Deep brain stimulation for refractory epilepsy - Consultation Document

Interventional procedure consultation document

Deep brain stimulation for refractory epilepsy

Deep brain stimulation for difficult to treat epilepsy

Epilepsy is a chronic neurological condition characterised by recurrent seizures, in which the brain’s normal electrical activity becomes overactive and abnormal. During deep brain stimulation, a thin wire is implanted into the brain. The wire is attached to an electrical stimulator, which is placed under the skin of the chest. The aim is that electrical stimulation of a particular area of the brain will suppress the abnormal electrical activity associated with a seizure.

The National Institute for Health and Clinical Excellence (NICE) is examining deep brain stimulation for refractory epilepsy and will publish guidance on its safety and efficacy to the NHS in England, Wales, Scotland and Northern Ireland. NICE’s Interventional Procedures Advisory Committee has considered the available evidence and the views of Specialist Advisers, who are consultants with knowledge of the procedure. The Advisory Committee has made provisional recommendations about deep brain stimulation for refractory epilepsy.

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 provisional recommendations
  • the identification of factual inaccuracies
  • additional relevant evidence, with bibliographic references where possible.

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

The process that NICE 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  • The Advisory Committee will then prepare draft guidance which will be the basis for NICE’s guidance on the use of the procedure in the NHS in England, Wales, Scotland and Northern Ireland.

For further details, see the Interventional Procedures Programme manual, which is available from the NICE website (www.nice.org.uk/ipprogrammemanual).

NICE is committed to promoting through its guidance race and disability equality and equality between men and women, and to eliminating all forms of discrimination. One of the ways we do this is by trying to involve as wide a range of people and interest groups as possible in the development of our guidance on interventional procedures. In particular, we aim to encourage people and organisations from groups in the population who might not normally comment on our guidance to do so. We also ask consultees to highlight any ways in which draft guidance fails to promote equality or tackle discrimination and give suggestions for how it might be improved. NICE reserves the right to summarise and edit comments received during consultations, or not to publish them at all, where in the reasonable opinion of NICE, the comments are voluminous, publication would be unlawful or publication would otherwise be inappropriate.

Closing date for comments: 21 September 2011

Target date for publication of guidance: December 2011

 

1   Provisional recommendations

1.1   The evidence on the safety of deep brain stimulation (DBS) for refractory epilepsy shows that there are well recognised and potentially serious side effects. There is some evidence of efficacy but this is limited in both quantity and quality. Therefore, this procedure should only be used with special arrangements for clinical governance, consent and audit or research.

1.2   Clinicians wishing to undertake DBS for refractory epilepsy should take the following actions.

  • Inform the clinical governance leads in their Trusts.
  • Ensure that patients understand the uncertainty about the procedure’s safety and provide them with clear written information. In addition, the use of NICE’s information for patients (‘Understanding NICE guidance’) is recommended (available from www.nice.org.uk/IPGXXX/publicinfo). [[details to be completed at publication]]
  • Audit and review clinical outcomes of all patients having DBS for refractory epilepsy (see section 3.1).

1.3   Further research should describe patient selection and define clearly the target area of the brain. Outcomes should include measures of seizure frequency, functional ability and quality of life.

2   The procedure

2.1   Indications and current treatments

2.1.1   Epilepsy is defined as a neurological condition characterised by recurrent epileptic seizures unprovoked by any immediately identifiable cause. An epileptic seizure is the clinical manifestation of an abnormal and excessive discharge of a set of neurons in the brain.

2.1.2   The main treatment is currently anti-epileptic drugs to prevent the recurrence of seizures. However, a substantial proportion of patients have epilepsy that is inadequately controlled by medical treatment. These patients experience frequent seizure activity and are at risk of status epilepticus and also sudden death in epilepsy (SUDEP).

2.1.3   If medical therapy fails to achieve adequate control, surgery to resect or disconnect parts of the brain may be considered. Vagus nerve stimulation is another treatment option for suitable patients.

2.2   Outline of the procedure

2.2.1   DBS is used for selected patients with medically refractory epilepsy who are considered to be unsuitable for surgical resection. It involves electrical stimulation of specific sites within the brain (such as the anterior or dorsal nucleus of the thalamus), which may suppress abnormal electrical activity associated with seizures.

