The Interventional Procedures Advisory Committee (IPAC) originally considered this procedure as part of coil embolisation for intracranial aneurysms. However, as a result of comments received during the initial consultation in June 2003, IPAC decided to consider the procedure separately for ruptured intracranial aneurysms and for unruptured intracranial aneurysms.

The National Institute for Health and Clinical Excellence (NICE) has issued full guidance to the NHS in England, Wales, Scotland and Northern Ireland on coil embolisation of unruptured intracranial aneurysms.

As part of the NICE's work programme, the current guidance was considered for review but did not meet the review criteria as set out in the IP process guide. The guidance below therefore remains current.

To be alerted to developments regarding the use of the procedure to treat ruptured intracranial aneurysms please refer to IPG106.


Intracranial aneurysms are dilated blood vessels within the skull. Usually, the cause is unknown but people with genetic causes of weak blood vessels are more likely to develop aneurysms.

Rupture of intracranial aneurysms causes subarachnoid haemorrhage and has a poor prognosis. About 30% of people die within 24 hours and a further 25-30% die within 4 weeks.

The traditional treatment for ruptured or unruptured aneurysms involves open surgery to clip the abnormal blood vessels inside the skull.

The coil technique involves approaching the aneurysm from inside the diseased blood vessel, avoiding the need to open the skull. The coil technique is therefore an endovascular technique. A thin tube containing the coil on a guidewire is inserted into a large artery, usually in the groin, and passed up into the skull under radiological guidance. The coil is placed inside the aneurysm and detached from the guidewire. Multiple coils may be placed into the aneurysm through the same tube until the aneurysm is densely packed. 

The coil technique is mainly carried out on ruptured aneurysms but may also be used to treat unruptured aneurysms.

Coding recommendations

The OPCS-4 codes are dependent on the size of the aneurysm:

O01.1 Percutaneous transluminal coil embolisation of small aneurysm of artery


O01.2 Percutaneous transluminal coil embolisation of medium aneurysm of artery 


O01.3 Percutaneous transluminal coil embolisation of large aneurysm of artery


O01.4 Percutaneous transluminal coil embolisation of giant aneurysm of artery

If the size of the aneurysm is other specified (.8), or unspecified (.9), then one of the following codes is assigned:

O01.8 Other specified transluminal coil embolisation of aneurysm of artery


O01.9  Unspecified transluminal coil embolisation of aneurysm of artery

Note: For balloon assisted coil embolisation a code from category O02.- Transluminal balloon assisted coil embolisation of aneurysm of artery is assigned instead of the above.

In addition to the primary procedure code above, two extra codes are both required:

Y53.- Approach to organ under image control

Z35.-Cerebral artery 

Note:  Codes within category Y53.- are used as secondary codes to classify interventions that are percutaneous and require some form of image control: if the method of image control is unspecified, Y53.9 Unspecified approach to organ under image control is assigned.