Regenerative Peripheral Nerve Interface (RPNI) Surgery for Treatment and Prevention of Painful Neuroma in Lower Limb Amputations: One Year Outcomes
Christine SW Best, MD1, Jennifer B. Hamill, MPH1, Hyungjin M Kim, ScD1, Melissa J Tinney, MD1, Paul S Cederna, M.D.1, Michael E Geisser, MD, PhD1, Stephen WP Kemp, Ph.D.1 and Theodore A Kung, MD2, 1University of Michigan, Ann Arbor, MI, 2Section of Plastic & Reconstructive Surgery, University of Michigan, Ann Arbor, MI
Introduction: Regenerative peripheral nerve interface (RPNI) surgery is an emerging strategy to reduce the experience of postamputation pain. We present one-year findings from a prospective clinical trial examining the efficacy of RPNI surgery to treat and prevent symptomatic neuromas in major lower limb amputation patients. We hypothesize that RPNI surgery used for treatment of painful existing neuromas and prophylactically at the time of surgery to mitigate neuroma formation will result in better patient reported outcomes for pain as well as psychosocial wellbeing and prosthetic use.
Methods: Patients were recruited into two arms for this study: Arm 1 (patients with previous lower extremity amputations undergoing amputation revision for painful neuroma); or Arm 2 (patients undergoing prophylactic RPNI surgery at time of lower extremity amputation). In Arm 1, patient postoperative measures at one year were compared to their preoperative values. In Arm 2, postoperative measures at one year were compared between the prophylaxis RPNI study group and the Control group (patients undergoing standard of care lower extremity amputation without RPNI). Primary outcomes included pain assessment surveys with Short Form McGill Pain Questionnaire (SF-MPQ) and Patient-Reported Outcome Measurement Information System (PROMIS) instruments for Pain Intensity and Pain Interference. Secondary outcomes included psychosocial wellbeing surveys including the Pain Catastrophizing Scale (PCS), Generalized Anxiety Disorder-7 (GAD-7) and prosthetic use (Orthotics and Prosthetics Users’ Survey (OPUS). Standardized mean difference (effect size, d) was calculated for statistical analysis.
Results: 60 patients total have enrolled in the study. Outcomes are presented in Table 1 and Table 2. There was overall improvement in pain, psychosocial wellbeing, and prosthetic use in both arms. In Arm 1, greatest effect size was observed for improved Pain Interference scores (PROMIS: d=0.70, p=0.03) and improved psychosocial wellbeing (PCS: d=1.27, p=0.003; GAD: d=0.97, p=0.002) after RPNI surgery. In Arm 2, patients who underwent prophylactic RPNI surgery at the time of lower extremity amputation had improved pain scores (MPQ-2 SF: d=0.65, p=0.08) and improved prosthetic use (OPUS: d=0.61, p=0.06) compared to Control patients.
Conclusion: RPNI surgery in lower extremity amputation patients can play a promising role in mitigating postamputation pain and improving quality of life. Existing pain and psychosocial wellbeing are improved with RPNI surgery in patients with symptomatic neuroma, and prophylactic RPNI surgery can mitigate development of neuroma and enhance prosthetic rehabilitation.
Back to 2024 Abstracts