Retrolaminar Analgesia for LuMbar Surgery (REALM)

Efficacy of Ultrasound-Guided Retrolaminar Block Combined With Standard Multimodal Analgesia for Postoperative Pain Management in Lumbar Spine Surgery: A Randomized Controlled Trial

This randomized controlled trial evaluates the effectiveness of ultrasound-guided retrolaminar nerve block in addition to standard multimodal analgesia for postoperative pain management in patients undergoing lumbar spine surgery. Fifty patients will be randomly assigned to receive either the retrolaminar block combined with standard pain management or standard pain management alone. The primary outcome is total opioid consumption in the first 24 hours after surgery. Secondary outcomes include pain intensity at multiple time points, time to first rescue analgesia, duration of sensory block, incidence of postoperative nausea and vomiting, length of hospital stay, patient satisfaction, and chronic pain development at 3 and 6 months follow-up.

Study Overview

• Status: Recruiting
• Conditions: Postoperative Pain; Lumbar Surgery; Back Pain Lower Back Chronic; Regional Anaesthesia; Opioid Analgesia
• Intervention / Treatment: Procedure: Ultrasound-Guided Retrolaminar Block; Other: Standard Analgesia

Detailed Description

BACKGROUND: Lumbar spine surgery is associated with significant postoperative pain, which can delay recovery and increase complications. Regional anesthesia techniques, specifically retrolaminar blocks, may provide superior analgesia compared to systemic opioids alone.

STUDY DESIGN: This is a prospective, randomized, controlled trial conducted at Clínica Universidad de Los Andes, Chile. Patients will be allocated using variable block randomization (block sizes 4 and 6) in a 1:1 ratio.

INTERVENTIONS: All patients will receive standardized general anesthesia (Propofol, Remifentanil, Rocuronium) and multimodal analgesia including paracetamol, metamizol, ketorolac, morphine, and pregabalin. The intervention group will additionally receive bilateral ultrasound-guided retrolaminar blocks with ropivacaine 0.5% (20 ml per side) at the end of surgery.

OUTCOMES: Primary outcome is cumulative morphine consumption via patient-controlled analgesia (PCA) during the first 24 postoperative hours. Secondary outcomes include pain scores (VAS 0-10) at 0, 6, 12, 24, 48, and 72 hours; time to first rescue analgesia; duration of sensory block; incidence of nausea/vomiting; hospital length of stay; time to ambulation; sleep quality; patient satisfaction; adverse events; and development of chronic pain at 3 and 6 months.

SAMPLE SIZE: 50 patients (25 per group) provides 80% power to detect a clinically significant difference in opioid consumption.

• Study Type: Interventional
• Enrollment (Estimated): 50
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Roberto Coloma, MD; Phone Number: (56) 22 618 3100; Email: rcoloma@clinicauandes.cl
• Study Contact Backup: Name: Nicolás Valls, MD, PhD; Phone Number: +56 9 33741332; Email: nvalls@clinicauandes.cl

Study Locations

• Chile
  • Santiago Metropolitan
    • Santiago, Santiago Metropolitan, Chile, 171571
      • Recruiting
      • Clínica Universidad de los Andes, Chile
      • Contact: Roberto Coloma, MD; Phone Number: +56 22 618 3100; Email: rcoloma@clinicauandes.cl

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Adult patients aged 18-80 years
• Scheduled for elective lumbar spine surgery (with instrumentation)
• American Society of Anesthesiologists (ASA) physical status I-III
• Willing and able to provide written informed consent
• Able to use patient-controlled analgesia (PCA) device

Exclusion Criteria:

• Refusal to participate in the study
• Known allergy to local anesthetics (bupivacaine - levobupivacaine - lidocaine) or any study medication
• Contraindication to regional anesthesia (infection at injection site, coagulopathy)
• Chronic opioid use (daily use for >3 months prior to surgery)
• Severe psychiatric disorder that precludes informed consent
• Emergency surgery
• Diabetes mellitus with preoperative glucose >180 mg/dl
• Pregnancy or breastfeeding
• Body mass index (BMI) >40 kg/m²
• Reoperation or revision of the same level of previous spinal surgery

