Acute PainPhase 2RESTNCT07068243
REctus Sheath Trial
A Phase 2 study testing 1.0% lidocaine with epinephrine (1:100,000) in people with Acute Pain and Postoperative Pain, Acute, run by Duke University.
Trial summary
Regional anesthesia techniques (or nerve blocks) are used to provide sensory blockade over the abdominal wall. The most established technique is thoracic epidural. This provides bilateral spread but is also associated with neuraxial complications, which has led to a decrease in clinical usage. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Acute Pain, Postoperative Pain, Acute
- What is being tested?
- 1.0% lidocaine with epinephrine (1:100,000)
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 25 participants
- Where
- No sites listed yet
- Study dates
- Sep 2026to Apr 2027
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- 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 > 60kg
Who cannot join
- BMI > 40kg.m-2
- Use of analgesics within 24 hours before the procedure
- History of abdominal trauma or surgery
- Abdominal deformities or abnormalities that may prevent proper block performance
- Abdominal tattoos in the supraumbilical area
- Systemic neuromuscular disease
Show all 10Show fewer
- Contraindications to regional anesthesia (e.g., infection, allergy)
- 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
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: Transverse Versus Longitudinal Approaches for Rectus Sheath Block: a Randomized Controlled Trial in Healthy Volunteers
Regional anesthesia techniques (or nerve blocks) are used to provide sensory blockade over the abdominal wall. The most established technique is thoracic epidural. This provides bilateral spread but is also associated with neuraxial complications, which has led to a decrease in clinical usage. The rectus sheath block (RSB) is an established regional anesthesia technique used to provide somatic analgesia to the midline anterior abdominal wall by depositing local anesthetic in the posterior rectus sheath, thereby targeting the terminal anterior branches of the lower thoracic intercostal nerves. The conventional approach involves placing the ultrasound (US) probe transversely across the rectus abdominis muscle and advancing the needle in-plane either lateral-to-medial or medial-to-lateral. While this technique achieves spread within the sheath, the cephalocaudal distribution of local anesthetic may be suboptimal, potentially limiting the extent of dermatomal coverage. A longitudinal probe orientation, with needle insertion from cephalad to caudad, may theoretically facilitate a more extensive cranio-caudal spread by aligning the injection axis with the anatomical fascial plane of the posterior rectus sheath. However, the relative efficacy of these two approaches has not been investigated in a controlled, comparative setting. Thus, this randomized, single-blinded trial aims to evaluate the dermatomal sensory distribution and ultrasound-assessed local anesthetic spread achieved by the transverse versus longitudinal in-plane approaches to ultrasound-guided RSB in healthy adult volunteers. To compare the dermatomal sensory block distribution, investigators will use dermatomal mapping with pinprick, and cold.
Read the detailed description
A total of 14-18 adult volunteers will be included. Each participant will receive bilateral rectus sheath blocks at a standardized supraumbilical level. The side receiving the transverse approach (US probe perpendicular to muscle fibers; needle in-plane lateral-to-medial) and the side receiving the longitudinal approach (US probe parallel to muscle fibers; needle in-plane cephalad-to-caudad) will be randomized. The blocks will be performed with a standardized volume and concentration of local anesthetic, under real-time US guidance by the same experienced anesthesiologist. The research team member assessing the block will be blinded. Immediately after injection of each block, US imaging will be used to assess and measure the length and pattern of spread within the posterior rectus sheath. At baseline and at 60 minutes post-block, dermatomal sensory mapping will be performed using standardized cold and pinprick stimuli over the anterior abdominal wall.
- Conditions
- Acute Pain, Postoperative Pain, Acute
- Being tested
- 1.0% lidocaine with epinephrine (1:100,000)
- Keywords
- Rectus Sheath Block, Abdominal Block, Fascial Plane Block, RSB
- Medical subject headings
- Acute Pain, Pain, Postoperative
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
1.0% lidocaine with epinephrine (1:100,000)Drug
The block will be performed by advancing the needle into the posterior rectus sheath compartment, with the local anesthetic deposited posterior to the rectus abdominis muscle and anterior to the posterior rectus sheath.
