COMPARISON OF OBTURATOR NERVE BLOCK TECHNIQUES IN TURBT

NCT07481123 | Completed

• 2 other identifiers: code 141/09 date 04.07.2022141/09-04/07/2022
• Study Type: interventional
• Target: 60
• Locations: 1 country
• Sites: 1

Brief Summary

Bladder cancer is one of the most common cancers in older adults. The standard treatment for many bladder tumors is a surgical procedure called transurethral resection of bladder tumor (TUR-BT). During this operation, tumors located on the side wall of the bladder may trigger an involuntary leg movement known as the "obturator reflex." This reflex occurs when electrical stimulation during surgery activates the obturator nerve, causing sudden contraction of the inner thigh (adductor) muscles. Such muscle spasms can lead to serious complications, including incomplete tumor removal or bladder perforation. To prevent this reflex, anesthesiologists perform an obturator nerve block (ONB), a procedure in which local anesthetic medication is injected around the nerve to temporarily stop its function. With advances in ultrasound technology, different ultrasound-guided techniques have been developed to perform this nerve block more safely and effectively. There are two commonly used approaches. The first is the interfacial (distal) technique, in which two separate injections are performed to block the anterior and posterior branches of the obturator nerve. The second is the subpectineal (proximal) technique, in which the nerve is blocked with a single injection at a more proximal location, potentially using a smaller amount of local anesthetic. The purpose of this study was to compare these two ultrasound-guided techniques in patients undergoing TUR-BT surgery. The aim of this study was to compare the effectiveness and safety of the subpectineal and interfacial obturator nerve block techniques in preventing adductor muscle spasm during surgery. Sixty patients aged between 50 and 80 years who were scheduled for TUR-BT were randomly assigned to receive either the subpectineal or the interfacial obturator nerve block. The main outcome measured was the occurrence and severity of adductor muscle spasm during surgery. Secondary outcomes included the number of needle insertions, duration of anesthesia and surgery, and any complications related to the block. The hypothesis of this study was that the subpectineal technique would provide comparable effectiveness in preventing adductor muscle spasm compared with the interfacial technique while requiring fewer injections and a lower volume of local anesthetic. The results of this study may help determine the most effective and practical technique for preventing surgical complications during bladder tumor surgery.

Conditions

Bladder Cancer

Keywords

Obturator Nerve Block; Transurethral Resection of Bladder Tumor; Adductor Muscle Spasm; Randomized Controlled Trial

Outcome Measures

Primary Outcomes (1)

• Incidence and Severity of Intraoperative Adductor Muscle Spasm

  Adductor muscle spasm was evaluated intraoperatively and graded using a four-level scale (Grade I-IV), with higher grades indicating stronger contraction and possible interference with the surgical procedure.

  During surgery (intraoperative period)

Secondary Outcomes (2)

• Number of Needle Insertions

  During the block procedure (preoperative period)

• Block-Related Complications

  From block procedure through end of surgery (perioperative period)

Study Arms (2)

Subpectineal Obturator Nerve Block

ACTIVE COMPARATOR

Participants in this arm received an ultrasound-guided subpectineal obturator nerve block prior to transurethral resection of bladder tumor. A single injection of 10 mL of 0.375% bupivacaine was administered into the fascial plane between the pectineus and obturator externus muscles to achieve proximal blockade of the obturator nerve.

Procedure: Subpectineal Obturator Nerve Block

Interfacial Obturator Nerve Block

ACTIVE COMPARATOR

Participants in this arm received an ultrasound-guided interfacial obturator nerve block prior to transurethral resection of bladder tumor. Two separate injections of 10 mL of 0.375% bupivacaine were administered between the adductor longus and brevis muscles and between the adductor brevis and magnus muscles to block the anterior and posterior branches of the obturator nerve.

Procedure: Interfacial Obturator Nerve Block

Interventions

Subpectineal Obturator Nerve Block PROCEDURE

Ultrasound-guided single-injection obturator nerve block performed between the pectineus and obturator externus muscles using 10 mL of 0.375% bupivacaine.

Subpectineal Obturator Nerve Block

Interfacial Obturator Nerve Block PROCEDURE

Ultrasound-guided obturator nerve block performed with two separate injections between adductor muscle groups using 0.375% bupivacaine.

Interfacial Obturator Nerve Block

Eligibility Criteria

• Age: 50 Years - 80 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Patients aged between 50 and 80 years
• Diagnosed with bladder tumor and scheduled for transurethral resection of bladder tumor (TURBT)
• Classified as American Society of Anesthesiologists (ASA) physical status I-III
• Provided written informed consent

You may not qualify if:

• Coagulopathy or anticoagulant therapy contraindicating regional anesthesia
• Known allergy to local anesthetics
• Infection at the injection site
• Pre-existing neuromuscular disorder affecting lower extremities
• Severe cardiac, hepatic, or renal dysfunction
• Inability to provide informed consent

Sponsors & Collaborators

• Yavuz Saygılı: lead

Study Sites (1)

Ankara Etlik City Hospital

Ankara, Ankara, Turkey (Türkiye)

Location

MeSH Terms

Conditions

Urinary Bladder Neoplasms

Condition Hierarchy (Ancestors)

Urologic Neoplasms; Urogenital Neoplasms; Neoplasms by Site; Neoplasms; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Urinary Bladder Diseases; Urologic Diseases; Male Urogenital Diseases

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Doctor

Model Details: This study was designed as a prospective, randomized, parallel-group clinical trial. Participants were randomly allocated in a 1:1 ratio to receive either ultrasound-guided subpectineal or interfacial obturator nerve block prior to transurethral resection of bladder tumor. Randomization was performed using a computer-generated sequence. Each participant received only one of the two interventions. All blocks were performed under ultrasound guidance by experienced anesthesiologists according to standardized protocols. The study was designed as a comparative superiority trial to evaluate differences in effectiveness between the two techniques in preventing intraoperative adductor muscle spasm.

Study Record Dates

• First Submitted: March 2, 2026
• First Posted: March 18, 2026
• Study Start: August 1, 2022
• Primary Completion: December 31, 2022
• Study Completion: December 31, 2022
• Last Updated: March 18, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)