RISS Versus Lower Thoracic ESP Block for Analgesia After Laparoscopic Abdominal Surgery: A Randomized Trial

Official title

Analgesic Efficacy of Ultrasound-Guided Rhomboid Intercostal and Subserratus (RISS) Block Versus Lower Thoracic Erector Spinae Plane Block (ESPB) After Abdominal Laparoscopic Surgery

Overview

The goal of this clinical trial is to investigate the analgesic efficacy of ultrasound-guided Romboid Intercostal and Subserratus (RISS) block versus lower thoracic Erector Spinae Plane (ESP) block after laparoscopic abdominal surgery. The main questions it aims to answer are: Does ultrasound-guided Romboid Intercostal and Subserratus (RISS) block is effective as the lower thoracic Erector Spinae Plane (ESP) block for intra and postoperative analgesia after laparoscopic abdominal surgery for the first 24 hours? What complications do participants have when doing these interventions? Researchers will compare the analgesic efficacy of ultrasound-guided Romboid Intercostal and Subserratus (RISS) block with the lower thoracic Erector Spinae Plane (ESP) block after laparoscopic abdominal surgery. Participants will: Start general anesthesia and be given either block according to the randomization chart. The blood pressure and heart rate will be measured at intervals to determine if the participants need extra intraoperative analgesics. Numerical Rating Scale (NRS) will be used postoperatively to test pain severity. Rescue morphine analgesia will be measured and compared in both groups. Any complications will be reported. Patient and surgeon satisfaction will be measured.

Detailed description

The aim of this study is to investigate the analgesic efficacy of ultrasound-guided Romboid Intercostal and Subserratus (RISS) block versus lower thoracic Erector Spinae Plane (ESP) block after laparoscopic abdominal surgery.

Hypothesis

This study hypothesize that both RISS and ESP blocks relieve somatic pain equally, but ESP block relieves visceral pain better than RISS block, thereby reducing opioid consumption and improving patient satisfaction.

Methodology using:

I. Study design

Double-blinded randomized clinical trial study.

II. Study setting and location The study will be conducted at the operative theater of Souad Kafafi University Hospital (SKUH), Misr University for Science and Technology (MUST).

III. Study population:

Patients aged from 18 to 60 years old scheduled for laparoscopic abdominal surgery will be randomized in a 1:1 ratio after induction of general anesthesia, either:

Group A: Receiving ultrasound-guided RISS block. A solution composed of 20 ml mixed xylocaine 1% + 0.25% bupivacaine + 4 mg dexamethasone on each side.

Group B: Receiving ultrasound-guided lower thoracic ESP block (T8-T9) A solution composed of 20 ml mixed xylocaine 1% + 0.25 % bupivacaine + 4 mg dexamethasone on each side.

The infiltrative local anesthesia will be administered via a 22-gauge, 80-mm Echogenic block needle.

Postoperative analgesia:

The participants in both groups will receive analgesia in accordance with the following protocol:

* Pain will be assessed using a Numerical Rating Scale (NRS) 0-10.

1. Mild pain (NRS 1-3) will be treated with 1 g paracetamol IV every six hours (maximum 4 g/day). 2. Moderate pain (NRS 4-6) will receive the same paracetamol regimen plus ketorolac 30 mg IV every eight hours (maximum 120 mg/day). 3. Severe pain (NRS 7-10) will receive the above plus 0.1 mg/kg IV morphine when indicated.

Study outcomes:

Primary Outcome Measure: * Efficacy of postoperative analgesia for first 24 hours.

Secondary Outcome Measures:

* Total morphine equivalent consumption (mg) in 24 h. * Surgeon satisfaction (ability to perform active movements, 1-5 scale). * Patient satisfaction (1-5 scale). * Onset time of analgesia (min). * Duration of postoperative analgesia (time to first rescue). * Pain intensity via NRS at 2, 6, 12, 18, and 24 h. * Intraoperative vital signs (HR, NIBP). * Possible complications (pneumothorax, LAST, and vascular puncture) intra- and post-operatively.

Sample size calculation The sample size calculation was performed using G. power 3.1.9.2 (Universität Kiel, Germany). The sample size was calculated according to the total morphine dose in 24hr (4.21 in RISS vs. 4.65 in ESP) according to previous studies (9, 10). Based on the following considerations: 0.05 α error and 80% power of the study. Four cases were added to overcome dropout. Therefore, 70 patients will be allocated.

