Advances in Ureteral Stent Design and Materials

Purpose of Review

There are three technological parameters that play a key role on the performance of an ideal stent. These are its material, design and surface coating. This article highlights some fundamental developments that took place in these three areas of stent’s technology, in order to contribute to the identification of an ideal stent.

Recent Findings

In addition to technological developments concerning stent’s material, design and surface coating, the flow dynamic performance of stents has recently attracted increasing attention. Notably, it has been postulated that the local flow field in a stent is correlated with the deposition of crystals and microorganisms. These findings could potentially revolutionise future stent’s designs, and complement developments made on materials and coatings.

Summary

The most relevant changes in materials, designs and surface coatings of ureteric stents are reviewed in this article. These are described in the context of a specific cause of stent’s failure they aim to address, with a particular focus on encrustation and biofilm formation.

     

A novel over-the-scope deployment method for enteral stent placement

Background

Over the last two decades, self-expanding enteral stents have gained popularity and shown therapeutic potential for strictures, obstructions, fistulae, and perforations of the gastrointestinal (GI) tract. Currently available stent delivery systems make deployment in many locations in the GI tract difficult due to the inability to traverse curves or impossible due to the size requirements of the deployment systems.

Methods

A 67-year-old male presented to our hospital with severe gallstone pancreatitis, requiring a prolonged intensive care unit course. Two days after discharge to a rehabilitation facility he developed acute abdominal pain and pneumoperitoneum. Operative exploration failed to identify a perforation. Subsequently, a left-upper-quadrant abscess developed that was drained percutaneously, yielding coliform bacteria. The drain produced several hundred milliliters of stool a day. A barium enema demonstrated a perforation in the descending colon from an old colo-colic anastomosis site. We proposed a novel over-the-scope (OTS) stent deployment method. Utilizing a heat-activated polymer sheath, the stent was affixed to the endoscope. A modified speed-banding attachment was created to permit release of the polymer sheath once endoscopic and fluoroscopic confirmation of the correct position was obtained.

Results

Utilizing this method of OTS stent deployment, a fully covered 23 × 155 mm self-expanding metal stent (WallFlex, Boston Scientific, Natick, MA) was placed in the colon. Endoscopic and fluoroscopic evaluation following stent placement confirmed stent coverage of the perforation with no ongoing evidence of leak. The patient was discharged to his home state 2 weeks after stent placement in stable condition.

Conclusion

We have developed a novel method of OTS stent placement that permits deployment of a variety of enteral stents on any available endoscope. This method permits placement of fully covered stents in locations in the GI tract not reachable with currently available delivery systems.     

Endoscopic laser fragmentation and removal of a nonremovable metal esophageal stent for persistent dysphagia: a technical note

Background

Self-expanding metal stents are widely used in the palliation of esophageal diseases (Todd, N Engl J Med 344(22):1681–1687, 2001). The majority are inserted for end-stage malignancy and are not designed to be removed.

Methods

We report the first recorded successful endoscopic removal of an “irremovable” stent by laser fragmentation after its placement became redundant. A 72-year-old man who had persistent dysphagia after esophageal stent insertion for Boerhaave’s syndrome had his stent removed by Nd-YAG laser fragmentation at staged endoscopies.

Results

The stent was removed in its entirety and the patients’ symptoms resolved.

Conclusions

We describe a successful technique for the removal of a nonretrievable stent using laser fracture and endoscopic retrieval. This method of stent removal has not been previously reported.     

Gastric Leak After Laparoscopic Sleeve Gastrectomy: Early Covered Self-Expandable Stent Reduces Healing Time

Background

Laparoscopic sleeve gastrectomy has become a very frequent procedure in bariatric surgery due to its efficacy and simplicity compared to gastric bypass. Gastric staple line leak (1 to 7 % of cases) is a severe complication with a long nonstandardized treatment. The aim of this retrospective study was to examine the success and tolerance of covered stents in its management.

Methods

From January 2009 to December 2011, nine patients with gastric staple line leaks after sleeve gastrectomy were treated with covered stents in our department (seven referred from other institutions). The leaks were diagnosed by CT scan and visualized during the endoscopy. Among the studied variables were operative technique, post-operative fistula diagnosis delay, stent treatment delay, and stent tolerance. In our institution, Hanarostent® (length 17 cm, diameter 18 mm; M.I. Tech, Seoul, Korea) was used and inserted under direct endoscopic control.

