Benign and malignant esophageal strictures: treatment with a polyurethane-covered retrievable expandable metallic stent

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.

Design and Biomechanical Analysis of a Novel Retrievable Peripheral Vascular Stent

Structurally retrievable drug-eluting stents may have valuable clinical applications because they do not leave any foreign materials inside the patient's body. This article presents a novel design of retrievable peripheral vascular stent and the results from biomechanical analysis of its performance. Using the finite element analysis method, principal parameters of the stent were studied. Moreover, to ensure the practicability of the retrieval process, simulation, and in vitro experiments were performed. The retrieval force reached the maximum value when the whole retrievable part had been retrieved. Furthermore, the force was gradually increased during the retrieval process and remained constant after the main part had been retrieved. When the stent was being compressed, the maximum strain of the stent occurred at the connection between the stent's retrieval part and the main body part, at a value of 4%. The index of nonuniformity of the stent was too small to be counted both at the end of the compression and self-expansion processes. With the increase of moment, the bending stiffness (EI) of the stent decreased gradually. After bending moment was applied, the large strain region was mainly located in the stent's main body part rather than the retrieval part. The results of preliminary stent retrieval experiments demonstrated that the stent could be retrieved successfully. This novel retrievable stent displays promising biomechanical performance. The preliminary experiments demonstrated that the stent could be retrieved smoothly from the blood vessels.

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.

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.

Refractory esophageal strictures: what to do when dilation fails

Benign esophageal strictures arise from a diversity of causes, for example esophagogastric reflux, esophageal resection, radiation therapy, ablative therapy, or the ingestion of a corrosive substance. Most strictures can be treated successfully with endoscopic dilation using bougies or balloons, with only a few complications. Nonetheless, approximately one third of patients develop recurrent symptoms after dilation within the first year. The majority of these patients are managed with repeat dilations, depending on their complexity. Dilation combined with intra lesional steroid injections can be considered for peptic strictures, while incisional therapy has been demonstrated to be effective for Schatzki rings and anastomotic strictures. When these therapeutic options do not resolve the stenosis, stent placement should be considered. Self bougienage can be proposed to a selected group of patients with a proximal stenosis. As a final step surgery is an option, but even then the risk of stricture formation at the anastomotic site remains. This chapter reviews refractory benign esophageal strictures and the treatment options that are currently available.

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.

Esophageal stenting after penetrating complete esophageal obstruction using a trocar stylet via a gastrostomy route: a case report

Complete esophageal obstruction developed after radiation and endoscopic submucosal dissection therapy for a cervical esophageal cancer in a 77-year-old woman. After failure to recanalize the esophageal obstruction by endoscopic and catheterization techniques, the esophageal obstruction was penetrated using a trocar stylet needle via a gastrostomy route. A covered stent was placed across the esophageal obstruction, letting her take water and liquid food until she died 2 months later. There was no complication related to the procedures except transient chest discomfort and pain that subsided with symptomatic treatment.

Evidence-based recommendations on upper gastrointestinal tract stenting: a report from the stent study group of the korean society of gastrointestinal endoscopy

Endoscopic stents have evolved dramatically over the past 20 years. With the introduction of uncovered self-expanding metal stents in the early 1990s, they are primarily used to palliate symptoms of malignant obstruction in patients with inoperable gastrointestinal (GI) cancer. At present, stents have emerged as an effective, safe, and less invasive alternative for the treatment of malignant GI obstruction. Clinical decisions about stent placement should be made based on the exact understanding of the patient's condition. These recommendations based on a critical review of the available data and expert consensus are made for the purpose of providing endoscopists with information about stent placement. These can be helpful for management of patients with inoperable cancer or various nonmalignant conditions in the upper GI tract.

Efficacy of intralesional corticosteroid injection in endoscopic treatment of esophageal strictures

BACKGROUND

The present study was conducted to determine the effectiveness of intralesional triamcinolone to improve the results of endoscopic dilation in esophageal strictures.

METHODS

We treated 9 patients with complex strictures of different etiologies (2 postsurgery, 3 gastroesophageal reflux disease, and 4 caustic) with intralesional injections of triamcinolone followed by endoscopic dilations. Outcomes of triamcinolone-treated patients were compared with those of historical control. We injected triamcinolone before dilating the strictures. All the patients were followed up for 1 year. The interval between dilations, frequency of dilation, and refractory rates were calculated.

RESULTS

There was no difference between the control group and the patients with steroids regarding baseline characteristics (age and sex distribution of patients and stricture etiologies, length, and location). The patients in the triamcinolone group had a bigger improvement of their dysphagia and had a lower refractority rate than the patients in control group, these differences being statistically significant.

CONCLUSIONS

Intralesional triamcinolone presented a higher improvement of dysphagia and a lower refractority rate in patients with complex strictures with statistically significant differences.

How to design the optimal self-expandable oesophageal metallic stents: 22 years of experience in 645 patients with malignant strictures

OBJECTIVES

To evaluate the clinical efficacy and safety of self-expandable metallic stent (SEMS) placement for malignant oesophageal strictures and their relationship with stent designs.

METHODS

Seven generations of SEMS were used to treat 645 consecutive patients with oesophageal strictures. Logistic regression models were constructed to identify predictive factors associated with complications.

