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Efficacy of ultrasound-guided obturator nerve block in transurethral surgery.

Thallaj A, Rabah D - Saudi J Anaesth (2011)

Bottom Line: USONB was successful (97.2%) in preventing an adductor spasm in all except one patient.USONB is safe and effective during TUR surgery.It provides optimal intra-and postoperative conditions.

View Article: PubMed Central - PubMed

Affiliation: Assistant Professor of Anesthesia, Urologist, College of Medicine, King Saud University, Riyadh, KSA.

ABSTRACT

Background: During transurethral resection surgery (TUR), accidental stimulation of the obturator nerve can cause violent adductor contraction, leading to serious intraoperative complications. General anesthesia with muscle relaxation is currently the preferred technique for TUR surgery. Spinal anesthesia combined with obturator nerve block has also been used for TUR surgery in geriatric population. Blind, anatomical methods for identifying the obturator nerve are often unsatisfactory. Therefore, we conducted this prospective study to validate the efficacy of ultrasound-guided obturator nerve block (USONB) during TUR procedures.

Methods: Eighteen male patients undergoing TURP surgery under spinal anesthesia were included in the study. Bilateral USONB with maximum 20 ml of 1% lidocaine per patient was performed. An independent observer was present to monitor any adduction movements during the operation and to record patient and surgeon satisfactions.

Results: In all patients, obturator nerve was visualized from the first attempt, requiring an average of 4.3 min for blocking of each side. USONB was successful (97.2%) in preventing an adductor spasm in all except one patient. Patient's and surgeon's satisfaction were appropriate. In all patients, adductor muscle strength recovered fully within 2 h following the surgical procedure.

Conclusions: USONB is safe and effective during TUR surgery. It provides optimal intra-and postoperative conditions.

No MeSH data available.


Related in: MedlinePlus

Ultrasound view of obturator nerve. PEC: pectineus muscle; AL: adductor longus muscle; AB: adductor brevis muscle; Arrow points at the anterior branch of the obturator nerve; triangles points at the needle
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Figure 0001: Ultrasound view of obturator nerve. PEC: pectineus muscle; AL: adductor longus muscle; AB: adductor brevis muscle; Arrow points at the anterior branch of the obturator nerve; triangles points at the needle

Mentions: The study was undertaken after approval of the hospital ethics committee. Informed patient consent was obtained from all patients. Exclusion criteria included patient’s refusal, neurological deficit, and abnormal coagulation profile. A total of 18 consecutive male patients who were admitted to our hospital and recommended for TURP surgery were included in the study. After receiving spinal anesthesia with heavy bupivacaine 10 mg in the usual standard way, all 18 patients were subjected to bilateral USONB, thus allowing us to independently evaluate a total 36 blocks. Each patient was in supine position, with the thigh abducted and rotated externally. Using a two-dimensional (2D) ultrasound, linear probe 38 mm 6–13 MHz (SonoSite M-Turbo, SonoSite Inc., Bothell, WA, USA) under sterile conditions, the antero-medial aspect of the thigh was scanned. The probe was positioned on and was parallel to the inguinal ligament. A short access view allowed visualization of the pectineus muscle and the obturator nerve was embedded between the adductor longus and adductor brevis muscles. A 50 mm insulated needle was inserted parallel to the long axis of the probe and passed under vision to the anterior branch of the obturator nerve [Figure 1]. A solution of 1% lidocaine, maximum 10 ml on each side, was injected to selectively block the obturator nerve. The procedure was repeated on the other thigh. A transurethral resectoscope was used for electro-cauterization, applied in five separate areas on each lateral wall of the bladder in the region that usually overlies the pelvic segment of the obturator nerve. All TURP procedures were performed by the same surgeon. An independent observer was present to monitor the patients for any adduction movements during the entire procedure. Data collection included, time required for obturator nerve, identification by ultrasound, volume of lidocaine administered, time required for regaining adductor strength following the procedure, patient and surgeon satisfactions, and adverse events if any. The sample size calculation was based on the assumption that the patients undergoing TUR will not show adductor spasm in 97% of the patients. Assuming a power of 90%, a level of significance of 5%, it was estimated that 18 patients would be required with 36 USONB procedures.


