Expression of Calcitonin Gene-related Peptide and Its Application to Cochlear Implantation Under Local Anesthesia With Monitored Anesthesia Care in the Very Elderly: The University of California, Los Angeles, Experience

HYPOTHESIS: Calcitonin gene-related peptide (CGRP), a neuropeptide implicated in nociception, localizes to areas of heightened pain sensitivity during cochlear implantation (CI) under local anesthesia with monitored anesthesia care (MAC). BACKGROUND: Many elderly patients would benefit from CI; however, implantation is often limited by medical comorbidities and risks of general anesthesia including postoperative cognitive decline. CI under local anesthesia with MAC offers a safer alternative; however, optimal analgesia remains unclear due to limited data on pain receptor distribution in the temporal bone. CGRP is a well-established marker in pain signaling pathways. The present study aims to describe its distribution in relation to CI as well as the anesthetic technique utilized at the University of California, Los Angeles (UCLA) in the very elderly. METHODS: Archival human temporal bones (HTB) acquired from healthy donors were stained for CGRP and neurofilament (NF). Findings were used to inform analgesic techniques in 17 very elderly patients (age >80 y) undergoing CI under local anesthesia with MAC. RESULTS: CGRP immunoreactivity (IR) was observed in the facial nerve, tympanic membrane, and epithelium of the external auditory canal-regions corresponding to areas of reported intraoperative discomfort. Modifying the analgesic approach with a targeted bony-cartilaginous injection improved patient tolerance. No major complications occurred, and all procedures were completed without conversion to general anesthesia. CONCLUSION: CGRP is a valuable marker for identifying pain-sensitive regions in the temporal bone relevant to CI. Histopathology-guided refinements in local anesthesia enhance intraoperative comfort and feasibility of CI under MAC in the very elderly with the potential to improve postoperative outcomes and broaden candidacy for this population.