Polytetrafluoroethylene-covered retrievable expandable nitinol stents for malignant esophageal obstructions: factors influencing the outcome of 270 patients

Hydrogel-Impregnated Robust Interlocking Nano Connector (HiRINC) for Noninvasive Anti-Migration of Esophageal Stent

Migration of implanted self-expandable metallic stent (SEMS) in the malignant or benign esophageal stricture is a common complication but not yet resolved. Herein, this research develops a hydrogel-impregnated robust interlocking nano connector (HiRINC) to ensure adhesion and reduce the mechanical mismatch between SEMSs and esophageal tissues. Featuring a network-like porous layer, HiRINC significantly enhances adhesion and energy dissipation during esophageal peristalsis by utilizing mechanical interlocking and increasing hydrogen bonding sites, thereby securing SEMS to tissues. The anti-swelling property of HiRINC prevents excessive hydrogel expansion, avoiding esophageal blockage. Ex vivo and in vivo adhesion tests confirm that the HiRINC outperforms flat surfaces without RINC structures and effectively prevents stent migration. HiRINC-coated SEMS maintains its position and luminal patency, minimizing stent-induced tissue hyperplasia and inflammatory responses in rat and porcine esophageal models during the 4-week follow-up. This novel HiRINC-SEMS can ensure anti-migration and prolonged stent patency in the rat and porcine esophagus and seems to be expanded to other nonvascular luminal organs and various implantable metallic devices.

Localized Photodynamic Therapy Using a Chlorin e6-Embedded Silicone-Covered Self-Expandable Metallic Stent as a Palliative Treatment for Malignant Esophageal Strictures

Localized photodynamic therapy (PDT) uses a polymeric-photosensitizer (PS)-embedded, covered self-expandable metallic stent (SEMS). PDT is minimally invasive and a noteworthy potential alternative for treating esophageal strictures, where surgery is not a viable option. However, preclinical evidence is insufficient, and optimized irradiation energy dose ranges for localized PDT are unclear. Herein, we validated the irradiation energy doses of the SEMS (embedded in a PS using chlorin e6 [Ce6] and covered in silicone) and PDT-induced tissue changes in a rat esophagus. Cytotoxicity and phototoxicity in the Ce6-embedded SEMS piece with laser irradiation were significantly higher than that of the silicone-covered SEMS with or without laser and the Ce6-embedded silicone-covered SEMS without laser groups (all p < 0.001). Moreover, surface morphology, atomic changes, and homogeneous coverage of the Ce6-embedded silicone-covered membrane were confirmed. The ablation range of the porcine liver was proportionally increased with the irradiation dose (all p < 0.001). The ablation region was identified at different irradiation energy doses of 50, 100, 200, and 400 J/cm2. The in vivo study in the rat esophagus comprised a control group and 100, 200, and 400 J/cm2 energy-dose groups. Finally, histology and immunohistochemistry (TUNEL and Ki67) confirmed that the optimized Ce6-embedded silicone-covered SEMS with selected irradiation energy doses (200 and 400 J/cm2) effectively damaged the esophageal tissue without ductal perforation. The polymeric PS-embedded silicone-covered SEMS can be easily placed via a minimally invasive approach and represents a promising new approach for the palliative treatment of malignant esophageal strictures.

A Functional Stent Encapsulating Radionuclide in Temperature-Memory Spiral Tubes for Malignant Stenosis of Esophageal Cancer

