Conventional Versus Posterior Approach in Ultrasound-Guided Parasagittal In-Plane Infraclavicular Brachial Plexus Block

Study Overview
=================
Brief Summary
-----------------
The lateral parasagittal in-plane is the current conventional approach in ultrasound-guided infraclavicular brachial plexus block. However this technique is less popular because brachial plexus at the infraclavicular level runs deeper compared to its course proximally, often give rise to impaired needle visualisation due to its steep angle of needle trajectory to the ultrasound beam. A new posterior parasagittal in-plane approach was introduced to improve needle visibility. This approach proved feasible from our case series hence the investigators would like to compare it with the conventional method in this study

Detailed Description
-----------------
This study compared the conventional lateral and posterior approach parasagittal in-plane ultrasound guided infraclavicular brachial plexus block for upper limb surgery. A cadaveric study was also performed to complement the findings. After obtaining approval from the Medical Ethics Committee, University Malaya Medical Centre (IRB reference no. 949.14 dated 17 October 2012), 46 patients undergoing upper limb surgery were prospectively recruited and randomized. A cadaveric dissection was also performed. DESIGN: Prospective randomized study SETTING: Single centre, University of Malaya Medical Centre, Kuala Lumpur, Malaysia; November 2012 to October 2013 INTERVENTION: Ultrasound guided, lateral or posterior parasagittal in-plane infraclavicular brachial plexus blocks were performed on patients, depending on randomization. All blocks were performed using 21G x 4 inch Stimuplex A (B Braun Medical) without nerve stimulation plus SonoSite M-Turbo with HFL38x/ 13-6 MHz linear transducer probe. A 25-ml local anaesthetic admixture [Lignocaine 2% (100mg) plus Ropivacaine 0.75% (150mg)] were injected to all patients. A total volume of normal saline 0.9% 25ml mixed with methylene blue (0.2ml) was used for cadaveric study.

Official Title
-----------------
A Prospective, Randomized Comparison Between Lateral and Posterior Approach In Ultrasound-Guided Parasagittal In-Plane Infraclavicular Brachial Plexus Block

Conditions
-----------------
Infraclavicular, Ultrasound Guided, Brachial Plexus Block

Intervention / Treatment
-----------------
* Procedure: Posterior approach
* Procedure: Conventional approach


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: American Society of Anesthesiologists (ASA) physical status I - III Body Mass Index (BMI) between 20 and 35 kg/m2 Surgery of the forearm, wrist, or hand Exclusion Criteria: Inability to give consent to the study Pre-existing neuropathy Infection at the site of puncture, skin ulcer Coagulopathy Contralateral phrenic nerve paralysis, contralateral recurrent laryngeal nerve paralysis or pneumothorax Allergy to amides local anaesthetics

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

Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Posterior approach<br>The main difference between this block approach and the conventional infraclavicular approach is the site and angle of needle insertion. Otherwise, the end point of local anaesthetic injection remained the same for both approaches. | Procedure: Posterior approach<br>* The needle insertion point was over the trapezius muscle sufficiently posterior to allow the needle to pass between the clavicle and the scapula in the direction of the axillary artery. The insertion point was strictly aligned with the long axis of the ultrasound beam i.e. in-plane technique.<br>|
| Active Comparator: Conventional approach<br>The main difference between this block approach and the conventional infraclavicular approach is the site and angle of needle insertion. Otherwise, the end point of local anaesthetic injection remained the same for both approaches. | Procedure: Conventional approach<br>* The needle insertion point would be at the cephalad (lateral) aspect of the ultrasound probe, beneath the clavicle and medial to the coracoid process. The insertion point was strictly aligned with the long axis of the ultrasound beam i.e. in-plane technique.<br>|

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

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Success rate (ability to proceed with surgery without the need for intravenous narcotics, general anaesthesia, rescue blocks or local infiltration by the surgeon) | Success rate - was equivalent to surgical anesthesia, defined as the ability to proceed with surgery without the need for intravenous narcotics, general anaesthesia, rescue blocks or local infiltration by the surgeon. The adequacy of block was determined during assessment of motor and sensory blockade at predetermined intervals, every 5 minutes until 30 minutes; Please refer to the study detailed description. | participants will be followed up throughout the operation duration; as stated each operation has variable duration of operation time, average operation time 2 to 4 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Performance parameters | This is a composite outcome measure. The anaesthesia assistant would record the time required to perform the procedure as follow below description: (i)Imaging time (defined as the time interval between contact of the ultrasound probe with the patient and the acquisition of a satisfactory sonoanatomy - a complete round short-axis view of the axillary artery), (ii) Needling time (defined as the time interval between the start of the needle insertion and the end of local anaesthetic injection through the needle), (iii) Performance time (defined as the sum of imaging and needling times). This timing definition had been published in other journals (please refer our references - 3) | participants will be followed up throughout the procedure (performing the blocks), average time for block perfomances 30 minutes | 
| Safety aspects and potential complications; we measured by any incidence of paraesthesia, vascular puncture, Horner's syndrome, dyspnoea and symptoms suggestive of LA toxicity | This is a composite outcome measure. We measured safety aspects and potential complications by recording any incidence of paraesthesia and vascular puncture during block performances, any Horner's syndrome, dyspnoea and symptoms suggestive of local anaesthetic toxicity were routinely checked after the procedure and during surgery. To further enhance patient's safety, we would still follow up patient by phone call 1 week after the surgery | Participants would be followed up throughout procedure (average duration 30 minutes), during operation (average duration 2 to 4 hours) and 1 week after the operation (via phone call) | 
| adequacy of block for tourniquet application | The incidence of tourniquet pain; this would describe whether the block technique covers for tourniquet pain | participants would be followed up throughout the operation duration whether they complained of pain at torniquet site during the operation duration; average duration of operation 2 - 4 hours |