Evaluation of a New Esophageal Stent for the Treatment of Malignant and Benign Esophageal Strictures

Multifunctional Meta-Tribomaterial Nanogenerators for Energy Harvesting and Active Sensing

Discovering novel multifunctional metamaterials with energy harvesting and sensing functionalities is likely to be the next technological evolution of the metamaterial science. Here, we introduce a novel concept called self-aware composite mechanical metamaterial (SCMM) that can transform mechanical metamaterials into nanogenerators and active sensing mediums. In pursuit of this goal, we examine new paradigms where finely tailored and seamlessly integrated self-recovering snapping microstructures composed of topologically different triboelectric materials can form self-powering and self-sensing meta-tribomaterial systems. We explore various deformation mechanisms required to induce contact electrification between these snapping microstructures under periodic deformations. The multifunctional meta-tribomaterial systems created under the SCMM concept will act as triboelectric nanogenerators capable of generating electrical signals in response to the applied mechanical excitations. The generated electrical signal can be used for active sensing of the applied force and can be stored for empowering sensors and embedded electronics. We conduct theoretical and experimental studies to understand the mechanical and electrical behavior of the multifunctional SCMM systems. The broad application of the proposed SCMM concept for designing artificial materials with novel properties and functionalities is highlighted via prototyping self-powering and self-sensing blood vessel stents and shock absorbers.

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.

Fluoroscopic self-expandable metallic stent placement for treating post-operative nonanastomotic strictures in the proximal small bowel: a 15-year single institution experience

OBJECTIVE

To evaluate the efficacy and safety of fluoroscopic self-expandable metallic stent (SEMS) placement for treating postoperative nonanastomotic strictures in the proximal small bowel.

METHODS

Data from 8 consecutive patients (mean age, 63.8 ± 6.9 years; 7 males and 1 female) who underwent 17 fluoroscopic SEMS placement procedures in total for treating postoperative nonanastomotic strictures in the proximal jejunum were retrospectively reviewed. The most recent surgery for all the patients was total gastrectomy with esophagojejunostomy. Strictures were located in the proximal jejunum in all patients. The mean length of the strictures was 5.8 ± 2.0 cm. Five patients with comorbidities were poor surgical candidates. Four patients underwent fluoroscopic balloon dilation, three of whom showed no resolution of obstructive symptoms and one demonstrated recurrence of symptoms.

RESULTS

Technical and clinical success was achieved in 100% (17/17) SEMS procedures. Complete resolution of obstructive symptoms and improvement in oral intake status occurred within 3 days after all procedures, rendering a clinical success rate of 100% (17/17). No complication occurred during or after the procedures. The median follow-up duration was 167 [interquartile range (IQR), 48-576] days. Stent malfunction occurred after 58.8% (10/17) of the procedures, including six occurrences of stent migration and four of benign tissue hyperplasia. Surgical removal of the migrated stents was performed in two patients. Recurrence of symptoms occurred after 64.7% (11/17) of the procedures. The median stent dwell and recurrence-free times were 32 (IQR, 20-193) and 68 (IQR, 38-513) days, respectively.

CONCLUSION

Fluoroscopic SEMS placement may be effective and safe for treating postoperative nonanastomotic strictures, but stent malfunction and recurrence are major drawbacks.

ADVANCES IN KNOWLEDGE

SEMS placement is effective and relatively safe in patients with postoperative nonanastomotic strictures in the proximal small bowel. Patients section and counseling is highly encouraged.

Stenting the Upper/Cervical Oesophagus with a Proximal Deployment Cervical Oesophageal Stent: Technique and Outcomes

INTRODUCTION

Proximal oesophageal stent deployment continues to provide challenges due to the proximity of the upper oesophageal sphincter and the associated subsequent complications such as globus sensation and stent migration. Patients with cervical oesophageal cancer have previously had limited stenting options available to them with a paucity of the literature describing the radiological technique for successfully placing these high-risk stents. In this paper, we present our experience using the Taewoong Niti-S CERVICAL Oesophageal Stent.

MATERIALS AND METHODS

We describe our method for stent deployment highlighting the importance of pre-procedural planning in ensuring an adequate proximal landing zone for the short proximal flare of the stent. Furthermore, we outline how we have adapted our placement technique to incorporate a routine pre-dilatation stage which has optimised retrieval of the proximal to distal deployment system.

RESULTS

We have placed eight cervical oesophageal stents within our institution. Contrast swallows in all the patients following stent deployment have demonstrated free flow of contrast to the stomach with all patients reporting symptomatic relief and no foreign body/globus sensation. There has been one episode of stent migration but no incidence of oesophageal perforation or haemorrhage.

DISCUSSION

Evolution of stenting technique and the properties of the stents themselves are improving accuracy of stent placement in relation to the important landmark of the upper oesophageal sphincter.

CONCLUSION

Stenting of cervical oesophageal malignancy has proved successful in our institution and provided symptom relief for a subset of palliative patients who were previously unable to benefit from oesophageal stenting.