Stent implantation is a commonly used palliative treatment for alleviating stenosis in advanced esophageal cancer. However, tissue proliferation induced by stent implantation and continuous tumor growth can easily lead to restenosis. Therefore, functional stents are required to relieve stenosis while inhibiting tissue proliferation and tumor growth, thereby extending the patency. Currently, no ideal functional stents are available. Here, iodine-125 (125 I) nuclides are encapsulated into a nickel-titanium alloy (NiTi) tube to develop a novel temperature-memory spiral radionuclide stent (TSRS). It has the characteristics of temperature-memory, no cold regions at the end of the stent, and a uniform spatial dose distribution. Cell-viability experiments reveal that the TSRS can reduce the proliferation of fibroblasts and tumor cells. TSRS implantation is feasible and safe, has no significant systemic radiotoxicity, and can inhibit in-stent and edge stenosis caused by stent-induced tissue proliferation in healthy rabbits. Moreover, TSRS can improve malignant stenosis and luminal patency resulting from continuous tumor growth in a VX2 esophageal cancer model. As a functional stent, the TSRS combines the excellent properties of NiTi with brachytherapy of the 125 I nuclide and will make significant contributions to the treatment of malignant esophageal stenosis.

Endoscopic Stenting for Malignant Dysphagia in Patients with Esophageal Cancer

Malignant dysphagia is a common problem in patients with esophageal cancer. Endoscopic stenting can resolve dysphagia caused by malignant stricture; however, controversy exists regarding the use of esophageal stenting for the treatment of malignant stricture, including whether stenting or radiotherapy is superior, whether stenting before or after radiotherapy is safe, whether stenting before or after chemotherapy is safe, and whether low-radial-force stents are safer than conventional stents. Among treatment options for malignant dysphagia, stenting may have some disadvantages in terms of pain relief and the risk of adverse events compared with radiotherapy and in terms of survival compared with gastrostomy. Additionally, the risk of stent-related adverse events is significantly associated with prior radiotherapy. The risk of perforation is especially high when a radiation dose of >40 Gy is delivered to the esophagus after stenting, whereas perforation is not associated with prior chemotherapy or additional chemotherapy after stenting. Nevertheless, stenting remains an important palliative option, especially for patients with a short life expectancy and a strong desire for oral intake, because stenting can facilitate a more rapid improvement in dysphagia than radiotherapy or gastrostomy. The application of a low-radial-force stent should be considered to reduce the risk of adverse events, especially in patients with prior radiotherapy.

Flexible 3D Nanonetworked Silica Film as a Polymer-Free Drug-Eluting Stent Platform to Effectively Suppress Tissue Hyperplasia in Rat Esophagus

Loading and eluting drugs on self-expandable metallic stents (SEMSs) can be challenging in terms of fabrication, mechanical stability, and therapeutic effects. In this study, a flexible 3D nanonetworked silica film (NSF) capable of withstanding mechanical stress during dynamic expansion is constructed to function as a drug delivery platform on an entire SEMS surface. Despite covering a broad curved area, the synthesized NSF is defect-free and thin enough to increase the stent strut diameter (110 µm) by only 0.4 percent (110.45 µm). The hydrophobic modification of the surface enables loading of 4.7 times the sirolimus (SRL) concentration in NSF than Cypher, polymer-coated commercial stent, which is based on the same thickness of coating layer. Furthermore, SRL-loaded NSF exhibits a twofold delay in release compared to the control group without NSF. The SRL-loaded NSF SEMS significantly suppresses stent-induced tissue hyperplasia than the control SEMS in the rat esophagus (all variables, p < 0.05). Thus, the developed NSF is a promising polymer-free drug delivery platform to efficiently treat esophageal stricture.

Palliation of malignant dysphagia with a segmented self-expanding metal stent: A STROBE-compliant article

