscopic session (no repeat SIS procedures were required for persistently embedded stents). The embedded PCSEMS had been in situ for a median of 76 days (range 26-501). Median SIS dwell time (FCSES in situ of PCSEMS) was 13 days (interquartile range 8-16 days; range 4-212 days). One adverse event (self-limited bleeding) occurred during a median follow-up period of 3 months (range 1-32). No patients died, required surgery, or had long-term disability due to adverse events attributed to the SIS technique. Twelve patients required additional interventions following SIS procedure for persistence or recurrence of the underlying pathology.

CONCLUSION

When performed by experienced endoscopists, safe and effective removal of embedded PCSEMS can be achieved via the SIS technique.

Silane surface modification for improved bioadhesion of esophageal stents

Stent migration occurs in 10-40% of patients who undergo placement of esophageal stents, with higher migration rates seen in those treated for benign esophageal disorders. This remains a major drawback of esophageal stent therapy. In this paper, we propose a new surface modification method to increase the adhesion between self-expandable metallic stents (SEMS) and tissue while preserving their removability. Taking advantage of the well-known affinity between epoxide and amine terminated silane coupling agents with amine and carboxyl groups that are abundant in proteins and related molecules in the human body; we modified the surfaces of silicone coated esophageal SEMS with these adhesive self-assembled monolayers (SAMs). We utilized vapor phase silanization to modify the surfaces of different substrates including PDMS strips and SEMS, and measured the force required to slide these substrates on a tissue piece. Our results suggest that surface modification of esophageal SEMS via covalent attachment of protein-binding coupling agents improves adhesion to tissue and could offer a solution to reduce SEMS migration while preserving their removability.

Endoscopic stenting for benign upper gastrointestinal strictures and leaks

BACKGROUND

Self-expandable metal stents (SEMS) and self-expandable plastic stents (SEPS) maybe used for the treatment of benign upper gastrointestinal (GI) leaks and strictures. This study reviewed our experience with stent insertions in patients with benign upper GI conditions.

METHODS

Patients who underwent stent placement for benign upper GI strictures and leaks between March 2007 and April 2011 at a tertiary referral academic center were studied using an endoscopic database and electronic patient records. The technical success, complications, and clinical improvement after stent removal were compared according to type of stent. The outcomes measured were clinical response, adverse events, and predictors of stent migration.

RESULTS

Thirty-eight patients (50 % male, mean age = 54 years, range = 12-82) underwent 121 endoscopic procedures. Twenty patients had stents placed for strictures, and 18 had stents placed for leaks. Stent placement was technically successful in all patients. The average duration of stent placement was 54 days (range = 18-118). Clinical improvement immediately after stent placement was seen in 29 of the 38 patients (76.3 %). Immediate post-procedure adverse events occurred in 8 patients. Late adverse events were seen in 18 patients. Evidence of stent migration occurred in 16 patients and was seen in 42 of the 118 successfully placed stents (35.5 %). Migration was more frequent with fully covered SEMS (p = 0.002). After stent removal, 27 patients were evaluable for long-term success (median follow-up time of 283 days, IQR 38-762). Resolution of strictures or leaks was seen in 11 patients (40.7 %). Predictors for long-term success included increasing age and if the stent did not cross the GE junction.

CONCLUSIONS

Placement of SEPS and SEMS for benign refractory strictures and fistulas has modest long-term clinical efficacy and is limited by a significant migration rate. Stent migration is common and frequent with fully covered SEMS compared to other types of stents, regardless of indication or location.

Esophageal stenting for treatment of refractory benign esophageal strictures in dogs

BACKGROUND

Benign esophageal strictures can recur despite multiple dilatation procedures and palliative management can be challenging.

OBJECTIVE

To describe the technique and determine the outcome of esophageal stenting for treatment of refractory benign esophageal strictures (RBES) in dogs.

ANIMALS

Nine dogs with RBES.

METHODS

Retrospective review of records for dogs with RBES. Indwelling intraluminal esophageal stents were placed transorally with endoscopy, fluoroscopic guidance, or both. Follow-up information was obtained via medical record or telephone interview.