Results

Stent treatment was successful in seven cases (78 %). Two other cases had total gastrectomy (405 and 185 days after leak diagnosis). Early stent removal (due to migration or poor tolerance) was necessary in three cases. The average stent treatment duration was of 6.4 weeks, and the average healing time was 141 days. The five patients with an early stent treatment (≤3 weeks after leak diagnosis) had an average healing time of 99 days versus 224 for the four others.

Conclusions

Covered self-expandable stent is an effective treatment of gastric leaks after sleeve gastrectomy. Early stent treatment seems to be associated with shorter healing time.     

Evaluation of a novel gel-based ureteral stent with biofilm-resistant characteristics

Purpose

Current ureteral stents, while effective at maintaining a ureteral lumen, provide a substrate for bacterial growth. This propensity for biofilm formation may be a nidus for bacterial growth leading to infection and a reason for early removal of a stent before it is clinically indicated. A newly devised stent, composed of a highly hydrated, partially hydrolyzed polyacrylonitrile polymer, is believed to have bacterial resistant properties. The objective of this study is to evaluate the biofilm growth and bacterial resistant properties of this novel stent.

Materials and methods

Multiple 1 cm sections of the pAguaMedicina? Pediatric Ureteral Stent (pAMS) (Q Urological, Natick, MA) and the conventional polymer stent (SS) (Boston Scientific, Natick, MA) were incubated for 3 days in the 3 different growth media. Afterward, J96 human pathogenic Escherichia coli was added. At 3, 6, 9, 12, and 15 days following bacterial inoculation, the stent segments were washed, sonicated, and analyzed for bacterial growth. Scanning electron microscopy (SEM) imaging was performed to assess biofilm formation.

Results

pAMS demonstrated significant reductions (43–71 %) in bacterial counts when compared to standard stents in all conditions tested. SEM imaging demonstrated biofilm formation on both types of stents in all media, with a relative reduction in apparent cell debris and bacteria on the pAMS.

Conclusions

In this study, the gel-based stent shows a demonstrable reduction in bacterial counts and biofilm formation. The use of the pAMS may reduce the risk of infection associated with stent usage.     

Endoscopic realignment in the management of complete transected ureter

Purpose

To present experience and feasibility of endoscopic realignment for treatment of delayed recognized iatrogenic complete transected ureteral injuries.

Patients and methods

Patients suffering from iatrogenic complete transected ureteral injuries were treated by two surgeons. Five women and 3 men with a mean age of 50.8 years (range 22–69) received diagnosis during the immediate postoperative period (2–6 days after surgery). Ureteral continuity was re-established using a technique combining antegrade flexible ureteroscopy and retrograde rigid ureteroscopy. Then, three ipsilateral 5F double J stents were inserted to assure ureteral patency.

Results

All eight realignment procedures were successful, and no major complications occurred. Average injury length was 1.9 cm (range 1.5–3.0). Average hospitalization time was 8 days (range 3–14). Nephrostomy tubes and stents were removed after a mean period of 3.9 weeks (range 2–6) and 6.8 months (range 5.9–7.1), respectively. At a mean follow-up of 21.5 months (range 10–56), 6 patients were stent-free without image evidence of obstruction, a patient developed strictures was treated with balloon dilation and another exchanged double J stents periodically. No patient has developed significant renal impairment.

Conclusion

Endoscopic realignment is a safe and efficient method as an initial procedure to manage iatrogenic complete transected ureteral injuries in properly selected cases.     

Effect of uropathogens on in vitro encrustation of polyurethane double J ureteral stents

Polyurethane stents are used when there is an obstruction to the flow of urine. A majority of the patients with such stents are at the risk of urinary tract infection and salt encrustation. The present study is aimed at analyzing the in vitro encrustation of calcium oxalate and other salts in the presence of common uropathogens (E. coli and P. mirabilis) on films made from Tecoflex^®, a commercial grade polyurethane. In the absence of uropathogens, sodium ions and ammonia favor calcium adsorption whereas magnesium ions greatly depress it, resulting in increased hydrophillicity of the stent. With E. coli, Mg ions enhance the encrustation of calcium, whereas the other salts decrease its deposition. In case of P. mirabilis, irrespective of the type of salt, it enhances calcium encrustation except in the presence of sodium ions. Adhesion of uropathogens to the stent surface was higher in the presence of bovine serum albumin. Understanding the dynamics between various salts and microorganism in the urine, and urine–stent interface would aid in designing stents that are inert, resist encrustation and biofilm formation.     

The first report of 3 forgotten encrusted double J stents in the same ureter: An endourology nightmare!