Statistical Analysis Statistical analysis will be done by SPSS v26 (IBM Inc., Chicago, IL, USA). Shapiro-Wilks test and histograms will be used to evaluate the normality of the distribution of data. Quantitative parametric variables will be presented as mean and standard deviation (SD) and compared between the two groups utilizing unpaired Student's t- test. Quantitative non-parametric data will be presented as median and interquartile range (IQR) and will be analyzed by Mann Whitney-test. Qualitative variables will be presented as frequency and percentage (%) and will be analyzed utilizing the Chi-square test or Fisher's exact test when appropriate. A two tailed P value \< 0.05 will be considered statistically significant.

Interventions

• Procedure Group A (n=35): Ultrasound-guided RISS block (RISS):
  The patient will be positioned in the lateral decubitus with the ipsilateral arm abducted to move the scapula laterally and open the intercostal and subscapular spaces. A high-frequency linear probe (10-14 MHz) will be applied 1-2 cm medial to the medial scapular border in an oblique-sagittal plane at the T5-T6 level. Using an in-plane approach, a 22 G, 80 mm block needle will be advanced from superomedial to inferolateral (cephalocaudal) until the tip lies between RM and ICM. After negative asp
• Procedure Group B (n=35): Ultrasound-guided lower thoracic ESP block
  The patient will be positioned laterally. A linear probe will be placed 3 cm lateral to the posterior midline at the T8-T9 level to identify the transverse process (TP) and erector spinae muscle (ESM). A 22 G, 80 mm Echogenic block needle will be advanced in-plane from cranial to caudal until the tip rests deep to ESM but superficial to the TP. After negative aspiration, 20 ml of the prepared solution (1% lidocaine + 0.25% bupivacaine + 4 mg dexamethasone) will be injected in 5 ml aliquots, with

Primary outcome measures

• Postoperative analgesia [Time frame: from 0 to 24 hours postoperative]

Secondary outcome measures (4)

• Total morphine consumption (mg) in 24 h. [Time frame: from 0 to 24 hours postoperative]
• Intra-operative vital signs (HR) [Time frame: Before induction of anesthesia till the end of surgery]
• • Intra-operative vital signs: Mean Blood Pressure (MBP) [Time frame: Before induction of anesthesia till the end of surgery]
• Possible complications [Time frame: Intra- and post-operatively for 24 hours.]

Eligibility criteria

Inclusion criteria

• Patients scheduled for laparoscopic abdominal surgery (e.g., cholecystectomy, colectomy, sleeve gastrectomy, hernia repair, appendectomy).
• Age from 18 - 60 years old.
• Both sexes.
• American Society of Anesthesiology (ASA) classification I, II. (i.e., ASA I: a normal healthy patient; ASA II: patients with mild controlled systemic disease.

Exclusion criteria

• Patients who refuse the research consent.
• Allergy to local anesthetic drugs.
• Cardiac arrhythmia.
• Bleeding tendency (including pre-existing blood disease and patients on full anticoagulant therapy).
• Morbid obese patients (BMI>35 kg/m2)
• Vascular compromise of lower extremity (e.g., Burger disease, Raynaud's disease).
• Connective tissue disease (e.g., Scleroderma).
• Suspected malignancy or intra-abdominal infection.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Double blind

Primary purpose

Treatment

Study locations

Egypt · 1 center

• Souad Kafafi University Hospital (SKUH), Faculty of Medicine, MUST — Giza

Publications

• Lin J, Wu H, Wen Z, Li Y, Jiang C, Lin B, Gu Y. Subserratus Anterior Plane Block vs Thoracic Paravertebral Block for Postoperative Analgesia in Laparoscopic Radical Nephrectomy: Protocol for a Randomized Controlled, Double-Blind, Non-Inferiority Clinical Trial. J Pain Res. 2025 Mar 25;18:1615-1625. doi: 10.2147/JPR.S506226. eCollection 2025. PMID 40161212
• Wang S, Wang H, Chen X, Li M, Xu D. Ultrasound-Guided Continuous Rhomboid Intercostal and Sub-Serratus Plane Block Comparison of Thoracoscopic Intercostal Nerve Block After Thoracoscopic Surgery: A Prospective Randomized Controlled Study. J Pain Res. 2024 Dec 21;17:4471-4481. doi: 10.2147/JPR.S484092. eCollection 2024. PMID 39726901
• Elsharkawy H, Maniker R, Bolash R, Kalasbail P, Drake RL, Elkassabany N. Rhomboid Intercostal and Subserratus Plane Block: A Cadaveric and Clinical Evaluation. Reg Anesth Pain Med. 2018 Oct;43(7):745-751. doi: 10.1097/AAP.0000000000000824. PMID 30169476

Identifiers

NCT: NCT07593300 · 2025/0124

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