An oesophageal dilatation is a stretching of an anastomotic stricture.
The terms dilatation and dilation are often used interchangeably; either way they mean a stretch of the stricture.
This procedure may be performed in an operating theatre while the doctor (surgeon or gastroenterologist) views the process directly with the endoscope (medical telescope) in the oesophagus – or in an x-ray (radiology) department with the doctor (radiologist) viewing the procedure indirectly using x-ray screening.
The traditional way of achieving a dilatation or stretch was with a bougie (pronounced ‘boojee’) which is a soft pliable plastic rod with a tapered end.
This is passed down the oesophagus, either viewed using a rigid oesophagoscope or done blind by feel (which requires a lot of experience). Some surgeons regard bougies as safe and effective, while others believe they create a shearing force and may increase the risk of oesophageal perforation (rupture).
Balloon catheter dilatation is considered safer as a radial or tangential force is applied to the oesophagus – rather than the shearing force applied by bougie. It may therefore be associated with a lesser risk of oesophageal perforation or rupture.
Dilatations are usually performed with a balloon that can be passed down the operating channel of a flexible endoscope, or alongside the endoscope. If the stricture is very tight and only a pinhole opening is visible, the safest manoeuvre is to first pass a thin flexible guidewire (visible on x-ray screening) down through the stricture, then the balloon catheter can be pushed over it.
Injection of an x-ray dye into the balloon allows it to be seen on x-ray screen.
When inflated to a certain diameter and pressure, the balloon will be indented by the stricture and be seen as a clear ‘waist’ in the balloon as visualised on the x-ray screen.
The maximum safe pressure and diameter is gauged by the surgeon, but the patient’s thumb diameter is an approximate guide to the expected diameter of their oesophagus.
A typical routine is to inflate the balloon for two minutes at one pressure and diameter, then a further two minutes at a greater diameter, followed by a final (third) diameter for two minutes. The increments of diameter are generally 1mm each time.
This has not been formally proven to be the best routine, but is widely practised. The rule of three has been taken from adult practice and applied to children as follows:
Increases greater than this may be used by individual surgeons, according to the nature of the patient’s difficulties.
Dilatation may become necessary within a few weeks after surgery and may need to be repeated on a regular basis.