Benign Esophageal Strictures

Introduction

In this chapter, we describe the evaluation, treatment, and subsequent long-term management for patients with benign esophageal strictures.

Patients with clinically significant esophageal strictures present with symptoms of dysphagia, typically first to solid foods. Symptoms may then progress in frequency and severity and some patients may develop dysphagia to liquids. Patients often modify their diets to avoid foods that lead to symptoms, and a thorough history is required to parse out the true severity of their symptoms. In the past, the most common etiology for esophageal strictures were peptic causes: however, the widespread use of proton pump inhibitor (PPI) therapy has markedly reduced the incidence of this etiology. Anastomotic and radiation-induced strictures are now the most common encountered overall, but the incidence of eosinophilic esophagitis associated strictures is increasing and being recognized more frequently in all age groups.

Initial Evaluation

The diagnosis of an esophageal stricture, both benign and malignant, commences with a clinical suspicion based on symptoms of esophageal dysphagia and is supported by elucidating a history of a known risk factor ( Box 21.1 ). The maximal inner diameter of an esophageal stricture that will typically result in symptoms of dysphagia is 13 mm. Use of a validated dysphagia score allows for an objective measurement of symptoms and may be used to gauge response to treatment and inform research studies ( Table 21.1 ).

When an esophageal stricture is suspected as the etiology of the dysphagia, the initial evaluation may begin with either a contrast esophagram or an upper endoscopy. In cases of mild, intermittent symptoms of dysphagia to certain foods (dysphagia score of 1 or less), most gastroenterologists will proceed to endoscopy, as this pathway allows for both diagnosis and treatment with one procedure. In the presence of more significant dysphagia to most solid food (dysphagia score of 2 or above) or indeterminate symptoms, a barium swallow with optional 12.7 mm barium tablet should be considered, as it may provide additional information regarding the location, likely severity, and characteristics of the stricture. Knowledge of stricture characteristics is helpful when planning for the therapeutic endoscopic procedure, including appropriate endoscope selection (standard versus pediatric endoscope or bronchoscope) and assessing the potential need for fluoroscopy and adjunctive endoscopic accessories. For example, if the luminal diameter is less than 10 mm, but greater than 6 mm, a pediatric endoscope (5.9 mm) may be more likely to traverse the stricture endoscopically and would be advantageous to have on hand at the start of the procedure. Likewise, for narrower or more complex (long, angulated, or irregular) strictures, fluoroscopy may be required and preprocedure arrangements completed beforehand. An esophagram may also provide information on gross esophageal dysmotility, findings suggestive of achalasia, or the presence of proximal lesions such as esophageal bars or diverticuli that may be difficult to definitively visualize during endoscopy.

Strictures are typically classified as simple or complex. Simple strictures are focal (< 2 cm), straight, and easily traversed by an endoscope. These strictures are typically easily treated with standard dilation techniques. Examples include Schatzki rings ( Fig. 21.1 ), esophageal webs ( Fig. 21.2 ), and some reflux-induced strictures ( Fig. 21.3 ). Complex strictures are defined as angulated, multiple, or longer (> 2 cm), and typically cannot be traversed with a standard endoscope. Examples of typical complex strictures include those that may be the result of surgical anastomosis ( Fig. 21.4 ), radiation therapy ( Fig. 21.5 ), caustic ingestion ( Fig. 21.6 ), ablative therapy, or neoplasm.

Treatment of esophageal inflammation with a PPI is recommended as inflammation may contribute to symptoms of dysphagia just as much as luminal strictures. The main etiologies of inflammation in the esophagus are reflux, ischemia from prior surgery, caustic ingestion, and radiation-induced injury. If the stricture is due to inflammation from reflux, acid suppression is essential to promote a durable response to dilation and to prevent stricture recurrence. If a patient has persistent dysphagia despite normal upper endoscopy and a trial of PPIs, a dedicated esophagram with a barium tablet should be obtained to rule out a subtle luminal narrowing that may have been missed on endoscopy, and/or esophageal manometry to assess for motility disorders including achalasia. Moreover, extrinsic compression of the esophagus by mediastinal tumors, lymph nodes, or vascular structures may lead to dysphagia and may be more easily diagnosed by contrast esophagram than by upper endoscopy. Symptoms due to extrinsic compression are not typically amenable to long-term remediation by endoscopic dilation and may require endoprosthetic placement.

