Management Of Benign Esophageal Strictures Research Articles

Esophageal stenting for benign and malignant disease: European Society of Gastrointestinal Endoscopy (ESGE) Guideline – Update 2021

1: ESGE recommends placement of partially or fully covered self-expandable metal stents (SEMSs) for palliation of malignant dysphagia over laser therapy, photodynamic therapy, and esophageal bypass.Strong recommendation, high quality evidence. 2 : ESGE recommends brachytherapy as a valid alternative, alone or in addition to stenting, in esophageal cancer patients with malignant dysphagia and expected longer life expectancy.Strong recommendation, high quality evidence. 3: ESGE recommends esophageal SEMS placement for sealing malignant tracheoesophageal or bronchoesophageal fistulas. Strong recommendation, low quality evidence. 4 : ESGE does not recommend SEMS placement as a bridge to surgery or before preoperative chemoradiotherapy because it is associated with a high incidence of adverse events. Other options such as feeding tube placement are preferable. Strong recommendation, low quality evidence. 5: ESGE recommends against the use of SEMSs as first-line therapy for the management of benign esophageal strictures because of the potential for adverse events, the availability of alternative therapies, and their cost. Strong recommendation, low quality evidence. 6: ESGE suggests consideration of temporary placement of self-expandable stents for refractory benign esophageal strictures. Weak recommendation, moderate quality evidence. 7: ESGE suggests that fully covered SEMSs be preferred over partially covered SEMSs for the treatment of refractory benign esophageal strictures because of their very low risk of embedment and ease of removability. Weak recommendation, low quality evidence. 8: ESGE recommends the stent-in-stent technique to remove partially covered SEMSs that are embedded in the esophageal wall. Strong recommendation, low quality evidence. 9: ESGE recommends that temporary stent placement can be considered for the treatment of leaks, fistulas, and perforations. No specific type of stent can be recommended, and the duration of stenting should be individualized. Strong recommendation, low quality of evidence. 10 : ESGE recommends considering placement of a fully covered large-diameter SEMS for the treatment of esophageal variceal bleeding refractory to medical, endoscopic, and/or radiological therapy, or as initial therapy for patients with massive bleeding. Strong recommendation, moderate quality evidence.

Management of Iatrogenic tracheoesophageal fistula in a patient with dyskeratosis congenita

: The management of benign esophageal strictures pose a challenging problem for general thoracic surgeons. The optimal timing of operative intervention is determined on a case by case basis. We present a case of benign esophageal stricturing secondary to dyskeratosis congenita (DKC). This was initially managed non-operatively with esophageal stenting. This led to the development of a tracheoesophageal fistula necessitating an emergent esophagectomy and tracheal repair. Esophageal manifestations of DKC are excessively rare. However, in patients with a genetic predisposition to esophageal stricturing esophagectomy as first line treatment may be warranted.

Risk factors and clinical outcomes of endoscopic dilation in benign esophageal strictures: a long-term follow-up study

Endoscopic dilation (ED) is still the mainstay of therapeutic management of benign esophageal strictures (BESs). This study aimed to establish risk factors for refractory BESs and assess long-term clinical outcomes of ED. We performed a retrospective study in 891 patients who underwent ED from 2003 to 2018 for BESs. We searched electronic medical records in 6 tertiary care centers in the Netherlands for data on clinical outcome of ED. Median follow-up was 39 months. The primary endpoint was risk factors for refractory BESs, defined as factors associated with an increased number of ED sessions during follow-up. Secondary endpoints were time from first to last ED session and adverse events. Dilation up to 13 to 15mm was associated with a higher number of ED sessions than dilation up to 16 to 18mm (5.0 vs 4.1; hazard ratio [HR], 1.4; P= .001). Compared with peptic strictures, anastomotic (4.9 vs 3.6; HR, 2.1; P< .001), radiation (5.0 vs 3.6; HR, 3.0; P< .001), caustic (7.2 vs 3.6; HR, 2.7; P< .001), and postendotherapy (3.9 vs 3.6; HR, 1.8; P= .005) strictures were associated with a higher number of ED sessions. After 1 year of follow-up, the proportions of patients who remained free of ED was 75% in anastomotic, 71% in radiation, 70% in peptic, 83% in postendotherapy, and 62% in caustic strictures. Esophageal perforation occurred in 23 ED sessions (.4%) in 22 patients (2.4%). More than 60% of patients with BESs remain free of ED after 1 year of follow-up. Because dilation up to 16 to 18mm diameter was associated with fewer ED sessions during follow-up, we suggest that clinicians should consider dilation up to at least 16mm to reduce the number of ED sessions in these patients.