Introduction

The ‘encrusted and forgotten double J ureteric stent (JJ) phenomenon has always proven to be a challenging dilemma facing the attending urologist.

Feasibility of insertion of a microcatheter through a Y-stent in coil embolization of cerebral aneurysms and its detailed geometry by micro-computed tomography

Background

In Y-stent-assisted coil embolization for cerebral aneurysms, open or closed cell stents are used. Different microcatheters for coil insertion are available. We investigated which microcatheter could be navigated into an aneurysm through a Y-stent with different stents.

Methods

Double Neuroform open-cell stents or double Enterprise closed-cell stents were deployed in Y-configuration in a silicon model of a bifurcation aneurysm. Two endovascular neurosurgeons independently tried to navigate an SL-10 microcatheter for 0.010” coils or a PX Slim microcatheter for 0.020” Penumbra coils into the aneurysm through the Y-stent. In addition, we measured lengths of stent pores of the Y-stents with double Enterprise stents deployed in the model by micro-computed tomography.

Results

It was feasible to navigate an SL-10 microcatheter into the aneurysm through the Y-stent with Enterprise or Neuroform stents. Navigation of a PX Slim microcatheter was feasible in the Y-stents only with Neuroform stents. In the Y-stent with double Enterprise stents, the lengths of the second stent pores were significantly smaller than those of the first stent (0.41?±?0.18 mm vs 0.69?±?0.20 mm; P?=?0.008). The SL-10 microcatheter was smaller than approximately 80 % of the stent pores of the first stent and 30 % of those of the second stent. The PX Slim microcatheter was smaller than 20 % of the stent pores of the first stent and 0 % of those of the second stent.

Conclusions

It was feasible to insert an SL-10 microcatheter into the aneurysm through Y-stents with Enterprise or Neuroform stents. Navigation of a PX Slim microcatheter for 0.020” Penumbra coils was feasible in Y-stents with Neuroform stents, but not with double Enterprise stents. The measurements of stent pores by micro-computed tomography supported this feasibility study. These results may be helpful to select appropriate stents and microcatheters in Y-stent-assisted coil embolization, especially in case of retreatments.     

Outcome and safety of self-expandable metallic stents for malignant colon obstruction: a Korean multicenter randomized prospective study

Background

Newly developed uncovered stents are designed to have varied radial force and high conformability to improve clinical outcome and safety. This study aimed to determine and compare the clinical outcome and safety of the Taewoong D-type uncovered stent and the Boston Scientific Wallfex stent.

Methods

Patients with acute malignant colonic obstruction were treated with a colonic stent. For the purpose of palliation, patients were randomly allocated. For the purpose of bridging, the type of stent was determined by the discretion of the individual doctors. Technical and clinical success and complication occurrence were measured as primary outcomes.

Results

From 12 university hospitals, 123 patients with malignant colonic obstruction were enrolled. Of these 123 patients, 58 were treated with colonic stents for palliative purposes. The technical and clinical success rate was 100?% for both stents in the palliative group. Perforation occurred for one patient (3.6?%) in the Wallflex stent group (n?=?28) on day 5 and for no patients in the D-type stent group (n?=?30). Two cases of migration occurred: one with the Wallflex stent and one with the D-type stent. Stent restenosis occurred for one patient with the Wallflex stent. Preoperative bridging stents were placed in 65 patients. The median time to surgery was 10?days. The technical success rate was 93.4?%, and clinical success was achieved for 86.2?% of the patients. Perforation occurred for five patients: four with the Wallflex stent and one with the D-type stent. The efficacy and safety of the two stents did not differ statistically.

Conclusions

The D-type colonic uncovered stent and the Wallflex colonic uncovered stent are effective and safe for both palliative and preoperative bridging therapy used to treat acute malignant colonic obstruction.     

Gastrojejunostomy by pure natural orifice transluminal endoscopic surgery using a newly designed anastomosing metal stent in a porcine model

Background

The accepted palliative treatment for malignant gastric outlet obstruction (GOO) is surgical bypass or placement of self-expandable metal stents. We developed a safe and simple natural orifice transluminal endoscopic surgery (NOTES) technique for gastrojejunostomy using a fully covered, anastomosing metal stent in a porcine model.

