UK guidelines on oesophageal dilatation in clinical practice

These are updated guidelines which supersede the original version published in 2004. This work has been endorsed by the Clinical Services and Standards Committee of the British Society of Gastroenterology (BSG) under the auspices of the oesophageal section of the BSG. The original guidelines have undergone extensive revision by the 16 members of the Guideline Development Group with representation from individuals across all relevant disciplines, including the Heartburn Cancer UK charity, a nursing representative and a patient representative. The methodological rigour and transparency of the guideline development processes were appraised using the revised Appraisal of Guidelines for Research and Evaluation (AGREE II) tool.Dilatation of the oesophagus is a relatively high-risk intervention, and is required by an increasing range of disease states. Moreover, there is scarcity of evidence in the literature to guide clinicians on how to safely perform this procedure. These guidelines deal specifically with the dilatation procedure using balloon or bougie devices as a primary treatment strategy for non-malignant narrowing of the oesophagus. The use of stents is outside the remit of this paper; however, for cases of dilatation failure, alternative techniques-including stents-will be listed. The guideline is divided into the following subheadings:(1) patient preparation; (2) the dilatation procedure;(3) aftercare and (4) disease-specific considerations. A systematic literature search was performed. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool was used to evaluate the quality of evidence and decide on the strength of recommendations made.
introduction Oesophageal dilatation is indicated in the treatment of symptomatic narrowing of the oesophagus, which may develop from of a wide range of anatomical and functional oesophageal disorders. The formation of benign strictures of the oesophagus is the end result of oesophageal inflammation and ulceration, which leads to deposition of collagen fibres that contract over time and cause narrowing of the oesophageal lumen. [bib_ref] Peptic strictures of the esophagus, Richter [/bib_ref] Reflux-induced strictures used to be a frequent indication for dilatation, but the increasing use of proton pump inhibitors (PPIs) has led to a relative decrease in their incidence. [bib_ref] Esophageal and pharyngeal strictures: report on 1,862 endoscopic dilatations using the Savary-Gilliard..., Piotet [/bib_ref] Other important causes of strictures include postoperative, post-endoscopic therapy (such as endoscopic resection (ER) and ablation), eosinophilic oesophagitis, post-radiation and corrosive strictures, as well as rings and webs. [bib_ref] Esophageal and pharyngeal strictures: report on 1,862 endoscopic dilatations using the Savary-Gilliard..., Piotet [/bib_ref] [bib_ref] Esophageal dilation, Egan [/bib_ref] [bib_ref] Guidelines on the use of oesophageal dilatation in clinical practice, Riley [/bib_ref] The characteristic symptom is dysphagia to solids more than liquids, in contrast to those with oesophageal motility disorders, in whom dysphagia to both solids and liquids occurs. [bib_ref] Peptic strictures of the esophagus, Richter [/bib_ref] In the latter group, dilatation does not consistently improve symptoms, with the exception of achalasia for which oesophageal dilatation is an effective treatment. [bib_ref] Pneumatic dilation versus laparoscopic Heller's myotomy for idiopathic achalasia, Boeckxstaens [/bib_ref] The primary aim of oesophageal dilatation is to alleviate symptoms, permit maintenance of oral nutrition and reduce the risk of pulmonary aspiration.

## Guideline development

## Assessing the quality of guidelines: agree ii instrument
The purpose of the AGREE II instrument is to provide a framework to assess the quality of the guideline, provide a methodological strategy for its development and inform the reporting process of the guideline. It includes the following six domains which were used by our guideline development group (GDG): scope and purpose, stakeholder involvement, rigour of development, clarity and presentation, applicability and editorial independence.

## Scope and purpose
This guideline will focus on the oesophageal dilatation procedure as a primary treatment for benign narrowing of the oesophagus using push or balloon dilators in adult patients (18 years). Palliative treatment of malignant strictures and the use of stents as a primary treatment option are outside the scope of this guideline, but their role in dilatation failure will be discussed. [bib_ref] Esophageal stenting for benign and malignant disease: European Society of Gastrointestinal Endoscopy..., Spaander [/bib_ref] Our objective is to provide a practical, evidence-based, guide for clinicians (gastroenterologists, upper GI surgeons, radiologists and non-medical endoscopists) on how to undertake oesophageal dilatation, as well as pre-and postprocedure considerations in order to maximise safety and efficacy in patients with dysphagia. This document is intended for use once a decision to perform oesophageal dilatation has been made. This decision ultimately resides with the caring clinician after discussion with the patient. As the practice of pure radiological dilatation is appropriate in some circumstances but not always advantageous for reasons of convenience, the term endoscopist and endoscopic dilatation can sometimes be interchanged with radiologist and radiological dilatation throughout this document. The decision should rest with a team approach by endoscopists and radiologists in each centre.
In addition to description of the dilatation procedure, specific aspects of management for different types of strictures will also be covered. This will include peptic strictures, post-endoscopic therapy (such as endoscopic resection and ablation), eosinophilic oesophagitis, anastomotic, post-radiation and corrosive strictures as well as rings and webs. The dilatation procedure for oesophageal achalasia will also be described.

## Stakeholder involvement
The GDG included individuals who are representative of all the relevant professional groups, including gastroenterologists (including one international expert), an upper GI surgeon, a radiologist and a nurse endoscopist. We also included a patient representative (who had had several dilatations for strictures and a perforation) and the chair of a relevant patient charity (Heartburn Cancer UK). All views were actively sought and incorporated in the guideline at every stage of its development through regular meetings and teleconference discussions.

## Rigour of development
A systematic literature search strategy was developed with the aid of an expert librarian. We searched MEDLINE, Embase and the Cochrane Central Register of Controlled Trials (CENTRAL), from the database inception through to 31 October 2015 and updated 1 January 2017. Other sources searched included reference lists of identified primary journal articles. All the guideline questions were designed in PICO (Problem/population, Intervention, Comparator, Outcome) format and incorporated into an extensive search strategy (online supplementary appendix 1) using all possible combination of search terms (both as free text and-where applicable-as Medical Subject Headings). No language limits were applied. The search results were divided among GDG members, who independently screened titles and abstracts relevant to their writing sections (two members for each section). Studies were included if they reported data on any aspect of the dilatation procedure that is relevant to the guideline scope and purpose.
The quality of included evidence was assessed using the Grading of Recommendations Assessment, Develop ment and Evaluation (GRADE) system, which specifically separates the strength of evidence from the strength of a recommendation. While the strength of a recommendation may often reflect the evidence base, the GRADE system allows for occasions where this is not the casefor example, where it seems good sense to make a recommendation despite the absence of high-quality scientific evidence such as a large randomised controlled trial [fig_ref] table 1: An overview of the GRADE system278 [/fig_ref].
To achieve transparency and simplicity, the GRADE system classifies the quality of evidence in one of four levels-high, moderate, low and very low [fig_ref] table 1: An overview of the GRADE system278 [/fig_ref]. Evidence based on randomised controlled trials begins as high-quality evidence, but our confidence in the evidence may be decreased for several reasons, including: study limitations; inconsistency of results; indirectness of evidence; imprecision; reporting bias. The GRADE system offers two grades of recommendations: 'strong' and 'weak'. When the desirable effects of an intervention clearly outweigh the undesirable effects, or clearly do not, guideline panels offer strong recommendations. On the other hand, when the trade-offs are less certain-either because of low-quality evidence or because evidence suggests that desirable and undesirable effects are closely balanced-weak recommendations become mandatory. In addition to the quality of the evidence, several other factors affect whether recommendations are strong or weak, such as: uncertainty about the balance between desirable and undesirable effects, uncertainty or variability in values and preferences and uncertainty about whether the intervention represents a wise use of resources.
Areas of disagreement on the recommendation grade were resolved by discussion, using a Delphi process. The guideline drafts and final manuscript were critically reviewed by an international expert (PDS) to ensure broader applicability and rigour. It is expected that a review and updating of this guideline will be required in 5 years in order to account for new developments.

## Clarity and presentation
We formulated recommendations that are specific and unambiguous. We considered both the general procedure of dilatation and specific aspects of stricture management according to the underlying health problem. Key recommendations are summarised at the beginning of the document.

## Applicability
We do not expect any barriers or resource implications to the implementation of this guideline, because described assessment and treatment techniques are already being performed in clinical practice. We will provide a quick reference guide and suggest a minimum requirement for procedure documentation in order to facilitate audit and monitoring of outcomes in individual units.

## Editorial independence
GDG members have declared their conflicts of interest. The views of any funding body did not influence the content of this guideline.

## Patient preparation
Oesophageal dilatation is best undertaken as a planned procedure in patients who have been appropriately investigated, prepared and consented. An assessment of the patient's nutritional status and referral to a dietician should also be considered.

## Predilatation investigations
(a) Should all strictures be biopsied before dilatation?  Obtain biopsy specimens from all strictures for histological analysis to exclude malignancy and eosinophilic oesophagitis 7-9 (GRADE of evidence: moderate; strength of recommendation: strong). Obtaining a definitive diagnosis before dilatation is desirable, because this will influence the overall management and estimation of perforation risk. [bib_ref] Ring(s)-related esophageal meat bolus impaction: biopsy first, dilate later, Rajagopalan [/bib_ref] [bib_ref] Management strategies for dysphagia with a normal-appearing esophagus, Arora [/bib_ref] [bib_ref] Prospective audit of perforation rates following upper gastrointestinal endoscopy in two regions..., Quine [/bib_ref] Oesophageal biopsy samples can be safely obtained immediately before oesophageal dilatation 7 ; however, if the stricture is tight or when the endoscopic features suggest malignancy, the results of biopsies are best awaited. 4  Repeat biopsy after cross-sectional imaging (CT or with endoscopic ultrasound (EUS) in cases where biopsies are negative, but clinical or endoscopic features are atypical or suspicious for malignancy [bib_ref] Biopsy-negative malignant esophageal stricture: diagnosis by endoscopic ultrasound, Faigel [/bib_ref] (GRADE of evidence: low; strength of recommendation: strong). EUS may be a more sensitive test than CT, but passage of the EUS probe is often not successful in the case of a stricture. [bib_ref] Biopsy-negative malignant esophageal stricture: diagnosis by endoscopic ultrasound, Faigel [/bib_ref]  Obtain oesophageal biopsy specimens in young patients with dysphagia or history of food impaction to exclude eosinophilic esophagitis 8 9 (GRADE of evidence: moderate; strength of recommendation: strong). (b) Are there any other recommended tests?  Perform barium swallow in patients with suspected complex strictures (such as post-radiation therapy or history of caustic injury) in order to establish the location, length, diameter and number of strictures (GRADE of evidence: low; strength of recommendation: strong). Barium swallow is also useful to evaluate the presence of associated pathology such as an oesophageal diverticulum or a hiatus hernia. This information will aid selection of the dilating technique, estimation of the number of sessions required and counselling the patient about the expected risks. 13

## Information and consent
The overall consent process should be in line with the published BSG guidance. [bib_ref] Guidance for obtaining a valid consent for elective endoscopic procedures, Shepherd [/bib_ref] (a) What information should patients be given?  Counsel all patients about the benefits and risks of dilatation and the likely need for multiple sessions before symptom resolution can be achieved (GRADE of evidence: low; strength of recommendation: strong).  Tailor information to the individual patient's risk profile, based on the underlying cause, location, length and diameter

