Botulinum Toxin A Before Hemorrhoidectomy to Prevent Postoperative Pain (BoTo-HEM)

March 7, 2026 updated by: Lomonosov Moscow State University Medical Research and Educational Center

Effect of Internal Anal Sphincter Botulinum Toxin A Injection 7 Days Before Hemorrhoidectomy on Postoperative Pain: A Multicenter, Randomized, Double-Blind, Placebo-Controlled Trial

Hemorrhoidectomy is an effective surgical treatment for advanced hemorrhoidal disease but is often associated with significant postoperative pain, which may delay recovery. One of the main contributors to pain after hemorrhoidectomy is spasm and increased tone of the internal anal sphincter.

This randomized, double-blind, placebo-controlled clinical trial evaluates whether preoperative injection of botulinum toxin type A into the internal anal sphincter, performed seven days before hemorrhoidectomy, can reduce postoperative pain compared with placebo. Adult patients with grade III-IV hemorrhoids scheduled for excisional hemorrhoidectomy will be randomized to receive either botulinum toxin A or saline injection prior to surgery.

Postoperative pain intensity, analgesic consumption, complications, functional outcomes, and patient satisfaction will be assessed during the first 30 days after surgery.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This multicenter, randomized, double-blind, placebo-controlled trial is designed to investigate the effect of preoperative botulinum toxin type A injection into the internal anal sphincter on postoperative pain following excisional hemorrhoidectomy.

Eligible adult patients with symptomatic grade III-IV hemorrhoids will be randomized in a 1:1 ratio to receive either botulinum toxin type A or placebo injection seven days prior to surgery. Botulinum toxin A will be injected into the internal anal sphincter in four quadrants using a standardized technique, while the control group will receive an identical volume of normal saline. Both patients and surgeons performing hemorrhoidectomy, as well as outcome assessors, will be blinded to treatment allocation.

All participants will subsequently undergo open or closed hemorrhoidectomy using standardized surgical and perioperative care protocols. Postoperative pain will be assessed using a visual analogue scale during the first seven postoperative days. Secondary outcomes include analgesic consumption, postoperative complications, length of hospital stay, transient fecal incontinence, time to first bowel movement, readmissions, and patient-reported satisfaction within 30 days after surgery.

The study aims to determine whether preoperative chemical sphincter relaxation with botulinum toxin A can improve postoperative recovery and reduce pain following hemorrhoidectomy.

Study Type

Interventional

Enrollment (Estimated)

292

Phase

  • Phase 2

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 Backup

Study Locations

  • Russia
    • Moscow
      • Moscow, Moscow, Russia, 119991
        • Recruiting
        • Lomonosov Moscow State University Medical Research and Educational Center
        • Contact:
        • 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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Adults ≥18 years, male and female
  • Symptomatic grade III-IV hemorrhoidal disease (Goligher), refractory to conservative treatment
  • Scheduled for open (Milligan-Morgan) or closed (Ferguson) hemorrhoidectomy

Exclusion Criteria:

  • Known hypersensitivity to botulinum toxin A, human albumin, or local anesthetics.
  • Neuromuscular junction disorders (e.g., myasthenia gravis, Lambert-Eaton syndrome).
  • Use of aminoglycosides or other agents interfering with neuromuscular transmission within 14 days.
  • Coagulopathy or ongoing anticoagulant therapy not suitable for perioperative interruption.
  • Active anorectal infection, fissure, abscess, or inflammatory bowel disease in the active phase.
  • Previous anal sphincter surgery or baseline fecal incontinence.
  • Pregnancy or breastfeeding.
  • ASA ≥ III or significant systemic disease compromising anesthesia or wound healing.
  • Participation in another interventional clinical trial within 30 days.