High-frequency miniprobe endoscopic ultrasonography in the management of benign esophageal strictures.

Background:Endoscopic ultrasonography (EUS) can predict the response to endoscopic dilatation by delineating the extent of esophageal wall involvement in benign strictures. In contrast to conventional echoendoscopes, the EUS miniprobe can be negotiated across the stricture and thus provide more information. This study retrospectively evaluated the role of miniprobe EUS in predicting the response to endoscopic dilatation in benign esophageal strictures.Methods:We analyzed the records of 24 patients (mean age: 48.1±17.9 years) with benign esophageal strictures (corrosive 11, peptic 5, post-radiation 3, anastomotic 2, and others 3) who underwent miniprobe EUS prior to endoscopic dilatation.Results:The stricture was located in the upper, middle and lower esophagus in 2, 9 and 13 patients, respectively. The mean length of the stricture was 3.4±1.9 cm. Miniprobe EUS was able to examine the stricture completely in all patients. The mucosa was involved in 6, mucosa and submucosa in 4, and mucosa, submucosa and muscularis propria in 14 patients. The mean maximum wall thickness of esophageal wall on EUS at the level of the stricture was 8.2±2.8 mm. The mean number of sessions required to achieve adequate dilation was 4.7±2.6. Patients with mucosal involvement required significantly fewer endoscopic sessions for adequate dilatation as compared to patients with muscularis propria involvement (1.8 vs. 6.2 sessions, respectively; P=0.0002). Patients with greater esophageal wall thickness required more endoscopic sessions (r=0.737) (P=0.00004).Conclusion:Miniprobe EUS, by delineating the extent of wall involvement as well as measuring wall thickness in benign esophageal strictures, can predict the response to endoscopic dilatation.

Management of benign esophageal strictures: a literature review.

The management of benign esophageal strictures is challenging. The first strategy includes endoscopic dilation using bougies or balloons. Although the immediate success rate of these is up to 90%, about 30-40% of patients experience recurrent dysphagia within the first year of follow-up. The management of refractory stenosis involves repeated sessions of endoscopic dilation. In order to obtain long-lasting functional results, alternative treatments have been developed, such as the use of self-expanding stents, particularly indicated in subgroups of patients with post-surgical stenosis or post-radiation therapy. If this approach fails, other possibilities are represented by self-decoding, PEG/J-tube positioning and, finally, reconstructive surgery.

Endoscopic Management of Benign Esophageal Stricture of Multifactorial Etiology Complicated by Esophageal Perforation

Endoscopic Management of Benign Esophageal Stricture of Multifactorial Etiology Complicated by Esophageal Perforation

Management of benign oesophageal strictures: our experience at tertiary care centre

Background: Oesophageal stricture is a common problem in general surgical practice. It can be benign or malignant, simple or complex. Benign oesophageal strictures include peptic, corrosive, post-surgical anastomotic strictures, post radiotherapy and drug induced strictures. The aetiology of this condition varies in developed and developing countries. Aim of present study was to determine the aetiology of benign oesophageal stricture, to evaluate the role of endoscopic dilatation of stricture and final outcome in these patients in our region.Methods: This prospective descriptive study was conducted in department of surgery at a tertiary care teaching hospital at Aurangabad from December 2009 to November 2013. All the patients, regardless of age and gender, admitted with diagnosis of benign oesophageal stricture were included in the study. Depending upon the type of stricture treatment was carried out. Postoperatively patients were followed up for detection of possible complications and their treatment.Results: Total 50 patients of oesophageal stricture were studied. Mean age was 33.65 years with male to female ratio 2.8:1. Ingestion of corrosive substance was the commonest etiology noted followed by peptic strictures.Conclusions: Corrosive ingestion was the commonest cause of benign oesophageal stricture in our region followed by peptic strictures. Endoscopic dilatation is safe and effective in treating benign oesophageal strictures.

Esophageal stenting for benign and malignant disease: European Society of Gastrointestinal Endoscopy (ESGE) Clinical Guideline.

