Bladder CancerNCT07481123
COMPARISON OF OBTURATOR NERVE BLOCK TECHNIQUES IN TURBT
A study testing Subpectineal Obturator Nerve Block and Interfacial Obturator Nerve Block in people with Bladder Cancer, run by Yavuz Saygılı at 1 site in Turkey (Türkiye).
Trial 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). Read more about this study
- Who is it for?
- Ages 50 to 80 years
- Conditions the study is for
- Bladder Cancer
- What is being tested?
- Subpectineal Obturator Nerve Block and Interfacial Obturator Nerve Block
- Type of treatment
- Injection or infusion, Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 60 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 1 Aug 2022to 31 Dec 2022
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 50 to 80 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country.
About this study
Official title: COMPARISON OF THE EFFECT OF SUBPECTINEAL OBTURATOR NERVE BLOCK AND INTERFASCIAL OBTURATOR NERVE BLOCK ON ADDUKTOR MUSCLE SPASM IN PATIENTS WHO UNDERWENT TUR-BT OPERATION
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.
Read more
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.
Read the detailed description
Transurethral resection of bladder tumor (TUR-BT) is the standard diagnostic and therapeutic procedure for non-muscle invasive bladder cancer. During resection of tumors located on the lateral bladder wall, electrical stimulation may activate the obturator nerve, resulting in sudden contraction of the adductor muscles of the thigh. This phenomenon, known as the obturator reflex, may cause incomplete tumor resection, bladder perforation, bleeding, or tumor cell dissemination.
Obturator nerve block (ONB) has been shown to significantly reduce the incidence and severity of adductor muscle spasm during TUR-BT. With the increasing use of ultrasound guidance, several proximal and distal approaches have been described to improve block success and safety profile.
The distal (interfacial) technique requires separate blockade of the anterior and posterior branches of the obturator nerve between the adductor muscle groups. This approach typically involves two injections and a higher total volume of local anesthetic. In contrast, the proximal (subpectineal) technique targets the obturator nerve before its division, allowing a single-injection block performed in the fascial plane between the pectineus and obturator externus muscles.
This prospective, randomized clinical study was conducted to compare the effectiveness of ultrasound-guided subpectineal and interfacial obturator nerve block techniques in patients undergoing TUR-BT. Patients were allocated into two groups using a computer-generated randomization method. All nerve blocks were performed under real-time ultrasound guidance by experienced anesthesiologists.
In the subpectineal approach, a single injection of 10 mL of 0.375% bupivacaine was administered into the fascial plane between the pectineus and obturator externus muscles. In the interfacial approach, 10 mL of 0.375% bupivacaine was injected between the adductor longus and brevis muscles to block the anterior branch, and an additional 10 mL was injected between the adductor brevis and magnus muscles to block the posterior branch.
The study was designed to evaluate whether the proximal subpectineal approach provides comparable prevention of adductor muscle contraction while potentially simplifying the procedure by reducing the number of injections and local anesthetic volume. Safety parameters and perioperative characteristics were also assessed.
Statistical analyses were performed using appropriate comparative tests according to data distribution. A p-value < 0.05 was considered statistically significant.
- Conditions
- Bladder Cancer
- Being tested
- Subpectineal Obturator Nerve Block, Interfacial Obturator Nerve Block
- Keywords
- Obturator Nerve Block, Transurethral Resection of Bladder Tumor, Adductor Muscle Spasm, Randomized Controlled Trial
- Medical subject headings
- Urinary Bladder Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Subpectineal Obturator Nerve BlockProcedure or surgery
Ultrasound-guided single-injection obturator nerve block performed between the pectineus and obturator externus muscles using 10 mL of 0.375% bupivacaine.
Interfacial Obturator Nerve BlockProcedure or surgery
Ultrasound-guided obturator nerve block performed with two separate injections between adductor muscle groups using 0.375% bupivacaine.
| Study group | Role | What they receive |
|---|---|---|
| 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. Receives: 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. Receives: Procedure: Interfacial Obturator Nerve Block |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: During surgery (intraoperative period)
Secondary outcomes (2)
Number of Needle Insertions
The number of needle insertions/attempts required to complete the ultrasound-guided obturator nerve block was recorded for each participant.
Measured: During the block procedure (preoperative period)
Block-Related Complications
The occurrence of complications potentially related to the obturator nerve block (e.g., vascular puncture, hematoma, bladder perforation) was recorded.
Measured: From block procedure through end of surgery (perioperative period)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Mar 2026
- Study start1 Aug 2022
- Primary completion31 Dec 2022
- Study completion31 Dec 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Bladder CancerStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- 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.
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 60 participants (actual)
Sponsor and investigators
- Lead sponsor
- Yavuz Saygılı
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Yavuz Saygılı, University of Gaziantep
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07481123
- Sponsor's protocol ID
- code 141/09 date 04.07.2022
- Other IDs
- 141/09-04/07/2022
- Status last verified
- Mar 2026
- First submitted
- 2 Mar 2026
- Last updated
- 18 Mar 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be publicly shared due to institutional policies and patient confidentiality considerations. Data may be made available upon reasonable request to the corresponding author and subject to approval by the institutional ethics committee.
Publications
Saygili Y, Kose HC, Kose SG, Akkaya OT. A prospective randomized controlled trial comparing subpectineal and interfascial obturator nerve block techniques in preventing adductor muscle spasm during transurethral resection of bladder tumors. BMC Anesthesiol. 2026 Jul 22;26(1):622. doi: 10.1186/s12871-026-04091-5.
