The National Institute for Clinical Excellence is examining auditory brain stem implants and will publish guidance on their 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 auditory brain stem implants.

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• The Advisory Committee will then prepare draft guidance, which will be the basis for the Institute's guidance on the use of the procedure in the NHS in England, Wales and Scotland.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: 22 June 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 auditory brain stem implants appears adequate to support the use of this procedure provided that normal arrangements are in place for consent, audit and clinical governance.

The procedure should be performed in a specialist neurosurgery unit with a multidisciplinary team.

This procedure is used to treat deafness caused by damage to the vestibulocochlear nerve as a result of tumours or surgery.

In people with vestibulocochlear nerve damage, hearing is not improved by hearing aids or cochlear implants.

The cochlear nucleus lies in the brain stem and is responsible for processing sound signals carried from the ear through the vestibulocochlear nerve. Auditory brain stem implants are electrodes placed in the cochlear nucleus.

Removal of vestibulocochlear nerve tumours and placement of auditory brain stem implants are often done at the same time. The surgeon makes an incision in the skin on the side of the head, and removes some of the bone behind the ear. This exposes the tumour so that it can be removed and also allows access to the brain stem beneath it. The surgeon can then implant the electrodes into the part of the brain stem called the cochlear nucleus. The surgeon may sometimes approach the brain stem through the back of the head. People with auditory brain stem implants wear an external receiver and speech processor. This device converts sounds into electrical signals, which are then sent to the implant.

The evidence was limited to case series data. One study reported that 85% (75/88) of patients received auditory sensations when their implants were activated. In another study, some hearing was reported in 94% (51/54) of patients. For more details, refer to the sources of evidence (see Appendix).

One Specialist Advisor commented that results were unpredictable.

The main complications reported in the identified studies were cerebrospinal fluid leak 3% (2/61); meningitis 2% (1/61); and pulmonary embolism 2% (1/54). Tingling in various parts of the body was reported to be 'not uncommon' in a study of 88 patients, but another study of 61 patients reported no severe or serious non-auditory sensations. For more details, refer to the sources of evidence (see Appendix).

The Specialist Advisors listed the potential adverse effects of the procedure as death, damage to lower cranial nerves, intracranial haematoma/brainstem stroke, meningitis, and infection of the device.

This procedure is applicable only to a small proportion of patients who have complete hearing loss, for which no alternative treatment would restore hearing.

Long-term data are needed for this procedure.

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

• Interventional procedure overview of auditory brain stem implants, December 2002

Available from: www.nice.org.uk/ip133overview