Key points from the evidence

A systematic review of 27 studies (n=358) found that IV lidocaine infusions provided a statistically significant but short-lived (generally a few hours or days) reduction in pain scores compared with placebo for people with chronic neuropathic pain.⁴ The clinical significance of the review findings was unclear because effect sizes were not reported for many of the primary studies.

Adverse effects from IV lidocaine infusions were mild and reported by relatively few patients. The most common adverse effects were light headedness, fatigue and nausea.⁴

In a single-arm meta-analysis (21 studies, n=2,370), facet joint injections of local anaesthetic with or without steroids resulted in statistically and clinically significant reductions in pain scores for up to 12 months in patients with chronic spinal pain of facet joint origin.⁵ In meta-analyses (three studies, n=320) comparing injections of local anaesthetic alone with local anaesthetic plus steroids, there were no statistically significant differences between groups in pain reduction or function improvement.⁵

A systematic review of eight randomised controlled trials (RCTs, n=587) found that facet joint injections were associated with an overall 31% reduction in pain scores and a 12.6% improvement in disability scores after 6–12 months follow-up in patients with facet joint osteoarthritis.⁶

The most common adverse effects associated with facet joint injections were a temporary increase in low back pain (20% of patients in one RCT, n=25) and discomfort (44% of patients in one RCT, n=99).⁷

A systematic review with comparative and single-arm meta-analyses of four RCTs (n=370) found that cervical interlaminar epidural injections of local anaesthetic alone or local anaesthetic plus steroids were associated with statistically significant reductions in pain scores and neck disability scores for up to 12 months in adults with chronic neck pain.⁸

A systematic review with comparative meta-analysis of ten RCTs (n=1,111) found no statistically significant differences in pain reduction or function improvement between epidural injections with local anaesthetic alone or local anaesthetic plus steroids in patients with chronic low back pain associated with disc herniation or lower limb radiculopathy.⁹ Duration of follow-up was not reported.

A systematic review of 52 RCTs (n=6,354) assessing epidural injections for treating chronic back pain with different causes reported mixed findings. While most studies demonstrated pain reductions, results varied and no effect sizes were provided. Results were not reported separately for injections with and without steroids.

Adverse effects were reported for less than 10% of patients across studies that recorded safety outcomes for epidural injections.^{8, 11} Examples of adverse effects included temporary soreness around the injection site. No serious adverse effects were reported.

A systematic review with single-arm meta-analysis of 14 studies (n=983) found statistically and clinically significant reductions in pain scores with sacroiliac joint injections of local anaesthetic plus steroids in patients with chronic back pain of sacroiliac origin after 3 and 6 months follow-up.¹² Statistically significant improvements in function were reported after 3 and 6 months follow-up, but were clinically significant only at 3-months follow-up. A lack of comparative analysis means it is unclear whether adding steroids to local anaesthetic injections offers additional benefits.

Safety outcomes relating to sacroiliac joint injections were not reported in the systematic
review.¹²

Continuous or pulsed RFA targeting the nerves supplying the shoulder joint may reduce pain and improve shoulder function in patients with chronic shoulder pain, but the magnitude and clinical significance of the effects are uncertain.^{13, 14}

• A systematic review of 29 studies (n=1,174), that did not report effect sizes, concluded there were statistically significant reductions in chronic shoulder pain scores and improvements in function scores 3–6 months after RFA.¹⁴
• A systematic review with comparative meta-analysis (eight RCTs, n=428) found no statistically significant differences in pain reduction or shoulder function between patients treated with RFA and those who received an active comparator or placebo after 1–3 months follow-up.¹³

A health technology assessment (HTA), based on a systematic review of 26 studies (number of patients unclear), concluded there was insufficient evidence to determine the effectiveness of continuous RFA for treating chronic hip pain.¹⁵

An HTA (two systematic reviews and two primary studies, n=491), a systematic review (19 studies, n=145) and a systematic review with a single-arm meta-analysis (eight studies, n=256), reported that RFA targeting the nerves supplying the knee led to statistically significant reductions in pain scores and improvements in function for up to 6 months in patients with chronic knee pain.^15-17 The magnitude of these effects varied across the primary studies included in the reviews.

Adverse effects were reported only in studies assessing RFA for chronic knee pain.^{15, 17} They were reported in the minority of studies and were not serious. Examples include subcutaneous bleeding around the knee, temporary numbness or transient pain.

