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NCT Number: NCT06005480

Understanding Rebound Pain After Regional Anesthesia Resolution 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.

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Key information

Conditions

Regional Anesthesia Morbidity Acute Pain Healthy Neurologic Manifestations Pain Pain, Acute Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 1

Primary location

Brigham and Women's Hospital

Boston, Massachusetts, 02115, United States

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Mepivacaine

Drug

Injection of 1.5% Mepivacaine in nerve block

Other names: Prilocaine

Primary outcomes

  1. 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

Secondary outcomes

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

Other outcomes

  1. 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

  2. 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

  3. Pain catastrophizing and gender differences

    Time frame: 6-8 hours

    Correlation between situational pain catastrophizing (0-24 scale) and gender

Sponsors and collaborators

Lead sponsor

Brigham and Women's Hospital

Other

Registry information

Official study title

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

Important dates

Study start
2023
Primary completion
2024
Study completion
2024
First posted
Aug 22, 2023
Registry last updated
Nov 5, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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