Drug: 20 mL injection of 1.0% lidocaine with epinephrine (1:100,000) on each side (40mL total/subject)
| Study group | Role | What they receive |
|---|---|---|
| Transverse Approach to the Rectus Sheath Block | Active comparator | In the transverse approach, the US probe will be positioned perpendicular to the he rectus abdominis muscle's fibers, and the needle will be inserted in-plane from lateral to medial. Receives: Drug: 1.0% lidocaine with epinephrine (1:100,000) |
| Longitudinal Approach to the Rectus Sheath Block | Experimental | In contrast, the longitudinal approach will involve aligning the probe parallel to the rectus muscle fibers, with the needle advanced in-plane from cephalad to caudad. Receives: Drug: 1.0% lidocaine with epinephrine (1:100,000) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Temperature discrimination
Skin temperature assessment using gloved ice on the chest wall, to discriminate blocked vs unblock areas.
Measured: 60 to 90 minutes post-block
Mechanical discrimination
Mechanical assessment using a neuropin (pinprick) on the chest wall, to discriminate blocked vs unblock areas.
Measured: 60 to 90 minutes post-block
Cutaneous distribution mapping
Mapping the blocked area (using the previous temperature and mechanical assessments, demarcating lines on the skin) to provide a visual map and, to calculate the area blocked.
Measured: 60 to 90 minutes post-block
Secondary outcomes (2)
Direct visualization of the local anesthetic spread
Direct visualization of the local anesthetic spread cephalad and caudad, marking the highest and lowest dermatomes where local anesthetic was still seen on the US, with the US oriented longitudinally.
Measured: Immediately post-block
Measurement of the local anesthetic spread in each dermatome with the US
Measurement of the local anesthetic spread in each dermatome with the US oriented transversely, by measuring hypoecoic area produced by the presence of local anesthetic.
Measured: Immediately post-block
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Jul 2025
- Study startSep 2026 (estimated)
- Primary completionFeb 2027 (estimated)
- Study completionApr 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Acute PainStudies of the same condition, open and under way.
- More trials run by Duke UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 25 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Duke University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07068243
- Sponsor's protocol ID
- Pro00118293
- Acronym
- REST
- Status last verified
- Jun 2026
- First submitted
- 7 Jul 2025
- Last updated
- 17 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 17 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Transverse Versus Longitudinal Approaches for Rectus Sheath Block: a Randomized Controlled Trial in Healthy Volunteers
- ClinicalTrials.gov ID
- NCT07068243
- Acronym / sponsor ID
- REST / Pro00118293
- Conditions
- Acute Pain, Postoperative Pain, Acute
- Keywords
- Rectus Sheath Block, Abdominal Block, Fascial Plane Block, RSB
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 25 participants (estimated)
- Lead sponsor
- Duke UniversityUniversity, hospital or other
- Study start
- Sep 2026 (estimated)
- Primary completion
- Feb 2027 (estimated)
- Study completion
- Apr 2027 (estimated)
- First posted
- 16 Jul 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Regional anesthesia techniques (or nerve blocks) are used to provide sensory blockade over the abdominal wall. The most established technique is thoracic epidural. This provides bilateral spread but is also associated with neuraxial complications, which has led to a decrease in clinical usage. The rectus sheath block (RSB) is an established regional anesthesia technique used to provide somatic analgesia to the midline anterior abdominal wall by depositing local anesthetic in the posterior rectus sheath, thereby targeting the terminal anterior branches of the lower thoracic intercostal nerves. The conventional approach involves placing the ultrasound (US) probe transversely across the rectus abdominis muscle and advancing the needle in-plane either lateral-to-medial or medial-to-lateral. While this technique achieves spread within the sheath, the cephalocaudal distribution of local anesthetic may be suboptimal, potentially limiting the extent of dermatomal coverage. A longitudinal probe orientation, with needle insertion from cephalad to caudad, may theoretically facilitate a more extensive cranio-caudal spread by aligning the injection axis with the anatomical fascial plane of the posterior rectus sheath. However, the relative efficacy of these two approaches has not been investigated in a controlled, comparative setting. Thus, this randomized, single-blinded trial aims to evaluate the dermatomal sensory distribution and ultrasound-assessed local anesthetic spread achieved by the transverse versus longitudinal in-plane approaches to ultrasound-guided RSB in healthy adult volunteers. To compare the dermatomal sensory block distribution, investigators will use dermatomal mapping with pinprick, and cold.
