Understanding Rebound Pain After Regional Anesthesia Resolution in Healthy Volunteers

November 4, 2025 updated by: Yun-Yun K. Chen, Brigham and Women's Hospital

Understanding Rebound Pain After Regional Anesthesia Resolution: Mechanistic Trial in Healthy Volunteers

Regional anesthesia decreases postoperative pain scores and opioid consumption, and may prevent chronic pain after surgery in patients undergoing surgery. However, some patients experience an increase of pain into the severe range when the nerve block wears off, also known as rebound pain. The investigators are studying if a nerve block (numbing injection) in the arm causes hyperalgesia (increased pain) when the nerve block is wearing off.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

This is a prospective, randomized study in healthy volunteers who will undergo sensory testing using quantitative sensory testing (QST), complete psychosocial and pain questionnaires, and ultrasound-guided peripheral nerve block of the arm (axillary nerve block) in a supervised, monitored setting (BWH Clinical Investigation Center). The investigators plan to assess the association between different QST modalities at different time points pre- and post-nerve block resolution. Semi-structured interviews and qualitative analysis will be used to explore patient's experiences with nerve block placement.

Study Type

Interventional

Enrollment (Actual)

40

Phase

  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Massachusetts
      • Boston, Massachusetts, United States, 02115
        • Brigham and Women's Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Age ≥ 18 years old, ≤ 65 years old
  • BMI >18, < 35
  • Able to speak and understand English
  • Willingness to undergo psychophysical testing (e.g., QST, pain questionnaires)
  • Willingness to have nerve block performed

Exclusion Criteria:

  • Ongoing acute or chronic pain in upper extremities
  • Skin or tissue infection affecting upper extremities
  • Previous hypersensitivity to mepivacaine or lidocaine
  • Previous neuropathy (numbness, paresthesia, or motor weakness) in either upper extremity
  • Loss of any limb
  • Bleeding issues or bleeding disorder
  • History of alcohol or drug abuse
  • Currently pregnant or breastfeeding
  • History of seizure or epilepsy

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Block upper extremity (arm)
Upper extremity with a nerve block
Drug: Mepivacaine
Injection of 1.5% Mepivacaine in nerve block
Other Names:
  • Prilocaine
No Intervention: Control upper extremity (arm)
Upper extremity without a nerve block

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Heat pain detection threshold at time 1 hr
Time Frame: 1 hour after nerve block resolution
Heat pain detection threshold (°C) between block arm and control arm using a heat probe at 1 hour after nerve block resolution
1 hour after nerve block resolution

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Heat pain detection threshold and tolerance
Time Frame: 0-3 hours after nerve block resolution
Heat pain detection threshold and tolerance (°C) between block arm and control arm using a heat probe at different time points up to 3 hours nerve block resolution
0-3 hours after nerve block resolution
Pressure pain threshold and tolerance
Time Frame: 0-3 hours after nerve block resolution
Pressure pain threshold and tolerance (N of force) between block arm and control arm using an algometer at different time points up to 3 hours nerve block resolution
0-3 hours after nerve block resolution
Temporal summation and sharp pain
Time Frame: 0-3 hours after nerve block resolution
Temporal summation and sharp pain (evaluated by numerical rating scale 0-10 pain score) between block arm and control arm using a pinprick device at different time points up to 3 hours nerve block
0-3 hours after nerve block resolution
Light touch detection
Time Frame: 0-3 hours after nerve block resolution
Light touch detection (mN of force) between block arm and control arm using von Frey filaments at different time points up to 3 hours nerve block
0-3 hours after nerve block resolution
Light touch pain threshold
Time Frame: 0-3 hours after nerve block resolution
Light touch pain threshold (mN of force) between block arm and control arm using von Frey filaments at different time points up to 3 hours nerve block
0-3 hours after nerve block resolution

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Temperature change
Time Frame: 6-8 hours
To observe the change in temperature between block arm and control arm (°C) pre, during, and post nerve block
6-8 hours
Patient's experiences with nerve block
Time Frame: 6-8 hours
Semi-structured interviews will be used to explore patient's experiences with nerve block placement using an immersion/crystallization approach to identify emergent themes
6-8 hours
Pain catastrophizing and gender differences
Time Frame: 6-8 hours
Correlation between situational pain catastrophizing (0-24 scale) and gender
6-8 hours

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Brigham and Women's Hospital

Investigators

  • Principal Investigator: Yun-Yun K Chen, MD, Brigham and Women's Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

September 28, 2023

Primary Completion (Actual)

May 28, 2024

Study Completion (Actual)

May 28, 2024

Study Registration Dates

First Submitted

July 16, 2023

First Submitted That Met QC Criteria

August 17, 2023

First Posted (Actual)

August 22, 2023

Study Record Updates

Last Update Posted (Estimated)

November 5, 2025

Last Update Submitted That Met QC Criteria

November 4, 2025

Last Verified

June 1, 2024

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2023P001767

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

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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