Effects of Injection Volume and Site on Sensory Distribution After Rectus Sheath Block

NCT07876297 | Not Yet Recruiting

• 1 other identifier: ANE-2569-0340
• Study Type: interventional
• Target: 120
• Locations: 1 country
• Sites: 1

Brief Summary

This randomized controlled study aims to evaluate the effects of local anesthetic injection volume and injection site on cutaneous sensory distribution following ultrasound-guided rectus sheath block (RSB). Participants undergoing laparoscopic abdominal surgery will be randomized to receive RSB using different injection sites and volumes (20 mL or 30 mL per side). Injection sites will be selected according to the surgical location, including upper, middle, or lower rectus sheath approaches. Cutaneous sensory distribution will be assessed to determine the extent and pattern of sensory blockade associated with each technique. The findings may help optimize injection techniques and local anesthetic volumes to achieve adequate sensory coverage for abdominal surgery.

Conditions

Cutaneous Sensory Blockade

Keywords

rectus sheath block; regional anesthesia; cutaneous sensory distribution; abdominal surgery; analgesia

Outcome Measures

Primary Outcomes (1)

• Cutaneous Sensory Blockade Area Assessed by Pinprick Testing

  The extent of cutaneous sensory blockade following ultrasound-guided rectus sheath block will be assessed using pinprick testing. Areas with reduced or absent pinprick sensation will be identified and mapped to determine the total cutaneous sensory blockade area (CSBA).

  30 minutes after surgery

Secondary Outcomes (9)

• Cutaneous Sensory Blockade Area Assessed by Pinprick Testing

  24 hours after block completion

• Cutaneous Sensory Blockade Area Assessed by Cold Testing

  30 minutes after surgery and 24 hours after block completion

• Number of Dermatomes With Sensory Blockade

  30 minutes after surgery and 24 hours after block completion

• Dermatomal Distribution of Sensory Blockade

  30 minutes after surgery and 24 hours after block completion

• Regression of Cutaneous Sensory Blockade Over Time

  30 minutes after surgery and 24 hours after block completion

Study Arms (6)

Upper RSB 20 mL (U-20)

EXPERIMENTAL

Participants undergoing laparoscopic upper abdominal surgery will receive bilateral ultrasound-guided upper rectus sheath block using 20 mL of local anesthetic per side.

Procedure: Ultrasound-Guided Upper Rectus Sheath Block (20 mL)

Upper RSB 30 mL (U-30)

EXPERIMENTAL

Participants undergoing laparoscopic upper abdominal surgery will receive bilateral ultrasound-guided upper rectus sheath block using 30 mL of local anesthetic per side.

Procedure: Ultrasound-Guided Upper Rectus Sheath Block (30 mL)

Middle RSB 20 mL (M-20)

EXPERIMENTAL

Participants undergoing either laparoscopic upper or lower abdominal surgery will receive bilateral ultrasound-guided middle rectus sheath block using 20 mL of local anesthetic per side.

Procedure: Ultrasound-Guided Middle Rectus Sheath Block (20 mL)

Middle RSB 30 mL (M-30)

EXPERIMENTAL

Participants undergoing either laparoscopic upper or lower abdominal surgery will receive bilateral ultrasound-guided middle rectus sheath block using 30 mL of local anesthetic per side.

Procedure: Ultrasound-Guided Middle Rectus Sheath Block (30 mL)

Lower RSB 20 mL (L-20) Copy

EXPERIMENTAL

Participants undergoing laparoscopic lower abdominal surgery will receive bilateral ultrasound-guided lower rectus sheath block using 20 mL of local anesthetic per side.

Procedure: Ultrasound-Guided Lower Rectus Sheath Block (20 mL)

Lower RSB 30 mL (L-30)

EXPERIMENTAL

Participants undergoing laparoscopic lower abdominal surgery will receive bilateral ultrasound-guided lower rectus sheath block using 30 mL of local anesthetic per side.

Procedure: Ultrasound-Guided Lower Rectus Sheath Block (30 mL)

Interventions

Ultrasound-Guided Upper Rectus Sheath Block (20 mL) PROCEDURE

Bilateral ultrasound-guided upper rectus sheath block will be performed using 20 mL of 0.25% bupivacaine with epinephrine per side. The local anesthetic will be injected into the plane between the rectus abdominis muscle and the posterior rectus sheath at the upper abdominal injection site.

Upper RSB 20 mL (U-20)

Ultrasound-Guided Upper Rectus Sheath Block (30 mL) PROCEDURE

Bilateral ultrasound-guided upper rectus sheath block will be performed using 30 mL of 0.25% bupivacaine with epinephrine per side. The local anesthetic will be injected into the plane between the rectus abdominis muscle and the posterior rectus sheath at the upper abdominal injection site.