## Grade-strength of evidence grade-strength of recommendation
High quality: Further research is very unlikely to change our confidence in the estimate of effect
The trade-offs: Taking into account the estimated size of the effect for main outcomes, the confidence limits around those estimates and the relative value placed on each outcome Guidelines of the stricture and coexistent adverse health problems (GRADE of evidence: low; strength of recommendation: strong). Our patient representatives suggested that the use of a diagram to illustrate the location, length and shape of the stricture is desirable to enhance the patient's understanding of the procedure. Moreover, the presence of a relative or a caregiver should be encouraged if deemed appropriate during the consent process.  Provide all patients with written information on oesophageal dilatation before the procedure and obtain written, signed consent. Inform patients about the perforation risk and the potential need for endoscopic or operative intervention should a perforation occur (GRADE of evidence: low; strength of recommendation: strong).  Inform patients-whenever appropriate-of any alternatives to dilatation, such as parenteral feeding or surgery in some cases (GRADE of evidence: low; strength of recommendation: strong). (b) What are the possible complications? Complications include pulmonary aspiration, bleeding, perforation, risks of sedation and chest pain [bib_ref] Complications of esophageal dilation and guidelines for their prevention, Tulman [/bib_ref] ; the last of these being more common in patients with eosinophilic oesophagitis. [bib_ref] Esophageal dilation in eosinophilic esophagitis: safety and predictors of clinical response and..., Dellon [/bib_ref] 17 A UK regional audit published in 1995 reported an overall perforation rate of 2.6% with a 30-day mortality of 1%. [bib_ref] Prospective audit of perforation rates following upper gastrointestinal endoscopy in two regions..., Quine [/bib_ref] Perforation was less common following dilatation of benign strictures (1.1% with a mortality of 0.5%) than following dilatation and/ or intubation of malignant strictures (6.4% with a mortality of 2.3%). [bib_ref] Prospective audit of perforation rates following upper gastrointestinal endoscopy in two regions..., Quine [/bib_ref] The risk of perforation was greater with less experienced endoscopists (performed <500 previous diagnostic endoscopies). [bib_ref] Prospective audit of perforation rates following upper gastrointestinal endoscopy in two regions..., Quine [/bib_ref] Hernandez et al reported a perforation rate of 4 out of 348 procedures (1.1%); however, all these four perforations occurred when Maloney dilators (non-wire guided) were passed blindly into complex strictures. No perforations occurred with Savary-Gilliard (wire-guided) and balloon dilators. [bib_ref] Comparison among the perforation rates of Maloney, balloon, and savary dilation of..., Hernandez [/bib_ref] Hagel et al reported the most recent large retrospective case series of 1497 procedures on 368 patients over a 10-year period. Operators used Savary-Gilliard bougies (Cook Medical, Bloomington, Indiana, USA) or through the scope (TTS) balloons (Controlled Radial Expansion, CRE, Boston Scientific Ltd, Cork, Ireland and Eclipse Wire Guided Balloon Dilators, Cook Ireland Ltd, Limerick Ireland). Eight perforations (0.53%) occurred in malignant, post-radiation or caustic strictures. No perforations were reported in other types of strictures, such as peptic, postoperative and eosinophilic oesophagitis. [bib_ref] Perforation during esophageal dilatation: a 10-year experience, Hagel [/bib_ref] The reported risk of perforation in achalasia has varied widely across studies from 0% to 8% (2-4% in most studies) with a mortality of 0-1%. [bib_ref] Review article: an analysis of the efficacy, perforation rates and methods used..., Katzka [/bib_ref] [bib_ref] Major complications of pneumatic dilation and Heller myotomy for achalasia: single-center experience..., Lynch [/bib_ref] Katzka et al [bib_ref] Review article: an analysis of the efficacy, perforation rates and methods used..., Katzka [/bib_ref] pooled data from all 25 studies in the literature and reported a perforation rate of 2%; however, the balloon size, pressure, dilatation times and single or multiple dilatations varied in almost every study. The perforation rate is lower with a graded approach to balloon dilatation and in experienced hands. [bib_ref] Major complications of pneumatic dilation and Heller myotomy for achalasia: single-center experience..., Lynch [/bib_ref] (c) What are the contraindications/cautions for stricture dilatation?  Do not perform oesophageal dilatation in patients with active or incompletely healed oesophageal perforation as it may extend the oesophageal defect and promote mediastinal soiling 3 4 (GRADE of evidence: low; strength of recommendation: strong).  Perform dilatation in patients with a recent, healed perforation; recent upper gastrointestinal surgery; pharyngeal or cervical deformity; or bleeding disorders after careful consideration of the benefits, risks and alternatives of the procedure 3 4 (GRADE of evidence: low; strength of recommendation: strong). Dilatation may be performed in patients who are having concurrent radiotherapy. fasting  Advise patients to fast for at least 6 hours before the procedure in order to ensure emptying of the oesophagus and stomach. Patients with achalasia are likely to have oesophageal stasis and are therefore required to fast for a longer time based on the clinician's judgement (GRADE of evidence: low; strength of recommendation: strong).

## Patient premedication
 Inform patients that dilatation is likely to be uncomfortable, in particular, when push dilators are used rather than dilatation balloons (GRADE of evidence: low; strength of recommendation: strong).  Offer patients intravenous sedation with a benzodiazepine and an opioid analgesic as a minimum. Propofol sedation (delivered by a suitably qualified person), or a general anaesthetic are valid alternatives based on the clinician's and patient's preference, procedure complexity, as well as local availability and expertise (GRADE of evidence: low; strength of recommendation: strong).

## Patients taking anticoagulants or antiplatelet agents and those at risk of endocarditis
UK-based clinicians must adhere to the BSG and NICE guidelines on management of anticoagulation and antibiotic prophylaxis during endoscopy. Clinicians in other countries should follow the corresponding guidelines in their country or region of practice. [bib_ref] Endoscopy in patients on antiplatelet or anticoagulant therapy, including direct oral anticoagulants:..., Veitch [/bib_ref] [bib_ref] Management of antithrombotic agents for endoscopic procedures, Anderson [/bib_ref] [bib_ref] Antibiotic prophylaxis for GI endoscopy, Khashab [/bib_ref] the dilAtAtion Procedure Personnel, training and equipment (a) Who should perform dilatation?  Oesophageal dilatation should only be undertaken only by (or under direct supervision of) an experienced operator who performs sufficient numbers to maintain their skills. The operator should be supported by at least two assistants (one of whom must be a trained nurse) in the endoscopy/radiology room [bib_ref] Guidelines on the use of oesophageal dilatation in clinical practice, Riley [/bib_ref] procedures) are four times more likely to cause a perforation than their more experienced colleagues. [bib_ref] Prospective audit of perforation rates following upper gastrointestinal endoscopy in two regions..., Quine [/bib_ref] In the UK, the JAG stipulates that training on therapeutic endoscopy should be undertaken only after competency in diagnostic procedures is achieved (minimum of 300 procedures) and the former should take place under direct supervision.No formal guidelines exist for interventional radiologists, but a similar level of experience in diagnostic and interventional procedures is recommended. Close collaboration of the radiologists with interventional endoscopists and upper GI surgeons is essential for the appropriate management of complications.
Appropriate staffing and equipment are important for the provision of safe and successful therapeutic endoscopy procedures. Poor staffing levels are associated with worse outcomes from dilatation. [bib_ref] Prospective audit of perforation rates following upper gastrointestinal endoscopy in two regions..., Quine [/bib_ref] Procedural assistants should be familiar with the dilatation equipment and capable of helping the operator in cases of an emergency. Qualified radiographers must be present when the procedure is performed under X-ray screening. (b) Where should the procedure be performed?  Perform the procedure in a dedicated, fully equipped endoscopy room with access to x-ray screening and surgical support, or a similarly equipped radiological suite (GRADE of evidence: moderate; strength of recommendation: strong).  Units must have an agreed protocol to follow in case of a perforation with clear identification of a qualified surgeon (on or off site) to manage this complication in cases where luminal treatment, such as a covered stent, is not feasible or appropriate 6 10 (GRADE of evidence: low; strength of recommendation: strong). Access to radiographic screening must be available to assist dilatation if there are difficulties in passing a guidewire or balloon catheter through the stricture.When a perforation occurs, prompt treatment should be started and the relevant surgical team must be informed immediately.

## Oesophageal dilators
There are two types of oesophageal dilators: the push (bougie) dilator and the balloon dilator.

## Push dilators
Push dilators are either wire guided (metal olives, Celestin-type dilators or polyvinyl bougies) or non-wire guided (tungsten-filled weighted rubber bougies). [bib_ref] Tools for endoscopic stricture dilation, Siddiqui [/bib_ref] Several models of wire-guided bougie dilators are available. The Savary-Gilliard (Cook Medical, Winston-Salem, North Carolina, USA) dilators are polyvinyl chloride, latex-free cylindrical solid tubes with a central channel to accommodate the guidewire. They are the most widely used (5-20 mm diameter). Each dilator has a 20 cm tapered tip and a radio-opaque band at the widest point of the dilator to aid radiological localisation. American Dilatation System (ConMed, Utica, New York, USA) and SafeGuide dilators (Medovations, Milwaukee, USA) are similar, but are totally radio-opaque throughout their length. [bib_ref] Tools for endoscopic stricture dilation, Siddiqui [/bib_ref] Bougie dilators have external markers indicating the distance from the tip (American System) or from the point of maximal diameter (Savary-Gilliard) or both (SafeGuide). The InScope Optical Dilator (Ethicon Endosurgery Inc, Blue Ash, Ohio, USA) is a flexible, transparent, bougie with three dilating segments fitted over a standard endoscope to allow sequential dilatation under direct vision, but data on its efficacy are scarce. [bib_ref] The Optical Dilator: a clear, over-the-scope bougie with sequential dilating segments, Jones [/bib_ref] The Eder-Puestow dilators comprise a series of graduated metal olives (6.6-19.3 mm diameter) mounted on a flexible shaft. At one time, this was the only system available for dilating complex or resistant strictures, but is now rarely used.
Non-wire-guided weighted bougies are passed blindly after the application of local anaesthetic while the patient is in a sitting position. This approach has been used for self-dilatation in carefully selected patients, but it is seldom used now owing to concerns about safety. [bib_ref] Tools for endoscopic stricture dilation, Siddiqui [/bib_ref] The Maloney dilator was the most commonly used. It has a tapered tip and is available in multiple sizes. Older versions were internally weighted with mercury, which has now been replaced by tungsten because of concerns about leakage and disposal of mercury.

