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Published on: March 8, 2024
Long-Term Treatment of Chronic Postamputation Pain With Bioelectric Nerve Block: Twelve-Month Results of the
Leonardo Kapural1, Billy Kim2, John Eidt3
1Carolinas Pain Institute and Center for Clinical Research, Winston-Salem, NC, USA.
Objective:
The multicenter, randomized, double-blinded, active-sham controlled trial (high-freQUEncy nerve block for poST amputation pain [QUEST]) was conducted to show the safety and efficacy of a novel, peripherally placed high-frequency nerve block (HFNB) system in treating chronic postamputation pain (PAP) in patients with lower limb amputations. The primary outcomes from QUEST were reported previously. This study presents the long-term, single-cross-over, secondary outcomes of on-demand HFNB treatment for chronic PAP.
Materials And Methods:
After the three-month randomized period, subjects in the active-sham group were crossed over to receive therapy for 12 months. Subjects self-administered HFNB therapy as needed and reported their pain (numerical rating scale [NRS]; range, 1-10) before and 30 and 120 minutes after each treatment. Pain medication use was reported throughout the study. Pain-days per week and quality of life (QOL) were assessed using the Brief Pain Inventory (BPI). Adverse events (AEs) were recorded for all subjects implanted for 12 months.
Results:
Of 180 subjects implanted in QUEST, 164 (91%) were included in the cross-over period, and 146 (82%) completed follow-up. By month 12, average NRS pain in the combined cohort was reduced by 2.3 ± 2.2 points (95% CI, 1.7-2.8; p < 0.0001) 30 minutes after treatment and 2.9 ± 2.4 points (95% CI, 2.2-3.6; p < 0.0001) 120 minutes after treatment. Mean pain-days per week were significantly reduced (-3.5 ± 2.7 days; p < 0.001), and subject daily opioid use was reduced by 6.7 ± 29.0 morphine equivalent dose from baseline to month 12 (p = 0.013). Mean BPI-interference scores (QOL) improved by 2.7 ± 2.7 points from baseline (p < 0.001). The incidence of nonserious AEs and serious AEs was 72% (130/180) and 42% (76/180), respectively; serious device-related AEs occurred in 15 of 180 subjects (8%).
Conclusion:
Overall, HFNB delivered directly to the damaged peripheral nerve provided sustained, on-demand relief of acute PAP exacerbations, reduced opioid utilization, and improved QOL for patients with lower limb amputations with chronic PAP.