ABSTRACT

Self-expanding metal stents (SEMSs) in different geometric shapes are an established palliative treatment for malignant tumors of the esophagus. Mechanical properties and stent design have an impact on patient comfort, migration rate, and removability. SEMS with a segmented design (segSEMS) have recently become available on the market, promising new biomechanical properties for stent placement in benign and malignant esophageal diseases. In this study, we evaluated recurrent dysphagia, quality of life as well as technical success and complications for segmented SEMS-implantation in a retrospective study in palliative patients with dysphagia caused by malignant tumors of the esophagus.Between May 2017 and December 2018, patients presented to the interdisciplinary department of endoscopy of the University Hospital Cologne underwent segmented SEMS placement for malignant dysphagia. Patient follow-up was evaluated, and complications were monitored. Quality of life and functional improvement were monitored using the EORTC QLQ-C30 and QLQ-OE18.A total of 20 consecutive patients (16 men, 4 women; mean age: 65.5, range: 46-82) participated in the study and were treated with 20 segSEMS in total. The success rate of stent placement was 100%. Stent migration occurred in 3 patients (15.0%). Insertion of segSEMS immediately lead to a 48.0% reduction of dysphagia in the first 2 months (P < .001). Pain while eating (odynophagia) could also be significantly reduced by 39.6% over the first 2 months (P < .001).Implantation of segSEMS is a feasible and effective treatment for dysphagia in palliative patients with malignant tumors of the esophagus, offering immediate relief of symptoms and gain of physical functions.

Photothermal therapy via a gold nanoparticle-coated stent for treating stent-induced granulation tissue formation in the rat esophagus

Minimally invasive therapies using stent technology are currently limited by stent-induced granulation tissue formation adjacent to the stent. The effectiveness of photothermal therapy (PTT) using a gold nanoparticle (AuNP)-coated stent for treating stent-induced granulation tissue formation in the rat esophagus was investigated. All experiments were approved by the animal research committee of our institution. An AuNP-coated, self-expandable metallic stent (SEMS) was produced to conduct PTT under near-infrared laser irradiation. Forty rats were randomly divided into four groups (10 rats each). The animals in group A (non-coated SEMS) and group B (AuNP-coated SEMS with local heating at 65 °C at 4 weeks) were sacrificed 4 weeks after stent placement. The rats in group C (AuNP-coated SEMS with local heating at 65 °C at 4 weeks) and group D (AuNP-coated SEMS with local heating at 65 °C at 4 and 8 weeks) were sacrificed 8 weeks after stent placement. The effectiveness of local heating was assessed by histopathology. All procedures were successful in all of the animals. Seven rats were excluded because of stent migration (n = 2) and death (n = 5). Granulation tissue formation-related variables were significantly higher in group A than in groups B-D (all p < 0.05). Heat-shock protein 70 (HSP70) and TUNEL expression were significantly lower in group A than in groups B-D (all p < 0.05). Granulation tissue formation-related variables were significantly higher in group C than in groups B and D (all p < 0.05). PTT using AuNP-coated SEMS successfully treated granulation tissue formation after stent placement in the rat esophagus.

Micro-endoscopy for Live Small Animal Fluorescent Imaging

Intravital microscopy has emerged as a powerful technique for the fluorescent visualization of cellular- and subcellular-level biological processes in vivo. However, the size of objective lenses used in standard microscopes currently makes it difficult to access internal organs with minimal invasiveness in small animal models, such as mice. Here we describe front- and side-view designs for small-diameter endoscopes based on gradient-index lenses, their construction, their integration into laser scanning confocal microscopy platforms, and their applications for in vivo imaging of fluorescent cells and microvasculature in various organs, including the kidney, bladder, heart, brain, and gastrointestinal tracts, with a focus on the new techniques developed for each imaging application. The combination of novel fluorescence techniques with these powerful imaging methods promises to continue providing novel insights into a variety of diseases.

Clinical effectiveness and safety of self-expanding metal stent placement following palliative chemotherapy in patients with advanced esophageal cancer

PURPOSE

To investigate the effect of prior chemotherapy on self-expanding metal stent (SEMS)-related complications in patients with locally advanced primary esophageal cancer.