## Balloon dilators
Through the scope (TTS) balloon dilators are available in a variety of designs, lengths and diameters from various manufacturers. They are designed to pass through the endoscope with or without wire guidance so that dilatation can be observed. The balloon is made of low-compliance, inflatable, thermoplastic polymers that allow uniform and reproducible expansion to the specified diameter. Most balloons allow for sequential expansion to multiple diameters. Larger ranges of wire-guided balloons are available for non-endoscopic dilatation under fluoroscopy. The balloon size needs to be carefully matched to the size of the stricture (see below). Dilating balloons are expanded by pressure injection of liquid (eg, water, radio-opaque contrast) using a handheld accessory device. Inflation with radio-opaque contrast allows for fluoroscopic observation. The hydraulic pressure of the balloon is monitored manometrically to gauge the radial expansion force. Balloon dilators are single-use only. [bib_ref] Tools for endoscopic stricture dilation, Siddiqui [/bib_ref] For achalasia dilatation, large-diameter (30, 35 and 40 mm) polyethylene balloon dilators with radio-opaque markers are used. [bib_ref] Tools for endoscopic stricture dilation, Siddiqui [/bib_ref] They are all wire-guided, single use, and do not pass through the endoscope. They are positioned using fluoroscopic guidance, and balloon insufflation pressure is monitored manometrically. [bib_ref] Tools for endoscopic stricture dilation, Siddiqui [/bib_ref] (a) Is there a difference in clinical outcomes between balloons and bougie dilators?  Use either balloon or wire-guided bougie dilators to perform oesophageal dilatation [bib_ref] Balloon or bougie for dilatation of benign esophageal stricture?, Cox [/bib_ref] [bib_ref] Prospective randomized comparison of polyvinyl bougies and through-the-scope balloons for dilation of..., Saeed [/bib_ref] [bib_ref] A randomized prospective study comparing rigid to balloon dilators for benign esophageal..., Scolapio [/bib_ref] (GRADE of evidence: high; strength of recommendation: strong). There is no difference in clinical outcomes-in particular, safety and efficacy, between wire-guided bougie and balloon dilators. Hence the choice should be based on clinician's preference, local expertise, equipment availability, cost and the availability of robust methods of decontamination of reusable medical devices as many push dilators are not single use. [bib_ref] Balloon or bougie for dilatation of benign esophageal stricture?, Cox [/bib_ref] [bib_ref] Prospective randomized comparison of polyvinyl bougies and through-the-scope balloons for dilation of..., Saeed [/bib_ref] [bib_ref] A randomized prospective study comparing rigid to balloon dilators for benign esophageal..., Scolapio [/bib_ref] Three randomised controlled trials compared these two techniques and found no difference in efficacy for dysphagia relief or safety at 1 year. Another retrospective study compared Maloney, balloon-type (both the hydrostatic and pneumatic type) and Savary-Gilliard dilators in 102, 156 and 90 sessions, respectively. The risk of oesophageal perforation was higher with Maloney dilators when passed, blindly, into complex strictures; hence they should be avoided in these cases, and in patients with a tortuous oesophagus and large hiatus hernia. [bib_ref] Comparison among the perforation rates of Maloney, balloon, and savary dilation of..., Hernandez [/bib_ref] Savary-Gilliard and balloon dilators are currently the most frequently used. [bib_ref] Tools for endoscopic stricture dilation, Siddiqui [/bib_ref] Although balloon dilators allow the procedure to be performed under direct vision, they are more costly than push dilators 28 but there Guidelines is no direct cost-effectiveness comparison of the two techniques in clinical practice.

## The dilatation technique
This section describes the general technique of benign stricture dilatation. Achalasia dilatation and disease-specific considerations will be discussed in subsequent sections.
Strictures can be simple or complex. Simple strictures are short (<2 cm), concentric, straight, and allow the passage of a normal diameter endoscope. Examples include Schatzki's rings, oesophageal webs and peptic strictures. Overall, one to three dilatation sessions are sufficient to relieve dysphagia in simple strictures. Only 25-35% of patients require additional sessions, with a maximum of five dilatations in >95% of patients. [bib_ref] Endoscopic dilation of benign esophageal strictures: report on 1043 procedures, Pereira-Lima [/bib_ref] Complex strictures are usually longer (2 cm), angulated, irregular or have a severely narrowed diameter. These are more difficult to treat and have a tendency to be refractory or to recur despite dilatation.
(a) What size dilator should be initially chosen?
The initial dilator choice should be based on the known or estimated stricture diameter, length and the underlying pathology.  Consider limiting the initial dilatation to 10-12 mm in diameter (corresponding to 30-36F) in cases of very narrow strictures not passable by the adult gastroscope. The target for filiform strictures should be even lower (9 mm) (GRADE of evidence: very low; strength of recommendation: weak). (b) What is the recommended number of dilatations or size increments per session?  Consider using no more than three successively larger diameter increments in a single session for both bougie and balloon dilators. The precise restriction of 31 mm diameter increments is not evidence based (GRADE of evidence: low; strength of recommendation: low). Although a 'rule of three' is recommended by many practice guidelines and authorities, no studies have demonstrated improvement in safety or efficacy with this approach. On the other hand, a recent retrospective study showed that non-adherence to the rule of three did not appear to increase the risk of adverse events, particularly perforation, after oesophageal dilatation using bougie dilators, except for malignant strictures. [bib_ref] Non-adherence to the rule of 3 does not increase the risk of..., Grooteman [/bib_ref] For very tight or long strictures, it may be safer to limit the initial dilatation to one or two size increments (21 mm) only. Conversely, larger increments may be safely used (41 mm or 32 mm) in less tight strictures or in those which have completely recurred after the first dilatation session. [bib_ref] Esophageal dilation can be done safely using selective fluoroscopy and single dilating..., Kozarek [/bib_ref] Patients usually need several sessions to achieve resolution of dysphagia and they should be informed of this possibility before the first procedure.
(c) The need for wire guidance or endoscopic control?  Use wire-guided (bougie or balloon) or endoscopically controlled (balloon) techniques for all patients to enhance safety (GRADE of evidence: moderate; strength of recommendation: strong). The use of radiographic screening in non-simple strictures gives additional assurance and control of the dilatation process. During wire-guided dilatation, it demonstrates that the wire has passed the stricture, and kinking of the wire has not occurred within or distal to the stricture. Fluoroscopy also shows that the dilator is following the line of the oesophageal lumen. During balloon dilatation, it indicates whether the balloon has slipped during inflation and whether obliteration of the stricture waist has occurred. Radiographic screening is particularly helpful when the stricture is tortuous or complex or associated with a large hiatus hernia or a diverticulum. It may also be of value when the guidewire meets resistance during passage through the stricture or when an adequate length of wire cannot be passed distal to the stricture. Although comparative trials are not available, the selective use of radiological screening appears safe and effective and is supported by extensive clinical experience. The use of small calibre gastroscopes should also be considered in narrow strictures.  Perform repeat endoscopy or injection of contrast after dilatation in cases where perforation is suspected, to consider immediate treatment with a fully covered self-expandable metal stent 6 (GRADE of evidence: low; strength of recommendation: strong).  Use carbon dioxide insufflation instead of air during endoscopy whenever possible, in complex strictures to minimise luminal distension and postprocedural pain 44 (GRADE of evidence: high; strength of recommendation: strong). Upper oesophageal sphincter disturbances, including motor disorders and mechanical disorders, can result in symptoms of dysphagia.Pathologies associated with disordered neurally mediated opening of the upper oesophageal sphincter, including oculopharyngeal muscular dystrophies, may be amenable to dilatation to relieve symptoms. [bib_ref] A pilot study on upper esophageal sphincter dilatation for the treatment of..., Mathieu [/bib_ref] Furthermore, while a cricopharyngeal bar is often an incidental radiological finding in cricopharyngeal fibrosis, treatment of associated dysphagia by both balloon and bougie dilatation methods can be successful. [bib_ref] Effectiveness of esophageal dilation for symptomatic cricopharyngeal bar, Wang [/bib_ref]  Suspect perforation when patients develop pain, breathlessness, fever or tachycardia. [bib_ref] Complications of esophageal dilation and guidelines for their prevention, Tulman [/bib_ref] Transient chest pain is not uncommon following dilatation but persistent pain should prompt a CT scan with oral contrast to look for perforation 54 (GRADE of evidence: low; strength of recommendation: strong). A chest X-ray examination may show pneumothorax, pneumomediastinum, air under the diaphragm or a pleural effusion but normal appearances do not exclude perforation. If clinical suspicion is high or if endoscopy examination raises the possibility of a deeper laceration than just mucosal, then ideally a CT scan with oral contrast should be performed. Conventional contrast studies are less sensitive and may miss small perforations. [bib_ref] Comparison between esophagography and chest computed tomography for evaluation of leaks after..., Lantos [/bib_ref] [bib_ref] Esophagography after pneumomediastinum without CT findings of esophageal perforation: is it necessary?, Wu [/bib_ref] Moreover, CT can detect other complications, such as pleural effusions, pneumopericardium and pneumoperitoneum. [bib_ref] Esophageal perforation: diagnostic work-up and clinical decisionmaking in the first 24 hours, Sreide [/bib_ref]  Perform endoscopic re-inspection if the patient becomes symptomatic while in the procedure room, in order to assess for the presence of perforation and to undertake treatment which may include immediate endoscopic stent placement 6 (GRADE of evidence: low; strength of recommendation: strong). Iatrogenic perforation is a medical emergency. The patient should be assessed by an experienced physician and experienced surgeon in order to formulate an appropriate plan, which may include surgical, endoscopic or conservative management. [bib_ref] Guidelines on the use of oesophageal dilatation in clinical practice, Riley [/bib_ref]  Provide patients with contact information for the on-call team should they experience chest pain, breathlessness or become unwell 4 (GRADE of evidence: low; strength of recommendation: strong). (b)Timing of next follow-up and procedure end points The timing of subsequent dilatation sessions may depend on the degree of success of initial dilatation and the patient's response to the procedure. Patients often require multiple sessions, especially if the stricture has a narrow diameter or any complex features. [bib_ref] Factors influencing clinical applications of endoscopic balloon dilation for benign esophageal strictures, Chiu [/bib_ref] In the majority of studies, a repeat procedure was performed after 1 week and a subsequent follow-up at 2-4 weeks. In some patients, however, symptoms tend to recur rapidly following dilatation, hence they may require more frequent weekly or biweekly dilatations based on symptoms and stricture resolution. As a general rule, the last dilator size used in the previous session must be passed first. However, the degree of fibrosis and stricture healing is unpredictable and not all patients are expected to tolerate passage of the largest diameter dilator used during the previous session. Reassessment of stricture diameter is required and a smaller size dilator may be used if deemed appropriate.
Most patients respond well to oesophageal dilatation but outcomes are influenced significantly by the underlying pathology, with better clinical response rates achieved in peptic and post-surgical strictures than in caustic and post-radiation pathology. [bib_ref] Endoscopic dilation of benign esophageal strictures without fluoroscopy: experience of 2750 procedures, Raymondi [/bib_ref] There is no consensus on the definition of end point for dilatation. In one case series of 321 patients, 98% of those in whom a 15 mm (45F) dilator was inserted, achieved clinical response over a mean follow-up period of 18.8 months. [bib_ref] Endoscopic dilation of benign esophageal strictures without fluoroscopy: experience of 2750 procedures, Raymondi [/bib_ref] In one prospective study, all patients underwent dilatation to 15 mm then were randomised to either a subjective (end point is alleviation of dysphagia, n=19) or objective (end point is passage of 12 mm barium pill, n=15) group. Patients in the objective group had less recurrent dysphagia (P=0.02) and required fewer redilatation sessions (P<0.05) than the subjective group. [bib_ref] An objective end point for dilation improves outcome of peptic esophageal strictures:..., Saeed [/bib_ref] The size of the oesophageal lumen will vary depending on the height and weight of the patient, and a 15 mm lumen end point is for someone of average size.  Perform weekly or two-weekly dilatation sessions until easy passage of a 15 mm dilator is achieved along with symptomatic improvement (GRADE of evidence: moderate; strength of recommendation: strong). A brief checklist is shown in [fig_ref] figure 1: Stricture dilatation procedure checklist [/fig_ref]. This may be used as a guide.