Efficacy of ultrasound-guided obturator nerve block in transurethral surgery.

Thallaj A, Rabah D - Saudi J Anaesth (2011)

Ultrasound view of obturator nerve. PEC: pectineus muscle; AL: adductor longus muscle; AB: adductor brevis muscle; Arrow points at the anterior branch of the obturator nerve; triangles points at the needle
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3101752&req=5

Figure 0001: Ultrasound view of obturator nerve. PEC: pectineus muscle; AL: adductor longus muscle; AB: adductor brevis muscle; Arrow points at the anterior branch of the obturator nerve; triangles points at the needle
Mentions: The study was undertaken after approval of the hospital ethics committee. Informed patient consent was obtained from all patients. Exclusion criteria included patient’s refusal, neurological deficit, and abnormal coagulation profile. A total of 18 consecutive male patients who were admitted to our hospital and recommended for TURP surgery were included in the study. After receiving spinal anesthesia with heavy bupivacaine 10 mg in the usual standard way, all 18 patients were subjected to bilateral USONB, thus allowing us to independently evaluate a total 36 blocks. Each patient was in supine position, with the thigh abducted and rotated externally. Using a two-dimensional (2D) ultrasound, linear probe 38 mm 6–13 MHz (SonoSite M-Turbo, SonoSite Inc., Bothell, WA, USA) under sterile conditions, the antero-medial aspect of the thigh was scanned. The probe was positioned on and was parallel to the inguinal ligament. A short access view allowed visualization of the pectineus muscle and the obturator nerve was embedded between the adductor longus and adductor brevis muscles. A 50 mm insulated needle was inserted parallel to the long axis of the probe and passed under vision to the anterior branch of the obturator nerve [Figure 1]. A solution of 1% lidocaine, maximum 10 ml on each side, was injected to selectively block the obturator nerve. The procedure was repeated on the other thigh. A transurethral resectoscope was used for electro-cauterization, applied in five separate areas on each lateral wall of the bladder in the region that usually overlies the pelvic segment of the obturator nerve. All TURP procedures were performed by the same surgeon. An independent observer was present to monitor the patients for any adduction movements during the entire procedure. Data collection included, time required for obturator nerve, identification by ultrasound, volume of lidocaine administered, time required for regaining adductor strength following the procedure, patient and surgeon satisfactions, and adverse events if any. The sample size calculation was based on the assumption that the patients undergoing TUR will not show adductor spasm in 97% of the patients. Assuming a power of 90%, a level of significance of 5%, it was estimated that 18 patients would be required with 36 USONB procedures.

Bottom Line: USONB was successful (97.2%) in preventing an adductor spasm in all except one patient.USONB is safe and effective during TUR surgery.It provides optimal intra-and postoperative conditions.

View Article: PubMed Central - PubMed

Affiliation: Assistant Professor of Anesthesia, Urologist, College of Medicine, King Saud University, Riyadh, KSA.

ABSTRACT

Background: During transurethral resection surgery (TUR), accidental stimulation of the obturator nerve can cause violent adductor contraction, leading to serious intraoperative complications. General anesthesia with muscle relaxation is currently the preferred technique for TUR surgery. Spinal anesthesia combined with obturator nerve block has also been used for TUR surgery in geriatric population. Blind, anatomical methods for identifying the obturator nerve are often unsatisfactory. Therefore, we conducted this prospective study to validate the efficacy of ultrasound-guided obturator nerve block (USONB) during TUR procedures.

Methods: Eighteen male patients undergoing TURP surgery under spinal anesthesia were included in the study. Bilateral USONB with maximum 20 ml of 1% lidocaine per patient was performed. An independent observer was present to monitor any adduction movements during the operation and to record patient and surgeon satisfactions.

Results: In all patients, obturator nerve was visualized from the first attempt, requiring an average of 4.3 min for blocking of each side. USONB was successful (97.2%) in preventing an adductor spasm in all except one patient. Patient's and surgeon's satisfaction were appropriate. In all patients, adductor muscle strength recovered fully within 2 h following the surgical procedure.

Conclusions: USONB is safe and effective during TUR surgery. It provides optimal intra-and postoperative conditions.

No MeSH data available.


Related in: MedlinePlus