Written and maintained by CASRAI Editorial Board
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General product information for laboratory, clinic and supply staff. It is not medical advice and does not describe how any procedure is performed.
Short answer
Esophageal dilators fall into two families: push (bougie) dilators, which are weighted or wire-guided, and through-the-scope (TTS) balloon dilators, which are inflated with liquid. CRE is a Boston Scientific TTS balloon line named in published guidance.
Definition and scope
Under 21 CFR 876.5365, an esophageal dilator is a device that consists of a cylindrical instrument that may be hollow and weighted with mercury, or a metal olive-shaped weight that slides on a guide such as a string or wire, and is used to dilate a stricture of the esophagus. The regulation says the generic type includes esophageal or gastrointestinal bougies and the esophageal dilator (metal olive). It is Class II (special controls) and exempt from premarket notification (510(k)) subject to the limitations in 21 CFR 876.9 (eCFR text, checked 2026-10-31).
The regulation text describes the weighted and olive types. In the FDA classification database, the product codes KNQ (Dilator, Esophageal), EZM (metal olive), FAT (bougie) and PRQ (Esophageal Dilator Kit) sit under 876.5365, while product code PID (Esophageal Dilator Balloon With Or Without Electrode Sensors) is listed under a different regulation, 876.5980, also Class II (openFDA classification records, checked 2026-10-31). This guide covers the device types; for one wire-guided bougie in depth see the Savary dilator guide. For the wider definition of a device see what is a medical device.
How the types differ in practice
The UK guideline on oesophageal dilatation (Sami et al., Gut 2018) states that there are two types of oesophageal dilators, the push (bougie) dilator and the balloon dilator. This page describes the devices only.
Bougie dilators: Maloney and wire-guided
Maloney-type weighted bougies
Non-wire-guided push dilators are tungsten-filled weighted rubber bougies. The Maloney dilator has a tapered tip and is available in multiple sizes; older versions were weighted with mercury, replaced by tungsten because of concerns about leakage and disposal of mercury. The guideline reports that in one series all four perforations (4 of 348 procedures) occurred when Maloney dilators were passed blindly into complex strictures.
Wire-guided bougies
Wire-guided push dilators include metal olives, Celestin-type dilators and polyvinyl bougies. The Savary-Gilliard dilators (Cook Medical) are latex-free polyvinyl chloride solid tubes with a central channel for the guidewire, described as the most widely used push dilator at 5 to 20 mm diameter, with a radio-opaque band at the widest point. Eder-Puestow dilators, a series of graduated metal olives (6.6 to 19.3 mm) on a flexible shaft, are now rarely used.
Balloon and CRE dilators
Through-the-scope balloons are designed to pass through the endoscope, with or without wire guidance. The balloon is made of low-compliance inflatable thermoplastic polymer, most allow sequential expansion to multiple diameters, and they are expanded with liquid such as water or radio-opaque contrast. The guideline states that balloon dilators are single-use only. Larger wire-guided balloons for achalasia (30, 35 and 40 mm) do not pass through the endoscope and are also single use.
CRE stands for Controlled Radial Expansion. In the guideline it appears as a Boston Scientific through-the-scope balloon used, alongside Eclipse wire-guided balloons and Savary-Gilliard bougies, in a retrospective series of 1,497 procedures. That series recorded eight perforations (0.53%), all in malignant, post-radiation or caustic strictures; the guideline does not break the figure down by device.
Comparison of types, as described in the guideline
| Type | Guidance | Construction and notes stated in the source |
|---|---|---|
| Maloney weighted bougie | Non-wire-guided | Tungsten-filled weighted rubber; tapered tip |
| Savary-Gilliard bougie | Wire-guided | Latex-free PVC solid tube with central channel; 5 to 20 mm; radio-opaque band |
| Eder-Puestow metal olives | Wire-guided | Graduated metal olives, 6.6 to 19.3 mm, on a flexible shaft; now rarely used |
| Through-the-scope balloon (including CRE) | Through the endoscope, with or without wire | Low-compliance thermoplastic balloon, liquid-inflated, sequential diameters; single-use only |
| Large achalasia balloon | Wire-guided, not through the endoscope | 30, 35 and 40 mm polyethylene with radio-opaque markers; single use |
Reusable versus single-use: what it means for supply decisions
- The guideline says the choice between bougie and balloon should rest on clinician preference, local expertise, equipment availability, cost and the availability of robust methods of decontamination of reusable devices, because many push dilators are not single use.
- Balloons are single-use only, so they carry no reprocessing step; the guideline adds that they are more costly than push dilators, with no direct cost-effectiveness comparison in clinical practice.
- For reusable push dilators, decontamination capacity is part of the decision. See endoscope reprocessing and the endoscopy center supply checklist.
Common misunderstandings
- Balloons are not classified under the same regulation as bougies: product code PID is under 876.5980, not 876.5365.
- A device class is not a quality ranking; 876.5365 devices are Class II and 510(k)-exempt subject to 876.9 limitations.
- CRE is a product name, not a separate dilator category; it is one through-the-scope balloon.
FAQ
What are the types of esophageal dilators?
Push (bougie) dilators, either wire-guided such as Savary-Gilliard or non-wire-guided weighted such as Maloney, and through-the-scope balloon dilators.
What is a CRE balloon?
CRE means Controlled Radial Expansion, a Boston Scientific through-the-scope balloon dilator named in the 2018 UK guideline. Balloon dilators are described there as single-use only.
Sources
- Sami SS et al. UK guidelines on oesophageal dilatation in clinical practice. Gut 2018;67(6):1000-1023. pmc.ncbi.nlm.nih.gov/articles/PMC5969363. Checked 2026-10-31.
- 21 CFR 876.5365, Esophageal dilator. law.cornell.edu/cfr/text/21/876.5365. Checked 2026-10-31.
- openFDA device classification records, product codes KNQ, EZM, FAT, PRQ, PID. api.fda.gov/device/classification.json. Checked 2026-10-31.
