Health Technology Assessment of electrical stimulation of peripheral nerves used in chronic pain

In December 2018, the Andalusian Agency for Evaluation of Health Technologies, AETSA, has released a systematic review on the effectiveness and safety of electrical stimulation of peripheral nerves for treating chronic refractory pain.

Chronic pain is among the most common reasons for seeking medical attention. Current treatment options for chronic pain include physiotherapy, psychological and/or pharmacological therapies. When chronic pain does not respond to standard treatments, more invasive procedures are used. Electrical stimulation of peripheral nerves has emerged as a potentially attractive option for treating chronic refractory pain due to being less invasive compared with stimulation of the central nervous system or other surgical procedures.

A systematic review was carried out searching for randomized controlled trials (RCT), non-randomized controlled trials, case series and case reports on several databases (e.g. The Cochrane (Wiley) CENTRAL Register of Controlled Trials, MEDLINE (Ovid) and MEDLINE In Process (Ovid), EMBASE (Ovid), The Cochrane Library (Wiley) and ClinicalTrials.gov). After the search of the electronic databases mentioned, 7 systematic reviews, 37 RCTs and 93 case series were included.

Results

• In chronic migraine patients, low-quality evidence showed a non-statistically significant reduction of 2.82 days with moderate or severe intensity headache with occipital nerve stimulation (ONS) compared with the simulation group at 4 weeks of follow up
• In patients with fibromyalgia, very-low-quality evidence found no statistically significant differences at 10 weeks of follow-up in PVAQ and mFIS questionnaire scores between ONS group and placebo
• In patients with cluster headache, low-quality evidence found significant differences favoring PNS (peripheral nerve stimulation) of sphenopalatine ganglion in the percentage of patients who reported pain relief (67.1% vs 7.4%, p < 0.0001) and who achieved complete analgesia (34.1% vs 1.5%, p < 0.0001) at 15, 30, 60 and 90 minutes after stimulation (55.5% vs 8.0%, 60.6% and 60.0% vs 11.5% and 12.9%, respectively, p < 0.0001, 1 RCT)
• In patients with injuries associated with surgical procedures, trauma or chemical assault, one RCT with 94 patients showed that PNS and pharmacological analgesia increased the percentage of participants reporting a reduction in pain intensity ( 27.2% vs 2.3%, very-low-quality evidence), worst pain crisis intensity (DM -2.4 ± 2.3 vs -0.3 ± 1.6, respectively, p < 0.0001, low-quality evidence), average score for the general activity (DM -2.3 ± 2.7 vs -0.4 ± 2.0, p = 0.001), QoL measured with the SF-36 questionnaire (MD 1.4 ± 5.9 vs -0.2 ± 3.4, p = 0.037, very-low-quality evidence) as well as patient satisfaction (4.4% vs 44.9%, p < 0.0001) compared to the control group at 90 days of follow-up
• In patients with chronic low back pain, very low-quality evidence showed that minimal PNS reduced pain intensity in 42.0% (p < 0.001) and improved the relief of pain (RR 4.35, 95% CI 1.67 to 11.31, p = 0.003) versus the standard stimulation group
• In women with chronic pelvic pain, pooled results of low and very low-quality evidence at 12 weeks of follow-up showed that, compared with the usual pharmacological treatment, the use of tibial PENS (percutaneous electrical nerve stimulation) improved intensity of the present pain measured with the VAS scale (PPI) (MD 4.41 points, CI 2.95 to 5.86, p < 0.00001, low-quality evidence), total pain score index (PRI) (MD 12.48 points, CI 5.51 to 19.46, p = 0.0005), sensory and affective McGill questionnaire domains scores (DM 7.07 points, CI 4.15-9.98 and 2.55 points, CI 1.44-3.66, respectively, p < 0.00001) and the mental (MD 16.46 points, CI 8.91 to 24.01, p < 0.0001) and physical SF-36 questionnaire components (DM 17.53 points, CI 6.04 to 29.02, p = 0.003)

Among the main conclusions, the authors declare that the current evidence on the effectiveness and safety of electrical stimulation of peripheral nerves for treating chronic refractory pain is limited and often remains undetermined due to deficiencies on methodology and patient’s selection for the studies. Therefore, the use of these techniques should be assessed individually according to the patient’s preferences, availability, response to treatment and the results from randomized clinical trials or prospective registers of patients with chronic pain.

See the full report in Spanish here.

Subscribe to our newsletter delivered every second week not to miss important reimbursement information.