This Guideline is an official statement of the European Society of Gastrointestinal Endoscopy (ESGE), endorsed by the European Society for Radiotherapy and Oncology (ESTRO), the European Society of Digestive Endoscopy (ESDO), and the European Society for Clinical Nutrition and Metabolism (ESPEN). The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system was adopted to define the strength of recommendations and the quality of evidence. Main recommendations for malignant disease 1 ESGE recommends placement of partially or fully covered self-expandable metal stents (SEMSs) for palliative treatment of malignant dysphagia over laser therapy, photodynamic therapy, and esophageal bypass (strong recommendation, high quality evidence). 2 For patients with longer life expectancy, ESGE recommends brachytherapy as a valid alternative or in addition to stenting in esophageal cancer patients with malignant dysphagia. Brachytherapy may provide a survival advantage and possibly a better quality of life compared to SEMS placement alone. (Strong recommendation, high quality evidence.) 3 ESGE recommends esophageal SEMS placement as the preferred treatment for sealing malignant tracheoesophageal or bronchoesophageal fistula (strong recommendation, low quality evidence). 4 ESGE does not recommend the use of concurrent external radiotherapy and esophageal stent treatment. SEMS placement is also not recommended as a bridge to surgery or prior to preoperative chemoradiotherapy. It is associated with a high incidence of adverse events and alternative satisfactory options such as placement of a feeding tube are available. (Strong recommendation, low quality evidence.) Main recommendations for benign disease 1 ESGE recommends against the use of self-expandable stents (SEMSs) as first-line therapy for the management of benign esophageal strictures because of the potential for adverse events, the availability of alternative therapies, and costs (strong recommendation, low quality evidence). 2 ESGE suggests consideration of temporary placement of SEMSs as therapy for refractory benign esophageal strictures (weak recommendation, moderate evidence). Stents should usually be removed at a maximum of 3 months (strong recommendation, weak quality evidence). 3 ESGE suggests that fully covered SEMSs be preferred over partially covered SEMSs for the treatment of refractory benign esophageal strictures, because of their lack of embedment and ease of removability (weak recommendation, low quality evidence). 4 For the removal of partially covered esophageal SEMSs that are embedded, ESGE recommends the stent-in-stent technique (strong recommendation, low quality evidence). 5 ESGE recommends that temporary stent placement can be considered for treating esophageal leaks, fistulas, and perforations. The optimal stenting duration remains unclear and should be individualized. (Strong recommendation, low quality evidence.) 6 ESGE recommends placement of a SEMS for the treatment of esophageal variceal bleeding refractory to medical, endoscopic, and/or radiological therapy, or as initial therapy for patients with massive esophageal variceal bleeding (strong recommendation, moderate quality evidence).

Estenosis esofágica por Histoplasma: manejo con prótesis metálica autoexpandible

Las estenosis esofágicas benignas son una causa común de consulta en los servicios de endoscopia y gastroenterología. Usualmente, dada su naturaleza no neoplásica, estas se han manejado con dilataciones endoscópicas a repetición, incómodas y costosas para el paciente, dada su constante repetición; además de tener siempre el riesgo de perforación esofágica en cada sesión. El uso de prótesis esofágicas para manejo de las estenosis esofágicas benignas viene en progresivo aumento con resultados prometedores para varias de las etiologías de este tipo de obstrucciones. Presentamos el caso de una estenosis esofágica benigna secundaria a infección por Histoplasma capsulatum, manejada con una prótesis metálica totalmente cubierta con resolución completa de la obstrucción.

Topical mitomycin C application is effective in management of localized caustic esophageal stricture: A double-blinded, randomized, placebo-controlled trial

BackgroundFrequent sessions of endoscopic dilatation are usually required in the management of benign esophageal strictures, especially caustic induced ones. Topical mitomycin C (MMC) has been recently used in the management of resistant strictures. This study evaluated the efficacy of MMC application in prevention of stricture recurrence after endoscopic dilatation. Patients and methodsThis double-blind, randomized, placebo-controlled trial included forty patients with caustic esophageal strictures dating from January 2008 to October 2010. Patients were randomized into 2 groups to undergo endoscopic dilatation with application of either MMC versus placebo on stricture site. Regular follow up and re-evaluation were done after 6months of management. The number of dilatation sessions needed for resolution of dysphagia in each group was our primary outcome. ResultsDuring the specified follow up period, 80 % of strictures in the MMC group got completely resolved compared to only 35% in the placebo group. The mean number of dilatation sessions needed in the MMC group was n=3.85±2.08 compared to n=6.9±2.12 in the placebo group which was statistically significant (p<0.001). ConclusionMitomycin C application significantly reduced the number of dilatation sessions needed to alleviate dysphagia in patients with caustic esophageal strictures.

