Pneumatic dilatation for achalasia is a type of esophageal dilatation and is a procedure to improve swallowing in patients with a disorder called achalasia. It is performed by placing an inflatable cylindrical balloon inside the esophagus where it joins the stomach and stretching the ring like muscular valve located there, which is known as the lower esophageal sphincter (LES). In achalasia the patient has problems swallowing because the LES remains contracted and fails to relax properly to allow food to pass into the stomach and the contractions in the esophagus that push food down, peristalsis, are dysfunctional or otherwise unable to push the food through the LES. Dilating (stretching) the LES to the point that it disrupts its fibers weakens it allowing food to pass through the constricted LES. Unlike a Heller myotomy where the fibers are disrupted in both the ring-like clasp muscle of the LES and the sling of gastric fibers below the clasp, dilatation only disrupts the clasp muscle. This difference may explain why dilatation is less likely in some, especially children, to provide as much relief of symptoms as Heller's myotomy, and why dilatation is less likely to produce an acid reflux problem. Both the clasp and sling muscles provide tone to the constriction of the LES.

The first record of esophageal dilatation for achalasia is by Sir Thomas Willis, more than 300 years ago, who used a whale bone. Today pneumatically inflated balloons, and other devices, are used instead of whale bone, but the concept is much the same. Three main sizes of balloons are used, 30, 35, and 40 mm. Smaller devices exist but generally do not provide long-term relief of symptoms in adults but may be useful in children, though there is less success with younger patients.

Opinions vary among doctors as to what dilation techniques are best. Many doctors prefer to use one size first on one day then in a few weeks use a larger size if the first did not improve symptoms enough, and continue doing so until the largest size is used. Other doctors prefer to use a series of dilatations on the same day.

Success rates have been report as high as 85%. Those numbers depend on information from follow-up visits by the patients. It is believed that many patients do not continue with follow-up, especially if results were not successful. This means that many of the reported success rates may be higher than should be accepted. Some studies suggest that the number of patient with remission of symptoms at one year may only be around 60%. Whatever the real success rate is many patients have received years of long-term relief of symptoms. There are reports of patients fallowed for 10 to 25 years with complete relief of symptoms. There is evidence that patients under forty years of age, especially children, have much less success than older patients.

The main complications are perforation and GERD. The rate of perforation is figured to be around 4% in general and there is more risk with larger balloons than smaller ones. The rate of GERD is believed to be about 2%. About 15% of patient experience severe chest pain immediately fallowing the procedure. Some surgeons have reported that they find doing Heller myotomies harder on patients that have had dilatations due to the fibrosis that develops in the tissue from dilatation. The impact on later surgeries is an ongoing debate.

Dilation can also be used after a Heller myotomy when the myotomy was not successful, or is failing, often with good results. If it does not improve the symptoms after a failed myotomy the patient may have to consider a myotomy redo or an esophagectomy.

Although the success rate may be lower than for Heller's myotomy and it may tend to fail sooner, pneumatic dilatation remains the best choice for first treatment for many older patients, because of its lower cost and quick recovery, and for those patients who are poor operative risks. Generally, if there are no complications, the patient returns home the same day and can return to work the next day and may receive years of symptom relief. Use in children is harder to justify.