Percutaneous electrical nerve (PENS) stimulator for neuropathic pain refractory to other treatments: consultation document

Interventional procedure consultation document

Percutaneous electrical nerve stimulation for refractory neuropathic pain

Treating refractory neuropathic pain by nerve stimulation

Neuropathic pain is caused by damage or changes to nerves so they don’t work properly. People with neuropathic pain sometimes describe the pain using words like shooting, stabbing, burning, tingling, or a sensation of pins and needles. The pain can come and go, or be there all the time. Refractory means that the pain does not respond to treatment. Percutaneous electrical nerve stimulation (PENS) aims to control neuropathic pain. The procedure is similar to TENS (transcutaneous electrical nerve stimulation), but involves inserting the electrode needles under the skin. Once the needles are inserted they are connected to a neurostimulator (a battery powered device that delivers electrical stimulation to the nerves). The stimulation causes a tingling sensation (paraesthesia) in the area of the body associated with the pain, easing the discomfort. The treatment can be repeated as often as necessary.

The National Institute for Health and Clinical Excellence (NICE) is examining percutaneous electrical nerve stimulation for refractory neuropathic pain 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 percutaneous electrical nerve stimulation for refractory neuropathic pain.

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 (

Through its guidance NICE is committed to promoting race and disability equality, 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 interventional procedures guidance. In particular, we aim to encourage people and organisations from groups who might not normally comment on our guidance to do so.

In order to help us promote equality through our guidance, we should be grateful if you would consider the following question:

Are there any issues that require special attention in light of NICE’s duties to have due regard to the need to eliminate unlawful discrimination and promote equality and foster good relations between people with a characteristic protected by the equalities legislation and others?

Please note that 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: 14 December 2012

Target date for publication of guidance: 27 March 2013

1                      Provisional recommendations

1.1                  Current evidence on the safety of percutaneous electrical nerve stimulation (PENS) for refractory neuropathic pain raises no major safety concerns and there is evidence of efficacy in the short-term. Therefore this procedure may be used with normal arrangements for clinical governance, consent and audit.

1.2                  Patient selection and treatment using PENS should be carried out by teams specialising in pain management.

1.3                  NICE encourages further research into PENS, particularly to provide more information about selection criteria and long-term outcomes, with clear documentation of the indications for treatment.

2                      The procedure

2.1                  Indications and current treatments

2.1.1              Neuropathic pain means pain arising from dysfunction of sensory nerves and pathways in the nervous system. It may occur in a heterogeneous group of disorders: examples include painful diabetic neuropathy, post-herpetic neuralgia and trigeminal neuralgia. People with neuropathic pain may experience altered pain sensation, areas of numbness or burning, and continuous or intermittent evoked or spontaneous pain. Neuropathic pain is an unpleasant sensory and emotional experience that can have a significant impact on a person's quality of life.

2.1.2              A range of different drugs are used to manage neuropathic pain, including antidepressants, anti-epileptic (anticonvulsant) drugs, opioids, and topical treatments such as capsaicin and lidocaine (see Neuropathic pain: the pharmacological management of neuropathic pain in adults in non-specialist settings [NICE clinical guideline 96]). Neuropathic pain is often difficult to treat, because it can be refractory to many medications and/or because of the adverse effects associated with some medications.

2.2                  Outline of the procedure

2.2.1              In PENS one or more individual nerves or dermatomes are stimulated using needle probes. Pairs of fine gauge needles are inserted into soft tissue near the targeted nerves or into the affected dermatomes. The needles are connected to a low-voltage pulse generator and an electrical current is then applied at a level that generates a sensation of paraesthesia but which does not cause muscle contraction. The duration of treatment varies but each session of stimulation typically lasts between 15 and 60 minutes.