Methods

Under general anesthesia, 11 pigs underwent gastrojejunostomy with a 4 cm length anastomosing metal stent. After gastrotomy formation using a needle knife, the jejunum was drawn into the stomach with alligator forceps. A jejunotomy was then performed in the gastric cavity, which was followed by deployment of an anastomosing metal stent under fluoroscopic guidance. Next, the first portion of the duodenum was resected by an endoscopic linear stapler via laparoscopy, thereby creating the model of GOO. Oral feeding was resumed 24 h after the procedure, and animals were euthanized at 1, 2, and 4 weeks after the operation.

Results

Side-to-side gastrojejunostomy was successfully completed through NOTES in 10/11 animals. Ten pigs stayed healthy until the planned sacrifice. The mean gastrojejunostomy procedure time was 41 min (range 15–94 min). By postmortem examination, anastomoses were still intact without intraperitoneal necrosis or adhesion. Histological examination revealed adequate submucosal apposition in all ten experimental pigs undergoing successful endoscopic gastrojejunostomy.

Conclusion

Creating a gastrojejunostomy by NOTES using an anastomosing metal stent seems to be a safe, feasible, durable, and reproducible method for GOO.     

Outcome of palliative self-expanding metal stent placement in malignant colorectal obstruction according to stent type and manufacturer

Background

Self-expandable metallic stents (SEMS) of varying designs and materials have been developed to reduce complications, but few comparative data are available with regard to the type of stent and the stent manufacturer. We analyzed the success rates and complication rates, according to stent type (uncovered vs. covered stent) and individual stent manufacturer, in malignant colorectal obstruction.

Methods

From November 2001 to August 2008, 103 patients were retrospectively included in this study: four types of uncovered stents in 73 patients and two types of covered stents in 30 patients. The SEMS was inserted into the obstructive site by using the through-the-scope method.

Results

Technical and clinical success rates were not different between stent type or among stent manufacturers: 100 and 100% (p?=?ns) and 100 and 96.6% (p?>?0.05), respectively, in uncovered and covered stents. Stent occlusion and migration rates were 12.3 and 3.3% (p?=?0.274) and 13.7 and 16.7% (p?=?0.761), respectively, in uncovered and covered stents, and 11.1, 5, and 9% (p?=?0.761) and 25.9, 15, and 0% (p?=?0.037) in Wallstent, Niti-S, and Bonastent uncovered stents, respectively.

Conclusions

The placement of SEMS is an effective and safe treatment for patients with malignant colorectal obstruction. Although minor differences in outcome were detected according to the type and the manufacturer of the stents, no statistically significant difference was observed, except in stent migration among the stent manufacturer.     

Partially covered esophageal stents cause bowel injury when used to treat complications of bariatric surgery

Background

We hypothesized that an esophageal nitinol stent that is mainly silicone-covered but partially uncovered may allow tissue ingrowth and decrease the migration rate seen with fully covered stents and still allow safe stent removal. The aim of this study was to evaluate the first human results of using partially covered stents for anastomotic complications of bariatric surgery.

Methods

This was a retrospective evaluation of all patients with staple-line complications after bariatric surgery who received a partly covered stent at a single tertiary-care bariatric center. The stents varied in length from 10 to 15 cm and in diameter from 18 to 23 mm.

Results

From April 2009 to April 2010, eight patients received partially covered stents on 14 separate occasions. The indications were gastrojejunal stricture in four, acute leak in two, acute leak followed by a later stricture in one, and a perforated anastomotic ulcer in one patient. Single stents were placed in 12 sessions and two overlapping stents in two sessions. At the time of stent deployment, one patient had the uncovered proximal end of the stent in the stomach, with all others in the distal esophagus. Immediate symptom improvement occurred in 12/14 stent placements. Oral nutrition was initiated for 10/14 stent treatments within 48 h. Stents were removed after 25 ± 10 days. Minor stent displacement occurred with 9/13 stents, with the proximal end of the stent moving into the stomach, though the site of pathology remained covered. The stents were difficult to remove when tissue ingrowth was present. One patient required laparoscopic removal and one required two endoscopy sessions for removal. At the time of removal of ten stents, where the proximal end was found in the stomach, four had gastric ulceration, three had gastric mucosa replaced by granulation tissue, and three had normal gastric mucosa. In four cases where the proximal portion of the stent stayed in the esophagus, the esophageal deployment zone had abnormalities: three with granulation tissue and one with denuding of the esophageal mucosa. The distal uncovered portion of the stent in the Roux limb never became embedded in the mucosa and caused minimal injury.

