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

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

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

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.

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