Topical Mitomycin C application for esophageal stricture: Safe, precise, and novel endoscopic technique

PurposeThe first line of management of benign esophageal stricture is endoscopic dilatation; however, multiple sessions are usually indicated especially in resistant cases. Topical Mitomycin C (MCC) application is a new adjuvant treatment in the management of esophageal stricture with promising results in different case series. Several techniques have been reported for application; nevertheless, the ideal technique has not been described yet. Material and MethodsIn this series we have devised a new technique using both the flexible and the rigid endoscope and a specially designed Nelaton catheter. ResultsThis technique was applied in 38 sessions for 16 caustic esophageal strictures with technical success in all cases. No procedure-related complications were observed in this series. ConclusionThis novel technique is feasible and effective and can be considered as standard for topical MMC application on esophageal stricture.

Control of severe strictures after circumferential endoscopic submucosal dissection for esophageal carcinoma: oral steroid therapy with balloon dilation or balloon dilation alone

Recent technological advances have allowed superficially spreading intramucosal carcinomas of the esophagus to be successfully resected by circumferential endoscopic submucosal dissection (cESD). After this procedure, esophageal strictures develop in most patients and are mainly treated by endoscopic balloon dilation (EBD). To compare oral steroids plus EBD with EBD alone for the management of benign esophageal strictures after cESD. Retrospective cohort study. Tertiary-care referral center. We studied 23 consecutive patients who underwent complete cESD for superficial esophageal carcinoma (22 squamous cell carcinomas and 1 adenocarcinoma associated with Barrett's esophagus). After cESD, patients were managed with EBD alone (EBD, n = 13) or with EBD and oral prednisolone (steroid + EBD, n = 10), 30 mg daily, started 2 days after cESD and gradually tapered and discontinued after 8 weeks. Total number of EBD sessions and total EBD period (months). Steroid + EBD patients required fewer sessions (13.8 ± 6.9 vs 33.5 ± 22.9; P < .001) and a shorter management period (4.8 ± 2.3 vs 14.2 ± 17.5 months, P = .005) compared with the EBD group. An additional 3 patients received oral steroids a mean interval of 158 days after cESD. These patients required more EBD sessions (46.3 ± 30.0; P = .002), and the EBD period was significantly longer (17.5 ± 13.0 months; P = .005) than in the early steroid + EBD group. Nonrandomized study; retrospective analysis. After cESD, oral steroid therapy dramatically reduced the need for EBD. We conclude that oral steroid therapy after EBD is an effective strategy for the management of esophageal strictures after complete cESD.

Sa1441 Role of Endoscopic Ultrasonography (EUS) in Management of Benign Esophageal Strictures

Sa1441 Role of Endoscopic Ultrasonography (EUS) in Management of Benign Esophageal Strictures

Fully Covered Alimaxx Esophageal Metal Stents in the Endoscopic Treatment of Benign Esophageal Diseases

Expandable esophageal stents are widely used for the palliation of dysphagia in patients with esophageal cancer and are also beginning to be used in patients with benign esophageal diseases such as refractory strictures and fistulas. There is concern regarding the increased risk of migration of the fully covered Alimaxx metal esophageal stent and experience with this stent in benign esophageal pathology has been reported in only a small series of patients. To evaluate the technical success in placement and removal, efficacy and complications of the Alimaxx esophageal stent for benign esophageal diseases. Our endoscopy database was retrospectively reviewed from 1/2003 to 2/2009 to identify patients with Alimaxx esophageal stent placement for benign diseases. Chart review was performed for age, gender, indication, site of the lesion, success of placement, outcome, and incidence of complications. Twenty-eight stents were successfully placed in 14 patients with benign esophageal diseases (mean: two stents/patient; range 1-7). Indications included esophageal fistula in seven (50%) and benign strictures in 7/14 (50%). Dysphagia improved in all patients while the fistula resolved in 6/7 (85.8%) patients. Complications related to stents included pain (2/28, 7%), stent related gastric ulcer (1/28, 4%), nausea and vomiting (3/21, 11%) and stent migration (11/28, 39%). All migrated stents were successfully endoscopically retrieved. The fully covered and removable Alimaxx stent is effective in the endoscopic management of benign esophageal strictures or fistulas, despite its relatively high rate of migration. Stent migration was successfully managed endoscopically without complications.