Conclusions

A partially covered stent was successful in keeping the site of the pathology covered and provided rapid symptom improvement and oral nutrition in most patients. The proximal end of the stent generally moved from the esophagus to the stomach, probably due to esophageal peristalsis. The proximal uncovered portion of the stent causes significant bowel mucosal injury and sometimes becomes embedded in the esophagus or the stomach, making removal difficult. We no longer use partially covered stents.     

Outcomes of second self-expandable metallic stent insertion for malignant gastric outlet obstruction

Background

Self-expandable metallic stents are used widely to relieve malignant gastric outlet obstruction (GOO). However, restenosis or migration of first stents is a frequent complication. The purpose of this retrospective cohort study was to evaluate the effectiveness of second stents as an approach to manage failure of first stents in patients with malignant GOO.

Methods

A total of 222 patients with gastric cancer received first stents due to inoperable GOO at National Cancer Center in Korea between January 2008 and June 2011. Monthly follow-up interviews were performed, and second stents (stent-in-stent or stent-after-migration) were inserted in 59 patients by June 2012. Technical and clinical successes and long-term complications were evaluated.

Results

The technical and immediate clinical success rates were 98.3 % (58/59) and 91.5 % (54/59), respectively. Patients who received a second stent due to late complications involving the first stent (migration, restenosis, and fracture) showed a higher clinical success rate (95.8 % [46/48]) than patients who received a second stent due to immediate clinical failure of the first stent (72.7 % [8/11], p = 0.04). The immediate clinical success rate of stent-after-migration (100 % [11/11]) was not different from that of stent-in-stent (89.6 % [43/48], p = 1.0). The stent dysfunction rate of stent-after-migration (27.3 % [3/11]) also was similar to that of stent-in-stent (29.2 % [14/48], p = 1.0). The median patencies of stent-in-stent and stent-after-migration were 27.4 and 58.4 weeks, respectively (p = 0.177). There were no significant prognostic factors for patency of second stents.

Conclusions

Insertion of a second stent is effective for treating the first-stent failure in gastric cancer patients with GOO, especially if the immediate outcome of the first stent was successful.     

The use of biodegradable (SX-ELLA) oesophageal stents to treat dysphagia due to benign and malignant oesophageal disease

Background

Biodegradable (BD) oesophageal stents have been available commercially only since 2008 and previous published research is limited. Our aim was to review the use of BD stents to treat dysphagia in benign or malignant oesophageal strictures.

Methods

Patients were identified from a prospective interventional radiological database. BD stents were inserted radiologically under fluoroscopic control.

Results

Between July 2008 and February 2011, 25 attempts at placing SX-ELLA biodegradable oesophageal stents were made in 17 males and five females, with a median age of 69 (range = 54–80) years. Two patients required more than one BD stent. Indications were benign strictures (n = 7) and oesophageal cancer (n = 17). One attempt was unsuccessful for a technical success rate of 96% with no immediate complications. Clinical success rate was 76%. Median dysphagia score before stent insertion was 3 (range = 2–4) compared to 2 (range = 0–3) after stent insertion (p = 0.0001).

Conclusion

BD stents provide good dysphagia relief for the life time of the stent. They may help avoid the use of feeding tubes in patients having radical chemoradiotherapy or awaiting oesophagectomy. They do not require removal or interfere with radiotherapy planning via imaging. However, the reintervention rate is high after the stent dissolves.     

Metallic ureteral stents in malignant ureteral obstruction: short-term results and radiological features predicting stent failure in patients with non-urological malignancies

Purpose

To provide short-term result of the metallic ureteral stent in patients with malignant ureteral obstruction and identify radiological findings predicting stent failure.

Materials and methods

The records of all patients with non-urological malignant diseases who have received metallic ureteral stents from July 2009 to March 2012 for ureteral obstruction were reviewed. Stent failure was detected by clinical symptoms and imaging studies. Survival analysis was used to estimate patency rates and factors predicting stent failure.

Results

A total of 74 patients with 130 attempts of stent insertion were included. A total of 113 (86.9 %) stents were inserted successfully and 103 (91.2 %) achieved primary patency. After excluding cases without sufficient imaging data, 94 stents were included in the survival analysis. The median functional duration of the 94 stents was 6.2 months (range 3–476 days). Obstruction in abdominal ureter (p = 0.0279) and lymphatic metastasis around ureter (p = 0.0398) were risk factors for stent failure. The median functional durations of the stents for abdominal and pelvic obstructions were 4.5 months (range 3–263 days) and 6.5 months (range 4–476 days), respectively. The median durations of the stents with and without lymphatic metastasis were 5.3 months (range 4–398 days) and 7.8 months (range 31–476 days), respectively.

