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

Study Overview
=================
Brief Summary
-----------------
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.

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.

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

Conditions
-----------------
Post-Mastectomy Chronic Pain Syndrome

Intervention / Treatment
-----------------
* Procedure: Regenerative Peripheral Nerve Interface


Participation Criteria
=================
Eligibility Criteria
-----------------
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.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
Female

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Regenerative Peripheral Nerve Interface (RPNI)<br>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<br>* 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.<br>|

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. | Baseline to 12 - 24 months | 
| 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. | Baseline to 12 - 24 months | 
| Change in opioid consumption | 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 to 12 - 24 months | 
| 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. | Up to 24 months | 
| 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. | Up to 24 months | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
neuroma,outcome-assessment health care, post-mastectomy, outcome-assessment health care, post-mastectomy, neuroma