## Disease-specific considerations
This section discusses features of specific diseases, which may affect the dilatation procedure and patient outcomes.

## Achalasia dilatation
Pneumatic balloon dilatation (PD) is one of a number of effective treatments for achalasia, which include surgical or endoscopic myotomy. However, the latter are outside the remit of this guideline. [bib_ref] Endoscopic and surgical treatments for achalasia: a systematic review and meta-analysis, Campos [/bib_ref] Bougie dilators are not used for achalasia dilatation. If the Eckardt score remains >3 after the third session, the treatment is usually considered to have failed. [bib_ref] Pneumatic dilation versus laparoscopic Heller's myotomy for idiopathic achalasia, Boeckxstaens [/bib_ref] Patients with a recurrence of symptoms during follow-up may require further dilatation. 5  Consider repeat dilatation (after the initial series) during follow-up to maintain symptom response 5 (GRADE of evidence: high; strength of recommendation: strong). The procedure is effective in 90% of patients in the first year and this reduces to 86% in the second year. [bib_ref] Pneumatic dilation versus laparoscopic Heller's myotomy for idiopathic achalasia, Boeckxstaens [/bib_ref] Up to one-third of patients may have recurrence of symptoms during 4-6 years of follow up. [bib_ref] Repeated pneumatic dilations as longterm maintenance therapy for esophageal achalasia, Zerbib [/bib_ref] [bib_ref] Long-term outcome of pneumatic dilation in the treatment of achalasia, Hulselmans [/bib_ref] The vast majority can be successfully treated by repeat dilatation, achieving remission rates of up to 97% and 93% at 5 and 10 years, respectively. 62  Perform dilatation under endoscopic or fluoroscopic control based on clinician's preference and local expertise [bib_ref] Endoscope-guided pneumatic dilatation of esophageal achalasia without fluoroscopy is another safe and..., Chuah [/bib_ref] [bib_ref] Rigiflex pneumatic dilation of achalasia without fluoroscopy: a novel office procedure, Rai [/bib_ref] [bib_ref] Pneumatic dilation for achalasia without fluoroscopic guidance: safety and efficacy, Lambroza [/bib_ref] (GRADE of evidence: moderate; strength of recommendation: strong). Fluoroscopic control is used in the majority of studies reporting safety and efficacy of balloon dilatation in achalasia; however, the safety of endoscopic control alone has been shown in a few studies. [bib_ref] Endoscope-guided pneumatic dilatation of esophageal achalasia without fluoroscopy is another safe and..., Chuah [/bib_ref] [bib_ref] Rigiflex pneumatic dilation of achalasia without fluoroscopy: a novel office procedure, Rai [/bib_ref] [bib_ref] Pneumatic dilation for achalasia without fluoroscopic guidance: safety and efficacy, Lambroza [/bib_ref] Comparative studies between the latter two approaches are lacking. Routine oesophagograms obtained after PD for achalasia did not reveal any clinically unsuspected perforations and no perforations were missed in cases that were not followed by oesophagograms. [bib_ref] Utility of clinical suspicion and endoscopic re-examination for detection of esophagogastric perforation..., Zori [/bib_ref] Impedance planimetry may be a tool that improves decision-making in dilating achalasia. [bib_ref] Hydraulic dilation with a shape-measuring balloon in idiopathic achalasia: a feasibility study, Kappelle [/bib_ref]  Consider proton pump inhibitor (PPI) therapy after dilatation as the technique has 10-40% rate of symptomatic gastro-oesophageal reflux disease (GORD) or ulcerative oesophagitis after treatment 69-72 (GRADE of evidence: high; strength of recommendation: strong).

## Guidelines
PD does not preclude a subsequent myotomy. Similarly, PD may be performed for recurrence of dysphagia following myotomy. 73-79  Consider performing a water-soluble contrast swallow after dilatation to screen for perforation, but it is not essential (GRADE of evidence: moderate; strength of recommendation: weak). PD is contraindicated in patients with poor cardiopulmonary function, frailty or other comorbid illnesses preventing surgery, should an oesophageal perforation occur. [bib_ref] Achalasia -an update, Richter [/bib_ref] Patients with hiatal hernia or oesophageal diverticulum have undergone PD safely by experienced operators. 82

## Peptic strictures
Peptic strictures requiring dilatation have been reported to occur in about 1-2% of patients with reflux oesophagitis, the proportion remaining relatively constant over the past three decades despite a rising incidence of reflux oesophagitis. [bib_ref] Oesophageal acid-peptic strictures in the histamine H2 receptor antagonist and proton pump..., Nayyar [/bib_ref] This has been attributed to the widespread adoption of PPI therapy. [bib_ref] Proton pump inhibitors and the time trends for esophageal dilation, Guda [/bib_ref] Between 40% and 60% of peptic strictures require only one dilatation, [bib_ref] Balloon or bougie for dilatation of benign esophageal stricture?, Cox [/bib_ref] with the need for redilatation being highest in the subsequent 1-2 years. [bib_ref] Natural history of benign esophageal stricture treated by dilatation, Patterson [/bib_ref] A recent snapshot of practice in the USA suggests that more than 80% of patients with peptic strictures require only one dilatation. [bib_ref] Practice patterns in the management of patients with esophageal strictures and rings, Olson [/bib_ref] This may be because peptic strictures tend to be short and straight, and with the widespread use of PPIs for GORD this more recent survey of practice may reflect the fact that peptic strictures are becoming less severe. Patients with smaller stricture diameter and longer strictures are less likely to respond to dilatation and vice versa. [bib_ref] A randomized prospective study comparing rigid to balloon dilators for benign esophageal..., Scolapio [/bib_ref] It is clear that dysphagia in patients with reflux oesophagitis may result from oesophagitis rather than stricture, and symptoms may improve with healing of oesophagitis using PPI therapy without the need for dilatation. [bib_ref] Dysphagia in patients with erosive esophagitis: prevalence, severity, and response to proton..., Vakil [/bib_ref] In addition, oesophagitis as well as stricture diameter contribute to the severity of dysphagia, 89-91 and healing of oesophagitis in patients with strictures is associated with a reduced need for redilatation. [bib_ref] Omeprazole versus H2-receptor antagonists in treating patients with peptic stricture and esophagitis, Marks [/bib_ref] Finally, PPI therapy, but not H2 receptor antagonist treatment, reduces the need for, and frequency of, dilatation of peptic strictures after the initial dilatation. 92-95  Offer PPI therapy to patients with GORD and dysphagia, as this treatment has been shown to reduce the need for oesophageal dilatation [bib_ref] Oesophageal acid-peptic strictures in the histamine H2 receptor antagonist and proton pump..., Nayyar [/bib_ref] 

## Schatzki's ring
Schatzki's ring is an annular constriction at the gastro-oesophageal mucosal junction, covered on its proximal side by squamous epithelium and distally by gastric mucosa. [bib_ref] The nature and location of lower esophageal ring, Goyal [/bib_ref] It was first appreciated on barium swallow radiology, provided the oesophagus was adequately distended, 97 occurring in 6-14% of barium swallow examinations and often asymptomatic. The natural history of asymptomatic Schatzki's ring is unknown so it is not established whether treatment (for instance, with a PPI) is indicated. Schatzki's ring is less often seen at endoscopy 100 unless the gastro-oesophageal junction is adequately distended by air insufflation. It is a common cause of intermittent dysphagia for solids and of food bolus obstruction: 'Schatzki's rule' states that dysphagia is usual with ring diameters of  13 mm, and rarely occurs if the diameter exceeds 20 mm, 101 with a 'grey' area in between where symptoms are less consistently observed.
Schatzki's ring is associated with gastro-oesophageal reflux and with eosinophilic oesophagitis, even in the absence of other endoscopic oesophageal mucosal abnormalities. This may explain why patients with rings and acid reflux (demonstrated by pH monitoring), and also unselected patients with Schatzki's rings appear to have fewer recurrences after dilatation when receiving PPI therapy. Dysphagia due to Schatzki's ring was relieved by PPI therapy without the need for dilatation in a small retrospective case series. [bib_ref] Effective treatment of symptomatic lower esophageal (Schatzki) rings with acid suppression therapy:..., Novak [/bib_ref] Dilatation therapy for symptomatic Schatzki's ring is directed toward achieving rupture of the ring; therefore, larger calibre dilators may be needed. [bib_ref] Schatzki's ring: a benign cause of dysphagia in adults, Jalil [/bib_ref] There is robust evidence for the efficacy of a single dilatation to 16-20 mm. [bib_ref] Single dilation of symptomatic Schatzki rings. A prospective evaluation of its effectiveness, Eckardt [/bib_ref] Electrosurgical incision of the ring has been reported to be at least as effective in relieving dysphagia due to Schatzki's ring as a single large calibre dilatation in randomised trials. [bib_ref] Schatzki's ring: to cut or break an unresolved problem, Ibrahim [/bib_ref] Two studies suggest that incision may lead to longer remission of dysphagia than bougienage, proposing this treatment for patients with recurrence after a course of bougienage. Relapses still occur, but long-term PPI therapy (omeprazole 20 mg/day) significantly reduces the risk of relapse compared with placebo at up to 48 months of follow-up. Biopsy excision was shown to be effective and safe in a small feasibility study of 10 patients with dysphagia due to a Schatzki's ring (six of whom had previously undergone bougie or balloon dilatation). Complete endoscopic obliteration of the ring and improvement of dysphagia was achieved (using jumbo biopsy forceps) in all 10 patients during 379 days (range 63-496 days) of follow-up with no serious complications. [bib_ref] Obliteration of symptomatic Schatzki rings with jumbo biopsy forceps (with video), Gonzalez [/bib_ref] In studies reporting this technique, the incision was performed using a standard needle-knife papillotome with a 5 mm cutting wire passed through the accessory channel of the endoscope. Three to four longitudinal incisions were performed radially to the junction of the base of the ring and the oesophageal wall. [bib_ref] A randomized, prospective trial of electrosurgical incision followed by rabeprazole versus bougie..., Wills [/bib_ref] Other experts recommend the use of standard endoscopic submucosal dissection (ESD) needle knife, IT knife or argon plasma coagulation.This procedure must be performed by a skilled operator who is familiar with the technique and uses it regularly (such as for ESD procedures).