MATERIALS AND METHODS

Data from patients with locally advanced primary esophageal cancer who received SEMS placement with or without prior chemotherapy were retrospectively reviewed. Patients were grouped according to prior palliative therapy: group A (n = 41) had received SEMS only, and group B (n = 64) had received palliative chemotherapy prior to SEMS placement. Patients' age, stricture length, tumor location, and dysphagia score prior to SEMS placement were evaluated. The overall patient cohort had a median follow-up period of 129 days (range 11-463). Outcomes after SEMS placement, including technical and clinical success rates, the occurrence of complications, and overall survival, were compared.

RESULTS

There were no significant differences between the two groups regarding patients' age, stricture length, tumor location, and dysphagia score prior to SEMS placement. SEMS placement was technically successful in all patients, with no procedure-related complications reported. Clinical success was achieved in 95.1% of patients in group A and 96.8% of patients in group B. The duration of stent patency was significantly shorter in group B [162 days; 95% confidence interval (CI) 126.6-198.4 vs. group A (339 days; 95% CI 258.8-419.3], p = 0.001. No significant differences were seen between the two groups regarding dysphagia score improvement [group A (3.15 ± 0.57 to 1.17 ± 0.83; p < 0.001) and group B (3.17 ± 0.80 to 1.14 ± 0.79; p < 0.001); p = 0.66], complications [group A (10/41), and group B (24/64); p = 0.094], or overall survival [the median and mean overall survival periods were 105 (95% CI 30-180) and 132 days (95% CI 97-167), respectively, in group A, and 126 (95% CI 88-164) and 156 days (95% CI 132-180), respectively, in group B; p = 0.592].

CONCLUSION

Prior chemotherapy did not increase the risk of complications following SEMS placement in patients with locally advanced esophageal cancer. SEMS patency was significantly longer in patients who did not receive chemotherapy prior to SEMS placement.

LEVEL OF EVIDENCE

Level 4, Case Series.

Fully covered self-expandable esophageal metallic stents in patients with inoperable malignant disease who survived for more than 6 months after stent placement

OBJECTIVES

To investigate the clinical outcomes of fully covered self-expanding metal stent (FCSEMS) placement in patients with malignant esophageal obstruction who survived longer than 6 months.

METHODS

From January 2002 to January 2018, 88 FCSEMS were placed in 64 patients (mean age 62.9 ± 11.6 years; 58 males) with inoperable malignant esophageal obstruction with or without esophago-respiratory fistula. Only patients who survived more than 6 months with FCSEMS in place were included. Data regarding technical and clinical success, complications, reinterventions, stent patency, and patient survival were obtained from a prospectively maintained hospital database.

RESULTS

The technical and clinical success rates were 100 % (64/64). During follow-up, the median dysphagia score significantly improved (3.09 ± 0.68 to 1.05 ± 0.60, p < 0.001). The complication rate was 48.8 %. Multivariate analysis revealed that only longer stenting duration was associated with complications [hazard ratio = 1.220, 95 % confidence interval (CI) (1.074-2.760), p = 0.039]. The median follow-up duration was 257 days (range, 181-969). The median stent patency duration was 289 days [95% CI (209.9-368.1)]. The median survival was 254 days [95% CI (219.7-288.3)].

CONCLUSIONS

Our data suggest that esophageal FCSEMS placement is an effective option for patients with malignant dysphagia when survival longer than 6 months is expected. The rate of complications increases with time, and SEMS development is needed to keep up with the advancement in oncological treatment.

ADVANCES IN KNOWLEDGE

Fully covered esophageal self-expandable stent placement is effective in patients surviving more than 6 months, however, the rate of complications also increases. SEMS development is needed to cope with the advancement in oncological treatment.