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: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Preoperative Botulinum Toxin A Injection
Participants receive a preoperative injection of botulinum toxin type A into the internal anal sphincter seven days prior to excisional hemorrhoidectomy, in addition to standard surgical treatment.
Drug: Botulinum toxin type A
Participants receive a single preoperative injection of botulinum toxin type A into the internal anal sphincter. The injection is administered seven days prior to excisional hemorrhoidectomy. Botulinum toxin type A is injected in divided doses at predefined points of the internal anal sphincter using standard technique. The intervention is performed once and no repeat injections are planned.
Other Names:
  • BTX-A
  • botox
Placebo Comparator: Preoperative Placebo Injection
Participants receive a preoperative injection of normal saline into the internal anal sphincter seven days prior to excisional hemorrhoidectomy, in addition to standard surgical treatment.
Drug: Saline (0.9% NaCl)
Participants receive a single preoperative injection of normal saline into the internal anal sphincter. The injection is administered seven days prior to excisional hemorrhoidectomy. Normal saline is injected in divided doses at the same predefined points and using the same technique and injection volume as in the experimental group. The intervention is performed once, with no repeat injections planned.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Postoperative Pain Intensity Within the First 7 Days After Hemorrhoidectomy
Time Frame: Postoperative days 1-7
Postoperative pain intensity assessed using a 100-mm visual analogue scale (VAS). Daily pain scores are recorded and used to calculate the area under the curve (AUC) over postoperative days 1-7 for comparison between study groups.
Postoperative days 1-7

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Total opioid consumption within 72 hours postoperatively
Time Frame: Within 72 hours after surgery (postoperative hours 0-72)
Total postoperative opioid consumption expressed in morphine equivalents (mg) measured within the first 72 hours after surgery. Opioid use is recorded and compared between the botulinum toxin type A group and the placebo group.
Within 72 hours after surgery (postoperative hours 0-72)
Length of hospital stay
Time Frame: From day of surgery until hospital discharge (up to 30 days postoperatively)
Length of postoperative hospital stay measured in days, calculated from the day of surgery to the day of hospital discharge, and compared between the botulinum toxin type A group and the placebo group.
From day of surgery until hospital discharge (up to 30 days postoperatively)
Incidence of postoperative complications within 30 days
Time Frame: Within 30 days after surgery
Incidence of postoperative complications occurring within 30 days after surgery, classified according to the Clavien-Dindo classification, and compared between the botulinum toxin type A group and the placebo group.
Within 30 days after surgery
Transient fecal incontinence rates assessed by Wexner score
Time Frame: Postoperative days 14 and 30
Transient fecal incontinence assessed using the Wexner score to evaluate severity and frequency of symptoms, and compared between the botulinum toxin type A group and the placebo group.
Postoperative days 14 and 30
Readmission or unplanned medical visits within 30 days
Time Frame: Within 30 days postoperatively
Hospital readmission or unplanned medical visits occurring within 30 days after surgery, compared between the botulinum toxin type A group and the placebo group.
Within 30 days postoperatively
Pain during defecation assessed by VAS
Time Frame: Postoperative days 1, 3, and 7
Pain intensity during defecation assessed using the Visual Analog Scale (VAS) and compared between the botulinum toxin type A group and the placebo group.
Postoperative days 1, 3, and 7
Time to first bowel movement
Time Frame: From day of surgery until first bowel movement (up to hospital discharge, maximum 7 days)
Time to first bowel movement measured in hours and compared between the botulinum toxin type A group and the placebo group.
From day of surgery until first bowel movement (up to hospital discharge, maximum 7 days)
Patient satisfaction score
Time Frame: Postoperative day 30
Patient satisfaction assessed using a numeric rating scale from 0 to 10, where higher scores indicate greater satisfaction. Scores are compared between the botulinum toxin type A group and the placebo group.
Postoperative day 30

Collaborators and Investigators

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

Sponsor

Lomonosov Moscow State University Medical Research and Educational Center

Investigators

  • Study Director: Tatiana Garmanova, MD, PhD, Lomonosov Moscow State University Medical Research and Educational Center

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)

February 1, 2026

Primary Completion (Estimated)

January 1, 2027

Study Completion (Estimated)

January 1, 2028

Study Registration Dates

First Submitted

January 20, 2026

First Submitted That Met QC Criteria

February 5, 2026

First Posted (Actual)

February 10, 2026

Study Record Updates

Last Update Posted (Actual)

March 10, 2026

Last Update Submitted That Met QC Criteria

March 7, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • BoTo-HEM RCT

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be shared due to institutional and ethical restrictions and because no data-sharing plan is specified in the study protocol.

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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