Upper RSB 30 mL (U-30)

Ultrasound-Guided Middle Rectus Sheath Block (20 mL) PROCEDURE

Bilateral ultrasound-guided middle rectus sheath block will be performed using 20 mL of 0.25% bupivacaine with epinephrine per side. The local anesthetic will be injected into the plane between the rectus abdominis muscle and the posterior rectus sheath at the middle abdominal injection site.

Middle RSB 20 mL (M-20)

Ultrasound-Guided Middle Rectus Sheath Block (30 mL) PROCEDURE

Bilateral ultrasound-guided middle rectus sheath block will be performed using 30 mL of 0.25% bupivacaine with epinephrine per side. The local anesthetic will be injected into the plane between the rectus abdominis muscle and the posterior rectus sheath at the middle abdominal injection site.

Middle RSB 30 mL (M-30)

Ultrasound-Guided Lower Rectus Sheath Block (20 mL) PROCEDURE

Bilateral ultrasound-guided lower rectus sheath block will be performed using 20 mL of 0.25% bupivacaine with epinephrine per side. The local anesthetic will be injected into the plane between the rectus abdominis muscle and the posterior rectus sheath at the lower abdominal injection site.

Lower RSB 20 mL (L-20) Copy

Ultrasound-Guided Lower Rectus Sheath Block (30 mL) PROCEDURE

Bilateral ultrasound-guided lower rectus sheath block will be performed using 30 mL of 0.25% bupivacaine with epinephrine per side. The local anesthetic will be injected into the plane between the rectus abdominis muscle and the posterior rectus sheath at the lower abdominal injection site.

Lower RSB 30 mL (L-30)

Eligibility Criteria

• Age: 20 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Patients scheduled for laparoscopic upper abdominal surgery and laparoscopic lower abdominal surgery, including urological procedures
• American Society of Anesthesia (ASA) physical status I-III
• Have ability to communicate and understand the study and accept to participate in the study

You may not qualify if:

• Aged \< 20 years
• Patients who have following underlying disease: severe hepatic impairment \[diagnosed of cirrhosis (Child-Pugh C)\], coagulopathy (diagnosed of disease associated with abnormal coagulation), pre-existing neurological deficits, end-stage renal disease (ESRD), chronic pain (diagnosed of chronic pain disease or current use regular analgesic drugs), or any drug addiction.
• Known allergy to bupivacaine or weighing less than 50 kg
• Patient with previous abdominal surgery
• Patient with Morbid obesity (BMI \> 40 kg/m2)

Sponsors & Collaborators

• Chiang Mai University: lead

Study Sites (1)

Maharaj Nakorn Chiang Mai Hospital, Faculty of Medicine, Chiang Mai University

Chiang Mai, Chiang Mai, 50200, Thailand

Location

Related Publications (2)

• Fernandes HDS, Azevedo AS, Ferreira TC, Santos SA, Rocha-Filho JA, Vieira JE. Ultrasound-guided peripheral abdominal wall blocks. Clinics (Sao Paulo). 2021 Jan 20;76:e2170. doi: 10.6061/clinics/2021/e2170. eCollection 2021.

  PMID: 33503184 RESULT

• Rojas A, McMillan DT, Allan JD, Nanda M, Anumudu C, Armbruster J, Jolly M, Magin J, Maquoit G, Grant SA. Evaluating Patterns of Injectate Spread After Rectus Sheath Block: A Cadaveric Dissection Study. Cureus. 2023 Jan 24;15(1):e34142. doi: 10.7759/cureus.34142. eCollection 2023 Jan.

  PMID: 36843817 RESULT

MeSH Terms

Conditions

Agnosia

Condition Hierarchy (Ancestors)

Perceptual Disorders; Neurobehavioral Manifestations; Neurologic Manifestations; Nervous System Diseases; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Central Study Contacts

Kittitorn Supphapipat, MD

CONTACT

+6653935522; kittitorn.pans@gmail.com

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Department of Anesthesiology, Faculty of Medicine, Chiang Mai University

Model Details: This prospective, randomized, parallel-group study will stratify participants according to surgical location (upper or lower abdominal surgery). Within each stratum, participants will be randomly assigned to one of four groups in a 2:2:1:1 ratio based on the injection site and local anesthetic volume (20 or 30 mL per side). Each participant will receive only the assigned rectus sheath block technique.

Study Record Dates

• First Submitted: October 9, 2026
• First Posted: October 15, 2026
• Study Start: October 12, 2026
• Primary Completion (Estimated): December 20, 2027
• Study Completion (Estimated): December 31, 2027
• Last Updated: October 15, 2026

Record last verified: 2026-10

Data Sharing

• IPD Sharing: Will not share

Locations

TH (1)