Intravenous Methocarbamol for Acute Pain After Spine Surgery

NCT ID: NCT06659965

Last Updated: 2025-11-14

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Total Enrollment

1270 participants

Study Classification

OBSERVATIONAL

Study Start Date

2020-01-01

Study Completion Date

2025-06-30

Brief Summary

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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.

Detailed Description

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The IMAPSS study is a target trial emulation evaluating the effect of intravenous (IV) methocarbamol on postoperative pain management and opioid consumption in adult patients undergoing elective spine surgery. The study employs a target trial emulation design to simulate the conditions of a randomized controlled trial using observational data extracted from electronic medical records. The main focus is to determine if administering IV methocarbamol within two hours after surgery reduces postoperative pain scores and opioid use.

Patients will be tracked from the point of their first recorded pain score in the Post-Anesthesia Care Unit (PACU) after surgery to assess for treatment assignment eligibility. Data will be collected at 15-minute intervals, which corresponds to the standard assessment frequency in Phase I PACU care, for up to 12 hours postoperatively for each patient. The primary analysis will use time-varying propensity score matching (TV-PSM) to control for baseline and time-varying confounders. Pain levels will be measured using a time-weighted average (TWA) of pain scores, and opioid consumption will be quantified in oral morphine equivalents (OME).

The primary analysis will utilize TV-PSM, with propensity scores estimated through a Cox proportional hazards model. Matching will create balanced treatment groups at each 15-minute interval. Generalized estimating equations (GEE) will then estimate the effect of IV methocarbamol on the primary outcome (TWA pain) and secondary outcome (cumulative OME) over a 6-hour postoperative period. As a sensitivity analysis, a marginal structural model (MSM) using inverse probability weighting (IPW) will assess the robustness of the findings to the time-varying confounder adjustment.

This study's findings will aim to inform evidence-based recommendations for postoperative pain management and opioid-sparing strategies, potentially providing safer alternatives to conventional opioid-based regimens.

Conditions

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

Keywords

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

Study Design

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Observational Model Type

COHORT

Study Time Perspective

RETROSPECTIVE

Study Groups

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IV methocarbamol

Patients who received intravenous methocarbamol

Intravenous Methocarbamol

Intervention Type DRUG

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

Usual Care

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

No interventions assigned to this group

Interventions

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Intravenous Methocarbamol

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

Intervention Type DRUG

Other Intervention Names

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Robaxin

Eligibility Criteria

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Inclusion Criteria

* 18 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

Exclusion Criteria

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

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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National Institutes of Health (NIH)

NIH

Sponsor Role collaborator

National Institute of General Medical Sciences (NIGMS)

NIH

Sponsor Role collaborator

The University of Texas Health Science Center, Houston

OTHER

Sponsor Role lead

Responsible Party

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Paul Potnuru

Associate Professor

Responsibility Role PRINCIPAL_INVESTIGATOR

Principal Investigators

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Paul Potnuru, MD

Role: PRINCIPAL_INVESTIGATOR

The University of Texas Health Science Center, Houston

Locations

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Memorial Hermann Health System

Houston, Texas, United States

Site Status

Countries

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United States

References

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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.

Reference Type BACKGROUND
PMID: 40921494 (View on PubMed)

Other Identifiers

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5T32GM135118-03

Identifier Type: NIH

Identifier Source: secondary_id

View Link

HSC-MS-24-1095

Identifier Type: -

Identifier Source: org_study_id