Oesophageal stenting: Status quo and future challenges

Oesophageal stents are widely used for palliating dysphagia from malignant obstruction. They are also used with increasing frequency in the treatment of oesophageal perforation, as well as benign strictures from a variety of causes. Improved oncological treatments have led to prolonged survival of patients treated with palliative intent; as a consequence, stents need to function and last longer in order to avoid repeat procedures. There is also increasing need for meticulous procedure planning, careful selection of the device most appropriate for the individual patient and planned follow-up. Furthermore, as more patients are cured, there will be more issues with resultant long-term side-effects, such as recalcitrant strictures due to radiotherapy or anastomotic scarring, which will have to be addressed. Stent design needs to keep up with the progress of cancer treatment, in order to offer patients the best possible long-term result. This review article attempts to illustrate the changing realities in oesophageal stenting, differences in current stent designs and behaviour, as well as the pressing need to refine and modify devices in order to meet the new challenges.

In Vivo Fluorescence Microendoscopic Monitoring of Stent-Induced Fibroblast Cell Proliferation in an Esophageal Mouse Model

PURPOSE

To evaluate the feasibility of self-expanding metal stent (SEMS) placement and fluorescence microendoscopic monitoring for determination of fibroblast cell proliferation after stent placement in an esophageal mouse model.

MATERIALS AND METHODS

Twenty fibroblast-specific protein (FSP)-1 green fluorescent protein (GFP) transgenic mice were analyzed. Ten mice (Group A) underwent SEMS placement, and fluoroscopic and fluorescence microendoscopic images were obtained biweekly until 8 weeks thereafter. Ten healthy mice (Group B) were used for control esophageal values.

RESULTS

SEMS placement was technically successful in all mice. The relative average number of fibroblast GFP cells and the intensities of GFP signals in Group A were significantly higher than in Group B after stent placement. The proliferative cellular response, including granulation tissue, epithelial layer, submucosal fibrosis, and connective tissue, was increased in Group A. FSP-1-positive cells were more prominent in Group A than in Group B.

CONCLUSIONS

SEMS placement was feasible and safe in an esophageal mouse model, and proliferative cellular response caused by fibroblast cell proliferation after stent placement was longitudinally monitored using a noninvasive fluorescence microendoscopic technique. The results have implications for the understanding of proliferative cellular response after stent placement in real-life patients and provide initial insights into new clinical therapeutic strategies for restenosis.

Radiation-induced esophageal strictures treated with fluoroscopic balloon dilation: clinical outcomes and factors influencing recurrence in 62 patients

Background Balloon dilation is safe and effective for the treatment of radiation-induced esophageal stricture (RIES), with favorable short-term and mid-term outcomes; however, few reports of long-term outcomes exist. Few studies have evaluated factors associated with recurrence after balloon dilation. Purpose To evaluate the long-term outcome of balloon dilation in patients with RIES and to identify factors associated with stricture recurrence. Material and Methods The medical records of 62 consecutive patients who had undergone fluoroscopic balloon dilation for RIES at our institution between December 1998 and June 2016 were reviewed. Results One hundred and twenty balloon dilation sessions were performed in 62 patients (mean = 1.9 sessions per patient). Clinical success was achieved in 53 (86%) patients after single (n = 37) or multiple (n = 16) dilation sessions. Complications occurred in 27% of the dilation sessions. The primary patency rates at one, two, three, and five years were 60%, 56%, 52%, and 52%, respectively. Secondary patency rates at one, two, three, and five years were 87%, 85%, 85%, and 80%, respectively. Multivariate logistic regression analysis identified an interval from radiation therapy (RT) to stricture of ≥6 months (hazard ratio [HR] = 0.205; P < 0.001), strictures located at the cervical esophagus (HR = 5.846; P < 0.001), and stricture length of ≥2 cm (HR = 2.923; P = 0.006) as significant predictors of recurrence. Conclusion Despite the high incidence of ruptures and recurrences, fluoroscopic balloon dilation is valuable as an initial therapeutic option for patients with RIES.

EW-7197 eluting nano-fiber covered self-expandable metallic stent to prevent granulation tissue formation in a canine urethral model

PURPOSE

To evaluate an EW-7197-eluting nanofiber-covered stent (NFCS) for suppressing granulation tissue formation after stent placement in a canine urethral model.

