Retrolaminar Analgesia for LuMbar Surgery (REALM)

April 10, 2026 updated by: Nicolás Valls, Universidad de los Andes, Chile

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

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

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

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
50

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • Chile
    • Santiago Metropolitan
      • Santiago, Santiago Metropolitan, Chile, 171571
        • Recruiting
        • Clínica Universidad de los Andes, Chile
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

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

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
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

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Total postoperative opioid consumption
Time Frame: First 24 hours after surgery
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

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Pain Intensity
Time Frame: Time in minutes from end of surgery until first request for rescue analgesia Time Frame: From end of surgery up to 72 hours
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
Time Frame: From block performance up to 72 hours
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 Frame: From end of surgery up to 24 hours
Time in minutes from end of surgery until first request for rescue analgesia
From end of surgery up to 24 hours
Incidence of PONV
Time Frame: First 24 hours postoperatively
Incidence of postoperative nausea and vomiting (PONV) requiring antiemetic rescue medication
First 24 hours postoperatively
Length of hospital stay
Time Frame: From admission to discharge, assessed up to 30 days
Total number of days from hospital admission to discharge
From admission to discharge, assessed up to 30 days

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Patient satisfaction
Time Frame: 72 hours postoperatively
Patient satisfaction with pain management measured using 5-point Likert scale (1=very dissatisfied to 5=very satisfied)
72 hours postoperatively
Chronic Pain Development
Time Frame: 3 months and 6 months postoperatively
Incidence of chronic pain defined as VAS > 3 at surgical site
3 months and 6 months postoperatively

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Universidad de los Andes, Chile

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Nicolas J Valls, M.D, Ph.D, Anesthesiologyst, Clinica Universidad de los Andes

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 1, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
November 13, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 5, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 12, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 13, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 10, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant 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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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