The National Institute for Clinical Excellence is examining supraorbital minicraniotomy and will publish guidance on its safety and efficacy to the NHS in England, Wales and Scotland. The Institute's Interventional Procedures Advisory Committee has considered the available evidence and the views of Specialist Advisors, who are consultants with knowledge of the procedure. The Advisory Committee has made provisional recommendations about supraorbital minicraniotomy for intracranial aneurysm.

This document summarises the procedure and sets out the provisional recommendations made by the Advisory Committee. It has been prepared for public consultation. The Advisory Committee particularly welcomes:

• comments on the preliminary recommendation
• the identification of factual inaccuracies
• additional relevant evidence.

Note that this document is not the Institute's formal guidance on this procedure. The recommendations are provisional and may change after consultation.

The process that the Institute will follow after the consultation period ends is as follows:

• The Advisory Committee will meet again to consider the original evidence and its provisional recommendations in the light of the comments received during consultation.
• The Advisory Committee will then prepare draft guidance which will be the basis for the Institute's guidance on the use of the procedure in the NHS in England, Wales and Scotland.

For further details, see the Interim Guide to the Interventional Procedures Programme, which is available from the Institute's website (www.nice.org.uk/ip).

Closing date for comments: 25 May 2004

Target date for publication of guidance: August 2004

Note that this document is not the Institute's guidance on this procedure. The recommendations are provisional and may change after consultation.

Current evidence on the safety and efficacy of supraorbital minicraniotomy for intracranial aneurysm appears adequate to support the use of this procedure provided that the normal arrangements are in place for consent, audit and clinical governance.

Cerebral aneurysms are small balloon-like dilated portions of blood vessels that may occasionally rupture, causing brain haemorrhage, stroke or death. Therapy is then designed to support recovery from the initial bleed, together with specific treatment to prevent re-bleeding.

The majority of cerebral aneurysms arise from the major blood vessels in the centre of the head as they cross the space between the skull and the brain (the subarachnoid space). The standard surgical approach to this area is through an incision in the scalp just in front of the ear and an opening in the underlying bone on the side of the head. The abnormal vessels are approached side-on in the subarachnoid space beneath the brain. The surgical treatment of cerebral aneurysms involves placing a permanent clip across the neck of the aneurysm (effectively closing the neck of the balloon) to separate it from the normal vessel while preserving blood flow to the brain. If clipping is not possible, the aneurysm may be reinforced by wrapping it with synthetic material to reduce the risk of rupture.

Supraorbital minicraniotomy is an alternative approach through a smaller incision made above the eyebrow and through the underlying skull. This allows a front-on approach to the abnormal vessels. The aneurysm is then clipped or wrapped using conventional microsurgical instruments.

No controlled studies were identified. In two studies, all the aneurysms were either successfully clipped or wrapped, but length of follow-up was not reported. In another study, 89% (33/37 patients) showed good recovery on the Glasgow Outcome Scale, but it was not clear how many of the patients were followed up for the entire duration of the study (17 months). This study also reported good cosmetic outcomes following surgery. For more details, refer to the sources of evidence (see Appendix).

One Specialist Advisor considered it unlikely that the efficacy of treating an aneurysm would be affected by the small exposure used in this procedure when compared with the standard surgical approach.

In the three case series reviewed, rupture of the aneurysm during surgery occurred in 3% (4/139), 2% (2/102) and 3% (1/37) of patients. Other adverse events were: death within 8 days of surgery (4%, 4/102 patients); central nervous system infection (2%, 2/102 patients); impaired cerebral spinal fluid circulation requiring shunting (7%, 7/102 patients); supraorbital nerve damage (11%, 4/37 patients); and wound infection (3%, 1/37 patients). For more details, refer to the sources of evidence (see Appendix).

The Specialist Advisors had no major safety concerns.

This procedure involves a different surgical approach for performing an established procedure (craniotomy for intracranial aneurysm) and although there may be a greater risk of per-operative rupture this has usually been managed successfully.

There is an increasing trend to deal with aneurysms by endoluminal techniques.

The following document, which summarises the evidence, was considered by the Interventional Procedures Advisory Committee when making its provisional recommendations.

• Interventional procedure overview of supraorbital minicraniotomy for intracranial aneurysm, December, 2002

Available from: www.nice.org.uk/ip015boverview