In some cases, history alone can be strongly suggestive of both the presence and etiology of an esophageal stricture, such as those patients with a prior history of caustic injury, radiation therapy, esophagectomy, or onset of symptoms following endoscopic therapy for Barrett's esophagus or squamous dysplasia. If symptoms arise within the early postoperative period following esophagectomy, anastomotic narrowing may be related to inflammation that will resolve with time or, alternatively, may be due to early ischemia that would carry significant risk for wound dehiscence if aggressively dilated.

Preprocedure Planning

Preparation prior to upper endoscopy with the potential for dilation includes anticoagulation management, obtaining informed consent, sedation planning, selection of the equipment anticipated to be utilized, and determination of the appropriate venue for the procedure.

The American Society for Gastrointestinal Endoscopy (ASGE) recommendations on the management of antithrombotic agents for patients undergoing gastrointestinal (GI) endoscopic procedures rate the risk of bleeding related to dilation of benign esophageal strictures as low. Despite the overall low risk of bleeding, the safety of dilation on anticoagulants remains unknown. Given the potential for bleeding at sites that are relatively difficult to access postdilation, dilation is categorized as a higher risk procedure as far as the use of antithrombotic agents. It is recommended that, when possible, anticoagulants and antiplatelet agents be held for sufficient time to allow for their effects to dissipate prior to dilation.

The 2015 ASGE Standards of Practice committee guideline on the use of prophylactic antibiotics for GI endoscopy does not recommend use of antibiotics prior to esophageal dilation. Patients with vascular anomalies such as a prosthetic heart valve, history of endocarditis, or congenital defect repairs in the absence of prior vascular infection, do not require antibiotics. Despite esophageal dilation having a high rate of transient bacteremia (12% to 22%) in several prospective trials, the degree and duration of the transient bacteremia associated does not differ significantly from that resulting from routine activities such as brushing one's teeth.

For most simple strictures, a standard upper endoscope without fluoroscopy is sufficient for a safe and successful dilation. For those patients with suspected complex esophageal strictures or high dysphagia scores (dysphagia score of 2 or above), having additional equipment available prior to the start of the procedure is recommended. Useful adjunctive equipment includes pediatric endoscope, bronchoscope, fluoroscopy, endoscopic retrograde cholangiopancreatography (ERCP) guidewires, and ERCP catheters for contrast injection. Whereas through-the-scope dilation balloons will not fit through the accessory channel of pediatric endoscopes, standard stainless-steel guidewires with flexible tips used for Savary wire-guided bougie dilation will pass.

In general, endotracheal intubation is not necessary prior to esophageal dilation. However, in the case of complete obstruction with a history raising the possibility of retained food or fluid in the esophagus, endotracheal intubation may be prudent. Most patients with simple strictures can be safely dilated in the ambulatory setting.

Risks/Adverse Events

The overall rate of adverse events of esophageal dilation is estimated to be between 0.1% and 0.4%. Perforation and bleeding are the most common adverse events with lower incidences for pain, aspiration, and infection.

Risk factors for adverse events related to dilation include the presence of a complex stricture, prior radiation therapy, caustic ingestion, esophageal pseudodiverticulum, and possibly chronic steroid use and surgically altered anatomy. Although there was initially concern for an increased risk for perforation in patients with eosinophilic esophagitis (EoE), more recent data (2010) does not appear to support this. Despite the absence of an increased risk of perforation in patients with EoE, the risk of postdilation pain is greater in these patients and the patient and physician should be aware of this.

Likely risk factors for clinically significant bleeding following dilation are radiation induced strictures and complex strictures. Most mucosal tears will stop bleeding spontaneously; however, if significant bleeding requiring transfusion is observed or suspected after the procedure, a repeat endoscopy to evaluate for utility of endoscopic therapy should be considered. Bleeding following dilation of complex strictures that cannot be traversed with an adult endoscope may be more challenging, or even impossible to treat endoscopically due to lack of access to the bleeding site. Pediatric endoscopes may be useful in this setting to assess and treat. Some patients may have a gastrostomy that would make retrograde endoscopy another potential approach for hemostasis.