## Post-endoscopic therapy strictures
Oesophageal stenosis can occur after Endoscopic Resection or after Endoscopic Mucosal Ablation for oesophageal neoplasia.
Post-endoscopic resection (ER): stricture dilatation ER procedures performed in the oesophagus include both endoscopic mucosal resection (EMR) and ESD.
It is generally accepted that once mucosal or submucosal resection of the oesophageal wall has encompassed greater than 75% of the circumference then symptomatic stenosis will occur. [bib_ref] Stepwise radical endoscopic resection versus radiofrequency ablation for Barrett's oesophagus with high-grade..., Van Vilsteren [/bib_ref] [bib_ref] Curative endoscopic therapy in patients with early esophageal squamous-cell carcinoma or high-grade..., Pech [/bib_ref] [bib_ref] Esophageal stenosis after endoscopic mucosal resection of superficial esophageal lesions, Katada [/bib_ref] [bib_ref] Predictive factors for esophageal stenosis after endoscopic submucosal dissection for superficial esophageal..., Mizuta [/bib_ref] [bib_ref] Management of complications associated with endoscopic submucosal dissection/ endoscopic mucosal resection for..., Isomoto [/bib_ref] [bib_ref] Risk factors for postoperative stricture after endoscopic submucosal dissection for superficial esophageal..., Shi [/bib_ref] [bib_ref] Risk of perforation during dilation for esophageal strictures after endoscopic resection in..., Takahashi [/bib_ref] Studies quote an OR for stricture formation of 44.2 (95% CI 4.4 to 443.6) once more than 75% of the circumference has been resected 119 and frequency of 49.7% when the length of resection was >40 mm.
For the majority of post-ER strictures, dilatation will resolve symptomatic dysphagia, although repeat procedures are often needed. Pouw et al 121 showed that by using either Savary bougienage or balloon dilatation, all (84) patients who developed symptomatic strictures after stepwise radical ER were adequately treated by a median of 3 (IQR 2-6) dilatation sessions, supplemented by placement of a stent (n=2) or incision therapy (n=4). In 28 (33%) patients the stenosis was graded as severe since more than five endoscopic dilatations, stent placement or incision therapy were required.
Endoscopic balloon dilatation has been shown to be an effective and safe first-line intervention in patients with post -ER strictures, with a reported success rate of 90% and a perforation rate of 0.3% 122 in patients with symptomatic dysphagia Guidelines after EMR for early oesophageal cancer. Balloon dilatation has also been used to prevent strictures after ER. In one study, dilatation was performed after ER and repeated once a week until the mucosal defect was completely healed. The remaining 12 cases were not treated and used as historic controls. Prophylactic dilatation decreased the incidence of stricture (59% vs 92%, P=0.04); reduced the severity of stricture; and shortened the duration required for resolving the stricture (29 days vs 78 days, P=0.04) even when stricture developed.
The main complications associated with post-ER stricture dilatation are perforation, bleeding and a low risk of bacteraemia. The potential risk of perforation associated with dilatation of post-ER strictures is slightly higher (1.1%) that that seen in benign strictures (0.1%-1.02%). [bib_ref] Comparison among the perforation rates of Maloney, balloon, and savary dilation of..., Hernandez [/bib_ref] Also, strictures resistant to repeated dilatation do occur, and as in peptic strictures, a fully covered self-expanding metal stent (SEMS) may need to be employed, but there are limitations, including chest pain and stent migration. [bib_ref] Stepwise radical endoscopic resection for eradication of Barrett's oesophagus with early neoplasia..., Pouw [/bib_ref] Further large-volume studies are needed to clarify the long-term outcome.  Inform patients of up to ~50% chance of developing symptomatic stricture requiring endoscopic dilatation after ER either following EMR or ESD in any of the following situations: resection size >75% of the oesophageal circumference; and a longitudinal resection length of >40 mm [bib_ref] Efficacy of preventive endoscopic balloon dilation for esophageal stricture after endoscopic resection, Ezoe [/bib_ref] 

## Post-er: stricture prevention
Endoscopic resection creates an ulcer which can be healed with PPI therapy based on previous studies on reflux oesophagitis and is known to reduce the risk of stricture formation. There are no comparative studies after endoscopic resection as PPI is a standard accepted treatment. Endoscopic intralesional injections of steroids are applied based on the concept that inflammation and fibrosis after oesophageal ER are inhibited by the direct administration of steroids to the resection site. Takahashi et al 129 carried out a randomised, controlled, open-label study to examine whether local steroid injection was an effective prophylactic treatment for oesophageal stenosis following extensive ESD. The authors found no difference in the frequency of stricture formation between the groups, but significantly fewer dilatation sessions were required in the steroid group than in the control group (6.1 (95% CI 2.8 to 9.4) vs 12.5 (95% CI 7.1 to 17.9); P=0.04).
Yamaguchi et al [bib_ref] Usefulness of oral prednisolone in the treatment of esophageal stricture after endoscopic..., Yamaguchi [/bib_ref] found that the stricture rate with oral prednisolone (5.3%, 1/19) was significantly lower than in the control group (31.8%, 7/22) (P<0.0001). The steroids were started at 30 mg/day on the third day after ESD, tapered gradually, and then discontinued 8 weeks later. Furthermore, the frequency of dilatation in the prednisolone group (mean 1.7, range 0-7) was significantly lower than in the control group (mean 15.6, range 0-48) (P<0.0001). Other studies have shown that using a reducing regimen of oral prednisolone in patients after large EMR or ESD reduces the need for repeated dilatation. [bib_ref] Control of severe strictures after circumferential endoscopic submucosal dissection for esophageal carcinoma:..., Sato [/bib_ref] [bib_ref] Effect of oral prednisolone on esophageal stricture after complete circular endoscopic submucosal..., Yamaguchi [/bib_ref] Wen et al 133 performed a single-centre randomised controlled trial and showed that the stricture rate and number of additional dilatations during a short-term follow-up period were significantly lower in subjects treated by stent placement for 8 weeks immediately after ESD than in patients who were not treated with stents. Further studies are required to establish the benefits and risks of SEMS in this setting-in particular, problems of postinsertion hyperplastic regenerative changes, which are difficult to distinguish from neoplastic residues.
Polyglycolic acid (PGA) is a synthetic compound that is completely degraded into a non-toxic degradation product, glycolic acid, over a period of 4-6 months in physiological conditions and has been employed in promoting tissue repair. Iizuka et al [bib_ref] Polyglycolic acid sheet application to prevent esophageal stricture after endoscopic submucosal dissection..., Iizuka [/bib_ref] 

## Post-ablative therapy: treatment and prevention
Field ablation is now accepted as an adjunctive treatment to endoscopic resection of oesophageal neoplasia and, in particular, neoplasia related to Barrett's oesophagus (BO). Most international guidelines now support this approach with much of the data supporting the use of radiofrequency ablation (RFA). [bib_ref] British Society of Gastroenterology guidelines on the diagnosis and management of Barrett's..., Fitzgerald [/bib_ref] These treatments result in oesophageal ulceration which can be healed with PPI therapy based on previous studies on reflux oesophagitis, and PPI treatment is known to reduce the risk of stricture formation. There are no comparative studies after ablation as PPI is a standard accepted treatment. Historically, photodynamic therapy (PDT) was the first-line ablation in patients with BO neoplasia. Owing to the toxicity and photosensitivity reactions associated with these agents its role is no longer advocated for the treatment of oesophageal neoplasia. One of the significant drawbacks of this technology was the high rate of stricturing in patients treated with PDT, which approached 36%. [bib_ref] Photodynamic therapy with porfimer sodium for ablation of high-grade dysplasia in Barrett's..., Overholt [/bib_ref] Most oesophageal strictures in the latter study were managed successfully through repeated dilatations, with one patient requiring an oesophagectomy after dilatation-related perforation.
RFA has now been accepted as the 'gold standard' approach in patients with BO neoplasia. Ablation to a depth of 500 m favours a reduced rate of stricture formation that is not the case with other ablation techniques. In a landmark randomised controlled trial, in which Shaheen et al 142 compared RFA with a sham procedure, high disease eradication rates were seen and the stricture rate in the treatment group after a median of two treatments was 6%. All patients underwent successful endoscopic dilatation (mean of 2.6 sessions). Data from the UK registry of patients undergoing RFA for BO neoplasia reported a similar stricture rate. Haidry et al [bib_ref] Radiofrequency ablation and endoscopic mucosal resection for dysplastic Barrett's esophagus and early..., Haidry [/bib_ref] showed an overall stricture rate requiring therapeutic dilatation of 9% (30 of 335 patients). All these cases were managed endoscopically with a mean of 1.3 dilatations (range 1-6). Patients who underwent EMR before initiating RFA were more likely to develop strictures than those who did not (12% vs 5.9%; P=0.04).
The role of RFA for early squamous cell neoplasia has been controversial with early data supporting its use in well-selected patients, [bib_ref] Radiofrequency ablation for the endoscopic eradication of esophageal squamous high grade intraepithelial..., Van Vilsteren [/bib_ref] but it is associated with a higher stricture rate than with the same intervention in BO neoplasia. van Vilsteren et al [bib_ref] Radiofrequency ablation for the endoscopic eradication of esophageal squamous high grade intraepithelial..., Van Vilsteren [/bib_ref] showed a stricture rate of 23% and Bergman et al 145 a stricture rate of 14%. Data from the UK registry, where 20 patients with early squamous neoplasia were treated with RFA, showed a stricture rate of 20%. [bib_ref] Radiofrequency ablation for early oesophageal squamous neoplasia: outcomes form United Kingdom registry, Haidry [/bib_ref]  Inform patients that stricture formation requiring dilatation is significantly higher in the following situations: after photodynamic therapy (PDT) (36%) compared with other forms of ablation ; where ER has preceded ablation (12% vs 6%) [bib_ref] Radiofrequency ablation and endoscopic mucosal resection for dysplastic Barrett's esophagus and early..., Haidry [/bib_ref] ; with use of higher doses of energy with RFA for Barrett's oesophagus (BO) ; and after RFA for early squamous cell neoplasia (14-23%) [bib_ref] Radiofrequency ablation for the endoscopic eradication of esophageal squamous high grade intraepithelial..., Van Vilsteren [/bib_ref] 

## Eosinophilic oesophagitis (eoe)
EoE is a common immune/antigen-mediated oesophageal disease characterised clinically by symptoms of oesophageal dysfunction and histologically, by eosinophil predominant inflammation. [bib_ref] Eosinophilic esophagitis: updated consensus recommendations for children and adults, Liacouras [/bib_ref] First described by Attwood and Straumann in 1993-94, EoE usually presents with dysphagia and is now the the most common cause of food bolus obstruction in patients under the age of 50 years. [bib_ref] Association of eosinophilic inflammation with esophageal food impaction in adults, Desai [/bib_ref] EoE is the the most common cause of spontaneous perforation of the oesophagus. It is the second most common benign disease of the oesophagus. [bib_ref] Advances in clinical management of eosinophilic esophagitis, Dellon [/bib_ref] It is often underdiagnosed and yet 50 times more common than achalasia. [bib_ref] Advances in clinical management of eosinophilic esophagitis, Dellon [/bib_ref] Preliminary medical treatment and diet elimination for EoE PPI, diet and topical steroids are all used as first-line treatments (in up to 50%). [bib_ref] Proton pump inhibitor-responsive oesophageal eosinophilia: an entity challenging current diagnostic criteria for..., Molina-Infante [/bib_ref] Dietary therapy with elimination of causative allergens, or topical corticosteroids may provide a durable longterm solution. Topical steroids (such as fluticasone) and budesonide are very effective in the short term, but longer-term studies are needed. [bib_ref] Systematic review with network meta-analysis: comparative effectiveness of topical steroids vs. PPIs..., Lipka [/bib_ref]  Offer dilatation along with other forms of disease modification using diet, topical steroids or other drugs (GRADE of evidence: moderate; strength of recommendation: strong).  Start other treatments for EoE before dilatation if possible, and those may be continued afterwards to prevent or delay recurrence of symptoms (GRADE of evidence: moderate; strength of recommendation: strong).  Offer preliminary topical steroids followed by dilatation as this is more cost-effective than using dilatation alone as first-line treatment (GRADE of evidence: moderate; strength of recommendation: strong).