Detailed description
A total of 14-18 adult volunteers will be included. Each participant will receive bilateral rectus sheath blocks at a standardized supraumbilical level. The side receiving the transverse approach (US probe perpendicular to muscle fibers; needle in-plane lateral-to-medial) and the side receiving the longitudinal approach (US probe parallel to muscle fibers; needle in-plane cephalad-to-caudad) will be randomized. The blocks will be performed with a standardized volume and concentration of local anesthetic, under real-time US guidance by the same experienced anesthesiologist. The research team member assessing the block will be blinded. Immediately after injection of each block, US imaging will be used to assess and measure the length and pattern of spread within the posterior rectus sheath. At baseline and at 60 minutes post-block, dermatomal sensory mapping will be performed using standardized cold and pinprick stimuli over the anterior abdominal wall.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Transverse Approach to the Rectus Sheath Block | Active comparator | Drug: 1.0% lidocaine with epinephrine (1:100,000)In the transverse approach, the US probe will be positioned perpendicular to the he rectus abdominis muscle's fibers, and the needle will be inserted in-plane from lateral to medial. |
| Longitudinal Approach to the Rectus Sheath Block | Experimental | Drug: 1.0% lidocaine with epinephrine (1:100,000)In contrast, the longitudinal approach will involve aligning the probe parallel to the rectus muscle fibers, with the needle advanced in-plane from cephalad to caudad. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- 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 > 60kg
Key exclusion criteria (10 listed)
- BMI > 40kg.m-2
- Use of analgesics within 24 hours before the procedure
- History of abdominal trauma or surgery
- Abdominal deformities or abnormalities that may prevent proper block performance
- Abdominal tattoos in the supraumbilical area
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| 1.0% lidocaine with epinephrine (1:100,000)The block will be performed by advancing the needle into the posterior rectus sheath compartment, with the local anesthetic deposited posterior to the rectus abdominis muscle and anterior to the posterior rectus sheath. Drug: 20 mL injection of 1.0% lidocaine with epinephrine (1:100,000) on each side (40mL total/subject) | Drug | Longitudinal Approach to the Rectus Sheath Block, Transverse Approach to the Rectus Sheath Block |
Primary outcome
Temperature discrimination
Time frame: 60 to 90 minutes post-block
Skin temperature assessment using gloved ice on the chest wall, to discriminate blocked vs unblock areas.
Mechanical discrimination
Time frame: 60 to 90 minutes post-block
Mechanical assessment using a neuropin (pinprick) on the chest wall, to discriminate blocked vs unblock areas.
Cutaneous distribution mapping
Time frame: 60 to 90 minutes post-block
Mapping the blocked area (using the previous temperature and mechanical assessments, demarcating lines on the skin) to provide a visual map and, to calculate the area blocked.
2 secondary outcomes
Direct visualization of the local anesthetic spread
Time frame: Immediately post-block
Measurement of the local anesthetic spread in each dermatome with the US
Time frame: Immediately post-block
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Jun 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing 1.0% lidocaine with epinephrine (1:100,000) in people with Acute Pain and Postoperative Pain, Acute, run by Duke University.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 17 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact David MacLeod, MBBS (9198123201, david.macleod@duke.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Temperature discrimination (time frame: 60 to 90 minutes post-block). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Jun 2026.