Trial Outcomes & Findings for Surgical Treatment of Post-surgical Mastectomy Pain Utilizing the Regenerative Peripheral Nerve Interface (NCT NCT04530526)
NCT ID: NCT04530526
Last Updated: 2025-12-24
Results Overview
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.
COMPLETED
NA
26 participants
24 months post enrollment
2025-12-24
Participant Flow
Participant milestones
| Measure |
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.
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.
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|---|---|
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Overall Study
STARTED
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26
|
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Overall Study
COMPLETED
|
20
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Overall Study
NOT COMPLETED
|
6
|
Reasons for withdrawal
| Measure |
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.
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.
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|---|---|
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Overall Study
Withdrawal by Subject
|
6
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Baseline Characteristics
Surgical Treatment of Post-surgical Mastectomy Pain Utilizing the Regenerative Peripheral Nerve Interface
Baseline characteristics by cohort
| Measure |
Regenerative Peripheral Nerve Interface (RPNI)
n=26 Participants
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.
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.
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|---|---|
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Age, Customized
20-29 years
|
1 Participants
n=30 Participants
|
|
Age, Customized
30-39 years
|
1 Participants
n=30 Participants
|
|
Age, Customized
40-49 years
|
9 Participants
n=30 Participants
|
|
Age, Customized
50-59 years
|
5 Participants
n=30 Participants
|
|
Age, Customized
60-69 years
|
8 Participants
n=30 Participants
|
|
Age, Customized
70-79 years
|
2 Participants
n=30 Participants
|
|
Sex: Female, Male
Female
|
25 Participants
n=30 Participants
|
|
Sex: Female, Male
Male
|
1 Participants
n=30 Participants
|
|
Ethnicity (NIH/OMB)
Hispanic or Latino
|
0 Participants
n=30 Participants
|
|
Ethnicity (NIH/OMB)
Not Hispanic or Latino
|
25 Participants
n=30 Participants
|
|
Ethnicity (NIH/OMB)
Unknown or Not Reported
|
1 Participants
n=30 Participants
|
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Race (NIH/OMB)
American Indian or Alaska Native
|
0 Participants
n=30 Participants
|
|
Race (NIH/OMB)
Asian
|
1 Participants
n=30 Participants
|
|
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
|
0 Participants
n=30 Participants
|
|
Race (NIH/OMB)
Black or African American
|
2 Participants
n=30 Participants
|
|
Race (NIH/OMB)
White
|
22 Participants
n=30 Participants
|
|
Race (NIH/OMB)
More than one race
|
0 Participants
n=30 Participants
|
|
Race (NIH/OMB)
Unknown or Not Reported
|
1 Participants
n=30 Participants
|
PRIMARY outcome
Timeframe: baseline, and 9 months post surgeryThe 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
Outcome measures
| Measure |
Regenerative Peripheral Nerve Interface (RPNI)
n=20 Participants
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.
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.
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|---|---|
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Change in Pain Level
Numerical Pain Rating Scale- Preoperative Score
|
6.9 score on a scale
Standard Error 0.4
|
|
Change in Pain Level
Numerical Pain Rating Scale- Postoperative Score
|
0.6 score on a scale
Standard Error 0.3
|
|
Change in Pain Level
Short Form McGill Pain Questionnaire 2- Preoperative
|
4.4 score on a scale
Standard Error 0.5
|
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Change in Pain Level
Short Form McGill Pain Questionnaire 2- Postoperative
|
2.5 score on a scale
Standard Error 0.6
|
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Change in Pain Level
Pain Catastrophizing Score- Preoperative
|
27.5 score on a scale
Standard Error 3.0
|
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Change in Pain Level
Pain Catastrophizing Score- Postoperative
|
14.1 score on a scale
Standard Error 2.9
|
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Change in Pain Level
PROMIS Intensity- Preoperative
|
7.9 score on a scale
Standard Error 0.5
|
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Change in Pain Level
PROMIS Intensity- Postoperative
|
4.9 score on a scale
Standard Error 0.8
|
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Change in Pain Level
PROMIS Interference- Preoperative
|
16.2 score on a scale
Standard Error 1.3
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Change in Pain Level
PROMIS Interference- Post Operative
|
11.0 score on a scale
Standard Error 2.0
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Change in Pain Level
PROMIS Neuropathic- Preoperative
|
8.6 score on a scale
Standard Error 1.4
|
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Change in Pain Level
PROMIS Neuropathic- Postoperative
|
6.0 score on a scale
Standard Error 1.4
|
PRIMARY outcome
Timeframe: baseline, and 9 months post surgeryEvaluated 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.
Outcome measures
| Measure |
Regenerative Peripheral Nerve Interface (RPNI)
n=20 Participants
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.
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.
|
|---|---|
|
Change in Depression/Anxiety Scores
Patient Health Questionnaire-9- Preoperative
|
10.3 score on a scale
Standard Error 1.3
|
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Change in Depression/Anxiety Scores
Patient Health Questionnaire-9- Postoperative
|
7.2 score on a scale
Standard Error 1.4
|
|
Change in Depression/Anxiety Scores
Generalized Anxiety Disorder-7- Preoperative
|
7.3 score on a scale
Standard Error 1.1
|
|
Change in Depression/Anxiety Scores
Generalized Anxiety Disorder-7- postoperative
|
4.3 score on a scale
Standard Error 1.2
|
PRIMARY outcome
Timeframe: baseline, and 9 months post surgeryEvaluated 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.
Outcome measures
| Measure |
Regenerative Peripheral Nerve Interface (RPNI)
n=20 Participants
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.
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.
|
|---|---|
|
Change in Opioid Consumption (Number of Opioid Medications)
Number of Opioid Medications- Preoperative
|
1.3 Opioid medications
Standard Error 0.2
|
|
Change in Opioid Consumption (Number of Opioid Medications)
Number of Opioid Medications- Postoperative
|
0.4 Opioid medications
Standard Error 0.2
|
PRIMARY outcome
Timeframe: 24 months post enrollmentData 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.
Outcome measures
| Measure |
Regenerative Peripheral Nerve Interface (RPNI)
n=20 Participants
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.
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.
|
|---|---|
|
Freedom From Neuroma Recurrence Evaluated by Physical Exam
|
20 Participants
|
PRIMARY outcome
Timeframe: 24 months post enrollmentData 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.
Outcome measures
| Measure |
Regenerative Peripheral Nerve Interface (RPNI)
n=20 Participants
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.
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.
|
|---|---|
|
Freedom From Neuroma Recurrence Evaluated by Ultrasound
|
20 Participants
|
PRIMARY outcome
Timeframe: baseline, and 9 months post surgeryEvaluated 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.
Outcome measures
| Measure |
Regenerative Peripheral Nerve Interface (RPNI)
n=20 Participants
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.
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.
|
|---|---|
|
Change in Opioid Consumption (Oral Morphine Equivalents)
Oral Morphine Equivalents (mg)- Preoperative
|
43.3 mg morphine equivalent
Standard Error 11.4
|
|
Change in Opioid Consumption (Oral Morphine Equivalents)
Oral Morphine Equivalents (mg)- Postoperative
|
12.0 mg morphine equivalent
Standard Error 4.9
|
Adverse Events
Regenerative Peripheral Nerve Interface (RPNI)
Serious adverse events
Adverse event data not reported
Other adverse events
Adverse event data not reported
Additional Information
University of Michigan Rogel Cancer Center ClinicalTrials.gov Admin
University of Michigan Rogel Cancer Center
Results disclosure agreements
- Principal investigator is a sponsor employee
- Publication restrictions are in place