The National Institute for Clinical Excellence is examining lumbar subcutaneous shunt 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 lumbar subcutaneous shunt.

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• The Advisory Committee will then prepare draft guidance, which will be the basis for the Institute's guidance on the use of the procedure in the NHS in England, Wales and Scotland.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: 24 February 2004

Target date for publication of guidance: May 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 lumbar subcutaneous shunt does not appear adequate for this procedure to be used without special arrangements for consent and for audit or research.

Clinicians wishing to undertake lumbar subcutaneous shunt should take the following action.

• Inform the clinical governance leads in their Trusts.
• Ensure that patients understand the uncertainty about the procedure's safety and efficacy and should provide them with clear written information. Use of the Institute's Information for the Public is recommended.
• Audit and review clinical outcomes of all patients having laser subcutaneous shunt. Publication of safety and efficacy outcomes will be useful in reducing the current uncertainty. The Institute may review the procedure upon publication of further evidence.

This procedure is used to treat communicating hydrocephalus (normal pressure hydrocephalus) and benign intracranial hypertension (pseudotumour cerebri).

Communicating hydrocephalus is an uncommon condition caused by excess cerebrospinal fluid collecting in the subarachnoid space. Causes include congenital abnormality, brain haemorrhage and meningitis, but in some cases no cause is found. The symptoms include confusion, gait disturbance and urinary incontinence. Untreated, the condition may cause brain damage or death.

Benign intracranial hypertension is an uncommon condition of unknown cause, in which the pressure of the cerebrospinal fluid is increased. The symptoms include headache, dizziness and visual problems. The prognosis is generally good, although a few people may experience permanent visual loss.

A cerebrospinal fluid shunt is a system of valved tubes that carries cerebrospinal fluid from the subarachnoid space to another part of the body to drain it and prevent damage to the brain or eyes. Usually, a shunt is tunnelled under the skin, with the upper end in a cerebral ventricle and the lower end in the heart (ventriculo-atrial shunt) or in the peritoneum (ventriculo-peritoneal shunt). Alternatively, the upper end of the shunt may be placed in the subarachnoid space in the lumbar part of the back, with the lower end draining fluid into the peritoneum (lumbo-peritoneal shunt).

A lumbar subcutaneous shunt differs from these types of shunt in that the cerebrospinal fluid drains into the potential space immediately under the skin. A narrow tube is inserted percutaneously into the subarachnoid space in the lumbar part of the back and is tunnelled under the skin to a site where fluid can drain, usually in the flank or abdomen. The advantage is that general anaesthetic is not required, unlike other shunt procedures.

No studies reporting efficacy outcomes of lumbar subcutaneous shunt were identified.

The Specialist Advisors noted that this procedure is only being undertaken by one surgeon in Britain. One Advisor stated that most neurosurgeons did not believe that the procedure could work, because the subcutaneous tissues do not absorb cerebrospinal fluid; however, data are being collected to investigate this.

No studies reporting safety outcomes of lumbar subcutaneous shunt were identified.

One Specialist Advisor considered the main potential adverse effects of the procedure to be infection, subdural haematoma and irritation of nerve roots.

The surgeon who has been carrying out this procedure has been collecting data for several years on patients who have undergone the procedure, but there have been no publications to date.

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

• Interventional Procedure Overview of lumbar subcutaneous shunt, December 2002

Available from: www.nice.org.uk/ip174overview