Management of benign oesophageal strictures in children

Managing oesophageal strictures, whether benign or malignant has always been a challenging task for ENT Surgeons, Endoscopists, Cardio-thoracic surgeons and Gastro-enterologists. Although various newer technological developments have helped in better management of malignant strictures, it is the benign strictures that are still being managed by conventional means with gum-elastic bougies and other dilatation techniques. Children are not immune to benign strictures, rather corrosive strictures, congenital webs and membranes etc. are much more common in the paediatric age group. We present the technical details and our experience in managing benign oesophageal strictures in five children by endoscopic balloon dilatation.

Invited Commentary

The management of benign esophageal strictures begins with dilation, and depending on the cause of the stricture, often repeated dilations are necessary. When self-expanding metallic stents became available they were used for benign and malignant strictures until it became evident that the inflammation often induced by these stents and the difficulty or inability to remove them made them unsuitable for use in benign disease. The development of the Polyflex self-expanding, removable stent (Boston Scientific, Natick, MA) has once again made stenting an option for patients with benign strictures. The purpose of the study by Martin and colleagues [1Martin R.C.G. Woodall C. Duvall R. Scoggins C.R. The use of self-expanding silicone stents in esophagectomy strictures: less cost and more efficiency.Ann Thorac Surg. 2008; 86: 436-440Abstract Full Text Full Text PDF PubMed Scopus (35) Google Scholar] was to compare the efficacy and cost associated with repeat dilations versus Polyflex stent placement in patients with a benign stricture. The majority of strictures were at the esophagogastric anastomosis after an esophagectomy, but a number of other causes were also represented. They concluded that early stenting was more cost effective, provided that at least two dilations were avoided. An important issue with removable stents has been migration. In the series reported here by Martin and colleagues [1Martin R.C.G. Woodall C. Duvall R. Scoggins C.R. The use of self-expanding silicone stents in esophagectomy strictures: less cost and more efficiency.Ann Thorac Surg. 2008; 86: 436-440Abstract Full Text Full Text PDF PubMed Scopus (35) Google Scholar], migration occurred in only 1 patient 2 days after placement. They replaced the migrated stent with a larger one and had no further difficulty. The authors attributed this low rate of migration to the use of a large diameter and long stents. Furthermore, they positioned the stent as high up in the esophagus as possible while still traversing the stricture in patients with esophago-anastomotic strictures in which stent migration has been a particular problem. These results certainly support the use of a Polyflex stent in any patient in which repeated dilations are likely to be necessary. However, an option the authors failed to discuss is the use of home self-dilation by patients. This is a very effective technique for the management of benign strictures, particularly an esophagogastric anastomotic stricture, and undoubtedly it would be more cost effective than either repeated endoscopic dilations or stent placement. In my own practice, this if the preferred approach for proximal esophageal strictures in which Polyflex stent migration is more likely to occur. Most patients can be quickly taught the technique of self-dilation and are sent home with an appropriate-sized (usually 52-French) Maloney dilator with instructions to dilate themselves first thing in the morning on a tapered schedule, such that the majority of patients no longer need dilation after 6 to 8 weeks. They then return the bougie. I have never had a patient who had a complication or perforation from self-dilation, and it is surprisingly well accepted by patients and their families. Teaching self-dilation to a patient takes 15 to 30 minutes, roughly similar to the time it takes to insert a stent; there is no added time for subsequent stent removal, and no need for sedation or fluoroscopy. Certainly the development of removable self-expanding stents has expanded our treatment options for patients with benign strictures. If these excellent results and low migration rates as reported by Martin and colleagues [1Martin R.C.G. Woodall C. Duvall R. Scoggins C.R. The use of self-expanding silicone stents in esophagectomy strictures: less cost and more efficiency.Ann Thorac Surg. 2008; 86: 436-440Abstract Full Text Full Text PDF PubMed Scopus (35) Google Scholar] are confirmed by others, then early stenting should be able to replace repeated endoscopic dilations. Future studies that compare stenting with home self-dilation, and studies that identify factors predictive of the need for more than two dilations, will help optimize the cost-effective and successful management of patients with benign esophageal strictures.

