Circumferential Spread of Anesthetic and Success in Sciatic Nerve Blockade

Sponsor

University Health Network, Toronto (Other)

Overall Status

Completed

CT.gov ID

NCT00802581

Collaborator

(none)

Enrollment

Location

Arms

Duration (Months)

3.4

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

Current practices when performing any peripheral nerve block may or may not involve ensuring circumferential spread of local anesthetic around the nerve. Ensuring circumferential spread can involve several redirections of the needle above and below the nerve, and potentially could result in either more discomfort for the patient or an increased chance of inadvertent direct trauma to the nerve. Not ensuring spread around the nerve may result in a slower and less complete blockade. The investigators suspect that by ensuring complete spread around the nerve, the speed of block onset would be quicker because it avoids the loss due to diffusion time.

Condition or Disease	Intervention/Treatment	Phase
Sciatic Nerve Blockade for Foot/Ankle Surgery	Procedure: Circumferential spread of local anesthetic Procedure: Non-circumferential spread of local anesthetic	N/A

Study Design

Study Type:

Interventional

Actual Enrollment :

64 participants

Allocation:

Randomized

Intervention Model:

Parallel Assignment

Masking:

Double (Participant, Outcomes Assessor)

Primary Purpose:

Treatment

Official Title:

Does Ensuring Circumferential Local Anesthetic Spread Improve the Success of Ultrasound Guided Sciatic Nerve Block at the Popliteal Fossa?

Study Start Date :

May 1, 2009

Actual Primary Completion Date :

Dec 1, 2010

Actual Study Completion Date :

Dec 1, 2010

Arms and Interventions

Arm	Intervention/Treatment
Experimental: 1 Ensuring circumferential spread of local anesthetic around the sciatic nerve.	Procedure: Circumferential spread of local anesthetic The anesthetist will ensure, under ultrasound guidance, that local anesthetic (1 mL of 1% lidocaine) surrounds the sciatic nerve.
Active Comparator: 2 Single shot injection of local anesthetic near the sciatic nerve will be performed, without ensuring circumferential spread.	Procedure: Non-circumferential spread of local anesthetic The anesthetist will perform a "single shot" injection of local anesthetic (1 mL of 1% lidocaine) near the sciatic nerve under ultrasound guidance, without ensuring circumferential spread around the nerve.

Arm

Intervention/Treatment

Experimental: 1

Ensuring circumferential spread of local anesthetic around the sciatic nerve.

Procedure: Circumferential spread of local anesthetic

The anesthetist will ensure, under ultrasound guidance, that local anesthetic (1 mL of 1% lidocaine) surrounds the sciatic nerve.

Active Comparator: 2

Single shot injection of local anesthetic near the sciatic nerve will be performed, without ensuring circumferential spread.

Procedure: Non-circumferential spread of local anesthetic

The anesthetist will perform a "single shot" injection of local anesthetic (1 mL of 1% lidocaine) near the sciatic nerve under ultrasound guidance, without ensuring circumferential spread around the nerve.

Outcome Measures

Primary Outcome Measures

Onset time of sciatic nerve blockade. [Every 5 minutes for 30 minutes after anesthetic injection]

Secondary Outcome Measures

Block success, time required to perform block, complications/adverse events, number of needle passes, patient discomfort [24 hours]

Eligibility Criteria

Criteria

Ages Eligible for Study:

18 Years to 85 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Inclusion Criteria:

English-speaking
ASA physical status I-III
18-85 years of age, inclusive
50-110 kg, inclusive
150 cm of height or grater
Scheduled for elective foot or ankle surgery

Exclusion Criteria:

Contraindications to sciatic nerve block (e.g., allergy to local anesthetics, coagulopathy, malignancy or infection in the popliteal area)
Significant peripheral neuropathy or neurologic disorder affecting the lower extremity
Pregnancy
Contraindications to, allergies to, and/or past adverse reactions to study medications (local anesthetics, opioid analgesics)
History of alcohol or drug dependency/abuse
History of long term opioid intake
History of significant psychiatric conditions that may affect patient assessment