REctus Sheath Trial

NCT07068243 | Not Yet Recruiting Phase 2 FDA Drug

• 1 other identifier: Pro00118293
• Study Type: interventional
• Target: 25
• Locations: 0 countries
• Sites: N/A

Brief 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. 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.

Conditions

Acute Pain; Postoperative Pain, Acute

Keywords

Rectus Sheath Block; Abdominal Block; Fascial Plane Block; RSB

Outcome Measures

Primary Outcomes (3)

• Temperature discrimination

  Skin temperature assessment using gloved ice on the chest wall, to discriminate blocked vs unblock areas.

  60 to 90 minutes post-block

• Mechanical discrimination

  Mechanical assessment using a neuropin (pinprick) on the chest wall, to discriminate blocked vs unblock areas.

  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.

  60 to 90 minutes post-block

Secondary Outcomes (2)

• Direct visualization of the local anesthetic spread

  Immediately post-block

• Measurement of the local anesthetic spread in each dermatome with the US

  Immediately post-block

Other Outcomes (1)

• Adverse Events

  End of study (2 days post blocks).

Study Arms (2)

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.

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.

Drug: 1.0% lidocaine with epinephrine (1:100,000)

Interventions

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)

Longitudinal Approach to the Rectus Sheath Block; Transverse Approach to the Rectus Sheath Block

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

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 \> 60kg

You may not qualify if:

• 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
• 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

Sponsors & Collaborators

• Duke University: lead

MeSH Terms

Conditions

Acute Pain; Pain, Postoperative

Interventions

Lidocaine; Epinephrine

Condition Hierarchy (Ancestors)

Pain; Neurologic Manifestations; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Postoperative Complications; Pathologic Processes

Intervention Hierarchy (Ancestors)

Acetanilides; Anilides; Amides; Organic Chemicals; Aniline Compounds; Amines; Ethanolamines; Amino Alcohols; Alcohols; Biogenic Monoamines; Biogenic Amines; Catecholamines; Catechols; Phenols; Benzene Derivatives; Hydrocarbons, Aromatic; Hydrocarbons, Cyclic; Hydrocarbons

Central Study Contacts

David MacLeod, MBBS

CONTACT

9198123201; david.macleod@duke.edu

Sara Amaral, MD

CONTACT

7373479570; sara.amaral@duke.edu

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Purpose: OTHER
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: July 7, 2025
• First Posted: July 16, 2025
• Study Start: May 1, 2026
• Primary Completion (Estimated): September 1, 2026
• Study Completion (Estimated): December 1, 2026
• Last Updated: January 22, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will not share