In a systematic review of eight studies (number of patients unclear), thermal RFA targeting cervical spinal nerves to treat chronic neck pain was associated with complete pain relief for 46% to 70% of patients at 6-months and 20% to 51% of patients at 12-months follow-up.¹⁸

A systematic review with comparative meta-analysis of 19 RCTs (n=1,530) found evidence that continuous RFA provided statistically significant short-term pain relief (<3 months) compared with sham controls in patients with chronic low back pain associated with the sacroiliac joints.¹⁹ The clinical significance of this result was unclear. No statistically significant differences between RFA and sham controls were reported for other RFA targets, such as facet joints or intervertebral discs.

A systematic review with comparative and single-arm meta-analysis (21 studies, n=1,947) found that RFA resulted in a statistically significant reduction in chronic sacroiliac joint pain at 3 and 6 months follow-up compared with active controls.²⁰ It is unclear whether the difference between groups was clinically significant. In single-arm meta-analyses, there were statistically and clinically significant reductions in pain and improvements in function for up to 12 months after RFA.

A systematic review with single-arm meta-analysis (seven studies, n=240) evaluating cooled RFA found statistically and clinically significant reductions in pain and increased function at maximum follow-up (3–24 months) in patients with chronic sacroiliac joint pain.²¹

No serious adverse effects were reported after the use of RFA to treat chronic spinal pain.^{7, 18, 22} Non-serious adverse effects were reported in a minority of studies and included symptoms such as a burning sensation and temporary pain.

Three economic evaluations assessed the cost effectiveness of RFA compared with exercise programmes (two studies) or conservative management (one study) for treating patients with chronic low back pain.^23-25 None of the studies used a United Kingdom (UK) NHS perspective and results were not generalisable to Scotland. Results from the studies were heterogeneous and contained substantial uncertainty.

Three network meta-analyses (NMA) and two systematic reviews (136 studies, total n=12,187) compared spinal injections with RFA for the treatment of different causes of chronic spinal pain.^{7, 26-29} Results for pain relief and function improvements varied across analyses, with authors reporting either no statistically significant differences between interventions or statistically significant improvements in the RFA groups compared with the spinal injections groups.

Two grey literature reports (interviews, n=92; survey, n=462) found that chronic pain affected all aspects of people’s lives, including daily activities, work and relationships.^{30, 31} Living with chronic pain negatively impacted people’s quality of life, mental health and well-being, sense of identity and social engagement.

Two grey literature reports (interviews, n=92; survey, n=462) and a systematic review of qualitative studies that used a survey (n=1,219) to validate the results of their review, described four themes from patient experiences of chronic pain:

• a lack of knowledge and understanding about chronic pain among healthcare
  professionals, carers, family and friends
• long waiting lists and delays in accessing treatment
• barriers to accessing chronic pain services, particularly specialist pain services
• poor communication between healthcare services and patients.^30-32

In a comparative meta-analysis of 19 observational studies (n=3,312,343) in patients with different types of chronic pain, the lifetime prevalence of suicidal ideation was 28.90% (95% confidence interval [CI] 17.95% to 41.26%) and the lifetime prevalence of suicide attempts was 10.83% (95% CI 5.72% to 17.30%).³³ In another comparative meta-analysis of 88 studies (number of patients unknown), people with physical pain of any duration were twice as likely to exhibit suicidal behaviour or attempt suicide compared with people without physical pain.³⁴

A primary study analysed user comments (n=405) posted on the Reddit online forum about RFA treatment for chronic pain.³⁵ Of the 405 comments, 187 users reported improved pain and 130 reported no meaningful change in their pain after RFA. Among 96 comments that mentioned the duration of pain relief, the range was 4 days to 3 years. Fifteen users reported that the pain relief was shorter than expected.

A patient organisation submission from the Scottish Cross-Party Group on Chronic Pain
reported that:

• there is substantial variation in the availability of specialist interventions across health boards in Scotland
• patients found the effects of specialist interventions to be life changing, allowing them to resume a near-normal life and to reduce their reliance on opioid medications
• untreated chronic pain is linked with an increased risk of suicidal behaviour
• four out of five people with chronic pain contacted at least one NHS unscheduled care service in Scotland over a 3-year period
• patients in Scotland are experiencing long delays in accessing chronic pain services, including appointments for repeat interventions
• for some patients IV lidocaine infusions were effective for up to 8 weeks.