RESULTS

Stent placement was technically successful in 641 of 645 patients (99.4%). The clinical success rate was 95.5%. There were 260 (40.3%) complications after stent placement. Due to complications, 68 stents were removed; 66 of 68 stents (97.1%) were removed successfully. Stainless steel (SS) stents (odds ratio [OR] 4.18; 95% confidence interval [CI] 2.10, 8.32) and radiation therapy (RT) before stent placement (OR 4.23; CI 2.02, 8.83) were significantly associated with severe pain. Flared ends (OR 9.63; CI 3.38, 27.43), stricture length <6 cm (OR 2.01; CI 1.13, 3.60), and a stent diameter <18 mm (OR 3.00; CI 1.32, 6.84) were predictive factors of stent migration. Polyurethane membranes were associated with more frequent tumour ingrowth than polytetrafluoroethylene (PTFE) membranes (P = 0.002).

CONCLUSIONS

Despite the relatively high complication rate, retrievable self-expandable PTFE-covered nitinol stents equipped with a head and a tail appeared to be an effective treatment for malignant oesophageal strictures.

Stent placement for esophageal strictures: an update

The use of stents for esophageal strictures has evolved rapidly over the past 10 years, from rigid plastic tubes to flexible self-expanding metal (SEMS), plastic (SEPS) and biodegradable stents. For the palliative treatment of malignant dysphagia both SEMS and SEPS effectively provide a rapid relief of dysphagia. SEMS are preferred over SEPS, as randomized controlled trials have shown more technical difficulties and late migration with plastic stents. Despite specific characteristics of recently developed stents, recurrent dysphagia due to food impaction, tumoral and nontumoral tissue overgrowth, or stent migration, remain a major challenge. The efficacy of stents with an antireflux valve for patients with distal esophageal cancer varies between different stent designs. Concurrent treatment with chemotherapy and/or radiotherapy seems to be safe and effective. In the future, it can be expected that removable stents will be used as a bridge to surgery to maintain luminal patency during neoadjuvant treatment. For benign strictures, new stent designs, such as fully covered SEMS and biodegradable stents, may potentially reduce complications during stent removal.

Outcomes following oesophageal stent insertion for palliation of malignant strictures: A large single centre series

BACKGROUND

Self-expanding metal stents (SEMS) are an accepted intervention for malignant dysphagia. Stents vary in ease of insertion, removability, migration and occlusion rates. This series reports the complications, morbidity and mortality associated with several SEMS.

METHOD

A prospective database of patients undergoing fluoroscopic guided oesophageal stent insertion for malignancy between June 2001 and June 2009 was analysed. Patient demographics, intervention outcomes and tumour variables were correlated with stent failure and patient survival. Multivariate analysis was performed to evaluate predictors for stent failure.

RESULTS

Two hundred and seventy-three stents were deployed using nine different types of SEMS. The median Mellow-Pinkas dysphagia score significantly improved from 3 to 1 post-stent insertion (P < 0.001), with a technical success rate of 98%. Stent complications occurred in 95 (36%) patients [recurrent dysphagia n = 49 (19%), migration n = 24 and occlusion n = 25]. Multivariate analysis demonstrates that the covered Niti S stent fails significantly more than the double-layered Niti S stent (OR = 4, P < 0.005).

CONCLUSION

Oesophageal stent insertion provides good palliation for malignant dysphagia, however recurrent dysphagia remains a problem. This major complication occurs more frequently with covered Niti S stents than double-layered Niti S stents. This finding may aid the stent choice used in advanced oesophageal malignancy.

Expandable stents for benign esophageal disease

Partially covered self-expandable esophageal stents have been associated with unacceptable complications when used for benign esophageal disorders. With the introduction of removable or potentially removable fully covered stents and biodegradable stents, interest in using expandable stents for benign indications has been revived. Although expandable stents can offer a minimally invasive alternative to surgery, they can be associated with serious complications; hence, this approach should be considered in carefully selected patients, preferably on a protocol basis.

Gastrointestinal stent update

The use of self-expanding metallic stents in the upper gastrointestinal tract, placed under radiologic imaging or endoscopic guidance, is the current treatment of choice for the palliation of malignant gastrointestinal outlet obstructions. Advances in metallic stent design and delivery systems have progressed to the stage where this treatment is now considered a minimally invasive therapy. Metallic stent placement will broaden further into the field of nonsurgical therapy for the gastrointestinal tract. To date, metallic stents placed in the esophagus, gastric outlet, colorectum, and bile ducts are not intended to be curative, but rather to provide a palliative treatment for obstructions. The evolution of metallic stent technology will render such procedures not only palliative but also therapeutic, by enabling local drug delivery, and the use of biodegradable materials will reduce procedure-related complications.

Stenting of the upper gastrointestinal tract: current status

Minimally invasive image-guided insertion of self-expanding metal stents in the upper gastrointestinal tract is the current treatment of choice for palliation of malignant esophageal or gastroduodenal outlet obstructions. A concise review is presented of contemporary stenting practice of the upper gastrointestinal tract, and the procedures in terms of appropriate patient evaluation, indications, and contraindications for treatment are analyzed, along with available stent designs, procedural steps, clinical outcomes, inadvertent complications, and future technology. Latest developments include biodegradable polymeric stents for benign disease and radioactive or drug-eluting stents for malignant obstructions.

