Diaphragm Sparing Effect of Subomohyoid Block With Infraclavicular or Subscapularis Blocks in Comparison With Interscalen Block for Postoperative Analgesia in Shoulder Surgeries

The gold standard for shoulder analgesia is the interscalene block (ISB), but it has its own share of disadvantages such as phrenic nerve block, recurrent laryngeal nerve involvement and Horner's syndrome may lead to patient discomfort .Others, such as intrathecal spread and systemic toxicity of local anesthetic, can have serious consequences. Phrenic nerve injury is a common complication with regional anesthesia. Its either temporary with Transient Phrenic Nerve Palsy leading to hemidiaphragmatic paresis after interscalene block or other injections of local anesthetic in the neck . Although studies of ISB have shown a reduction in the incidence in hemidiaphragmatic paralysis with low-volume ISB, the risk of phrenic paralysis is not completely eliminated. To bypass this complication, distal block of the shoulder innervation is recommended such as subomohyoid infraclavicular and subomohyoid subscapularis blocks.