Surgical Treatment of Post-surgical Mastectomy Pain Utilizing the Regenerative Peripheral Nerve Interface (RPNI)

Surgical Treatment of Post-surgical Mastectomy Pain Utilizing the Regenerative Peripheral Nerve Interface (RPNI)

Post-mastectomy pain due to nerve injury leads to long-term opioid use and diminished quality-of-life. The investigators on this study will evaluate the regenerative peripheral nerve interface (RPNI), a novel surgical approach to neuroma treatment, to improve patient-reported post-mastectomy pain and definitively treat intercostal neuromas after mastectomy.

Study Overview

• Status: Completed
• Conditions: Post-Mastectomy Chronic Pain Syndrome
• Intervention / Treatment: Procedure: Regenerative Peripheral Nerve Interface

Detailed Description

Up to 40% of patients who undergo mastectomy suffer from chronic pain, defined as pain lasting greater than three months. Chronic post-mastectomy pain due to nerve injury leads to long-term opioid use and diminished quality-of-life. A novel surgical approach to neuroma treatment, the regenerative peripheral nerve interface (RPNI) developed to treat painful neuromas associated with limb amputation has shown significant reductions in patient-reported pain. RPNI surgery is now available through Michigan Medicine's Multi-Disciplinary Peripheral Nerve (MDPN) Clinic to improve post-mastectomy pain and definitively treat intercostal neuromas following mastectomy. Using patient-reported outcomes and clinical data the investigators will evaluate the use of RPNI surgery to reduce persistent post- mastectomy pain in women seeking surgical consultation through the Plastic Surgery or MDPN clinics.

• Study Type: Interventional
• Enrollment (Actual): 26
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Michigan
    • Ann Arbor, Michigan, United States, 48109
      • University of Michigan Rogel Cancer Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

In order to be eligible to participate in this study, a subject must meet all of the following criteria:

• Reporting post-mastectomy pain at least six months removed from mastectomy or partial mastectomy (lumpectomy).
• Willing to comply with all study procedures and be available for the duration of the study
• Fluent in English
• Women of reproductive potential must use highly effective contraception (specify methods of contraception acceptable for the study, e.g., licensed hormonal methods) and/or willingness to undergo a pregnancy test.

Exclusion Criteria:

A potential subject who meets any of the following criteria will be excluded from participation in this study:

• Previous surgical management for chronic post-mastectomy pain
• Signs/symptoms which are not suggestive of neuropathic pain based on physical exam at time of consultation.
• Pregnancy or lactation
• Men will not be enrolled in this study due to the low prevalence of male mastectomy.
• Anything that, in the opinion of the investigator, would place the subject at increased risk or preclude the subject's full compliance with or completion of the study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Other: Regenerative Peripheral Nerve Interface (RPNI); Using evaluative ultrasound measurements and a standard panel of patient-reported outcome measures (PROMs) to measure pain experience, anxiety and depression, patients will be evaluated at baseline (T1=0months), pre-operatively following 3 months of standard neuropathic pain management therapy (T2=3months) and at three months (T3=6months) and nine months (T4=12months) post RPNI surgery.