Role of esophageal stents in benign and malignant diseases

These recommendations provide an evidence-based approach to the role of esophageal stents in the management of benign and malignant diseases. These guidelines have been developed under the auspices of the American College of Gastroenterology and its Practice Parameters Committee and approved by the Board of Trustees. The following guidelines are based on a critical review of the available scientific literature on the topic identified in Medline and PubMed (January 1992-December 2008) using search terms that included stents, self-expandable metal stents, self-expandable plastic stents, esophageal cancer, esophageal adenocarcinoma, esophageal squamous cell carcinoma, esophageal stricture, perforations, anastomotic leaks, tracheoesophageal fistula, and achalasia. These guidelines are intended for use by health-care providers and apply to adult, but not pediatric, patients. As with other practice guidelines, these guidelines are not intended to replace clinical judgment but rather to provide general guidelines applicable to the majority of patients. Clinicians need to integrate recommendations with their own clinical judgment, and with individual patient circumstances, values, and preferences. They are intended to be flexible, in contrast to standards of care, which are inflexible policies designed to be followed in every case. Specific recommendations are based on relevant published information. The quality of evidence and strength of recommendations have been assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system, which is a system that has been adopted by multiple national and international societies. The GRADE system is based on a sequential assessment of quality of evidence, followed by assessment of the balance between benefits vs. downsides (harms, burden, and costs) and subsequent judgment regarding the strength of recommendation.

Treatment of thoracic esophageal anastomotic leaks and esophageal perforations with endoluminal stents: efficacy and current limitations

BACKGROUND

Intra-thoracic esophageal leakage after esophageal resection or esophageal perforation is a life-threatening event. The objective of this non-randomized observational study was to evaluate the effects of endoluminal stent treatment in patients with esophageal anastomotic leakages or perforations in a single tertiary care center.

METHODS

Thirty-two consecutive patients with an intrathoracic esophageal leak, caused by esophagectomy (n = 19), transhiatal gastrectomy (n = 3), laparoscopic fundoplication (n = 2), and iatrogenic or spontaneous perforation (n = 8), undergoing endoscopic stent treatment were evaluated. Hospital stay, mortality and morbidity, sealing rate, extraction rates, complications, and long-term effects were measured.

RESULTS

Median time interval between diagnosis and stent treatment was 3 and 5 days, respectively. Eighteen patients had futile surgical closure of the defect before stenting, while in 14 patients, stent placement was the primary treatment for leakage. Stent placement was technically correct in all patients. Functional sealing was achieved in 78%. Mortality was 15.6%. Stent extraction rate was 70%. Overall method-related complications occurred in nine patients (28%).

CONCLUSIONS

Implantation of self-expanding stents after esophageal resection or perforation is a feasible and safe procedure with an acceptable morbidity even if used as last-choice treatment.

Retrievable esophageal stents for benign indications

Until recently, esophageal stents have not been a realistic option for the management of benign disease owing to difficulty removing the stents and associated high complication rates. However, progress in esophageal stent design has led to the development of retrievable esophageal stents. Clinical experience has shown promise for the management of benign esophageal diseases with retrievable stents, including refractory strictures, esophageal leaks, fistula and perforations. They have been shown to be safe and effective, though stent migration remains a concern. This article reviews the current designs, indications, efficacy and complications of retrievable esophageal stents.

The use of self-expandable plastic stents for non-malignant esophago-pleural fistulas

Anastomotic leaks and fistulas are unfortunate complications of esophageal-gastric surgery and esophageal dilations. Traditional management options have included surgery or a more conservative approach. There have been few reports describing the use of self-expandable plastic stents for the treatment of esophageal perforations and tracheoesophageal fistulas from benign diseases. We are reporting the use of self-expandable plastic stents for the treatment of non-malignant esophago-pleural fistulas occurring after esophagectomy in one case and esophageal perforation post dilation in the other.

Fate of migrated esophageal and gastroduodenal stents: experience in 70 patients

PURPOSE

To investigate the frequency of esophageal and gastroduodenal stent migration and the fate of such stents.

MATERIALS AND METHODS

The authors studied five types of covered metal stents. Type A stents were nonretrievable polyurethane-covered stents with shouldered ends (n = 169), type B stents were retrievable polyurethane-covered stents with shouldered ends (n = 62), type C stents were retrievable polyurethane-covered stents with flared ends (n = 72), type D stents were retrievable polytetrafluoroethylene-covered stents with shouldered ends (n = 369), and type E stents were separated stents (n = 216). Types A-D stents were esophageal stents, and the type E stent was a gastroduodenal stent. Stents were placed in 888 patients with either benign (n = 43) or malignant (n = 845) causes of stricture. The rate of stent migration was analyzed relative to completeness of migration, the cause of obstruction, stent type, and stent placement location. The fate of migrated stents and the treatment of patients were evaluated.