MATERIALS AND METHODS

All experiments were approved by the committee of animal research. A total of 12 NFCSs were placed in the proximal and distal urethras of six dogs. Dogs were divided into two groups with 3 dogs each. The control stent (CS) group received NFCSs and the drug stent (DS) group received EW-7197 (1000 μg)-eluting NFCSs. All dogs were sacrificed 8 weeks after stent placement Histologic findings of the stented urethra were compared using the Mann-Whitney U test.

RESULTS

Stent placement was technically successful in all dogs without procedure-related complications. On urethrographic analysis, the mean luminal diameter was significantly larger in the DS group than in the CS group at 4 and 8 weeks after stent placement (all p < 0.001). On histological examination, mean thicknesses of the papillary projection, thickness of submucosal fibrosis, number of epithelial layers, and degree of collagen deposition were significantly lower in the DS group than in the CS group (all p < 0.001), whereas the mean degree of inflammatory cell infiltration was not significantly different (p > 0.05).

CONCLUSION

The EW-7197-eluting NFCS is effective and safe for suppressing granulation tissue formation after stent placement in a canine urethral model.

Feasibility of esophageal stent fixation with an over-the-scope-clip for malignant esophageal strictures to prevent migration

BACKGROUND AND STUDY AIMS

 Fixation of an esophageal self-expandable metal stent (SEMS) with an over-the-scope-clip (OTSC) system for a benign stricture to prevent migration has been reported. However, the efficacy of SEMS fixation with an OTSC for malignant esophageal stricture remains unclear. The aim of this retrospective study was to evaluate the feasibility of SEMS fixation with an OTSC for a malignant esophageal stricture.

PATIENTS AND METHODS

Twelve patients who underwent esophageal SEMS placement and fixation with an OTSC for a malignant esophageal stricture were included in this retrospective study. The primary endpoint was technical success. The secondary endpoint was clinical success, which was defined as an improvement of at least 1 grade in the dysphagia score 1 week after SEMS placement or changes in the dysphagia score from before SEMS placement to 1 week after SEMS placement.

RESULTS

 The technical success rate was 100 %. The clinical success rate was 92.3 %. In 6 mild stricture cases in which a standard peroral endoscope could be used, no migration of the SEMS was observed. The median dysphagia score before and at 1 week after SEMS placement was 3 (range 2 - 4) and 0 (0 - 4), respectively, which indicated improvement at 1 week after SEMS placement compared with before SEMS placement ( P  = 0.002). There were no adverse events associated with placement of SEMS and deployment of an OTSC.

CONCLUSIONS

SEMS fixation with an OTSC is feasible for prevention of migration due to a malignant esophageal stricture.

Fluoroscopic removal of retrievable self-expandable metal stents in patients with malignant oesophageal strictures: Experience with a non-endoscopic removal system

OBJECTIVES

To evaluate clinical outcomes of fluoroscopic removal of retrievable self-expandable metal stents (SEMSs) for malignant oesophageal strictures, to compare clinical outcomes of three different removal techniques, and to identify predictive factors of successful removal by the standard technique (primary technical success).

METHODS

A total of 137 stents were removed from 128 patients with malignant oesophageal strictures. Primary overall technical success and removal-related complications were evaluated. Logistic regression models were constructed to identify predictive factors of primary technical success.

RESULTS

Primary technical success rate was 78.8 % (108/137). Complications occurred in six (4.4 %) cases. Stent location in the upper oesophagus (P=0.004), stricture length over 8 cm (P=0.030), and proximal granulation tissue (P<0.001) were negative predictive factors of primary technical success. If granulation tissue was present at the proximal end, eversion technique was more frequently required (P=0.002).

CONCLUSIONS

Fluoroscopic removal of retrievable SEMSs for malignant oesophageal strictures using three different removal techniques appeared to be safe and easy. The standard technique is safe and effective in the majority of patients. The presence of proximal granulation tissue, stent location in the upper oesophagus, and stricture length over 8 cm were negative predictive factors for primary technical success by standard extraction and may require a modified removal technique.

