Occasionally, tumours grow so large that they obstruct the normal flow route in areas of the body that should remain open, such as the biliary tree, the digestive tract, the airway or the urinary tract. This blockage causes fluids that would normally pass through the area to build up in the body. If left untreated, the blockage and resulting build-up may cause pain, infection and organ failure.
There are a number of minimally invasive techniques available to relieve the obstruction, including therapeutic treatments (which treat the blockage) and palliative treatments (which reduce discomfort caused by the blockage). These techniques aim to drain the fluid collections or bypass the obstruction, allowing the fluid to drain normally.
How does the procedure work?
There are two types of minimally invasive techniques available: the collection of fluid may be drained or the blockage may be bypassed, so fluid can pass through the vessel.
Percutaneous drainage is a minimally invasive method which involves using a catheter (a thin, flexible tube) to drain a fluid collection or abscess. The procedure is carried out under image guidance; the type of imaging used depends on the blockage and the build-up of fluid. You will receive local anaesthetic or be sedated for the procedure.
Alternatively, the vessel with the blockage can be opened using minimally invasive devices. These include guidewires, tiny balloons (which when inflated expand the area), and stents (metal mesh tubes which are inserted to support the vessel’s walls and keep the vessel open). Once the blockage is relieved, the collected fluid can drain normally.
Why perform it?
If left untreated, such obstructions and the resulting collections of fluids or other substances can cause pain, infection and organ failure.
What are the risks?
There are some possible complications, but these are rare. In 2-5% of cases, bacteria enter the bloodstream. Septic shock, in which organs fail as a result of infection or bacteria in the blood, occurs in 1-2% of cases. Other complications include haemorrhage and infection in a fluid collection. Some patients experience stent migration, in which the stent travels to another area of the body, or re-obstruction, meaning the vessel once again becomes blocked. If you have a re-obstruction, you may need to undergo further treatment.
1. Society of Cardiovascular and Interventional Radiology Standards of Practice Committee. Quality improvement guidelines for adult percutaneous abscess and fluid drainage. J Vasc Intervent Radiol 1995; 6:68-90.