Procedure: Regenerative Peripheral Nerve Interface; The regenerative peripheral nerve interface (RPNI) has emerged as a novel strategy to treat neuromas in peripheral nerves. The RPNI consists of the residual peripheral nerve end implanted in a skeletal muscle graft, following surgical resection of the injured terminal nerve portion (neuroma). The free muscle graft is separated from its native nerve innervation, leaving open neuromuscular junctions for ingrowth and attachment of nerve fibers from the implanted nerve.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Pain Level	The use of RPNI surgery to reduce post-mastectomy pain will be evaluated by validated patient-reported outcome (PRO) surveys administered at 4 timepoints: at baseline (at time of enrollment), at the RPNI pre-operative visit (approximately 3 months after enrollment), and at approximately 3 and 9 months after RPNI surgery. The average time of study involvement for each patient will be 12 months. Patients enrolled during the first year of the study's 2-year recruitment period may be followed until the study stops. Numerical Pain Rating Scale (0-10)- 10 indicating more pain Short Form McGill Pain Questionnaire 2 (0-10)- 10 indicating more pain Pain Catastrophizing Score (0-52)- 52 indicating more pain PROMIS Intensity (0-12)- 12 indicating more pain PROMIS Interference (0-24)- 24 indicating more pain PROMIS Neuropathic (0-20)- 20 indicating more pain	baseline, and 9 months post surgery
Change in Depression/Anxiety Scores	Evaluated by validated patient-reported outcome (PRO) surveys administered at 4 timepoints: at baseline (at time of enrollment), at the RPNI pre-operative visit (approximately 3 months after enrollment), and at approximately 3 and 9 months after RPNI surgery. The average time of study involvement for each patient will be 12 months. Patients enrolled during the first year of the study's 2-year recruitment period may be followed until the study stops. Patient Health Questionnaire-9 range is 0-27. 27 indicates a worse outcome. Generalized Anxiety Disorder-7 range is 0-21. 21 indicates a worse outcome.	baseline, and 9 months post surgery
Change in Opioid Consumption (Number of Opioid Medications)	Evaluated by validated patient-reported outcome (PRO) surveys administered at 4 timepoints: at baseline (at time of enrollment), at the RPNI pre-operative visit (approximately 3 months after enrollment), and at approximately 3 and 9 months after RPNI surgery. The average time of study involvement for each patient will be 12 months. Patients enrolled during the first year of the study's 2-year recruitment period may be followed until the study stops.	baseline, and 9 months post surgery
Freedom From Neuroma Recurrence Evaluated by Physical Exam	Data will be derived from standard clinical care for patients seeking surgical management of post-mastectomy chronic pain. Physical examinations will be performed at the time of patient enrollment and subsequent follow-up visits, as part of routine clinical evaluation, up to approximately 9 months after RPNI surgery. Patients enrolled during the first year of the study's 2-year recruitment period may be followed until the study stops.	24 months post enrollment
Freedom From Neuroma Recurrence Evaluated by Ultrasound	Data will be derived from standard clinical care for patients seeking surgical management of post-mastectomy chronic pain. Ultrasound will be performed at the time of patient enrollment and subsequent follow-up visits, as part of routine clinical evaluation, up to approximately 9 months after RPNI surgery. Patients enrolled during the first year of the study's 2-year recruitment period may be followed until the study stops.	24 months post enrollment
Change in Opioid Consumption (Oral Morphine Equivalents)	Evaluated by validated patient-reported outcome (PRO) surveys administered at 4 timepoints: at baseline (at time of enrollment), at the RPNI pre-operative visit (approximately 3 months after enrollment), and at approximately 3 and 9 months after RPNI surgery. The average time of study involvement for each patient will be 12 months. Patients enrolled during the first year of the study's 2-year recruitment period may be followed until the study stops.	baseline, and 9 months post surgery

Collaborators and Investigators

• Sponsor: University of Michigan Rogel Cancer Center
• Collaborators: National Cancer Institute (NCI)
• Investigators: Principal Investigator: David L Brown, M.D., University of Michigan

Publications and helpful links

General Publications

• Nag S, Kennedy P, Aris K, Moore AM, Farhadi R. The Role of Nerve Surgery in the Management of Post-Breast Surgery Pain Syndrome: A Systematic Review and Meta-analysis. Ann Plast Surg. 2025 Dec 1;95(6):625-629. doi: 10.1097/SAP.0000000000004516. Epub 2025 Oct 16.

Study record dates

Study Major Dates

• Study Start (Actual): July 12, 2019
• Primary Completion (Actual): June 30, 2023
• Study Completion (Actual): September 30, 2023

Study Registration Dates

• First Submitted: August 24, 2020
• First Submitted That Met QC Criteria: August 24, 2020
• First Posted (Actual): August 28, 2020

Study Record Updates

• Last Update Posted (Estimated): December 24, 2025
• Last Update Submitted That Met QC Criteria: December 23, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: neuroma,outcome-assessment health care, post-mastectomy; outcome-assessment health care; post-mastectomy; neuroma
• Additional Relevant MeSH Terms: Neoplasms; Neoplasms by Histologic Type; Neoplasms, Nerve Tissue; Nerve Sheath Neoplasms; Neuroma
• Other Study ID Numbers: UMCC 2018.124; HUM00149189 (Other Identifier: University of Michigan); R21CA234760 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No