Regenerative peripheral nerve interface reduces the incidence of neuroma in the lower limbs after amputation: a retrospective study based on ultrasound

Abstract

Background Amputees suffer from symptomatic neuroma and phantom limb pain. Regenerative peripheral nerve interface (RPNI) has recently been regarded as an effective method to prevent neuroma after amputation. However, the verifications of RPNI efficacy are mostly based on subjective evaluation, lacking objective approaches. This study aims to unveil the effect of RPNI on preventing neuroma formation and provide evidence supporting the efficacy of RPNI based on ultrasound. Methods Amputees of lower limb at Peking University People’s Hospital from July 2020 to March 2022 were analyzed retrospectively. The clinical data collected consisted of general information, pathology of primary disease, history of limb-salvage treatment, amputation level of nerve, pain scales such as the Numerical Rating Scale (NRS) and the Manchester Foot Pain and Disability Index (MFPDI). Three months after amputation, the transverse diameter, anteroposterior diameter, and cross-sectional area of neuromas in stump nerves at the end of residual limbs were measured using ultrasound and compared to adjacent normal nerves. Results Fourteen patients were enrolled in the study, including 7 in the traditional amputation group (TA group) and 7 in the RPNI group. There was no significant difference in basic information and amputation sites between the two groups. The NRS and MFPDI scores of patients in RPNI group were significantly lower than those in TA group, and decreased with the follow-up time increasing, indicating that RPNI could reduce symptomatic neuroma pain. The comparison of preoperative ultrasound and postoperative pathology showed ultrasound could reflect the size of neuroma in vivo. Independent-sample t tests indicated that the ratios of anteroposterior diameter, transverse diameter and area of the cross section of both the neuroma and adjacent normal nerve obtained via ultrasound were significantly reduced in the RPNI group. Conclusion This study suggested that RPNI can effectively prevent the formation of symptomatic neuroma after amputation using ultrasound.

Regenerative Peripheral Nerve Interface Surgery for the Management of Chronic Posttraumatic Neuropathic Pain

“…31 In retrospective cohort studies that compared patients who underwent standard limb amputation with and without prophylactic RPNI surgery, patients who underwent RPNI surgery consistently had statistically significant better outcomes. [33][34][35] A smaller proportion of RPNI patients developed symptomatic neuromas postoperatively, which was also verified through ultrasound imaging. 33,34 Highresolution ultrasound (US) has been demonstrated in previous studies to be a useful and effective mechanism for diagnosing neuroma.…”

“…[33][34][35] A smaller proportion of RPNI patients developed symptomatic neuromas postoperatively, which was also verified through ultrasound imaging. 33,34 Highresolution ultrasound (US) has been demonstrated in previous studies to be a useful and effective mechanism for diagnosing neuroma. 36,37 On quantified US assessments of the nerve stumps, measurements of cross-sectional area, transverse diameter, and anteroposterior diameter confirmed that control patients developed neuromas while RPNI patients did not.…”

“…36,37 On quantified US assessments of the nerve stumps, measurements of cross-sectional area, transverse diameter, and anteroposterior diameter confirmed that control patients developed neuromas while RPNI patients did not. 33 Pain scores were also significantly lower at all postoperative time points in RPNI patients compared to control patients. 33,35 Furthermore, postoperative pain scores in RPNI patients improved over time, directly contrasting the control patients whose pain scores worsened.…”

“…33 Pain scores were also significantly lower at all postoperative time points in RPNI patients compared to control patients. 33,35 Furthermore, postoperative pain scores in RPNI patients improved over time, directly contrasting the control patients whose pain scores worsened. 33 In addition, patients who underwent RPNI surgery reported significantly more prosthetic use.…”

“…33,35 Furthermore, postoperative pain scores in RPNI patients improved over time, directly contrasting the control patients whose pain scores worsened. 33 In addition, patients who underwent RPNI surgery reported significantly more prosthetic use. 35 A subset of patients who underwent RPNI surgery reported persistent postoperative pain, and upon further investigation, it was revealed that these patients had unmasked neuropathic pain at a subsequent different site from their initial surgery.…”