RESULTS

Stent migration occurred in 70 of the 888 patients (7.9%). Migration occurred in 11 of the 43 patients (25%) with benign cause of strictures and 591 of the 845 patients (7.0%) with malignant cause. The migration rates for types A, B, C, D, and E stents were 10%, 4.8%, 24%, 7.3% and 2.8%, respectively. Of the 70 migrated stents, 45 had complete migration and 25 had partial migration. The anastomotic sites were the areas most commonly associated with migration (16%), but this was not statistically significant. Forty of the 70 migrated stents were removed with retrieval devices under fluoroscopic guidance because they were not passed with stool and possibility of complications related to migrated stents. The remaining 30 stents exited via the rectum (n = 15), remained in the body without complications (n = 12), or were surgically removed because they caused complicated intestinal obstructions (n = 3).

CONCLUSION

The overall migration rate for esophageal and gastroduodenal stents was 7.9%. Most migrated stents were removed nonsurgically, exited the body spontaneously, or remained in the body in an uncomplicated state. Surgical stent removal was necessary in three patients (4.3%) due to complicated intestinal obstructions.

Removal of a Covered Esophageal Metallic Stent 8 Years after Placement

A covered expandable esophageal metallic stent was placed to treat a corrosive esophageal stricture that was refractory to repeated balloon dilations. The stent was removed 8 years after placement due to severe dysphagia. The stented esophageal area has since maintained long-term patency for 2 years. These results suggest the feasibility of removal of a metallic stent after long-term stent placement.

Covered Retrievable Prostatic Urethral Stents: Feasibility Study in a Canine Model

PURPOSE

To evaluate the feasibility of use of a covered, retrievable prostatic urethral stent and to determine urethrographic and histologic changes in the prostate induced by the stent in a canine model.

MATERIALS AND METHODS

Polytetrafluoroethylene-covered retrievable nitinol stents were placed in the normal prostatic urethras of 13 dogs. The stents were removed 8 weeks after placement. The dogs were killed immediately after stent removal (group 1, n = 5) or 8 weeks after stent removal (group 2, n = 8). Retrograde urethrograms were obtained every 2 weeks after stent placement and after stent removal in dogs that had not been killed. The histologic changes in the prostate were compared between the two groups.

RESULTS

Stent placement was technically successful in all dogs. In two dogs, a second stent was placed because of migration of the first stent into the urinary bladder. Stent removal was successful in 12 dogs. One stent was removed in its expanded state. On follow-up urethrograms, dilation of the prostatic urethra persisted until animals were killed (P = .14). The mucosal hyperplasia that occurred after stent placement at both ends of the stent gradually decreased after stent removal (P < .001). Histologic examination revealed prostate glandular atrophy and periurethral fibrosis, which did not differ between the two groups (P = .72 and P = .83, respectively). Papillary hyperplasia of the uroepithelium and submucosal inflammatory cell infiltration was decreased significantly in group 2 compared with group 1 (P = .002, P = .011, respectively).

CONCLUSIONS

Covered retrievable prostatic urethral stents seem to be feasible for use in the canine prostatic urethra. The stent-induced prostatic urethral dilation and prostate glandular atrophy persist until 8 weeks after stent removal.

Quality improvement guidelines for placement of esophageal stents

Esophageal cancer is now the sixth leading cause of death from cancer worldwide. During the past three decades, important changes have occurred in the epidemiologic patterns associated with this disease. Due to the distensible characteristics of the esophagus, patients may not recognize any symptoms until 50% of the luminal diameter is compromised, explaining why cancer of the esophagus is generally associated with late presentation and poor prognosis. Esophageal cancer has a poor outcome, with an overall 5 year survival rate of less than 10%, and fewer than 50% of patients are suitable for resection at presentation. As a result palliation is the best option in this group of patients. The aims of palliation are maintenance of oral intake, minimizing hospital stay, relief of pain, elimination of reflux and regurgitation, and prevention of aspiration. For palliative care, current treatment options include thermal ablation, photodynamic therapy, radiotherapy, chemotherapy, chemical injection therapy, argon beam or bipolar electrocoagulation therapy, enteral feeding (nasogastric tube/percutaneous endoscopic gastrostomy), and intubation (self-expanding metal stents (SEMS) or semi-rigid prosthetic tubes) with different success and complications rates.

Comparison of Temporary and Permanent Stent Placement with Concurrent Radiation Therapy in Patients with Esophageal Carcinoma

PURPOSE

To assess the clinical effectiveness of temporary metallic stent placement with concurrent radiation therapy in patients with esophageal carcinoma by comparing it with permanent stent placement with concurrent radiation therapy.

MATERIALS AND METHODS

Covered retrievable expandable nitinol stents were placed in 47 patients with esophageal carcinoma 1 week before starting radiation therapy; the stents were electively removed 4 weeks after placement in 24 patients (group A), while not electively removed in the other 23 patients (group B). In cases of complications, the stents were also removed from patients in groups A and B. The dysphagia score, complications (severe pain, granulation tissue formation, stent migration, esophagorespiratory fistula, and hematemesis), tumor overgrowth/regrowth, reintervention rates, and dysphagia-progression-free and overall survival rates were compared in the two groups.

