Study of QL Analgesic Response and Extent
SQUARE
Anterior Versus Posterior Versus Lateral Quadratus Lumborum Block: a Randomized Control Trial in Healthy Volunteers
1 other identifier
interventional
25
0 countries
N/A
Brief Summary
A total of 14-18 healthy volunteers will be included. There will be three different procedure days, separated by at least one week. On each visit, the subjects will receive a QL block, according to the randomization process. Each volunteer will undergo pre-procedure screening on the first visit. The blocks will be performed on the same side, by the same anesthesiologist, with at least one week between each block. An anterior QL block will be administered on one day, a posterior QL block on another, and a lateral QL block on the third. The order will be randomized, and both the subject and the research team member assessing the block will be blinded. To compare the dermatomal sensory block distribution, the investigators will use detailed mapping with pinprick, cold, and heat stimuli. A handheld dynamometric assessment of lower extremity strength. The testing will be performed 60 to 90 minutes after performance of the blocks.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at below P25 for phase_4
Started May 2026
Shorter than P25 for phase_4
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
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Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
April 29, 2026
CompletedStudy Start
First participant enrolled
May 1, 2026
CompletedFirst Posted
Study publicly available on registry
May 5, 2026
CompletedPrimary Completion
Last participant's last visit for primary outcome
November 1, 2026
ExpectedStudy Completion
Last participant's last visit for all outcomes
December 1, 2026
May 5, 2026
April 1, 2026
6 months
April 29, 2026
April 29, 2026
Conditions
Keywords
Outcome Measures
Primary Outcomes (3)
Number of participants with blocked areas as measured by skin temperature discrimination
Skin temperature assessment using gloved ice on the chest wall, to discriminate blocked vs unblock areas.
60 to 90 minutes post-block
Number of participants with blocked areas as measured by mechanical discrimination
Mechanical assessment using a neuropin (pinprick) on the chest wall, to discriminate blocked vs unblock areas.
60 to 90 minutes post-block
Blocked area as measured by cutaneous distribution mapping
Mapping the blocked area (using the previous temperature and mechanical assessments, demarcating lines on the skin) to calculate the area blocked.
60 to 90 minutes post-block
Secondary Outcomes (3)
Skin temperature of the chest wall
60 to 90 minutes post-block
Blocked area as measured by nociceptive discrimination
60 to 90 minutes post-block
Lidocaine systemic absorption
0, 30, 60, 120, and 240 minutes after lidocaine administration
Other Outcomes (1)
Number of participants with block-related Adverse Events
End of study (2 days post blocks)
Study Arms (3)
Lateral Quadratus Lumborum block
ACTIVE COMPARATORParticipants receive quadratus lumborum block under ultrasound guidance, with 30mL of 1.5% lidocaine on one visit.
Anterior Quadratus Lumborum Block
EXPERIMENTALParticipants receive anterior quadratus lumborum block under ultrasound guidance, with 30mL of 1.5% lidocaine on one visit.
Posterior Quadratus Lumborum Block
EXPERIMENTALParticipants receive posterior quadratus lumborum block under ultrasound guidance, with 30mL of 1.5% lidocaine on one visit.
Interventions
For the anterior QL block, a curvilinear probe and nerve stimulator will be used. Local anesthetic will be deposited anterior to the QL muscle but posterior to the psoas muscle. A nerve stimulator at 2 Hz frequency, 1.5 mA will be used to aid in identification of intramuscular placement of the needle. Local anesthetic will only be deposited if no twitch is seen in either the QL or psoas muscle with an appropriate circuit formed. For the posterior QL block, a linear or curvilinear probe will be used, at the discretion of the anesthesiologist. Local anesthetic will be deposited posterior to the QL muscle such that anterior depression of the muscle is seen. For the lateral QL block, local anesthetic will be deposited lateral to the QL muscle.
Eligibility Criteria
You may qualify if:
- Ability to provide written informed consent
- Ability and willingness to comply with the study procedures and duration requirements
- ASA physical status 1 or 2
- Age ≥ 18 years
- Weight \> 70kg
You may not qualify if:
- BMI \> 35kg.m2
- Use of analgesics within 24 hours before the procedure
- History of thoracic trauma or surgery
- Abdominal deformities or abnormalities that may prevent proper block performance
- Abdominal tattoos in the area of block performance
- Systemic neuromuscular disease
- Contraindications to regional anesthesia (e.g., infection, allergy, challenging sonoanatomy)
- Structures are unable to be visualized by ultrasound
- Pregnancy
- Other known health conditions that would affect the participant's ability to successfully complete the study
Contact the study team to confirm eligibility.
Sponsors & Collaborators
- Duke Universitylead
MeSH Terms
Conditions
Interventions
Condition Hierarchy (Ancestors)
Intervention Hierarchy (Ancestors)
Study Officials
- PRINCIPAL INVESTIGATOR
Brian Mendelson, MD
Duke University
Central Study Contacts
Study Design
- Study Type
- interventional
- Phase
- phase 4
- Allocation
- RANDOMIZED
- Masking
- DOUBLE
- Who Masked
- PARTICIPANT, OUTCOMES ASSESSOR
- Masking Details
- Double
- Purpose
- OTHER
- Intervention Model
- PARALLEL
- Sponsor Type
- OTHER
- Responsible Party
- SPONSOR
Study Record Dates
First Submitted
April 29, 2026
First Posted
May 5, 2026
Study Start
May 1, 2026
Primary Completion (Estimated)
November 1, 2026
Study Completion (Estimated)
December 1, 2026
Last Updated
May 5, 2026
Record last verified: 2026-04
Data Sharing
- IPD Sharing
- Will not share