Comparative Study of Superficial Cervical Plexus Block and Nerve of Arnold Block and Incidence of PONV for Inner Ear Surgery

Overview

The investigators would like to compare the therapeutic and cost effectiveness of established therapies for postoperative nausea and vomiting to regional nerve blocks of the head and neck area an intervention known for analgesia but for which the antiemetic effects hasn't been entirely explored. The rational is based on the knowledge of the anatomical innervation of the inner ear and the role of the parasympathetic nervous system in the emetic act. A lot of focus has been given on its counterpart the sympathetic nervous system and its role in painful conditions. The investigators believe that the nerve blockade of the parasympathetic innervation can have some beneficial effect in the post-surgical patient.

The researchers hypothesize another potential antiemetic mechanism by the blockade of the auricular branch of the vagus nerve at the ear canal (commonly described as nerve of Arnold) in conjunction with a block of the greater auricular nerve and lesser occipital nerve at the superficial cervical plexus level. The block would cover both the sensory innervation and of the ear canal and the inner ear. A regional anesthetic block prior to the surgical intervention on the inner ear at the superficial cervical plexus block is performed. This latter is a branch of the vagus nerve at the superficial cervical plexus (erb's point). The block would inhibit the vagal afferent to area postrema through inhibition of afferent vagal input to the medullary center. The emetic act (vomiting) is a highly integrated physiologic reflex involving both the somatic and autonomic nervous system. Researchers do not know how much of a relation there is between the vagal nerve branches involvement and incidence of nausea and vomiting effects are from the inner ear injury and or the inflammatory response type of response triggering the area postrema. The usual prophylactic treatment of PONV (post operative nausea and vomiting) has been limited to anti-emetics such as dexamethasone along with aggressive fluid therapy and adequate analgesia. Investigators are proposing to conduct a comparative study of the therapeutic and cost effectiveness of regional anesthesia and antiemetic therapy in the prevention and treatment of PONV in children undergoing inner ear surgical procedures.