## Indications for dilatation in eoe
The indications for dilatation in EoE include established tight stricture, narrow calibre oesophagus, food bolus obstruction and failure of symptoms to respond to diet or drugs. Dilatation of the oesophagus is now a standard treatment for EoE, along with other forms of chronic disease modification using diet, topical steroids or other drugs. Other treatments for EoE should be started before dilatation if possible, and continued afterwards to prevent or delay recurrence of symptoms. A recent randomised controlled study by Kavitt et al 170 has shown that preliminary topical steroids followed by dilatation is more cost-effective than using dilatation as the first treatment. In some patients, dilatation can be used as the only treatment. [bib_ref] Esophageal dilation in eosinophilic esophagitis: effectiveness, safety, and impact on the underlying..., Schoepfer [/bib_ref] 

## Risks and complications of dilatation in eoe
Dilatation of EoE is no more dangerous than dilatation for other oesophageal diseases (such as peptic stricture or achalasia), and the perforation rates are similar if safe techniques and flexible endoscopy are employed by experienced operators. [bib_ref] Esophageal dilation in eosinophilic esophagitis: effectiveness, safety, and impact on the underlying..., Schoepfer [/bib_ref] Mucosal tears and associated minor bleeding are common after dilatation of EoE (8%), and can be managed conservatively. [bib_ref] Esophageal dilation in eosinophilic esophagitis: safety and predictors of clinical response and..., Dellon [/bib_ref] The risk of postprocedural chest pain is particularly common after EoE dilatation and may last for up to 48 hours. [bib_ref] Intermittent dysphagia for solids associated with a multiringed esophagus: clinical features and..., Lee [/bib_ref] Patients should be warned about this possibility, and the need to take fluids and analgesia along with their maintenance EoE therapy.  Reassure patients that dilatation of EoE is no more dangerous than dilatation for other oesophageal diseases, and the perforation rates are similar [bib_ref] Esophageal dilation in eosinophilic esophagitis: safety and predictors of clinical response and..., Dellon [/bib_ref] 

## Follow-up treatment after dilatation in eoe
A good clinical outcome is dysphagia resolution and avoidance of food bolus obstruction after dilatation. Most experts recommend gradual slow dilatation with sessions separated by 3-4 weeks and aim for a diameter of 16-18 mm, if possible. [bib_ref] Eosinophilic esophagitis dilation in the community--try it--you will like It--but start low..., Richter [/bib_ref] Repeat dilatation should be offered if symptoms of severe dysphagia recur or if a symptomatic stricture is diagnosed during follow-up. [bib_ref] Ring(s)-related esophageal meat bolus impaction: biopsy first, dilate later, Rajagopalan [/bib_ref] Symptom response after initial dilatations (about three sessions over several weeks) usually lasts for up to 1 year. Dilatation of the oesophagus in EoE may be repeated if needed. [bib_ref] Esophageal dilation: simple and effective treatment for adults with eosinophilic esophagitis and..., Bohm [/bib_ref] Maintenance treatment with either topical steroid or dietary elimination should continue after dilatation of EoE. A repeat endoscopy is recommended at 6-12 weeks. Guidelines  Inform patients that symptom response after dilatation usually lasts up to 1 year 167 169 (GRADE of evidence: moderate; strength of recommendation: strong).  Repeat dilatation if needed [bib_ref] Eosinophilic esophagitis: clinical features, endoscopic findings and response to treatment, Enns [/bib_ref] high; strength of recommendation: strong).

## Method of dilatation in eoe
There are no credible data comparing balloon with bougie dilatation in EoE, but most observers prefer balloon to reassure the operator that a perforation is not occurring. Otherwise the technique remains the same as for other types of stricture.

## Use of distensibility measure to guide dilatation in eoe
Endoscopic Functional Luminal Imaging Probe (EndoFLIP, Crospon, Galway, Ireland) is used in some specialist centres to measure compliance and distensibility. EndoFLIP and Balloon pull through techniques may help in judging the optimal calibre to dilate to but require further study. These techniques are innovative, safe and seem effective. More research on their cost-effectiveness is warranted. The availability and cost-effectiveness will be the main considerations before formulating recommendations for their routine use in clinical practice. A recent study has shown that endoscopy has a sensitivity of only 25% in detecting narrowed oesophagus 15 mm in diameter among patients with EoE compared with barium radiology. [bib_ref] Oesophageal narrowing is common and frequently under-appreciated at endoscopy in patients with..., Gentile [/bib_ref]  Consider the use of special techniques such as EndoFLIP and Balloon pull through to judge the optimal calibre and position of dilatation (GRADE of evidence: low; strength of recommendation: weak).

## Postoperative strictures frequency and situation
All surgical interventions have the potential for fibrotic stricturing at the anastomotic site as a complication. Oesophagectomy with oesophago-gastrostomy for oesophageal or gastric cardia malignancy can lead to stricturing in 4% 185 to 66%. [bib_ref] Endoscopic and symptomatic assessment of anastomotic strictures following esophagectomy and cervical esophagogastrostomy, Williams [/bib_ref] These strictures tend to be short and straight, but occasionally can be complicated. Methods for prevention of stricturing by surgical technique to maximise vascularisation of the anastomosis is a key strategy in the prevention of oesophageal anastomotic strictures. Fundoplication for GORD, both partial and total, is also associated with postoperative dysphagia, affecting 5-43% of people. Mechanisms behind this include a tight wrap, a slipped wrap and paraoesophageal hernia. Partial wraps are less likely to cause significant postoperative dysphagia than a Nissen. Intraoperative evaluation of the oesophagusfor example, using the EndoFLIP device, could allow the operator to determine the length of wrap and optimal tightness of the gastro-oesophageal junction during the fundoplication procedure, 197 thereby reducing postoperative dysphagia and/or the need for dilatation.

## Preliminary medical treatment and investigations
Nutritional supplementation, particularly in patients with cancer, and PPI therapy following bariatric surgery 198 are important. Specific investigations, including endoscopy and barium swallow, are helpful.  Consider performing upper GI endoscopy, manometry, pH studies and barium swallow first in patients with persistent dysphagia post-fundoplication surgery, in order to assess the integrity of the wrap and understand the cause of dysphagia prior to dilatation or repeat surgery (GRADE of evidence: low; strength of recommendation: weak).

## Methods of dilatation of postoperative strictures
Treatment of postoperative stricture has used both bougienage [bib_ref] Incidence and management of benign anastomotic stricture after cervical oesophagogastrostomy, Pierie [/bib_ref] and balloon dilatation, both under direct endoscopic visualisation or with fluoroscopy, [bib_ref] Fluoroscopically guided balloon dilation or temporary stent placement for patients with gastric..., Lee [/bib_ref] and no data exist to show which is optimal. [bib_ref] Endoscopic and symptomatic assessment of anastomotic strictures following esophagectomy and cervical esophagogastrostomy, Williams [/bib_ref] Symptoms improve after the first dilatation session in up to 43% of individuals [bib_ref] Stenosis of esophago-jejuno anastomosis after gastric surgery, Fukagawa [/bib_ref] and therefore repeat dilatation is the norm. Typically, a median of three sessions is used before satisfactory relief of dysphagia is achieved. [bib_ref] Endoscopic bougienage of benign anastomotic strictures in patients after esophageal resection: the..., Marjanovic [/bib_ref] Treatment success is difficult to define, limiting comparisons between studies but may be obtained in between 62% 195 and 100%. [bib_ref] Endoscopic bougienage of benign anastomotic strictures in patients after esophageal resection: the..., Marjanovic [/bib_ref] Delayed gastric emptying appears to be an additional risk factor for stricture formation, and treatment of this by pyloroplasty or pyloromyotomy may help to reduce the frequency of dilatation sessions required to achieve successful treatment of anastomotic stricture. [bib_ref] Anastomotic strictures and delayed gastric emptying after esophagectomy: incidence, risk factors and..., Sutcliffe [/bib_ref] In the post-fundoplication setting, dilatation of the lower oesophageal sphincter typically requires 30-40 mm balloons, similar to those used in the management of achalasia. [bib_ref] Esophageal pneumatic dilation for postfundoplication dysphagia: safety, efficacy, and predictors of outcome, Hui [/bib_ref] Success can be achieved in approximately two-thirds of patients, although non-responders may require revisional surgery. [bib_ref] Symptomatic and functional outcome after laparoscopic reoperation for failed antireflux surgery, Byrne [/bib_ref] 

## Use of supplementary methods
The use of steroid injection (0.5 mL aliquots of triamcinolone 40 mg/mL to four quadrants) has been evaluated in anastomotic strictures in a randomised double-blind study and found to be safe when injected with a 4 mm-long, 23-gauge needle immediately before bougie dilatation of anastomotic strictures. [bib_ref] Endoscopic corticosteroid injections do not reduce dysphagia after endoscopic dilation therapy in..., Hirdes [/bib_ref] In this study, the steroid arm appeared superior in the length of time required between dilatation sessions (108 days vs 42 days in the saline group), and the total number of dilatation sessions required (two in the steroid group versus three in the saline group). However neither of these outcomes reached significance. Steroid-treated patients with stricture were found to have significantly more complications, specifically oesophageal candidiasis.
Needle knife incision has also been evaluated in refractory strictures and in the primary treatment of anastomotic strictures. In experienced hands, this technique is as safe as conventional dilatation methods, but evaluation of the success of this treatment strategy is more variable. Primary treatment with incisional therapy appears to confer no significant advantage over bougie dilatation in the mean number of dilatations or overall success rate at reducing symptoms of dysphagia. [bib_ref] A randomized comparison of electrocautery incision with Savary bougienage for relief of..., Hordijk [/bib_ref] Specific methods used for incisional therapy include either an endoscopic needle knife or an 'IT' knife, incising in four quadrants with the aid of a transparent cap, which enhances the safety of the procedure. The procedure is best done by an operator who is familiar with techniques of incision through experience with ESD or endoscopic retrograde cholangiopancreatography. Incisional therapy appears to maintain luminal patency, at 12 months' follow-up in 61.5% of cases compared with 19.8% in controls who underwent continued endoscopic balloon dilatation,and so has a role in the treatment of unresponsive anastomotic stricture.  Use steroid injections (0.5 mL aliquots of triamcinolone 40 mg/mL to the four quadrants) to reduce the frequency of repeat dilatations in anastomotic strictures refractory to initial dilatation approaches. Use a 4 mm-long, 23-gauge needle immediately before bougie dilatation while leaving the needle in for at least 1 min to minimise leakage of the drug and ensure delivery of the full dose to the target area (GRADE of evidence: moderate; strength of recommendation: weak).  Consider using needle knife incision for anastomotic strictures as an alternative to dilatation (GRADE of evidence: moderate; strength of recommendation: weak).

## Risks and follow-up
After treatment of postoperative strictures, complication rates such as bleeding or rupture have been reported in up to 30% of cases, but perforation with mediastinal leakage appears to be no more common than in other types of strictures. There appears to be no evidence to warrant surveillance of patients postoperatively for anastomotic stricture.