KEY POINTS

• Fluoroscopic retrievable SEMS removal is safe and effective. • Standard removal technique by traction is effective in the majority of patients. • Three negative predictive factors of primary technical success were identified. • Caution should be exercised during the removal in those situations. • Eversion technique is effective in cases of proximal granulation tissue.

Interventional Therapy of Esophageal Cancer

Esophageal cancer (EC) is the fourth leading cause of cancer death in China. Despite a lot of advances in diagnosis and therapy, the survival rate of patients with EC is low. There is urgent need for a variety of methods and techniques to improve the survival time and alleviate the lesions of EC. Nowadays, alternative and less invasive approaches to the treatment of ECs are being identified. Here, we review several main interventional methods at different stages of EC, including endoscopic resection, stent placement, arterial infusion, photodynamic therapy, and radiofrequency ablation. This review will focus on the indications, methods, clinical outcomes, and complications of these methods, which may help guide the way forward.

Preliminary Results of Temporary Placement of Retrievable Expandable Metallic Stents during Preoperative Neoadjuvant Chemoradiotherapy in Patients with Resectable Esophageal Cancer

PURPOSE

To evaluate the clinical efficacy of temporary placement of a retrievable expandable metallic stent (REMS) during preoperative neoadjuvant chemoradiotherapy (CRT) in patients with resectable esophageal cancer.

MATERIALS AND METHODS

REMSs were placed in 25 patients who underwent preoperative neoadjuvant CRT for resectable esophageal cancer. Stent removal was scheduled between 4 and 6 weeks after starting neoadjuvant CRT. Clinical effectiveness was assessed using the following variables: technical and clinical success, dysphagia score before and after stent placement and removal, and complications and their management.

RESULTS

REMS placement was technically successful in all patients, with 24 of 25 patients (96%) showing symptomatic improvement. Stents were removed electively 32 days (range, 27-42 d) after starting neoadjuvant CRT (n = 20; 80%) or after stent migration and exit through the anus with no evidence of symptom recurrence (n = 5; 20%). The dysphagia score (before stent, 3.1 ± 0.5) improved by 3 days after stent placement (1.3 ± 0.4; P < .001) and was maintained up to 1 month after stent removal (1.2 ± 0.7; P < .001). The median survival was 18.6 months.

CONCLUSIONS

In patients with resectable esophageal cancer, temporary placement of a REMS during preoperative neoadjuvant CRT showed clinical efficacy in the bridge to surgery. Stent removal between 4 and 6 weeks after starting neoadjuvant CRT seems to be a feasible time frame with symptom improvement.

Migration of retrievable expandable metallic stents inserted for malignant esophageal strictures: incidence, management, and prognostic factors in 332 patients

OBJECTIVE

The purpose of this study was to evaluate the incidence, prognostic factors, and secondary management of stent migration in patients with malignant esophageal strictures.

MATERIALS AND METHODS

A retrospective study was performed in a single tertiary referral university hospital to identify the incidence, management, and prognostic factors for stent migration in 332 consecutive patients with placement of a retrievable expandable metallic stent. Stent migration was classified into four patterns as locations of a migrated stent: pattern I, partially migrated in the proximal direction; pattern II, partially migrated in the distal direction; pattern III, completely migrated into the stomach; and pattern IV, completely migrated into the bowel.

RESULTS

Stent migration occurred in 42 (12.6%) of 332 patients. Migration was partial (n = 21) or complete (n = 21), and nine (21%), 12 (29%), 11 (26%), and 10 (24%) patients had patterns I, II, III, and IV, respectively. Multivariate analysis identified the following prognostic factors: esophagogastric junction strictures caused by cancer of the gastric cardia (odds ratio 1.330; p = 0.004), patients who underwent anticancer treatment after stent placement (17.514; p < 0.001), and patients with a longer survival time (1.994; p < 0.001). Secondary management was needed for 33 of 42 patients. The strictures in the remaining nine patients improved throughout follow-up.