Although a full discussion of the management of dilation-related esophageal perforation is beyond the scope of this chapter, it is critical to be aware of the signs of, and initial evaluation of, a suspected perforation. Early recognition and steps to avoid gross mediastinal contamination are of paramount importance and vital to reducing the risk of death. In 390 patients with acute esophageal perforation, when comparing the mortality rate of those who received care either within 24 hours or those treated after 24 hours, it was demonstrated that the mortality rate was twice as high (27% vs. 14%) in those treated after 24 hours. Perforations may occur in the cervical, intrathoracic, or subdiaphragmatic regions following dilation. Clinical manifestations of perforation include pain in the neck, ear, chest, or abdomen, odynophagia, dysphagia, fever, tachycardia, and the finding of subcutaneous emphysema. Lack of any of these signs and symptoms does not definitely exclude perforation; clinical suspicion plays an important role to lead to further investigation and early diagnosis ( Fig. 21.7 ).

If there is any question of perforation, the patient should be kept NPO until either the pain subsides or studies are done to exclude perforation and the concern for perforation is resolved. Broad-spectrum antibiotics should be instituted and a nasogastric (NG) tube placed for decompression of the stomach to minimize reflux of contents into any potential esophageal defect. The NG tube may require additional modalities (e.g., fluoroscopy) to ensure that it is intragastric and not exiting through a potential site of perforation. Although a chest x-ray is frequently the initial test ordered when there is concern for perforation, extraluminal air alone is not associated with significant morbidity, except in cases of significant pneumothorax. The major concern is leakage of fluid and particulate matter into the mediastinum. Assuming the perforation was not directly visualized during the endoscopy, the initial study should be a water-soluble esophagram to evaluate for extravasation of contrast into the mediastinum. If demonstrating a leak, a computed tomography scan should be considered to evaluate for fluid collections that may require separate drainage; a surgical consultation should be obtained.

Often mature anastomotic strictures or those resulting from radiation are fibrotic, and tissue planes are obliterated such that free uncontained perforations are less common even in the setting of a significant esophageal wall defect. Contained perforations ( Fig. 21.8 ) can often be managed conservatively; surgical teams should be consulted to assist as patients with esophageal perforation may become septic and unstable early in the course.

Attempts at closure of the esophageal defect with hemoclips or an over-the-scope (OTS) clip can be considered and is more likely to be successful when the perforation is within the chest and not at or extending across the gastroesophageal (GE) junction. If the stricture is relatively fibrotic, closure with clips can be challenging due to a lack of flexibility of the esophageal wall. If an OTS clip is used, one should use caution not to compromise the lumen of the esophagus, which would effectively make matters significantly worse. Endoscopic treatment options also include bridging the defect with a fully covered, self-expanding stent. Esophageal stents have been shown to be relatively effective in managing esophageal perforations in several case series and prospective studies ; however, the Practice Parameters Committee of the American College of Gastroenterology felt the quality of evidence to be low and strength of recommendation for their use weak. If endoscopic closure is attempted, efforts to close the leak to limit mediastinal contamination should be performed expeditiously. An esophagram to ensure effective diversion around the defect following stent placement should be obtained. Fully covered stents have a relatively high rate of migration and a chest x-ray may be obtained to ensure lack of migration for the first few days or if concern for displacement occurs. Repeat endoscopy to remove the covered stent in 4 to 6 weeks should again be typically followed by an esophagram to ensure remediation of the defect.

Initial Inspection

Relative contraindications to dilation include recent esophageal perforation and malignant appearing strictures. If, upon initial inspection of an esophageal stricture, an underlying malignancy or infectious etiology is suspected, the lesion should be biopsied prior to aggressive therapeutic intervention. Tissue sampling should also be considered if there are findings consistent with eosinophilic esophagitis, concurrent inflammation, or ischemia. As biopsies are almost always mucosal with very rare exception, biopsy prior to dilation is considered safe.

Types of Dilators

There are three primary types of dilators used for esophageal dilation: (1) metal filled rubber bougies with either a blunt (Hurst) or tapered tip (Maloney) used without a guidewire, (2) polyvinyl wire-guided bougies, and (3) through-the-scope (TTS) balloon dilators. With the exception of the indication of patient self-dilation, liquid metal filled bougies have been largely supplanted by wire-guided and balloon dilators. Wire-guided bougies range in size from 5 mm to 20 mm (15 Fr to 60 Fr) and dilation balloons are available in a comparable range of sizes ( Table 21.2 ).