Post Operative Pain and Vagal Stimulation (VAGANAL)

"Evolution of Postoperative Anal Pain Following Elective Proctological or Rectal Surgery Under the Effect of Transcutaneous Vagal Auricular Stimulation: a Feasibility Study - VAGANAL - Postoperative Pain and Vagal Stimulation"

Anorectal surgery is a type of surgery that can cause anal pain, particularly in the context of hemorrhoid surgery or anal fissure surgery. Generally, the period of discomfort related to the pain lasts about two weeks. There is a nerve (the vagus nerve) whose stimulation via a probe placed in the ear can reduce stress and chronic pain. Its ease of use makes it a promising tool for treating pain. Vagal auricular stimulation could be an interesting option in the management of postoperative pain of the anus and rectum. Its efficacy or feasibility in this context has never been evaluated.

The aim of this study is to evaluate the feasibility in this context and to assess the extend of pain reduction associated with perioperative nerve vagus stimulation by a medical device (Transcutaneous Electrical Nerve Stimulator (TENS ECO Plus)). It is offered to adult patients undergoing transanal anal or rectal surgery on an outpatient or inpatient basis as part of a scheduled procedure.

Patients to be included in the study are selected during the initial pre-operative consultation with the surgeon. Once the surgical indication is confirmed and the patient fulfills the study eligibility criteria, the investigator provides them with oral information about the study. The patient is also given an information sheet (written in language understandable to the patient) and a consent form.

During this initial visit, demographic data and information regarding the surgical indication are collected.

Stimulation begins two days before surgery (twice daily), followed by stimulation on the morning of surgery, one hour before arrival in the operating room. Successful completion of the stimulation, as well as any complications, are recorded in the patient diary.

On the day of surgery (day 0), data concerning the procedure and the maximum visual analogue scale (VAS) are collected in the recovery room. Analgesic consumption is also recorded.

On the evening of the procedure, stimulation is performed and adherence is recorded.

Maximum and mean VAS are collected on postoperative day 1 and then daily in the patient diary for 15 days.

Vagus nerve stimulation is performed morning and evening for 15 days. VAS scores, adherence, analgesic consumption, the date of the first bowel movement and its painfulness, as well as any complications related to the stimulation are noted in the patient diary. On day 3 (+/- 2 days) after the procedure, and at the end of the 15-day postoperative period, the patient will be contacted by phone or text message by the investigator team to remind them to complete the notebook.

On day 30 (+/- 5 days), the patient returns for a follow-up visit. The patient diary and equipment are collected. Complications are recorded, as well as quality of life during the postoperative month (SF-36 form).

For patients, the expected benefits are significant, as postoperative quality of life is expected to improve through reduced pain. Furthermore, decreasing the use of step II and III analgesics should shorten the recovery period and promote better overall recovery.

Study Overview

• Status: Not yet recruiting
• Conditions: Vagal Nerve Stimulation; Rectal Surgery; Pain (Visceral, Somatic, or Neuropathic)
• Intervention / Treatment: Device: Experimental arm; Device: Control arm

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

Contacts and Locations

• Study Contact: Name: Sarfati Marine, MD; Phone Number: +33 2 41 35 36 17; Email: Marine.SarfatiLebreton@chu-angers.fr

Study Locations

• France
  • Maine et Loire
    • Angers, Maine et Loire, France, 49933
      • Angers Hospital
      • Contact: venara aurélien, MD, PhD; Phone Number: +33 2 41 35 36 18; Email: AuVenara@chu-angers.fr
      • Principal Investigator: sarfati Marine, MD

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Adult patient
• Underwent anal or rectal surgery via the transanal route
• Managed on an outpatient basis or in conventional hospitalization
• Having signed a consent to participate in the study

Exclusion Criteria:

• Patient operated on as an emergency
• Rectal surgery via abdominal approach or requiring an abdominal approach during the procedure
• Known epileptic patient
• Patient with a pacemaker
• Patient refusing to participate in the study
• Pregnant, breastfeeding, or laboring woman
• Patient not affiliated with a social security scheme
• Person deprived of liberty by judicial or administrative decision
• Person subject to compulsory psychiatric care - Any contraindication mentioned in the instructions for use of the medical device under investigation

Exclusion Criteria:

• Unscheduled conversion from the transanal route to the abdominal route during surgery

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: active nerve vagus stimulator; assessment of rectal post operative pain with active nerve vagus stimulation	Device: Experimental arm; active vagus nerve stimulation
Sham Comparator: control arm; assessment of rectal post operative pain without active nerve vagus stimulation	Device: Control arm; no active vagus nerve stimulation

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Reduction of pain after perioperative auricular vagus nerve stimulation	The intensity of anal pain is measured by the Visual Analog Scale (VAS) from 0 to 10 in the recovery room and then every day for 15 days. This VAS is assessed in patients treated with auricular vagus active nerve stimulation and in patients with a inactive device	day 0, day 1, day 2, day 3, day 4, day 5, day 6, day 7, day 8, day 9, day 10, day 11, day 12, day 13, day 14, day 15
consumption of analgesic	the post-operative consumption of analgesic is evaluated in the recovery room (day 0) and then every day for 15 days. Post-operative consumption is assessed in patients treated with auricular vagus active nerve stimulation and in patients with a inactive device.	From Day 0 to Day 15

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Delay in gastrointestinal motility recovery (passage of stool) and post-defecatory pain	The gastrointestinal transit recovery after surgery is recorded in the patients treated with active device and in patients treated with inactive device. Post defecatory pain more than 30 min is also reported in the patients with active and with incative device.	from day 0 to day 30
Quality of life of patients after surgery	quality of life by health survey SF 36 is assessed at the day 30 after surgery in the two groups of patients (active device and no active device)	Day 30
adverse events	adverse events occuring during the first month after surgery and specifically related to the surgery are collected by the investigator for the two groups of patients	day 30
acceptability of perioperative auricular vagus nerve stimulation by the patient	The acceptability of treatment by perioperative auricular vagal stimulation is assessed at day 15 by asked question to the two groups of patients. The question is "do you think that the treatment with vagus nerve stimulation is non-binding?"	day 15

Collaborators and Investigators

• Sponsor: University Hospital, Angers

Study record dates

Study Major Dates

• Study Start (Estimated): November 9, 2026
• Primary Completion (Estimated): November 9, 2027
• Study Completion (Estimated): January 9, 2028

Study Registration Dates

• First Submitted: June 15, 2026
• First Submitted That Met QC Criteria: June 15, 2026
• First Posted (Actual): June 22, 2026

Study Record Updates

• Last Update Posted (Actual): June 22, 2026
• Last Update Submitted That Met QC Criteria: June 15, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neurologic Manifestations; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Pain
• Other Study ID Numbers: 49RC25-0293; 2026-A01004-47 (Other Identifier: ANSM)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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