Conclusion

Metallic ureteral stents are effective and safe in relieving ureteral obstructions resulting from non-urological malignancies, and abdominal ureteral obstruction and lymphatic metastasis around ureter were associated with shorter functional duration.     

Update on biofilm infections in the urinary tract

Purpose

Biofilm infections have a major role in implants or devices placed in the human body. As part of the endourological development, a great variety of foreign bodies have been designed, and with the increasing number of biomaterial devices used in urology, biofilm formation and device infection is an issue of growing importance.

Methods

A literature search was performed in the Medline database regarding biofilm formation and the role of biofilms in urogenital infections using the following items in different combinations: ??biofilm,?? ??urinary tract infection,?? ??bacteriuria,?? ??catheter,?? ??stent,?? and ??encrustation.?? The studies were graded using the Oxford Centre for Evidence-based Medicine classification.

Results

The authors present an update on the mechanism of biofilm formation in the urinary tract with special emphasis on the role of biofilms in lower and upper urinary tract infections, as well as on biofilm formation on foreign bodies, such as catheters, ureteral stents, stones, implants, and artificial urinary sphincters. The authors also summarize the different methods developed to prevent biofilm formation on urinary foreign bodies.

Conclusions

Several different approaches are being investigated for preventing biofilm formation, and some promising results have been obtained. However, an ideal method has not been developed. Future researches have to aim at identifying effective mechanisms for controlling biofilm formation and to develop antimicrobial agents effective against bacteria in biofilms.     

Plasmadeponierte Kohlenstoffbeschichtung auf urologischen Verweilkathetern

Background

Any material placed in the urinary tract is susceptible to the formation of encrustations of crystalline bacterial biofilms. These biofilms cause severe complications in some cases. The strategies used so far for reduction of these complications by surface modifications of the implant material failed to show the expected results.

Patients and methods

In this study, we investigated amorphous carbon coatings (a-C:H) for their ability to effectively reduce or to repress the progressive formation of infection-enhancing crystalline biofilms as new functional surface coatings. In nine patients suffering for several years from stenting, a-C:H-coated ureteral stents were tested in treatment attempts. The current replacement intervals amounted to a mean of 77 days; the principle cause for early replacement was massive stent encrustations associated with symptomatic urinary tract infections.

Results

In total, 20 coated ureteral stents were tested spanning indwelling times between 3 and 4 months. No stent-related complications occurred. In all cases extraordinarily facile handling, less pain during replacement, and markedly increased tolerance were observed. Symptomatic urinary tract infections were reduced by more than 50%. The stents remained virtually free of encrustations.

Conclusion

a-C:H coatings are a novel strategy leading to an enhancement of long-term applicability of ureteral stents and catheters and to improved patient comfort.     

Endoscopic stenting for benign upper gastrointestinal strictures and leaks

Background

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

Methods

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

Results

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

Conclusions

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

Endoscopic therapy for esophageal perforation or anastomotic leak with a self-expandable metallic stent

Background

Leaks of the esophagus are associated with a high mortality rate and need to be treated as soon as possible. Therapeutic options are surgical repair or resection or conservative management with cessation of oral intake and antibiotic therapy. We evaluated an alternative approach that uses self-expandable metallic stents (SEMS).

Methods

Between 2002 and 2007, 31 consecutive patients with iatrogenic esophageal perforation (n = 9), intrathoracic anastomotic leak after esophagectomy (n = 16), spontaneous tumor perforation (n = 5), and esophageal ischemia (n = 1) were treated at our institution. All were treated with endoscopic placement of a covered SEMS. Stent removal was performed 4 to 6 weeks after implantation. To exclude continuous esophageal leak after SEMS placement, radiologic examination was performed after stent implantation and removal.

Results

SEMS placement was successful in all patients and a postinterventional esophagogram demonstrated full coverage of the leak in 29 patients (92%). In two patients, complete sealing could not be achieved and they were referred to surgical repair. Stent migration was seen in only one patient (3%). After removal, a second stent with larger diameter was placed and no further complication occurred. Two patients died: one due to myocardial infarction and one due to progressive ischemia of the esophagus and small bowl as a consequence of vascular occlusion. Stent removal was performed within 6 weeks, and all patients had radiologic and endoscopic evidence of esophageal healing.

Conclusions

Implantation of covered SEMS in patients with esophageal leak or perforation is a safe and feasible alternative to operative treatment and can lower the interventional morbidity rate.