Intravenous Methocarbamol for Acute Pain After Spine Surgery

NCT06659965 | Completed

• 2 other identifiers: HSC-MS-24-10955T32GM135118-03
• Study Type: observational
• Target: 1,270
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this target trial emulation is to evaluate the impact of intravenous (IV) methocarbamol on postoperative pain and opioid use in adults undergoing elective spine surgery. The main questions it aims to answer are:

• Does IV methocarbamol reduce pain in the 6 hours following surgery?
• Does IV methocarbamol decrease the need for opioid pain medications in the same period? Participants who receive IV methocarbamol as part of their routine postoperative care will have their pain scores and opioid consumption tracked for 6 hours after treatment. Pain levels will be measured using standard assessments, and opioid use will be quantified in oral morphine equivalents.

Conditions

Acute Post Operative Pain; Postsurgical Pain Management; Spine Surgery; Acute Pain, Postoperative; Multimodal Analgesia

Keywords

methocarbamol; postoperative pain; Robaxin; spine surgery; acute postsurgical pain; postsurgical pain; target trial emulation; postoperative analgesia; postoperative pain management; multimodal pain management

Outcome Measures

Primary Outcomes (1)

• Time-Weighted Average Pain Score

  The primary outcome of this study is the Time-Weighted Average (TWA) pain score measured over the 6-hour period following treatment assignment. Pain scores are collected using a standardized numerical pain rating scale, ranging from 0 (no pain) to 10 (worst possible pain). These scores are assessed in 15-minute intervals, the standard frequency for Phase I PACU assessments, throughout the 6-hour follow-up period. The TWA pain score is calculated by averaging these pain ratings, giving greater weight to scores recorded more frequently or for longer periods. This method provides a comprehensive summary of the patient's pain experience over the observed time frame, accounting for fluctuations in pain intensity during recovery. A lower TWA score indicates better pain control and a potentially greater effect of the intervention.

  6 hours after treatment assignment

Secondary Outcomes (1)

• Cumulative Opioid Use

  6 hours after treatment assignment

Study Arms (2)

IV methocarbamol

Patients who received intravenous methocarbamol

Drug: Intravenous Methocarbamol

Usual Care

Patients who received usual postoperative pain management after surgery without any intravenous methocarbamol administration

Interventions

Intravenous Methocarbamol DRUG

At least 500 mg of intravenous methocarbamol administered within 2 hours after the end of elective spine surgery for acute postoperative pain management

Also known as: Robaxin

IV methocarbamol

Eligibility Criteria

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

Study Population

The study population consists of adult patients undergoing elective spine surgeries at multiple hospitals within a large health system in Houston, TX. This includes individuals receiving surgical interventions for conditions such as degenerative disc disease, spinal stenosis, or other spinal pathologies that require procedures like ACDF, posterior spinal fusion, or laminectomy. Participants will be selected from those who receive perioperative care across various hospital settings within the health system, including postoperative management in the Post-Anesthesia Care Unit (PACU).

You may qualify if:

• years of age or older
• Undergoing one of the following three elective spine surgeries: (i) Anterior Cervical Discectomy and Fusion (ACDF), (ii) Posterior Spinal Fusion, or (iii) Laminectomy, Laminotomy, or Discectomy
• At least 8h of valid pain scores recorded postoperatively

You may not qualify if:

• Emergency Surgery
• Pregnancy
• Sensitivity to methocarbamol (allergy)
• End-stage renal disease (ESRD)
• Myasthenia gravis
• Missing a valid electronic anesthesia record

Sponsors & Collaborators

• The University of Texas Health Science Center, Houston: lead
• National Institutes of Health (NIH): collaborator
• National Institute of General Medical Sciences (NIGMS): collaborator

Study Sites (1)

Memorial Hermann Health System

Houston, Texas, 77007-1708, United States

Location

Related Publications (1)

• Potnuru P, Baranov A, Khudirat M, Turan A. Intravenous methocarbamol for acute pain after spine surgery: a target trial emulation. Reg Anesth Pain Med. 2025 Sep 8:rapm-2025-107010. doi: 10.1136/rapm-2025-107010. Online ahead of print.

  PMID: 40921494 BACKGROUND

MeSH Terms

Conditions

Pain, Postoperative

Interventions

Methocarbamol

Condition Hierarchy (Ancestors)

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

Intervention Hierarchy (Ancestors)

Phenylcarbamates; Carbamates; Acids, Acyclic; Carboxylic Acids; Organic Chemicals; Guaifenesin; Guaiacol; Methyl Ethers; Ethers; Phenyl Ethers; Phenols; Benzene Derivatives; Hydrocarbons, Aromatic; Hydrocarbons, Cyclic; Hydrocarbons

Study Officials

• Paul Potnuru, MD

  The University of Texas Health Science Center, Houston

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: RETROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Study Record Dates

• First Submitted: October 24, 2024
• First Posted: October 26, 2024
• Study Start: January 1, 2020
• Primary Completion: December 31, 2023
• Study Completion: June 30, 2025
• Last Updated: November 14, 2025

Record last verified: 2025-11

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, CSR
• Time Frame: January 2025-January 2027
• Access Criteria: A proposal that describes planned analyses must be submitted by email to the corresponding author. The study team will review the request before approval.

Locations

US (1)