Novel Biodegradable Stents for Benign Esophageal Strictures Following Endoscopic Submucosal Dissection

The application of metallic stents for benign stenosis is limited due to long-term complications. We report here the results of the implantation of a novel biodegradable poly-L-lactic acid (PLLA) esophageal stent in two patients with benign esophageal stenosis after endoscopic submucosal dissection (ESD). Case 1 was a 64-year-old man who received ESD for an early squamous esophageal cancer in the middle esophagus. The mucosal defect was seven-eighths of the circumference, and the distal margin of the resection scar formed the stenosis. After balloon dilatation, the PLLA esophageal stent was endoscopically placed; for 6 months, he has not experienced any symptoms of re-stenosis. Case 2 consisted of a 62-year-old man who developed an early squamous esophageal cancer in the middle esophagus. The lesion was resected by ESD, and the mucosal defect was seven-eighths of the circumference. The resection scar formed the stenosis, and the PLLA esophageal stent was endoscopically placed. He also has not experienced any symptoms of re-stenosis for 6 months. In conclusion, the PLLA esophageal stent provides a new possibility for the management of benign esophageal strictures after ESD. Due to the biodegradable features of this stent, longer term studies are necessary to investigate the relationship between the expected disappearance of the stent and the patency of the stricture.

Short-segment jejunoplasty: the option treatment in the management of benign esophageal stricture

A non-dilatable benign stricture of the esophagus is a problem for the patient and always a challenge for the surgeon. The present study is intended to provide some details of surgical technique and the physiological concept that constitutes the basis for patient selection for short-segment jejunoplasty. In this study, out of 98 patients, 91 had complex stricture of the lower, and seven of the cervical esophagus. The main cause of stenosis in 60 patients (61.2%) was gastroesophageal reflux, in 34 (34.7%) post-corrosive damage, and in three (3.0%) it was other causes. All patients were treated by three methods of jejunoplasty: group I (n=54 patients) short-segment of the jejunum; group II (n=37 pts) Roux-en-Y double tract; and group III (n=7 patients) short jejunal segment on the long vascular pedicle. Intraoperative complications occurred in 17 (17.34%) of the patients. An anastomotic leak occurred only in three (3.29%) in group I and II, and 1/98 patients (1.02%) died from mediastinitis. Follow-up of functional results for up to 36 months (average 18 months) was available in 77/97 (79.3%) hospital survivors. Fifty-seven (74%) patients are satisfied with their ability to take food, postoperative reflux was completely denied by 72 (93.5%) patients. Postvagotomy diarrhea was transient and gradually subsided over the course of the first 6 months.

Endoscopic Management of the Difficult Benign Esophageal Stricture

The incidence of benign esophageal strictures is decreasing, likely due to the widespread use of proton pump inhibitors. Although most strictures respond well to dilation, a minority of them, mostly those of nonpeptic origin, may be difficult to manage. Challenges include the need for repeat dilations, not being able to reach a minimum diameter, and inability to provide significant symptomatic relief. The mainstay of management of benign esophageal strictures is esophageal dilation. Several techniques for dilation exist. The use of a specific dilation technique is dictated by the character of the stricture. Adjuncts to the management of difficult benign esophageal strictures include steroid injection, use of cautery, and more recently, the use of removable stents. As a result of these improvements on endoscopic techniques, the indications for surgical intervention in difficult esophageal strictures are changing and likely will decrease in the future.

Evaluation and management of benign esophageal strictures

Patients with progressive or solid food dysphagia should be evaluated for the presence of an esophageal stricture. Barium esophagram and endoscopy can define strictures as benign or malignant. The majority of benign strictures are acid-related. Benign strictures are best managed by esophageal dilation with acid-suppressing medications if a peptic stricture is suspected. If dysphagia recurs, repeat dilation should be performed. There are a variety of interventions for refractory strictures which include injection of intralesional corticosteroids, temporary placement of self-expanding plastic stents and surgery.