PubMed 42894134
Study at a glance
From the registry record, last updated by the sponsor on 18 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- COMPARISON OF THE EFFECT OF SUBPECTINEAL OBTURATOR NERVE BLOCK AND INTERFASCIAL OBTURATOR NERVE BLOCK ON ADDUKTOR MUSCLE SPASM IN PATIENTS WHO UNDERWENT TUR-BT OPERATION
- ClinicalTrials.gov ID
- NCT07481123
- Acronym / sponsor ID
- code 141/09 date 04.07.2022
- Conditions
- Bladder Cancer
- Keywords
- Obturator Nerve Block, Transurethral Resection of Bladder Tumor, Adductor Muscle Spasm, Randomized Controlled Trial
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 60 participants (actual)
- Lead sponsor
- Yavuz SaygılıUniversity, hospital or other
- Study start
- 1 Aug 2022 (actual)
- Primary completion
- 31 Dec 2022 (actual)
- Study completion
- 31 Dec 2022 (actual)
- First posted
- 18 Mar 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
Transurethral resection of bladder tumor (TUR-BT) is the standard diagnostic and therapeutic procedure for non-muscle invasive bladder cancer. During resection of tumors located on the lateral bladder wall, electrical stimulation may activate the obturator nerve, resulting in sudden contraction of the adductor muscles of the thigh. This phenomenon, known as the obturator reflex, may cause incomplete tumor resection, bladder perforation, bleeding, or tumor cell dissemination.
Obturator nerve block (ONB) has been shown to significantly reduce the incidence and severity of adductor muscle spasm during TUR-BT. With the increasing use of ultrasound guidance, several proximal and distal approaches have been described to improve block success and safety profile.
The distal (interfacial) technique requires separate blockade of the anterior and posterior branches of the obturator nerve between the adductor muscle groups. This approach typically involves two injections and a higher total volume of local anesthetic. In contrast, the proximal (subpectineal) technique targets the obturator nerve before its division, allowing a single-injection block performed in the fascial plane between the pectineus and obturator externus muscles.
This prospective, randomized clinical study was conducted to compare the effectiveness of ultrasound-guided subpectineal and interfacial obturator nerve block techniques in patients undergoing TUR-BT. Patients were allocated into two groups using a computer-generated randomization method. All nerve blocks were performed under real-time ultrasound guidance by experienced anesthesiologists.
In the subpectineal approach, a single injection of 10 mL of 0.375% bupivacaine was administered into the fascial plane between the pectineus and obturator externus muscles. In the interfacial approach, 10 mL of 0.375% bupivacaine was injected between the adductor longus and brevis muscles to block the anterior branch, and an additional 10 mL was injected between the adductor brevis and magnus muscles to block the posterior branch.
The study was designed to evaluate whether the proximal subpectineal approach provides comparable prevention of adductor muscle contraction while potentially simplifying the procedure by reducing the number of injections and local anesthetic volume. Safety parameters and perioperative characteristics were also assessed.
Statistical analyses were performed using appropriate comparative tests according to data distribution. A p-value < 0.05 was considered statistically significant.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 2
- Model description
- 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.
| Arm | Type | Receives |
|---|---|---|
| Subpectineal Obturator Nerve Block | Active comparator | Procedure: Subpectineal Obturator Nerve BlockParticipants 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. |
| Interfacial Obturator Nerve Block | Active comparator | Procedure: Interfacial Obturator Nerve BlockParticipants 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. |
Who may qualify
- Ages
- 50 to 80 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- 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
Key exclusion criteria (6 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Subpectineal Obturator Nerve BlockUltrasound-guided single-injection obturator nerve block performed between the pectineus and obturator externus muscles using 10 mL of 0.375% bupivacaine. | Procedure or surgery | Subpectineal Obturator Nerve Block |
| Interfacial Obturator Nerve BlockUltrasound-guided obturator nerve block performed with two separate injections between adductor muscle groups using 0.375% bupivacaine. | Procedure or surgery | Interfacial Obturator Nerve Block |
Primary outcome
Incidence and Severity of Intraoperative Adductor Muscle Spasm
Time frame: During surgery (intraoperative period)
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.
2 secondary outcomes
Number of Needle Insertions
Time frame: During the block procedure (preoperative period)
Block-Related Complications
Time frame: From block procedure through end of surgery (perioperative period)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 18 Mar 2026.
- Derived from this study: PubMed 42894134Saygili Y, Kose HC, Kose SG, Akkaya OT. A prospective randomized controlled trial comparing subpectineal and interfascial obturator nerve block techniques in preventing adductor muscle spasm during transurethral resection of bladder tumors. BMC Anesthesiol. 2026 Jul 22;26(1):622. doi: 10.1186/s12871-026-04091-5.
- Individual participant dataSharing planned: No. Individual participant data will not be publicly shared due to institutional policies and patient confidentiality considerations. Data may be made available upon reasonable request to the corresponding author and subject to approval by the institutional ethics committee.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Subpectineal Obturator Nerve Block and Interfacial Obturator Nerve Block in people with Bladder Cancer, run by Yavuz Saygılı at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 18 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Incidence and Severity of Intraoperative Adductor Muscle Spasm (time frame: During surgery (intraoperative period)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07481123, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 18 Mar 2026.