Treatment of residual and phantom limb pain using percutaneous ablation: a systematic review and meta-analysis

Limb loss is estimated to affect 176 million people globally. Up to 80% of patients experience significant residual limb pain (RLP) and phantom limb pain (PLP) following amputation, and generally respond poorly to conventional therapies. Percutaneous ablation has emerged as a promising intervention for both RLP and PLP pain. We sought to systematically review and evaluate the efficacy and adverse outcomes of thermal radiofrequency ablation (RFA), pulsed RFA, and cryoablation in the treatment of post-amputation pain.

Medline, Embase, PubMed, and Scopus databases were systematically search on August 19, 2024 for all English language articles related to post-amputation pain treated with an ablation technique. Articles were assessed for risk of bias using the Joanna Briggs Institute tool for case reports and case series. Outcomes included response to standardized pain scales (either numeric rating scale or visual analog scale), functional outcomes, and adverse events.

Out of 1233 articles, 20 were included for analysis. This included 1 randomized control trial (n = 144 patients), 9 case series (n = 74), and 10 case reports (n = 10). Comparing across 3 studies (n = 32 patients), thermal radiofrequency ablation (RFA) improved RLP compared to baseline at 2-weeks [weighted mean difference from baseline: 7.0 (95% CI: 6.8-7.3; p < 0.0001)] and 6-month [6.7 (6.7-6.8; p < 0.0001)]. For pulsed RFA we compared across 4 studies (n = 6 patients) to show improvement in RLP from baseline to 1-month [7.8 (7.1-8.5; p < 0.0001)] and 6-months [6.4 (4.7-8.1; p < 0.0001)], as well as across 7 studies (n = 10 patients) to show improvement in PLP from baseline at 1-month [5.9 (4.0-7.7; p < 0.0001)] and 6-months [5.6 (3.7-7.5); p < 0.0001]). In 3 studies (n = 27 patients) cryoablation decreased PLP compared to baseline at 6-months [3.9 (3.7-4.1; p < 0.0001), but a randomized control trial (n = 144 patients] did not demonstrate significant benefit at 4-months. There was one report of a fall secondary to temporary motor block with no other significant complications reported across all studies.

Both thermal and pulsed RFA appear to be safe and effective treatments for post-amputation pain. Further research is required to better assess their effectiveness and safety profile in larger and more well controlled studies.