Evaluation of the Analgesic Efficacy of an Ultrasound-guided Transperineal Pudendal Block in Outpatient Hemorrhoidal Surgery (BACH)

GCS Ramsay Santé pour l'Enseignement et la Recherche

Status: Not yet enrolling

Conditions: Hemorrhoids

Treatments: Procedure: Ultrasound; Procedure: Neurostimulation

Study type: Interventional

Funder types: Other

Identifiers

NCT07015775

2025-A00534-45

Details and patient eligibility

About

In a population of patients undergoing hemorrhoidal surgery under general anesthesia and divided into two equal groups based on the method used for intraoperative pudendal nerve block and its branches in the ischioanal fossa:

Group 1: Pudendal block guided by neurostimulation Group 2: Pudendal block guided by ultrasound

The primary objective of this study is to compare the maximum immediate postoperative pain score between the two groups (pain reported by the patients in the recovery room on a simple numeric scale before morphine titration).

Full description

This is a multicenter, prospective, randomized, double-blind study conducted on two parallel groups of patients undergoing hemorrhoidal surgery (pudendal block guided by neurostimulation versus pudendal block guided by ultrasound).

Study Duration The total study duration per patient is 7 days. The recruitment period is set at 12 months.

Justification of the Experimental Protocol The aim of this study is to compare two methods of performing a pudendal block. Patient allocation to either strategy will be determined by randomization. Bilateral pudendal nerve block and its branches in the ischioanal fossa will be performed after induction of general anesthesia.

To maintain double blinding, postoperative data will be collected by a physician other than the anesthesiologist performing the block, and by nursing staff under their supervision. None of these personnel will be informed of the patient's group allocation.

Enrollment: 202 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Adult male or female patient
• Patient who has signed informed consent to participate in the study
• Patient scheduled for outpatient hemorrhoidal surgery under general anesthesia

Exclusion criteria

• History of hemorrhoidal surgery
• Allergy or contraindication to any of the medications used in the study
• Patient undergoing surgery under spinal anesthesia
• History of chronic pain requiring opioid use, unrelated to hemorrhoids
• Mental impairment or any other condition that could hinder understanding or strict adherence to the protocol
• Patient not affiliated with the French national health insurance system
• Patient under legal protection (e.g., guardianship, trusteeship, or court protection)
• Pregnant woman or woman at risk of being pregnant (i.e., of childbearing age without effective contraception and without an HCG test)
• Patient already enrolled in another therapeutic clinical trial or within the exclusion period of another clinical trial

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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202 participants in 2 patient groups

Pudendal block guided by neurostimulation

Active Comparator group

Description:

Neurostimulation involves using an electrical impulse to trigger a nerve signal and a specific motor response. A short-bevel, insulated 80 mm needle connected to a neurostimulator is used. The puncture point lies midway between the ischial tuberosity and the anus. Stimulation starts at 2.5 mA, 1 Hz, and the needle is advanced 4-5 cm until anal sphincter contraction occurs ("anal wink"). The needle is adjusted to maintain the response while reducing intensity to 0.5 mA. If lost, intensity is increased; if too intense at 0.3 mA, the needle is repositioned. After confirming no vascular puncture, 1 mL of Ropivacaine 3.5 mg/mL is injected to stop contraction, followed by slow injection of 15 mL total. The procedure is repeated on the other side. If no motor response occurs, a blind injection is performed after negative aspiration at 5 cm depth using the same landmarks.

Treatment:

Procedure: Neurostimulation

Pudendal block guided by ultrasound

Experimental group

Description:

A 6 MHz convex probe is placed in the frontal plane along the line between the ischial tuberosity and the anal margin to visualize the bony prominence. The pudendal artery and nearby nerves are identified using color Doppler. A 22-gauge, 80 mm echogenic needle is inserted out-of-plane in front of the probe, targeting the lateral ischioanal fossa just medial to the pudendal artery, if visible. The probe is adjusted to center the artery. Block confirmation is based on ultrasound visualization of local anesthetic spreading into the fatty tissue medial to the pudendal artery. The procedure is repeated on the other side. If the artery is not visible, the injection is performed after negative aspiration on the medial aspect of the ischial tuberosity, along the line to the anus, at a depth of 4-5 cm.

Treatment:

Procedure: Ultrasound