DBS for refractory epilepsy is carried out with the patient under local or general anaesthesia. One or more permanent electrodes are inserted into the brain using imaging guidance. The exact position of the targeted nucleus may be different in each patient.

2.2.2   Following satisfactory electrode testing, a pulse generator is implanted under the chest wall and connected by tunnelled wires to the electrodes. The generator usually remains switched ‘on’.

Sections 2.3 and 2.4 describe efficacy and safety outcomes from the published literature that the Committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the overview, available at www.nice.org.uk/IP/806/overview

2.3   Efficacy

2.3.1   A randomised controlled trial (RCT) of 109 patients with DBS electrodes implanted in the anterior nucleus of the thalamus treated by DBS (stimulation ‘on’) or control (stimulation ‘off’) reported that at the end of a 3-month blinded phase there was a 29% greater reduction in seizure frequency among the 54 patients with stimulation ‘on’ compared with the 55 patients with stimulation ‘off’ (p = 0.002). After the blinded phase, all patients received stimulation and there was a 56% median reduction in seizure frequency from baseline at 2-year follow-up (n = 81).

2.3.2   Following the use of stimulation in all patients after the 3-month blinded phase in the RCT of 109 patients, Quality of Life in Epilepsy scores improved significantly at 13- and 25-month follow-up (p < 0.001 at both time intervals)

2.3.3   The Specialist Advisers listed key efficacy outcomes as reduction in seizure frequency and medication use, and improvement in quality of life.

2.4   Safety

2.4.1   Subdural haemorrhage during DBS implantation leading to increased intracranial pressure was reported in 1 patient in a case series of 17 patients. Evacuation of the haemorrhage and a right frontal resection were performed; the patient was reported as hemiparetic and obtunded 1 week after the event.

2.4.2   The RCT of 109 patients implanted with DBS electrodes reported that 5% (5/109) of patients had asymptomatic haemorrhages detected incidentally by neuroimaging.

2.4.3   The RCT of 109 patients reported that 13% (14/109) of patients developed implant site infections. All infections were treated with antibiotics, and 9 patients had additional removal of hardware.

2.4.4   The RCT of 109 patients reported depression in 15% (8/54) of patients treated by DBS compared with 2% (1/55) of control patients during the blinded phase (p = 0.016). Symptoms of depression resolved in 4 of the 8 patients in the DBS group.

2.4.5   The RCT of 109 patients reported memory impairment during the 3-month blinded phase in 13% (7/54) of patients in the DBS group and 2% (1/55) of patients in the control group (p = 0.032). This was not judged to be serious in any of the patients and resolved in 12–476 days (no further information was given).

2.4.6   The RCT of 109 patients reported a total of 5 deaths during a mean follow-up of 3 years: 1 patient died before implantation of electrodes due to probable SUDEP; 2 further patients died from SUDEP (1 during the 9-month unblinded phase and the other during subsequent follow-up); 1 patient drowned; and 1 committed suicide during the follow-up phase. None of the deaths were judged to be device-related.

2.4.7  The Specialist Advisers listed adverse events (reported in the literature or known from experience) as stroke, neurological deficit, and breakage and displacement of leads.

2.5   Other comments

2.5.1   The Committee recognised the disability and distress that refractory epilepsy can cause and noted that patients may die from a variety of causes. Any treatment that is shown to reduce seizure frequency to an extent which improves the lives of patients and their carers would be a welcome addition to the options for management.  

3   Further information

3.1   This guidance requires that clinicians undertaking the procedure make special arrangements for audit. NICE has identified relevant audit criteria and is developing audit support (which is for use at local discretion), which will be available when the guidance is published.

3.2   For related NICE guidance see www.nice.org.uk

Bruce Campbell

Chairman, Interventional Procedures Advisory Committee

August 2011

Personal data will not be posted on the NICE website. In accordance with the Data Protection Act names will be anonymised, other than in circumstances where explicit permission has been given.

It is the responsibility of consultees to accurately cite academic work in order that they can validated.

 

This page was last updated: 21 September 2011