RESULTS

Stent placement or removal was technically successful and well tolerated in all patients. The dysphagia score was significantly improved in both groups after stent placement (P < .01). Each of the stent-related complications was less in group A than in group B but there was no significant difference. However, the total number of patients with one or more than one complications and who needed related reinterventions was significantly less in group A than in group B (P = .042 and .030, respectively). Tumor overgrowth/regrowth and the total number of patients who required related reinterventions was not significantly different (P = 1.00 and .517, respectively). Dysphagia-progression-free and overall survival rates were significantly longer in group A than in group B (P = .005 and .001, respectively).

CONCLUSION

Temporary placement of a covered retrievable expandable metallic stent with concurrent radiation therapy for patients with esophageal carcinoma is beneficial for reducing complications and related reinterventions and for increasing resultant survival rates compared with permanent esophageal stent placement.

Removal of retrievable esophageal and gastrointestinal stents: experience in 113 patients

OBJECTIVE

Although there are frequent clinical situations in which esophageal and gastrointestinal stents should be removed, nonsurgical stent removal has been difficult. The purpose of our study was to describe the safety and efficacy of removing the retrievable nitinol stents with a retrieval hook.

MATERIALS AND METHODS

Under fluoroscopic guidance, the removal of 119 esophageal, six gastroduodenal, and five rectal retrievable stents was attempted in 113 patients using a retrieval hook. Indications for stent removal included migration (n = 35), severe pain (n = 23), formation of a new stricture (n = 13), incomplete stent expansion (n = 7), airway compression (n = 2), esophagorespiratory fistula (n = 2), malpositioned stent (n = 1), and hematemesis (n = 1). The remaining 46 stents were electively removed.

RESULTS

Of the 130 stents, 127 (97.7%) were successfully removed despite the following difficulties: untied drawstrings (n = 4), separation of the stent (n = 3), and fracture (n = 2) or disconnection (n = 2) of a retrieval hook. The removal procedure failed in three cases (2.3%). The causes of failure were the inability to place the hook into the migrated stent (n = 2) and a tight stricture above the migrated stent (n = 1). The procedure-related complications included minor (n = 4) and major (n = 1) bleeding and intramural rupture (n = 3). One patient died of major bleeding after removal of an esophageal stent.

CONCLUSION

The stent retrieval hook is useful for removing retrievable esophageal and gastrointestinal stents.

Treatment of a benign anastomotic duodenojejunal stricture with a polytetrafluoroethylene-covered retrievable expandable nitinol stent

Temporary placement of a polytetrafluoroethylene (PTFE)-covered retrievable expandable nitinol stent was performed to treat a benign anastomotic duodenojejunal stricture that was refractory to repeated balloon dilation procedures. The procedure provided a favorable outcome for the patient and was completed without complications. This result suggests that successful treatment of benign strictures of the gastric outlet or duodenum is possible with use of retrievable stents.

Self-expandable metallic stents for palliation of malignant esophageal obstruction: special reference to quality of life and survival of patients

SUMMARY. Self-expandable metallic stents (EMS) provide a common option for malignant esophageal stenosis because of the low complication rate and high dysphagia improvement rate. However, there are few studies on the functional duration of EMS and the extent of improvement of the quality of life. We retrospectively analyzed 18 patients who received EMSs in our division from 1996 to 2002. The median duration of possible food intake and the median survival period were 94.5 and 108 days. The median duration of domiciliary treatment was 56 days. Six of the 18 patients were not discharged from hospital after EMS insertion. The Karnofsky index was found to be a significant determinant of the feasibility of domiciliary treatment. One-third of the patients are incapable of obtaining the benefits of the palliative therapy. EMS deployment should be prudently selected for patients exhibiting low performance status.

Temporary partially-covered metal stent insertion in benign esophageal stricture

AIM: To study the therapeutic efficacy of temporary partially-covered metal stent insertion on benign esophageal stricture.

METHODS: Temporary partially-covered metal stent was inserted in 83 patients with benign esophageal stricture. All the patients had various dysphagia scores.

RESULTS: Insertion of 85 temporary partially-covered metal stents was performed successfully in 83 patients with benign esophageal stricture and dysphagia was effectively remitted in all the 83 cases. The dysphagia score was 3.20 ± 0.63 (mean ± SD) and 0.68 ± 0.31 before and after stent insertion, and 0.86 ± 0.48 after stent removal. The mean diameter of the strictured esophageal lumen was 3.37 ± 1.23 mm and 25.77 ± 3.89 mm before and after stent insertion, and 16.15 ± 2.96 mm after stent removal. Follow-up time was from 1 week to 96 months (mean 54.26 ± 12.75 months). The complications were chest pain (n = 37) after stent insertion, and bleeding (n = 12) and reflux (n = 13) after stent removal.

CONCLUSION: Temporary partially-covered metal stent insertion is one of the best methods for treatment of benign esophageal stricture.

Severe complications in advanced esophageal cancer treated with radiotherapy after intubation of esophageal stents: a questionnaire survey of the Japanese Society for Esophageal Diseases

PURPOSE

A questionnaire survey was performed to evaluate the complications and prognosis of esophageal cancer treated with esophageal intubation before or during radiotherapy.

METHODS AND MATERIALS

Clinical data were accumulated on a total of 47 patients treated at 17 institutions in Japan. Five patients had Stage II, 30 Stage III, and 11 Stage IV, and the stage was unknown in 1 patient. Covered expandable metallic stents were inserted in 30 patients, uncovered expandable metallic stents in 13, plastic or silicon prosthesis in 3, and an unknown type in 1 patient. Esophageal stenting was performed before the start of RT for 23 patients and during the course of RT for 24 patients. The reasons for the stenting were severe stricture in 32 patients (Group 1) and esophageal fistula in 15 patients (Group 2).

