Medial Versus Lateral Approach in Ultrasound (US)-Guided Supraclavicular Block

Medial vs. Lateral Approach to Ultrasound-Guided Supraclavicular Block: A Prospective Randomized Controlled Trial

The ultrasound guided supraclavicular block is a peripheral nerve block which is considered safe, has a fast onset, is dense and provides complete block of the nerves supplying the hand, forearm and arm. However retrospective studies done at Toronto Western Hospital have highlighted the fact that most commonly the ulnar nerve fibres (responsible for sensations in the ring finger, little finger and the corresponding part of hand), sometimes escape this block and need additional supplementary block at a distal peripheral nerve site. It is a confusing fact since all nerve fibres are compactly arranged in a sheath at the supraclavicular level. The local anaesthetic agent at this level should be equally distributed among all nerve fibres. The purpose of this study is to compare two different approaches (medial and lateral) adopted by our clinicians to perform this block and to test the effectiveness of each approach for successful ulnar nerve fibre blockade.

Inclusion Criteria:

• Adult patients presenting for upper limb surgery, excluding shoulder surgery
• Age 18-80 yrs
• BMI < 35
• ASA I - III
• Consent for the study

Exclusion Criteria:

• Pre-existing sensory or motor neurodeficit.
• Sensitivity to local anaesthetic agents.
• Patients on anticoagulants or antiplatelet medications (Minidose Aspirin is acceptable) with abnormal coagulation profile.
• Compromised pulmonary reserve due to COPD, Kypho-scoliosis or Restricted lung disease.
• Infection or any obvious pathology at the site of block performance
• History of drug abuse.
• Psychiatric disease or any condition that precludes an informed consent.