## Post-radiation strictures
Radiotherapy treatment has revolutionised the management of most solid organ malignancies, but may induce stricturing of the oesophagus. The risk of stricturing can be anticipated before radiotherapy in patients with greater tumour invasion (T-score) and greater circumferential involvement. [bib_ref] Success of endoscopic pharyngoesophageal dilation after head and neck cancer treatment, Chapuy [/bib_ref] [bib_ref] Esophageal stenosis associated with tumor regression in radiotherapy for esophageal cancer: frequency..., Atsumi [/bib_ref] [bib_ref] Predictive factors of esophageal stenosis associated with tumor regression in radiation therapy..., Atsumi [/bib_ref] Radiotherapy induces tissue ischaemia, fibrosis and subsequent oesophageal stenosis. In contrast to other oesophageal strictures, the fibrosis often affects the tissues surrounding the oesophagus, creating a non-compliant mediastinum. As a consequence, radiation strictures are frequently refractory to dilatation and progressive. The risk is increased with higher radiation doses. [bib_ref] Endoscopic management of radiation-induced complete upper esophageal obstruction with an antegrade-retrograde rendezvous..., Maple [/bib_ref] [bib_ref] Dose-response relations for stricture in the proximal oesophagus from head and neck..., Alevronta [/bib_ref] [bib_ref] Dosimetric factors associated with long-term dysphagia after definitive radiotherapy for squamous cell..., Caudell [/bib_ref] [bib_ref] Esophageal stricture after radiotherapy in patients with head and neck cancer: experience..., Ahlberg [/bib_ref] [bib_ref] Factors affecting the success of endoscopic bougia dilatation of radiation-induced esophageal stricture, Tuna [/bib_ref] [bib_ref] Factors associated with long-term dysphagia after definitive radiotherapy for locally advanced head-and-neck..., Caudell [/bib_ref] Furthermore, radiotherapy with concurrent chemotherapy increases the likelihood of stricture and is a cause of completely obstructed oesophagus,. Prior insertion of a gastrostomy should be considered to aid nutrition in already malnourished individuals and this offers an additional conduit through which dilatation attempts of subsequent oesophageal strictures can be made. Where antegrade passage of a guidewire is unsuccessful, a retrograde attempt through the gastrostoma can be made using catheter and guidewire under fluoroscopic control.
The endoscopic CARD approach can be considered in patients with a completely occluded oesophagus. In most circumstances, this requires a general anaesthetic, although conscious sedation has also been used. A CT scan is also recommended to exclude nearby vessels. [bib_ref] Efficacy of the endoscopic rendez-vous technique for the reconstruction of complete esophageal..., Gonzalez [/bib_ref] Visualisation of the proximal aspect of the stricture is undertaken by insertion of an antegrade endoscope. A second endoscope is inserted through the gastrostomy site and the stricture is trans-illuminated in order to identify the now obstructed lumen. Typically, a guidewire is passed from the distal oesophagus proximally under fluoroscopic guidance, puncturing through the stricture and then removed per-orally. [bib_ref] Success of endoscopic pharyngoesophageal dilation after head and neck cancer treatment, Chapuy [/bib_ref] [bib_ref] Efficacy of the endoscopic rendez-vous technique for the reconstruction of complete esophageal..., Gonzalez [/bib_ref] or EUS fine aspiration needle [bib_ref] Efficacy of the endoscopic rendez-vous technique for the reconstruction of complete esophageal..., Gonzalez [/bib_ref] has also been shown to be effective at traversing the stricture by incision. Biplanar fluoroscopy or cone-beam CT may be used to facilitate an axial alignment of the endoscopes and needles and reduce the risk of perforation. Once a guidewire has been passed a bougie or balloon can dilate to 12-15 mm. 219-221 223 In some patients, the placement of a temporary (up to 1 month) fully covered SEMS is necessary to maintain the luminal patency with or without a nasogastric tube for feedig. [bib_ref] Efficacy of the endoscopic rendez-vous technique for the reconstruction of complete esophageal..., Gonzalez [/bib_ref] No large studies have been undertaken to evaluate the use of the CARD procedure, and it should be regarded as a last resort for use in expert hands only. Evidence from case series suggests it is safe, with no patients requiring emergency surgical intervention. [bib_ref] Efficacy of the endoscopic rendez-vous technique for the reconstruction of complete esophageal..., Gonzalez [/bib_ref] The majority of larger series suggest good success (defined as discontinuation of percutaneous endoscopic gastrostomy feeding), although in most instances, repeated dilatation is still required every 2-3 months. [bib_ref] Endoscopic management of radiation-induced complete upper esophageal obstruction with an antegrade-retrograde rendezvous..., Maple [/bib_ref] 

## Caustic strictures
Oesophageal injury can be caused by ingestion of caustic substances. Alkalis are the the most common caustic agents ingested in Western countries, while acid ingestion is more common in developing countries, such as India. Caustic oesophageal injury can lead to the lower oesophageal sphincter pressure becoming impaired, which in turn leads to gastro-oesophageal reflux that can worsen stricture formation. After initial radiological assessment, an upper gastrointestinal tract endoscopy, with gentle air insufflations or preferably with CO 2 , should be considered after caustic ingestion within the first 12-48 hours to determine prognosis and management, including oesophageal stricture formation and subsequent requirement for dilatation. [bib_ref] The role of fiberoptic endoscopy in the management of corrosive ingestion and..., Zargar [/bib_ref] Contraindications to endoscopy include radiological suspicion of perforation or burns to the supraglottic and epiglottic areas. A CT grading system for caustic lesions has been proposed, but there is insufficient evidence to demonstrate its widespread utility. [bib_ref] Caustic injury: can CT grading system enable prediction of esophageal stricture?, Ryu [/bib_ref] antibiotics, mitomycin C and intraluminal stents, [bib_ref] Prevention of stricture with intraluminal stenting through laparotomy after corrosive esophageal burns, Wang [/bib_ref] but there is limited evidence on outcomes.
Late management makes dilatation more complex owing to fibrosis in the oesophageal wall. Dilatation can be carried out with either bougie or balloon dilators. There is no clear advantage of one technique over another. The Savary-Gilliard type was used in the majority of studies reporting on efficacy of bougie dilatation and is preferred by some practitioners in consolidated and fibrotic strictures.  Ensure timely management of oesophageal strictures with dilatation as this plays a key role in affecting patient Guidelines outcomes 242-246 (GRADE of evidence: moderate; strength of recommendation: strong). Dilatation is more hazardous between 1 and 3 weeks after injury and some avoid this time interval. From approximately week 3, scar retraction begins, resulting in stricture formation. The time interval between dilatations varies in published reports but should be less than 2-3 weeks. The number of sessions required to achieve the desired outcome varies; usually three or four are required but the number can be significantly higher.
The perforation rate for caustic strictures is higher than the standard benign oesophageal stricture dilatation rate with anything from 0.4% up to 32% recorded in the literature. The complication rate is lower when performed by those with more experience, and reported to be 4.5%.  Consider avoiding dilatation within 3 weeks of initial caustic ingestion (GRADE of evidence: low; strength of recommendation: weak).  Consider a time interval between dilatations of <2 weeks (GRADE of evidence: very low; strength of recommendation: weak). Refractory strictures are more common in caustic ingestion. Management has been reported with intralesional steroid injection or topical mitomycin C at the time of dilatation, temporary stent placement, biodegradable stents and a suspended oesophageal silicone prosthesis. If oesophageal dilatation fails then surgical resection can be considered. There is no consensus for the optimum management of these strictures. 

## Refractory strictures
A stricture should be considered refractory after an inability to maintain a luminal diameter of 14 mm after five sequential dilatation sessions 1-2 weeks apart or maintain the target diameter for 4 weeks once it has been reached. [bib_ref] The refractory and the recurrent esophageal stricture: a definition, Kochman [/bib_ref] Refractory strictures are rare and challenging. Before embarking on any particular management the clinician and patient should be aware of the poor level of data for the outcomes and risks of most techniques.  Inform patients about the lack of good quality evidence for best approach to treatment of refractory strictures (GRADE of evidence: low; strength of recommendation: strong).  Consider discussion with, and/or referral to, centres with expertise in treatment and follow-up of patients with refractory strictures (GRADE of evidence: low; strength of recommendation: weak).  Ensure optimal management of ongoing inflammation with high dose PPI therapy before defining a stricture as refractory [bib_ref] Oesophageal acid-peptic strictures in the histamine H2 receptor antagonist and proton pump..., Nayyar [/bib_ref] 

## Intralesional steroid therapy
Intralesional steroid therapy involves the injection of 0.5 mL aliquots of 40 mg/mL triamcinolone to all four quadrants of the stricture. Experts advocate predilatation, although there are no studies directly comparing this with postdilatation injection. Two randomised controlled trials in patients with refractory strictures of mixed, but mostly peptic, aetiology, have demonstrated benefit, with reduction in the number of repeat dilatations and an increase in the dysphagia-free period. Results have been disappointing for refractory strictures of other aetiologies, with randomised controlled trials failing to show improvement in anastomotic [bib_ref] Endoscopic corticosteroid injections do not reduce dysphagia after endoscopic dilation therapy in..., Hirdes [/bib_ref] and causticaetiologies. In addition, an increase in complications was seen in the steroid-treated patients. [bib_ref] Endoscopic corticosteroid injections do not reduce dysphagia after endoscopic dilation therapy in..., Hirdes [/bib_ref]  Use intralesional steroid therapy combined with dilatation in refractory strictures with evidence of inflammation (macro-or microscopically) on the assumption that anti-reflux therapy has been maximised previously with no benefit (GRADE of evidence: high; strength of recommendation: strong).

## Incisional therapy
Use of a needle or IT knife to perform radial incisions of refractory strictures parallel to the longitudinal axis of the oesophagus has been evaluated. The procedure is performed under direct visualisation with or without a transparent cap. For circumferential strictures, incisions in the four quadrants may be most effective. The outcomes are best for short strictures (<1.5 cm). [bib_ref] Electrocautery therapy for refractory anastomotic strictures of the esophagus, Hordijk [/bib_ref] Longer strictures may initially respond, but most will require re-treatment. [bib_ref] Radial incision and cutting method for refractory stricture after nonsurgical treatment of..., Yano [/bib_ref]  Consider incisional therapy in patients with refractory Schatzki's rings and anastomotic strictures at centres experienced in the use of such techniques (GRADE of evidence: very low; strength of recommendation: weak).