RESULTS

The most frequent toxicity was formation or worsening of esophageal fistulas in 13 patients (28%), followed by massive hematemesis or GI bleeding in 10 patients (21%). In total, 24 patients (51%), including 10 patients with possible treatment-related deaths (Grade 5), had nonhematologic toxicities of Grade 3-5. The interval from the start of RT to the nonhematologic toxicity ranged from 16 to 312 days (median 78). The incidence of toxicities was higher for Group 1 (59%) than for Group 2 (33%), although the difference was not statistically significant. The median survival time for those with Stage II-III and Stage IV was 5 and 3.5 months, respectively.

CONCLUSIONS

Patients with esophageal intubation before or during RT have a high risk of life-threatening complications, especially for those with severe esophageal stricture. Because long survival is expected for a substantial proportion of patients with locally advanced esophageal cancer after chemoradiotherapy, palliative intubation should be delayed until radiotherapy or chemoradiotherapy appears to have failed.

Obstruction of the lacrimal system: treatment with a covered, retrievable, expandable nitinol stent versus a lacrimal polyurethane stent

PURPOSE

To compare the clinical effectiveness of a covered nitinol stent with that of a polyurethane stent for treatment of lacrimal system obstructions.

MATERIALS AND METHODS

A nitinol stent was knit from a single thread of 0.1-mm nitinol wire in a tubular configuration and was covered by dipping the stent into a polyurethane solution. The stent was 4 mm in diameter and 30 or 35 mm long. With fluoroscopic guidance, a covered nitinol stent (n = 33, group A) or a polyurethane stent (n = 35, group B) was placed in 68 patients. The following items were evaluated retrospectively: technical success, procedure time, cumulative patency rate, and complications. An unpaired Student t test was used to analyze the difference between the procedure times. Kaplan-Meier survival curves and a log-rank test were used to compare the cumulative patency rates.

RESULTS

Stent placement was technically successful in 31 (94%) of 33 patients in group A and in all 35 (100%) patients in group B. After stent placement, all patients showed resolution of epiphora. Average procedure time was 400 seconds (range, 270-900 seconds) in group A and 260 seconds (range, 150-900 seconds) in group B. The difference between the procedure times was statistically significant (P =.0003). During the mean follow-up period of 40 months, there was recurrence of epiphora in 30 of 31 patients in group A and 26 of 35 patients in group B. The difference of the cumulative patency rates was statistically insignificant (P =.2).

CONCLUSION

Although the polyurethane stent used for treatment seemed to be more effective than the nitinol stent, selection of these stents for placement should be made with caution, because the long-term patency rates are not encouraging.

Self-expandable covered metallic esophageal stent impregnated with beta-emitting radionuclide: an experimental study in canine esophagus

PURPOSE

A specially designed self-expandable covered metallic stent impregnated with the beta-emitting radioisotope 166Ho (166Ho, energy: 1.85 and 1.76 MeV, T12: 26.8 h) was developed at our institute for the purpose of intraluminal palliative brachytherapy, as well as for treating malignant esophageal stricture and swallowing difficulty. The aim of this study was to evaluate the tissue response to brachytherapy and the safety of the radioactive metallic stent with regard to the normal canine esophagus before clinical application.

METHODS AND MATERIALS

166Ho was impregnated into the polyurethane membrane (50 micron thickness) covering the outer surface of a self-expandable metallic stent (diameter, 18 mm; length, 40 mm). Stents with radioactivity 4.0-7.8 mCi (Group A, n = 15), 1.0-1.8 mCi (Group B, n = 5), and 0.5-0.7 mCi (Group C, n = 5) were placed in the esophagi of 25 healthy beagle dogs, and the stents were tightly anchored surgically to prevent migration. The estimated radiation dose calculated by Monte Carlo simulation was 194-383 Gy in Group A, 48-90 Gy in Group B, and 23-32 Gy in Group C. The dogs were killed 8-12 weeks after insertion of the stents, and histologic examinations of the esophageal walls were performed.

RESULTS

In Group A, 3 of 15 dogs died of wound infection, so specimens were obtained from only 12 dogs; all 12 cases showed esophageal stricture with mucosal ulceration. Microscopically, severe fibrosis and degeneration of the muscular propria were found in 3 dogs, complete fibrosis of the entire esophageal wall was found in 7 dogs, and esophageal fibrosis with radiation damage within periesophageal soft tissue was found in 2 dogs. However, esophageal perforation did not develop, despite extremely high radiation doses. In Group B, glandular atrophy and submucosal fibrosis were found, but the muscular layer was intact. In Group C, no histologic change was found in 3 dogs, but submucosal inflammation and glandular atrophy with intact mucosa were found in 2 dogs.

CONCLUSIONS

A radioactive, self-expandable covered metallic stent can be used as an alternative therapeutic modality for the palliative treatment of malignant esophageal stricture.