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

2.3                  Efficacy

2.3.1              A crossover randomised controlled trial (RCT) of 64 patients comparing PENS against sham PENS or transcutaneous electrical nerve stimulation (TENS) in patients with pain from sciatica reported a significant reduction in pain after the last treatment session (measured on a visual analogue scale [VAS]; 0–10 from best to worse) compared with baseline in both PENS (from 7.2 to 4.1, p<0.05) and TENS (from 7.0 to 5.4, p<0.05) groups, but not in the sham-PENS group (from 6.6 to 6.1, p=not significant). The reduction in the PENS group was significantly greater than the reductions in the TENS and sham-PENS groups (p<0.01).

2.3.2              A crossover RCT of 50 patients with diabetic neuropathic pain in the legs comparing PENS with sham PENS reported a significantly greater reduction in pain (measured on a VAS; 0–10 from best to worse) in the PENS group (from 6.2 to 2.6) compared with the sham-PENS group (from 5.2 to 4.8) after the last treatment session (p<0.05).

2.3.3              The RCT of 64 patients reported a significant improvement after the last treatment session from baseline in physical activity (measured on a VAS, 0–10 from best to worse) in both the PENS group (from 6.4 to 4.0, p<0.05) and the TENS group (from 5.8 to 4.5, p<0.05) but not in the sham-PENS group (from 6.0 to 5.5, p=not significant). The improvement in the PENS group was significantly greater than in the TENS and sham-PENS groups (p<0.01).

2.3.4              The RCT of 50 patients reported baseline physical and mental component SF-36 scores of 31.2 and 41, respectively (mean scores taken 24 hours before the first treatment session). These scores increased to 36.8 (p<0.01) and 43.9 (p<0.01), respectively, for the PENS group; and to 32.4 (p<0.05) and 42 (p<0.05), respectively, for the sham-PENS group (these were mean scores taken 36 hours after the last treatment session). Improvement was significantly greater for the PENS group (p<0.05). In both RCTs of 64 and 50 patients, the post-intervention scores for PENS groups were still below the normal population score of 50.

2.3.5              The RCT of 64 patients reported a 50% reduction over 3 weeks in daily analgesic use with PENS treatment compared with TENS (29%) and sham PENS (8%) (level of significance not reported).

2.3.6              The RCT of 64 patients reported a significant improvement from baseline in quality of sleep after the last treatment session (measured on a VAS; 0–10 from best to worse) in both the PENS group (from 5.5 to 3.1, p<0.05) and the TENS group (from 5.0 to 4.0, p<0.05) but not in the sham-PENS group (from 5.2 to 4.9, p=not significant). The improvement in the PENS group was significantly greater than the reductions in the TENS and sham-PENS groups (p<0.01).The RCT of 64 patients reported that most patients (73%) rated PENS as the most desirable treatment, compared with TENS (21%) and sham PENS (6%).

2.3.7              The Specialist Advisers listed key efficacy outcomes as reduction in pain (alleviation of localised neuropathic pain, relief of allodynia and hyperpathia, reduction in the frequency of sharp shooting pains, reduction in the burning sensation) and its associated functional and emotional improvements.

2.4                  Safety

2.4.1              The RCT of 64 patients did not report safety findings.

2.4.2              The RCT of 50 and an RCT of 31 patients stated that no adverse events were reported.

2.4.3              The Specialist Advisers listed exacerbation of pain, bruising and bleeding as anecdotal adverse events. They listed theoretical adverse events as vascular damage; damage to local nerves with sequelae, depending on which nerve was damaged; pneumothorax; possible interaction with a cardiac pacemaker if used above the waistline; possible epileptogenic effect if used near the head; possible effects if used in pregnancy; dislodgement (with loss of effect); unpleasant paraesthesias; and local bruising or haematoma.

2.5                  Other comments

2.5.1              The Committee noted that clinical response to treatment with PENS may differ according to the indication treated.

3                      Further information

3.1                  For related NICE guidance see

Bruce Campbell

Chairman, Interventional Procedures Advisory Committee

November 2012

This page was last updated: 02 January 2013