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

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

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

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
40

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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 Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.
  • Name: Yun-Yun K Chen, MD
  • Phone Number: 6176510932
  • Email: ykchen@mgb.org

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

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

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
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

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
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

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
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

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
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

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Brigham and Women's Hospital

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • 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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 28, 2023

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 28, 2024

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
May 28, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 16, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 17, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
August 22, 2023

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
November 5, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 4, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2024

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant 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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