Covered, retrievable, expandable urethral nitinol stent: feasibility study in dogs

PURPOSE

To evaluate the feasibility of using a retrievable urethral stent and to evaluate whether granulation tissue resolves after stent removal in a canine urethra.

MATERIALS AND METHODS

Polyurethane-covered retrievable 0.10-mm-thick (n = 11) or 0.15-mm-thick (n = 10) nitinol wire stents were placed in the urethras of 20 dogs. In one dog, a second stent was placed in the urethra because of complete migration of the first stent into the urinary bladder. The stents were removed with retrieval hook wires 4 weeks (n = 10) and 8 weeks (n = 10) after placement. Fourteen dogs were sacrificed just after stent removal, and the other six dogs were sacrificed 2 weeks after stent removal. Information concerning procedure success, stent migration, and tissue response was obtained.

RESULTS

Stent placement was technically successful in all dogs. Follow-up urethrograms showed partial (n = 4) or complete (n = 1) stent migration. Stent removal failed in two dogs due to partial or complete migration. Granulation tissue was observed at both ends of the stent in 17 dogs. Urethrograms and urethral specimens obtained 2 weeks after stent removal showed diminished granulation tissue and decreased thickness of the papillary projections of the epithelium compared with results obtained immediately after stent removal.

CONCLUSION

Although some design modifications are necessary to reduce current complications, the polyurethane-covered retrievable nitinol stent seems feasible for use in the urethra. Stent-induced granulation tissue formation improved after stent removal.

Retrievable covered nitinol stents: experiences in 108 patients with malignant esophageal strictures

PURPOSE

The authors report their experience with three types of retrievable covered nitinol stents in patients with malignant esophageal strictures.

MATERIALS AND METHODS

Three types of retrievable covered nitinol stents were designed. Type A stents were placed in 45 patients, type B stents were placed in 29 patients, and type C stents were placed in 34 patients. The stents were removed with use of a stent retrieval set under fluoroscopic guidance when the stents caused complications. Stent patency, symptom relief, survival rate, and complications were analyzed relative to stent type and radiation therapy.

RESULTS

The timing of radiation and the stent type have significant effects on occurrence of complications such as stent migration and fistula formation (P =.002 and P = 0.029, respectively). Complications were significantly more frequent in patients with the type B stent than those with type A or type C stents (P =.008). Patients who underwent radiation therapy before stent placement or who underwent no radiation therapy experienced substantially less complications than those who underwent radiation therapy after stent placement (P =.005 and P <.001, respectively). The survival period was significantly longer in patients who underwent radiation therapy after stent placement than in the other groups (P =.034). Stents were removed from 15 patients (14%) 2 days to 16 weeks (mean, 4 weeks) after stent placement as a result of severe pain (n = 7), stent migration (n = 6), or stent deformity (n = 2). Stent removal was well tolerated in all patients.

CONCLUSION

Use of retrievable covered nitinol stents seems to be a safe and effective method of treatment in patients with malignant esophageal strictures. However, removal of the stents was needed in 14% of the patients because of complications. Patients who underwent radiation therapy after stent placement and those with the type B stent experienced more complications than other patients.

The role of oesophageal stenting in the non-surgical management of oesophageal strictures

The role of oesophageal stenting continues to evolve, with several new stents currently on the market. These stents possess anti-reflux valves, internal plastic coatings and retrievable threads. In patients with malignant dysphagia, management should ideally take place within multi-disciplinary teams such that accurate tumour staging occurs prior to treatment. Multi-modality therapy can not only improve dysphagia and response rates but may also improve survival. Several non-surgical palliative techniques are available to recanalize malignant obstruction, including oesophageal stenting. Other therapeutic modalities include the use of endoluminal laser therapy, photodynamic therapy, argon beam and bipolar electrocoagulation, ethanol injection and intracavity brachytherapy. Their use often depends on local availability and expertise. Although the initial costs of metal stents are high, the overall costs compare favourably with other forms of palliative therapy that often require multiple procedures with repeated inpatient hospitalization. Treatment of refractory benign strictures with oesophageal stents remains uncommon and several recent reports using retrievable stents appear to improve outcome, although more work is required in this area.

Use of metallic stents and balloons in the esophagus and gastrointestinal tract

The majority of malignant and benign strictures in the esophagus and GI tract can be treated with use of minimally invasive alternatives to surgery such as balloon dilation or metallic stents. Virtually any obstructing lesion in the esophagus, stomach, duodenum, colon, and rectum can be treated with these methods with use of interventional radiologic or endoscopic techniques. In general, metallic stents are reserved for malignant strictures and balloon dilation is indicated for benign lesions. Patients with malignant esophageal fistulas and perforations can be palliated effectively and promptly by sealing the fistula or leak by deployment of a covered stent. Patients with malignant disease may benefit from a treatment regime that includes metallic stent placement, chemotherapy, radiation therapy and/or brachytherapy, although the efficacy of such combined therapies has yet to be defined. Further refinements to stent design are required. The ideal stent would be resistant to tumor ingrowth and migration. Placing a coating material on uncovered stents to prevent tumor ingrowth may achieve these aims. Finally, a biodegradable stent that dissolves before the development of intimal hyperplasia might enable stents to be used to treat benign strictures.