CONCLUSION

Stent migration occurs most commonly in patients with cancer of the gastric cardia, patients with longer survival time, and those who underwent anticancer treatment after stent placement. Stent migration is successfully managed by further intervention. Accurate knowledge of the pattern of stent migration is important for successful management.

In situ cooling with ice water for the easier removal of self-expanding nitinol stents

BACKGROUND

It is yet to be determined what effects temperature has on the properties of nitinol in order to simplify the process of removing nitinol self-expanding metal stents (SEMS).

MATERIALS AND METHODS

We describe the procedure for removal of SEMS in a total of 11 cases with 9 patients. A study involving cooling of nitinol stents in situ with ice water just before their removal was attempted.

RESULTS

All stents were removed successfully. In partially covered and in fully covered stents, the stent rigidity was noticeably reduced following cooling. Stent removal was performed by inversion, which was achieved by pulling on the stent from its distal end. No adverse events were observed during this trial.

CONCLUSION

The higher pliability of the stents after ice-water cooling facilitates stent removal. With this method, a mobilization of all stents by the invagination technique was achieved. The separation of the uncoated stent ends from the intestinal wall by the invagination technique, as well as the mucosal vasoconstriction resulting from the cooling, lead to an easier SEMS removal and may serve to prevent severe bleeding of the mucosal wall during this process.

Treatment of esophagopleural fistulas using covered retrievable expandable metallic stents

PURPOSE

To evaluate the clinical efficacy of placement of covered retrievable expandable metallic stents for esophagopleural fistulas (EPFs).

MATERIALS AND METHODS

During the period 1997-2013, nine patients with EPF were treated using covered retrievable expandable metallic stents. The underlying causes of EPF were esophageal carcinoma (n = 6), lung cancer (n = 2), and postoperative empyema for Boerhaave syndrome (n = 1).

RESULTS

Technical success was achieved in eight patients (88.9%). In one patient, incomplete EPF closure was due to incomplete stent expansion. Clinical success, defined as complete EPF closure within 7 days, was achieved in five patients (55.6%). Overall fistula persistence (n = 1) or reopening (n = 4) occurred in five patients (55.6%) 0-15 days after stent placement. The causes of reopening were due to the gap between the stent and the esophagus (n = 3) or stent migration (n = 1). For fistula persistence or reopening, additional interventional management, such as gastrostomy, stent removal, or stent reinsertion, was performed. Stent migration occurred as a complication in one patient with EPF from a benign cause secondary to postoperative empyema. In the eight patients who died during the follow-up period, the mean and median survival times were 78.8 days and 46 days, respectively.

CONCLUSIONS

Placement of a covered expandable metallic esophageal stent for the palliative treatment of EPF is technically feasible, although the rate of clinical success was poor secondary to fistula persistence or reopening. Fistula reopening was caused by the gap between the stent and the esophagus or by stent migration, and additional interventional treatment was useful to ensure enteral nutritional support.

Endoscopic management and prevention of migrated esophageal stents

The use of self-expandable metallic stents has increased recently to palliate inoperable esophageal neoplasia and also in the management of benign strictures. Migration is one of the most common complications after stent placement and the endoscopist should be able to recognize and manage this situation. Several techniques for managing migrated stents have been described, as well as new techniques for preventing stent migration. Most stents have a "lasso" at the upper flange which facilitates stent repositioning or removal. An overtube, endoloop and large polypectomy snare may be useful for the retrieval of stents migrated into the stomach. External fixation of the stent with Shim's technique is efficient in preventing stent migration. Suturing the stent to the esophageal wall, new stent designs with larger flanges and double-layered stents are promising techniques to prevent stent migration but they warrant validation in a larger cohort of patients.