To compare ISB vs anterior and posterior approaches of suprascapular block in terms of lung function and analgesia

Interscalene block (ISB) is commonly used to provide pain control for shoulder surgeries. However, it is associated with several side effects, in particular, a high incidence of phrenic nerve blockade.

The suprascapular nerve block (SSB) has been proposed as an alternative to the ISB as it has a lower likelihood of causing phrenic nerve blockade. There are 2 commonly used approaches for the suprascapular nerve block, anterior and posterior. The anterior approach may still result in some degree of impairment of lung function.

The primary aim is to assess the pulmonary function after performance of ISB, aSSB and pSSB. Secondary outcomes are analgesic effects and incidence of adverse effects of these blocks.

Inclusion Criteria:

• Patients scheduled for elective arthroscopic shoulder surgery under general anaesthesia
• Patients 21 years old and above
• American Society of Anesthesiologists (ASA) physical status 1 to 3
• BMI 18-35 kg/m2

Exclusion Criteria:

• Patients unable to give consent or inability to communicate/ cooperate
• Patients with chronic use of strong opioids (morphine, oxycodone)
• Patients with allergy to local anaesthetics or any drugs included in the study
• Patients with contraindications for regional anaesthesia such as coagulopathy
• Patients with pre-existing neurological deficits in upper limb/ phrenic nerve palsy
• Patients with pre-existing lung disease (COPD, uncontrolled asthma)