Palliation of postoperative gastrointestinal anastomotic malignant strictures with flexible covered metallic stents: preliminary results

PURPOSE

To evaluate the efficacy of the placement of covered metallic stents for palliation of gastrointestinal anastomotic strictures secondary to recurrent gastric cancer.

METHODS

Under fluoroscopic guidance, placement of one or two self-expandable covered metallic stents was attempted perorally in 11 patents (aged 48-76 years) with anastomotic stenoses due to recurrent gastric malignancies. The strictures involved both the afferent and efferent loops in three patients. All patients had poor peroral food intake with severe nausea and vomiting after ingestion. The technical and clinical success was evaluated.

RESULTS

Placement of the covered stent was technically successful in 13 of 15 (87%) attempts in ten patients. After the procedure, 9 of 11 (82%) patients overall were able to ingest at least a liquid diet and had markedly decreased incidence of vomiting. During the follow-up of 2-31 weeks (mean 8.5 weeks) there were no major complications.

CONCLUSION

These preliminary results suggest that flexible, covered stents may provide effective palliation of malignant anastomotic stricture secondary to recurrent gastric cancer.

Malignant colonic obstruction due to extrinsic tumor: palliative treatment with a self-expanding nitinol stent

OBJECTIVE

The purpose of this study was to evaluate the usefulness of self-expanding nitinol stents for palliative treatment of malignant colorectal obstruction caused by unresectable extrinsic tumor, colorectal metastasis, or peritoneal seeding.

SUBJECTS AND METHODS

One covered stent and 10 uncovered stents were deployed in eight patients with colorectal obstruction due to extrinsic tumor under fluoroscopic guidance. The sites of obstruction were located in the rectum (n = 5), in the rectosigmoid colon (n = 2), and from the transverse colon to the descending colon (n = 1). Clinical usefulness and complications were analyzed.

RESULTS

Stents were placed successfully in all patients. Minor modifications of the delivery system were required in the tortuous rectosigmoid and lower rectum strictures. Symptoms of obstruction were initially resolved in all but one patient. In that patient, the presence of other points of obstruction was suspected. Bowel obstruction recurred in two patients: one obstruction was due to migration of a covered stent 4 days after the procedure, and the other obstruction was due to peritoneal seeding 33 days after the procedure. Both required colostomy or ileostomy. All patients died 12-111 days after stent placement (mean, 56 days). In five patients (63%), colonic obstruction was palliated by placing a stent until the patients' death between 39 and 111 days after stent placement (mean, 62 days). Six complications occurred in four patients and included stent migration (n = 1), anal bleeding (n = 2), anal pain that required analgesia (n = 1), and fever (n = 2). CONCLUSION; This self-expandable nitinol stent adequately palliated 63% of patients with colonic obstruction due to extrinsic tumor in this small series. Patient selection is very important to the success of this treatment.

Covered retrievable expandable nitinol stents in patients with benign esophageal strictures: initial experience

PURPOSE

To investigate the safety and clinical effectiveness of covered retrievable expandable nitinol stents in 25 patients with a benign esophageal stricture.

MATERIALS AND METHODS

Under fluoroscopic guidance, covered retrievable expandable nitinol stents were placed in 25 patients with a benign esophageal stricture and were removed with a retrieval hook 1-8 weeks later.

RESULTS

Stent placement was successful in all patients, with no procedural complications. After stent placement, all patients could ingest solid food. The stents were successfully removed from all but two patients. One patient passed the stent via the rectum, and the other regurgitated a high cervical stent. After stent removal, one patient developed a small esophagobronchial fistula, which spontaneously sealed within 1 week of stent removal. After stent removal or migration, all patients could ingest solid food. During follow-up (mean, 13 months; range, 2-25 months) after stent removal or migration, 12 patients maintained their improvement in dysphagia and needed no further treatment. Thirteen patients with recurrence were treated by means of repeat balloon dilation.

CONCLUSION

Use of retrievable expandable nitinol stents seems to be a safe and effective method of treatment in selected patients with benign esophageal strictures.

Patient tolerance of cervical esophageal metallic stents

PURPOSE

To demonstrate that proximal esophageal stenoses and tracheoesophageal fistulas can be adequately palliated with use of metallic stents without significant foreign-body sensation.

MATERIALS AND METHODS

Between June 1994 and March 1999, 22 patients with lesions within 3 cm of the cricopharyngeus were treated by placement of metallic stents. The series was reviewed retrospectively. Twenty patients had surgically unresectable malignant lesions, two patients had benign disease. Ten patients had associated tracheoesophageal fistulas. In all, the upper limit of the stent was between C5 vertebral body inferior endplate and the T2 vertebral body superior endplate. The case-notes were reviewed until patient death (range, 6-198 days), or to date in the two surviving patients with benign disease.

RESULTS

Immediate technical success was 93% (27 of 29). Dysphagia scores improved from a median of 3 to 2 after stent placement. Eighteen of 22 (82%) patients reported no foreign-body sensation. There have been no cases of proximal migration, periprocedural perforation, or deaths. The two patients with benign disease experienced significant complications.

CONCLUSION

Lesions in proximity to the cricopharyngeus can be successfully palliated without significant foreign-body sensation in the majority of patients with use of metallic stents. The authors urge caution in placing stents in patients with benign disease.