Functional electrical stimulation for drop foot of central neurological origin (interventional procedures consultation)

NATIONAL INSTITUTE FOR HEALTH AND CLINICAL EXCELLENCE

Interventional Procedure Consultation Document

Functional electrical stimulation for drop foot of central neurological origin

Drop foot is the inability to lift the foot and toes when walking. It can result from conditions such as stroke, multiple sclerosis or spinal cord injury. Functional electrical stimulation involves stimulation of the peripheral nerves that supply the paralysed muscle using electrodes that may be implanted or placed on the surface of the skin. The aim is to restore muscular function.

 

The National Institute for Health and Clinical Excellence is examining functional electrical stimulation for drop foot of central neurological origin and will publish guidance on its safety and efficacy to the NHS in England, Wales, Scotland and Northern Ireland. The Institute'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 functional electrical stimulation for drop foot of central neurological origin.

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  • The Advisory Committee will then prepare draft guidance which will be the basis for the Institute's guidance on the use of the procedure in the NHS in England, Wales, Scotland and Northern Ireland.

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

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 how it might be improved.

Closing date for comments: 28 July 2008
Target date for publication of guidance: October 2008

 

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

 

1 Provisional recommendations
1.1 Current evidence on the safety and efficacy (in terms of improving gait) of functional electrical stimulation (FES) for drop foot of central neurological origin appears adequate to support the use of this procedure provided that normal arrangements are in place for clinical governance, consent, and audit.
1.2 Patient selection for FES for drop foot of central neurological origin should involve a multidisciplinary team specialising in rehabilitation.
1.3 Further publication on efficacy, including patient-reported outcomes such as quality of life and activities of daily living, would be useful. The Institute may review the procedure upon publication of further evidence.
2 The procedure
2.1 Indications and current treatments
2.1.1 Drop foot can be caused by upper or lower motor neuron lesions. FES is used to treat upper motor neuron lesions (injury to the corticospinal tracts in the brain or spinal cord) which can result from stroke, cerebral palsy, multiple sclerosis and spinal cord injury. Symptoms and signs include muscle weakness in a pyramidal distribution (an imbalance causing arm flexion and leg extension), hypertonicity, exaggerated reflexes, clonus and an extensor plantar response.
2.1.2 First-line treatment is usually physiotherapy or an ankle foot orthosis to align the lower leg and control the motion of the ankle and foot, providing stability and improving gait. Medical therapy includes oral administration of muscle relaxant drugs or botulinum toxin type A injections into the most affected muscles. Surgery is usually reserved for refractory cases and includes selective tendon release of muscles.
2.2 Outline of the procedure
2.2.1 FES aims to produce muscle contractions that mimic normal voluntary movement, lifting the foot off the ground and improving gait, by applying electrical pulses to the common peroneal nerve through skin surface or implanted electrodes.
2.2.2 In skin surface FES, electrodes placed over the nerve are connected by leads to a stimulator unit and controlled with a foot switch. Electrodes must be repositioned each time the stimulator unit is used.
2.2.3 Implanted FES electrodes are usually inserted into the epineurium of the peroneal nerve under general anaesthesia. They are operated either by leads passed through the skin or by radiofrequency waves.
Sections 2.3 and 2.4 describe efficacy and safety outcomes which were available in the published literature and which the Committee considered as part of the evidence about this procedure. For more details, refer to the Sources of evidence.
2.3 Efficacy
2.3.1 A meta-analysis including three controlled studies of 71 patients with stroke reported a mean increase of 0.18 metres/second (95% CI 0.08 to 0.28) in gait speed in 36 patients treated by skin surface-applied FES versus 35 patients treated by conventional therapy (absolute numbers not given).
2.3.2 A case series including 111 patients with stroke treated by skin surface FES reported a therapeutic carry-over effect: mean increase in walking speed of 14% (p < 0.01) and a reduction in physiological cost index of 19% (p < 0.01).
2.3.3 A randomised controlled trial (RCT) of 29 patients with stroke reported a 23% improvement in walking speed in the patients treated by FES through implanted electrodes, compared with a 3% improvement with conventional therapy at 26 weeks (p = 0.010).
2.3.4 A second RCT of 29 patients with stroke who received implanted electrodes reported subjective achievement of functional milestones (such as 'prepared dinner', 'walked outside') in 53 instances in the FES group and 11 instances in the control group at 1-day follow-up.
2.3.5 An RCT of 60 children with cerebral palsy reported no significant difference in strength or function between the children treated by skin surface FES (n = 18) and the placebo group (n = 22) at 6-week follow-up (peak torque measurement of the less affected leg was -0.05 [p = 0.72], the more affected leg was -0.09 [p = 0.50] and the gross motor function measurement was 1.93 [p = 0.07]).
2.3.6 The Specialist Advisers considered key efficacy outcomes to include improved gait and walking speed, reduction in energy expenditure when walking, reduction in pain and discomfort, reduction in falls, return to work and other quality of life outcomes.
2.4 Safety
2.4.1 An RCT of 29 stroke patients and a case series of 17 patients who all received implanted electrodes reported skin erythema in 4 and 6 patients (14 instances), respectively (1 of the 6 required electrode removal). A case series of 15 patients reported wound infection in 2 patients following electrode implantation. The second RCT of 29 stroke patients reported one instance of device malfunction after 10 weeks.
2.4.2 The RCT of 60 children treated by skin surface electrodes reported exacerbation of eczema in 1 child and four instances of itch or rash following electrode placement.
2.4.3 The Specialist Advisers noted anecdotal adverse events including an increase in seizure incidence among patients with epilepsy, automonic dysreflexia in patients with spinal cord injuries, problems with CT or MRI scanning with implanted electrodes, increases in spasticity or spasms, infection with implanted systems, and skin intolerance. They considered theoretical adverse events to include skin irritation from electrodes, fibrillation and problems caused by faulty equipment or when using this procedure on patients who are pregnant or use a pacemaker.
2.5 Other comments
2.5.1 The Committee noted that the majority of the evidence related to patients with stroke. In addition, the Committee noted there are a number of different FES devices and that the technology is evolving.
2.5.2 The Committee noted that interpretation of the evidence was difficult because the evidence is based on studies that used different methods of applying the procedure (skin surface or implanted).
3 Further information
3.1 The Institute has produced interventional procedures guidance on selective dorsal rhizotomy for spasticity in cerebral palsy and is developing a clinical guideline on the diagnosis and management of stroke and transient ischaemic attacks (available from www.nice.org.uk).

Bruce Campbell
Chairman, Interventional Procedures Advisory Committee
June 2008

Appendix: Sources of evidence
The evidence considered by the Interventional Procedures Advisory Committee is described in the overview, available at: www.nice.org.uk/ip657overview.

This page was last updated: 30 March 2010