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Retrolaminar Block & Standard Analgesia; Patients receive bilateral ultrasound-guided retrolaminar blocks with Bupivacaine 0.25% and Epinephrine 50mcg (15 ml total volume per side) before surgery, along with standard multimodal analgesia.	Procedure: Ultrasound-Guided Retrolaminar Block; Patients will receive bilateral ultrasound-guided retrolaminar blocks with Bupivacaine 0.25% and Epinephrine 50mcg (15 ml total volume per side) before surgery. The block will be performed by an experienced anesthesiologist using real-time ultrasound guidance.
Active Comparator: Standard Analgesia Only; Patients receive standard multimodal analgesia without regional anesthesia block.	Other: Standard Analgesia; Patients receive standard multimodal analgesia without regional anesthesia block.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total postoperative opioid consumption	Cumulative morphine consumption (in mg morphine equivalents) delivered via patient-controlled analgesia (PCA) pump during the first 24 postoperative hours	First 24 hours after surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pain Intensity	Pain intensity measured using Visual Analog Scale (VAS, 0-10 where 0=no pain and 10=worst imaginable pain) Time Frame: 0, 6, 12, 24, 48, and 72 hours postoperatively	Time in minutes from end of surgery until first request for rescue analgesia Time Frame: From end of surgery up to 72 hours
Duration of Sensory Block	Duration in hours from block performance until complete sensory recovery assessed by thermal and tactile testing	From block performance up to 72 hours
Time to First Rescue Analgesia	Time in minutes from end of surgery until first request for rescue analgesia	From end of surgery up to 24 hours
Incidence of PONV	Incidence of postoperative nausea and vomiting (PONV) requiring antiemetic rescue medication	First 24 hours postoperatively
Length of hospital stay	Total number of days from hospital admission to discharge	From admission to discharge, assessed up to 30 days

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Patient satisfaction	Patient satisfaction with pain management measured using 5-point Likert scale (1=very dissatisfied to 5=very satisfied)	72 hours postoperatively
Chronic Pain Development	Incidence of chronic pain defined as VAS > 3 at surgical site	3 months and 6 months postoperatively

Collaborators and Investigators

• Sponsor: Universidad de los Andes, Chile
• Investigators: Study Director: Nicolas J Valls, M.D, Ph.D, Anesthesiologyst, Clinica Universidad de los Andes

Publications and helpful links

General Publications

• Gerbershagen HJ, Aduckathil S, van Wijck AJ, Peelen LM, Kalkman CJ, Meissner W. Pain intensity on the first day after surgery: a prospective cohort study comparing 179 surgical procedures. Anesthesiology. 2013 Apr;118(4):934-44. doi: 10.1097/ALN.0b013e31828866b3.
• Batra RK, Krishnan K, Agarwal A. Paravertebral block. J Anaesthesiol Clin Pharmacol. 2011 Jan;27(1):5-11. No abstract available.
• Zeballos JL, Voscopoulos C, Kapottos M, Janfaza D, Vlassakov K. Ultrasound-guided retrolaminar paravertebral block. Anaesthesia. 2013 Jun;68(6):649-51. doi: 10.1111/anae.12296. No abstract available.
• Ardon AE, Prasad A, McClain RL, Melton MS, Nielsen KC, Greengrass R. Regional Anesthesia for Ambulatory Anesthesiologists. Anesthesiol Clin. 2019 Jun;37(2):265-287. doi: 10.1016/j.anclin.2019.01.005. Epub 2019 Mar 15.

Study record dates

Study Major Dates

• Study Start (Actual): March 1, 2026
• Primary Completion (Estimated): June 1, 2027
• Study Completion (Estimated): June 1, 2027

Study Registration Dates

• First Submitted: November 13, 2025
• First Submitted That Met QC Criteria: January 5, 2026
• First Posted (Actual): January 12, 2026

Study Record Updates

• Last Update Posted (Actual): April 13, 2026
• Last Update Submitted That Met QC Criteria: April 10, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: regional anesthesia; opioid consumption; Multimodal analgesia; lumbar spine surgery; retrolaminar block; Ultrasound-guided nerve block
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Postoperative Complications; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Pain, Postoperative
• Other Study ID Numbers: CUA2025-42

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Individual participant data that underlie the results reported in the published article, after deidentification, will be available upon reasonable request.
• IPD Sharing Time Frame: Data will be available beginning 6 months and ending 5 years following article publication.
• IPD Sharing Access Criteria: Data will be shared with researchers who provide a methodologically sound proposal for use in achieving the aims of the approved proposal. Proposals should be directed to rcoloma@clinicauandes.cl. To gain access, data requestors will need to sign a data access agreement. Data will be shared after approval by the principal investigator and the institutional review board.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No