## Stents
The benefit of self-expanding removable stents has been demonstrated in a recent systematic review and meta-analysis, with complete relief of dysphagia in approximately 40% (median follow-up 0-1281 days over the 18 included studies). [bib_ref] Clinical outcomes following stent placement in refractory benign esophageal stricture: a systematic..., Fuccio [/bib_ref] The majority of refractory strictures will respond to placement of between 4 and 8 weeks, although longer periods of up to 3 months may be required. [bib_ref] Clinical outcomes following stent placement in refractory benign esophageal stricture: a systematic..., Fuccio [/bib_ref] It is recommended that stents should not be left in longer than this owing to the risk of embedding.
Recurrence rates of refractory strictures remain as high as 69% after stent removal, particularly in patients with long strictures (>7 cm), [bib_ref] Temporary metallic stent placement in the treatment of refractory benign esophageal strictures:..., Kim [/bib_ref] illustrating the difficulties in achieving a satisfactory long-term outcome.
In trials directly comparing metal and plastic stents, outcomes were more favourable with metal stents, with lower migration rates and need for re-intervention. Stent migration is a considerable problem with both stent types, occurring in approximately 30% of cases. [bib_ref] Clinical outcomes following stent placement in refractory benign esophageal stricture: a systematic..., Fuccio [/bib_ref] Stent placement is associated with adverse events (chest pain, bleeding, perforation, aspiration pneumonia) in 20% and thus patients should give consent accordingly. [bib_ref] Clinical outcomes following stent placement in refractory benign esophageal stricture: a systematic..., Fuccio [/bib_ref] Use of partially or uncovered metal stents must be avoided owing to risk of embedding of the stent in the oesophageal wall, which may preclude safe removal.  Offer temporary placement of fully covered self-expanding removable stents in patients where previous methods have been unsuccessful in maintaining adequate oesophageal patency [bib_ref] Clinical outcomes following stent placement in refractory benign esophageal stricture: a systematic..., Fuccio [/bib_ref] [bib_ref] Temporary metallic stent placement in the treatment of refractory benign esophageal strictures:..., Kim [/bib_ref] [bib_ref] A comparison of the temporary placement of 3 different self-expanding stents for..., Canena [/bib_ref] [bib_ref] Removable esophageal stents have poor efficacy for the treatment of refractory benign..., Dan [/bib_ref] [bib_ref] Esophageal stents for benign refractory strictures: a meta-analysis, Thomas [/bib_ref] [bib_ref] Use of a fully covered self-expandable metal stent for the treatment of..., Bakken [/bib_ref] [bib_ref] Success and complications associated with placement of fully covered removable self-expandable metal..., Eloubeidi [/bib_ref] (GRADE of evidence: low; strength of recommendation: weak).  The optimum duration of stent placement is usually between 4 and 8 weeks, but may vary depending on stricture aetiology and length, and type of stent 264 (GRADE of evidence: very low; strength of recommendation: weak). Single biodegradable stent placement appears to be only temporarily effective in the majority of patients with refractory benign oesophageal stricture. It can, however, reduce the frequency of serial dilatation in selected patients. In the largest study to date, sequential placement of a first, second and then third biodegradable stent resulted in a median dysphagia free period of 90, 55 and 106 days, respectively. [bib_ref] Single and sequential biodegradable stent placement for refractory benign esophageal strictures: a..., Hirdes [/bib_ref] No patients were dysphagia free at the end of the study, suggesting that this strategy is not effective for long-term dysphagia relief.  Consider biodegradable stent placement to reduce the frequency of dilatation in selected cases (GRADE of evidence: low; strength of recommendation: weak).

## Options for failed stricture resolution
Self-dilatation is safe and effective for short, proximal strictures. [bib_ref] Home self-dilatation for esophageal strictures, Zehetner [/bib_ref] [bib_ref] Self-dilation for refractory oesophageal strictures: an Auckland City Hospital study, Wong [/bib_ref] [bib_ref] Self dilation as a treatment for resistant benign esophageal strictures: outcome, technique,..., Dzeletovic [/bib_ref] For appropriate, well-trained patients willing to undertake this, it appears to be well tolerated, can prevent surgery and the burden of repeated hospital visits. [bib_ref] Home self-dilatation for esophageal strictures, Zehetner [/bib_ref] 

## Economic implications
Oesophageal stricturing has a significant impact on quality of life owing to both dysphagia symptoms and the need for repeated dilatation. Quality of life scores are often further affected by underlying diagnosis, such as head and neck cancer. No studies have investigated the cost-effectiveness of dilatation, but it is generally appreciated that bougienage has better economic benefits than balloon dilatation. This is owing to the absence of symptomatic or endoscopic difference between the two modalities in addition to the non-significant difference in the need for repeated treatments. Hence the consumable costs of disposing of and replacing TTS balloons outweigh those of reusable Savary bougies. Furthermore, extrapolation from studies in the lower GI tract comparing balloon versus bougienage in the management of postoperative anastomotic strictures has shown similar findings (median cost 680 vs 22.30; P<0.001). [bib_ref] Comparative study of balloon and metal olive dilators for endoscopic management of..., Xinopoulos [/bib_ref] These considerations obviously require to be balanced with expertise, local availability and endoscopist preference, for example, to allow direct visualisation during the dilatation procedure.
Use of oesophageal stenting is outside the remit of these guidelines, but it may also be considered in cases where repeated dilatation is required and can be considered to add cost-effectiveness when two or more dilatations are avoided. [bib_ref] The use of self-expanding silicone stents in esophagectomy strictures: less cost and..., Martin [/bib_ref] There are no other special economic effects of these guidelines, as they are a formalisation of current practice with the evidence base, and we do not advocate any changes or new directions in care that have a major economic impact.

## Audit of effectiveness
Items that could be subject to audit to establish good clinical standards of oesophageal dilatation include:  Completeness of consent forms with clear documentation in each section (including procedure risks and benefits).

## Box 1 considerations in specific disease areas
Achalasia:  Use pneumatic balloons 30-40 mm in diameter  Start at 30 mm in the first session to reduce the risk of complications  Perform a second dilatation 2-28 days later with a larger balloon (usually 35 mm)  Consider PPI therapy after dilatation Peptic strictures:  PPI therapy long term  No role for H2 receptor antagonists schatzki's ring:  Asymptomatic=no dilatation  Symptomatic=single session (aim for 16-20 mm diameter)  Exclude eosinophilic oesophagitis  Consider PPI  Consider needle knife incision if dilatation not effective Post-endotherapy:  Perforation risk may be higher (around 1.1%)  Consider steroid injection to reduce risk of stricture formation  Offer PPI to reduce risk of recurrence eosinophilic oesophagitis:  Consider additional treatments (PPI, steroids, elimination diet)  Aim for histological remission  Consider dilatation in narrow calibre oesophagus or failure of medical treatment in the absence of a visible stricture  Inform patients that chest pain is common Postoperative:  Post-fundoplication: -Assess wrap integrity with upper endoscopy, barium swallow, manometry and pH impedance -Use pneumatic balloon 30-40 mm as for achalasia  Anastomotic: -Consider concomitant steroid injection in four quadrants -Consider needle knife incision as an alternative to dilatation Post-radiation:  Consider CARD in completely obstructed oesophagus caustic:  Careful evaluation as usually complex  Dilatation not advised in first 3 weeks after ingestion refractory:  Ensure optimal dose PPI and control of inflammation  Consider: -Discussion with expert centres -Alternative causes/underlying pathology -Concomitant steroid injection four quadrants -Needle knife incision -Fully covered SEMS as temporary measure 4-8 weeks  Offer patient the option of self-dilatation CARD, combined anterograde retrograde dilatation; PPI, proton pump inhibitor; SEMS, self-expanding metal stent.

## Guidelines
 Success rate, comfort scores, re-intervention rate (number of dilatations per patient), complication rates, 30-day readmission rates and 30-day mortality rates. 27  Using a standard scoring system for dysphagia (such as Ogilvie, in >90% of patients to provide an objective measure of the efficacy of the therapeutic intervention. 27  Timeliness of follow-up serial sessions for endoscopic dilatation (within 2 weeks). 33 59  Perforation rates. The overall perforation rate following dilatation should be <1% for benign strictures 27 and 1-2% for achalasia. AreAs for future reseArch  Identification of the learning curve, assessment parameters required and direct observation of procedure or skills design for formative and summative assessments for trainees undertaking dilatation.  The number of dilatation procedures performed each year required to achieve competency and maintain skill.  Direct cost-effectiveness comparison between balloon and bougie dilators.  Assessment of the optimal interval between repeat dilatations for tight, complex or refractory strictures.  Available data on the role of acid suppression, proton pump inhibition, elimination diet and steroids in EoE are limited by variation in clinical practice and reported outcomes. Randomised controlled trials are needed to identify the optimum treatment to prevent oesophageal strictures in EoE.  Clarification of the role of steroids and other methods in reducing the incidence and severity of post-ER strictures.
There is an ongoing phase III clinical trial comparing oral steroid versus local steroid injection therapy for the prevention of oesophageal stricture after ESD. 277  Research into the true incidence of refractory strictures with details of aetiology and comparative outcomes after different treatments.
[fig] : Perform dilatation with pneumatic balloons 30-40 mm in diameter starting at 30 mm in the first session to reduce the risk of complications 5 19 61 (GRADE of evidence: high; strength of recommendation: strong). The dilatation technique varies across different studies and there is no consensus in the literature on the optimal method of performing pneumatic dilatation for achalasia. The balloon is usually positioned at the oesophagogastric junction and inflated according to the manufacturers' instructions for 1-3 min. Perform a second dilatation session 2-28 days later with a larger size balloon of 35 mm 5 (GRADE of evidence: high; strength of recommendation: strong). Most authors advocate a third session either routinely or in cases where symptoms remain (Eckardt score >3) with the cautious use of 40 mm balloon if possible. [/fig]
[fig] figure 1: Stricture dilatation procedure checklist. [/fig]
[table] table 1: An overview of the GRADE system278 [/table]
[table] 25: 26 (GRADE of evidence: moderate; strength of recommendation: strong). The specific number of dilatation procedures required each year to maintain the operator's skills remains unknown. It is good practice for independent operators to audit their outcomes and be regularly involved in the care of patients with upper GI disorder. Professional bodies such as Joint Advisory Group on Gastrointestinal Endoscopy (JAG) may define the suitable number of procedures for training and maintenance of practice standards.  Ensure that trainees performing dilatation have adequate knowledge and understanding of the indications for, contraindications to, and complications of, this therapeutic procedure. An understanding of the steps for recognition and management of complications is required. Trainees should be familiar with different dilatation techniques as well as alternative and complementary treatment options 27 (GRADE of evidence: moderate; strength of recommendation: strong). It is estimated that less experienced endoscopists (who have performed fewer than 500 diagnostic upper endoscopy [/table]
[table] 212: 219 222-224 A needle knife,225 straight catheter [/table]
[table] 219: 223  Consider a combined anterograde and retrograde dilatation (CARD) or rendezvous approach under general anaesthetic as an alternative to surgery in the treatment of the completely obstructed oesophagus, where local expertise is available209 212 218 219 221 222 225-228 (GRADE of evidence: moderate; strength of recommendation: weak).  Use fluoroscopic guidance to assist with the rendezvous procedure 209 212 218 219 221 222 225-227 (GRADE of evidence: moderate; strength of recommendation: strong).  Use a guidewire to navigate through the obstruction when using the CARD approach to re-establish luminal patency 209 212 219 222 225 (GRADE of evidence: low; strength of recommendation: strong).  After gaining luminal patency using the CARD procedure, perform subsequent dilatation using either balloon 224 226 229 or bougie 212 219-221 228 (GRADE of evidence: moderate; strength of recommendation: strong). [/table]
[table] 84: 89 92 (GRADE of evidence: high; strength of recommendation: strong).  Consider alternative neuromuscular causes in patients with ongoing dysphagia despite a seemingly adequate oesophageal diameter 126 (GRADE of evidence: low; strength of recommendation: strong). Complex strictures (>2 cm, angulated, irregular, severely narrowed) of the following aetiologies are most often implicated in refractory strictures: anastomotic, radiation induced, caustic, post-ablative therapy. 33 Method of dilatation No trials have compared types of dilators for refractory strictures.  Use fluoroscopic guidance during dilatation of refractory oesophageal strictures 126 (GRADE of evidence: very low; strength of recommendation: weak).  Use either bougie or balloon dilators with the decision individualised on a case by case basis dependent on the nature [/table]