Clinical trial NCT01547637: Preventing the Obturator Nerve Reflex
Official title: Preventing the Obturator Nerve Reflex: A Comparison of Ultrasound Guided Obturator Nerve Block and Classic Anatomic Block Technique.
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Bladder Injury
Keywords: Obturator nerve block
Regional anesthesia
TURBT
Lead sponsor: Milton S. Hershey Medical Center
Sponsor class: OTHER
First posted: 2012-03-08
Enrollment: 40
Sex: ALL
Minimum age (years): 35
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: The key objective of this study is to compare success rates of ultrasound guided obturator nerve block and anatomic landmark guided obturator nerve block as determined by neuromonitoring endpoints and surgeon observations.

Detailed description: Transurethral resection of bladder tumor (TURBT) is a urologic surgery used in the treatment of non-muscle invasive bladder cancer. A potential complication of this procedure is bladder rupture or injury secondary to adductor muscle contraction from obturator nerve stimulation. This risk is increased in resection of lateral wall tumors, as electrosurgical resection of these lesions is more likely to inadvertently stimulate the obturator nerve.

There are several mechanisms for preventing the obturator reflex. Pharmacologic paralysis can reliably inhibit thigh adduction. However, TURBT is often a short procedure that is not amendable to intermediate duration neuromuscular blocking medications. The use of succinylcholine is another option but is limited by its short duration of action which may not be adequate for the time needed to resect the tumor. Additionally, many patients have contraindications to the use of succinylcholine. Spinal anesthesia does not reliably prevent the obturator reflex.

Regional anesthesia is another potential treatment modality to prevent the obturator reflex during TURBT. Motor blockade of the obturator nerve will prevent this adduction in the event of inadvertent nerve stimulation. Peripheral blockade of the obturator nerve can be combined with either general or spinal anesthesia. Historically, obturator nerve block (ONB) has been considered a technically challenging procedure. Recently, however, successful ultrasound guided ONB techniques have been reported. To the best of our knowledge there has been no study to date comparing the effectiveness of ONB achieved by anatomic landmarks (with nerve stimulation) versus ultrasound guided ONB (with nerve stimulation) at preventing the obturator reflex during TURBT surgery.

The key objective of this study is to compare success rates of ultrasound guided obturator nerve block and anatomic guided obturator nerve block as determined by neuromonitoring endpoints and surgeon observations.

Eligibility criteria: Inclusion Criteria:

* Patients undergoing TURBT for lateral wall bladder tumors at risk for electrical stimulation as determined by the attending surgeon.

Exclusion Criteria:

* Pre-existing obturator nerve injury
* Thigh adductor muscle weakness
* Neuropathy
* Local anesthetic allergy
* Infection at the site of injection
* Abnormal coagulation studies
* use of neuromuscular blocking medications (if deemed necessary by attending anesthesiologist caring for the patient).

Primary outcomes:
measure: Nerve conduction velocity
timeFrame: 1 day
Secondary outcomes:
Other outcomes:
Locations:
city: Hershey
country: United States
facility: Penn State Milton S. Hershey Medical Center
state: Pennsylvania
Study officials:
affiliation: Milton S. Hershey Medical Center
name: Jonathan A Anson, MD
role: PRINCIPAL_INVESTIGATOR
References: