Sciatic Nerve Block for Ankle/Foot Surgeries. A Comparison Between a Premixed Solution of Lidocaine Plus Bupivacaine and Consecutive Infiltration of Lidocaine and Bupivacaine

Study Overview
=================
Brief Summary
-----------------
Regional anaesthesia has become the cornerstone of multimodal analgesia. With the advent of ultrasound guided nerve blocks regional anaesthesia has achieved both greater efficacy and a better safety profile as the injection of local anaesthetic is performed under direct vision. This has allowed a reduction of the amount of local anaesthetic injected as compared to peripheral nerve stimulation technique . Blockade of sciatic nerve combined with saphenous nerve provides anaesthesia and analgesia for ankle/foot surgeries. Various combinations of local anaesthetics have been used to provide optimal blockade . A mixture of lidocaine with a long acting local anaesthetic is commonly used. This provides a rapid onset of blockade, but of a consistently shorter duration compared to a long acting local anaesthetic alone. We hypothesize that sequential perineural injection of lidocaine and bupivacaine provides similar onset but a longer duration of sensory block compared to the same dose and volume of local anaesthetic mixed in advance.

Official Title
-----------------
Sciatic Nerve Block for Ankle/Foot Surgeries. A Comparison Between a Premixed Solution of Lidocaine Plus Bupivacaine and Consecutive Infiltration of Lidocaine and Bupivacaine. A Double Blinded Randomised Controlled Prospective Study

Conditions
-----------------
Open Reduction Internal Fixation(ORIF) of Lateral Malleolus

Intervention / Treatment
-----------------
* Drug: 2% lidocaine/adrenaline and 0.5% bupivacaine


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Patients with ASA 1 - 3 status scheduled to undergo semi-elective ankle/foot surgery under regional anaesthesia +/- sedation/opioid free general anaesthesia will be recruited Exclusion Criteria: Patients having surgery on the medial aspect of the ankle/ foot allergy to local anaesthetics coagulopathy malignancy or infection in the popliteal area significant peripheral neuropathy neurologic disorder of the lower extremity any other contraindication to sciatic nerve block pregnancy history of alcohol or drug dependency/abuse (defined as >40 IU/week) a history of significant cognitive or psychiatric disorder that may affect patient assessment

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Premixed group<br>Patients will receive sciatic nerve block with premixed 7.5 mls of 2% lidocaine/adrenaline and 7.5 mls of 0.5% bupivacaine followed by an interval of 90 seconds with an injection of same amount of both drugs. | Drug: 2% lidocaine/adrenaline and 0.5% bupivacaine<br> <br> |
| Experimental: Sequential Group<br>Patients will receive a sciatic nerve block with 15 mls of 2% lidocaine/adrenaline followed by an interval of 90 seconds with 15 mls of 0.5% bupivacaine. | Drug: 2% lidocaine/adrenaline and 0.5% bupivacaine<br> <br> |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Postoperative analgesia/duration of block |  | 24 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| onset of block | the block will be assessed every 5 minutes from the time of needle withdrawal till complete loss of sensation to touch. | 40 minutes | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
sciatic nerve block, ORIF lateral malleolus, sequential injection, premixed injection, local anaesthetics