The goal of this study is to find out if using the BougieCap device is a safe and effective way to stretch narrow areas in the esophagus (food pipe) in children. The main questions this study wants to answer are:

• Does the BougieCap work well to treat narrow areas in the esophagus comparing with other methods to widen these narrow areas?
• Is BougieCap easy to use and does it cause fewer problems or discomfort for children?

Researchers will compare two groups: one using the BougieCap, and the other using traditional methods like balloon dilation, to see which one works better and is safer.

Participants will:

• Answer questions about their symptoms before treatment, 24 hours after, and 14 days later.
• Complete these questions during regular hospital visits or over the phone for the final check-up.

This study does not involve any extra risks or burdens for the participants.

There are two categories of esophageal stricture in children: acquired and congenital. The development of benign esophageal stricture is based on significant fibromuscular alterations, inflammation in residual muscle layers and a deposition of collagen based on an inflammatory process . In children, these changes are most common in the context of a postoperative anastomotic stenosis in the case of esophageal atresia (usually type IIIb according to Vogt), as well as after caustic injury, peptic stricture and eosinophilic esophagitis. Rarely, children are born with congenital esophageal stricture. Therapeutic radiation can lead to stenoses requiring dilation. Likewise, children suffering from epidermolysis bullosa can suffer from esophageal stenosis. In rare cases, the ingestion of a foreign body in children causes symptomatic stenosis as a buried foreign body covered by esophageal hyper granulated tissue. Malignant stenosis is not considered in this study, as its treatment is different.

There are different options for endoscopic esophageal dilations of clinically relevant esophageal strictures, which promise effective treatment. Relevant strictures are usually noticed by dysphagia.

One possible dilation method uses the Savary-Gilliard bougies. These are wire-guided polyvinyl dilators. The advancement of the wire is performed under radiological fluoroscopy. Once the guide wire is placed into the stomach, the dilator is passed over the guidewire, lubricated, and pushed over the stenosis in order to dilate the stenotic area. There are also non-guidewire bougie dilators. Longitudinal shearing force and radial force occurs when the dilator passes across the stenotic area. Initially, the size of the dilator that corresponds to the diameter of the stenosis is used. The same procedure is then followed stepwise with a larger dilator of 1mm, respectively. It is generally recommended not to increase the dilator size more than 3mm in a single session.

A major disadvantage of this method is the exclusively tactile control of the dilation. At the end of the Bougie dilation, the result should be checked by reinserting the endoscope to rule out deeper mucosal injuries and persistent bleeding.

Furthermore, there is experience in the treatment of esophageal stenosis in children with balloon dilations. The balloon is inserted either blind or under endoscopic control, The balloon is then mostly inflated to 1 mm beyond the estimated stenosis diameter and the pressure is maintained for 1 minute or less. The dilation may be controlled radiologically or endoscopically. A dilation up to 5mm above the initial stricture diameter may not increase the risk of perforation. Only radial forces arise. Here, too, insufficient visual control is to be criticized. In particular, the distal area of the stenosis cannot be viewed during the procedure, or only with difficulty. In addition to the poor visual control, there is no tactile control of the dilation, since the volume of liquid applied to the balloon determines the diameter. Furthermore, there is no standard protocol for the stepwise dilation that is required for treating children at different ages. Finally, small esophageal balloons specifically for small children are missing, which is why balloon catheters from other areas and indications are used (e.g. urological balloon catheters, biliary catheters), respectively.

Due to the severely restricted visual control of the dilation with the current dilation techniques, a conical cap made of transparent plastic was developed that can be attached to the tip of standard endoscopes, the BougieCap (Ovesco, Tübingen). The cap is a single-use product, available in different outer diameters (7- 16mm) and offers direct visual and tactile control upon introduction into the upper gastrointestinal tract under visual and tactile control. The advantage of this technique is that the endoscope acts as a carrier of the radial and longitudinal force vectors for the dilation. A comparable technique is one with the optical dilator, a clear, over-the-scope bougie with sequential dilating segments. However, the limitation of this optical dilator is that it can only be used for the dilation of relatively large stenoses (from 15mm) due to the large diameter. A main reason why the optical dilator is not suitable for children.

There are currently no studies in the literature investigating the use of the BougieCap technique for treating benign esophageal strictures in children.

The aim of this randomized controlled pilot study is to demonstrate the probable efficacy of the BougieCap technique, the improvement of patient and operator dependent conditions and the absence or reduction of related adverse events such as perforations, bleeding, infections as well as the number of dilation sessions and intervals, compared to the above mentioned other techniques.

The BougieCap is an endoscopic attachment cap for bougienage/dilatation of stenoses and strictures of the upper gastrointestinal tract. No specific restrictions based on age, weight, health status or ethnicity. The decision on whether a patient is eligible for treatment with the product lies solely with the intended user. The BougieCap Ovesco is a medical device primarily composed of the cap and the adhesive tape that may come into contact with tissues (mainly Oesophagus mucosa) or bodily fluids (salive) during its application. As per regulatory standards, it's crucial to note that this device does not contain pharmaceuticals, human or animal tissues, their derivatives, or any other biologically active substances.

Inclusion Criteria:

• Age under 18 years of age
• Indication for endoscopic esophageal dilation
• Benign stenosis
• Written Informed Consent signed by the subject and/or parent/legal representative (if applicable)

Exclusion Criteria:

• Stenosis that cannot be treated endoscopically
• Malignant esophageal strictures
• Contraindications and limitations of the MD as described in the instructions for use