A Comparison between Ultrasound Guided Suprascapular Nerve Block versus Ultrasound Guided Interscalene Brachial Plexus Block on Respiratory Mechanics in Patients Undergoing Arthroscopic Shoulder Surgery: A Randomized Controlled Study

Background: Diaphragmatic dysfunction may manifest on spirometry as reduced forced expiratory volume at First second (FEV1) and forced vital capacity (FVC), or on ultrasound (US) as diminished diaphragmatic excursion (DE); the latter has emerged as the gold standard for thoracic evaluation.Objectives: The purpose of our study was to evaluate the impact of suprascapular nerve block (SSNB) anterior approach and interscalene brachial plexus block (ISB) on the respiratory mechanics after shoulder surgery.Patients and methods: In this prospective, randomized, double-blind clinical study, 60 cases were enrolled that were scheduled for elective arthroscopic shoulder surgery and classified as physical status by the American Society of Anesthesiologists (ASA I or II). The patients were randomly assigned to two equal categories: the first group (ISB) received US-guided interscalene approach for brachial plexus plane block, while the second group (SSNB) received US-guided suprascapular nerve block anterior approach.Results: Regarding the pulmonary function, group (SSNB) had significantly higher FVC and FEV1 at 1-hour after block in comparison to group ISB (P<0.001). Additionally, the reduction of FVC and FEV1 were significantly reduced in group (SSNB) than group (ISB) (P<0.001). Concerning the DE, group (SSNB) had significantly higher change of ipsilateral DE than group ISB (P<0.001).Conclusion: Anterior SSNB preserved pulmonary function more effectively than ISB, and their analgesic effects did not vary significantly.