RESULTS

Nine dogs had 10 stents placed including biodegradable stents (BDS) (6/10), self-expanding metallic stents (SEMS) (3/10), and a self-expanding plastic stent (SEPS) (1/10). All dogs had short-term improved dysphagia. Complications included ptyalism, apparent nausea, gagging, vomiting, or regurgitation (8/9), confirmed recurrence of stricture (6/9), stent migration (3/9), stent shortening (1/9), megaesophagus (1/9), incisional infection (1/9), and tracheal-esophageal fistula (1/9). Eight of 9 dogs required intervention because of the complications of which 4 of 8 dogs were eventually euthanized because of stent-related issues. One dog was lost to follow-up examination.

CONCLUSIONS AND CLINICAL IMPORTANCE

Findings suggest that esophageal stent placement was safe and technically effective, but unpredictably tolerated in dogs with RBES. If a stent is placed, dogs should be monitored carefully for stent migration, dissolution of absorbable stents, and recurrence of strictures.

Stent-associated esophagorespiratory fistulas: incidence and risk factors

BACKGROUND

Esophageal self-expandable stents (SESs) effectively treat strictures and leaks but may be complicated by a stent-associated esophagorespiratory fistula (SERF). Little is known about SERFs.

OBJECTIVE

To determine the incidence, morbidity, mortality, and risk factors for SERF.

DESIGN

Retrospective case-control study.

SETTING

Single referral center.

PATIENTS

All adults undergoing esophageal SES placement during a 10-year period.

INTERVENTION

Stent placement.

MAIN OUTCOME MEASUREMENTS

Occurrence of SERF, morbidity, and mortality.

RESULTS

A total of 16 of 397 (4.0%) patients developed SERF at a median of 5 months after stent placement (range 0.4-53 months) including 6 of 94 (6%), 10 of 71 (14%), and 0 of 232 (0%) of those with lesions in the proximal, middle, and distal esophagus, respectively (overall P < .001). SERF occurred in 10% of those with proximal and mid-esophageal lesions, including 14% with benign strictures, 9% with malignant strictures, and none with other indications for SES placement (P = .27). The risk was highest (18%) in patients with benign anastomotic strictures. Risk factors for development of SERF included a higher Charlson comorbidity index score (odds ratio [OR] 1.47 for every 1-point increase; P = .04) and history of radiation therapy (OR 9.41; P = .03). Morbidity associated with SERF included need for lifelong feeding tubes in 11 of 22 (50%) and/or tracheostomy or mechanical ventilation in 5 of 22 (23%). Median survival after diagnosis was 4.5 months (range 0.35-67), and 7 patients survived less than 30 days.

LIMITATIONS

Retrospective design, limited statistical power.

CONCLUSION

SERF is a morbid complication of SES placement for strictures of the proximal and mid-esophagus. The dominant risk factors for development of SERF are prior radiation therapy and comorbidity score.

Achalasia

Endoscopic therapy for achalasia is centered on disrupting or weakening the lower esophageal sphincter. The three traditional treatment options for achalasia are surgical myotomy, pneumatic dilation, and botulinum toxin injection. Pneumatic dilation yields results that are generally better than botulinum toxin injection and may approach a clinical response comparable with surgery. Per oral endoscopic myotomy is a newer endoscopic modality that will likely change the treatment paradigm for achalasia.

Reducing complications in upper gastrointestinal endoscopy

This article reviews the principal aspects related to sedation in endoscopy and to the prevention of adverse events in some of the most frequently performed therapeutic upper gastrointestinal (GI) endoscopic procedures (esophageal dilation and stenting, endoscopic resection of upper GI early neoplasia, hemostasis of upper GI bleeding and percutaneous endoscopic gastrostomy insertion). These procedures have an inherent risk of negative outcomes that cannot be entirely avoided. Endoscopic procedures are best performed by well-trained, competent and thoughtful endoscopists in facilities suited to provide for patient safety. Attention to clinical risk management may effectively reduce the frequency and intensity of adverse events, enhance recognition and early detection, and improve responsiveness.