Novel Multiportal Approach to the Internal Auditory Canal for Hearing-Preserving Surgery: Feasibility Assessment in Dissections.

OBJECTIVE: State-of-the-art, minimally invasive endoscopic transcanal surgery of the internal auditory canal (IAC) sacrifices the cochlea with complete hearing loss. With a combination of the transcanal infracochlear and transmastoid retrolabyrinthine approaches, we aim to preserve hearing and enable minimally invasive surgical treatment of vestibular schwannoma. In this study, we investigate the anatomical indications and the feasibility of both approaches in dissections, in human whole head specimens. METHODS: We operated whole head anatomical specimens with a four-handed technique, using the retrolabyrinthine approach as the main surgical corridor and the infracochlear approach for endoscopic visualization. We tested 4 different powered surgical systems. We collected intraoperative data on the size of the access windows, the surgical freedom, and the exposed area of the IAC. Finally, we evaluated the outcome in postoperative computed tomography scans. RESULTS: Six out of 14 sides were anatomically suitable and qualified for the surgery based on preoperative computed tomography. In all attempted sides, the IAC could be reached and opened, leaving the ossicular chain and the labyrinth intact. 51%-75% of the length and 22%-40% of the circumference of the IAC could be exposed. All tested instruments were beneficial at different stages of the surgery. The four-handed technique enabled good maneuverability of the instruments. CONCLUSIONS: The combined multiportal approach to the IAC is feasible with a good surgical exposure and full anatomical preservation of hearing. State-of-the-art surgical instruments in specimens with suitable anatomy are sufficient to perform this approach.

Epinephrine Use in Endoscopic Ear Surgery: Quantitative Safety Assessment.

INTRODUCTION: The management of bleeding in exclusive endoscopic ear surgery (EES) is largely dependent on epinephrine use. However, to date its suitability and safety have not been assessed. The aim of the present study would be to assess the safety profile of topical application and/or local infiltrationof diluted epinephrine during EES regarding the intra- and postoperative periods. We hypothesize that epinephrine may be safely used during EES. METHODS: Retrospective analysis of 90 EES cases performed at the University Hospital of Modena, Italy. Patient's charts and video recordings of the operations were assessed. RESULTS: Epinephrine was used in all cases for hemostatic purposes as following: (1) diluted epinephrine (1:200,000) injection: mean 1.2 mL (range: 0-3.5) corresponding to 0.006 mg (range 0-0.018), and (2) topical application (1:1,000) directly in the surgical field: mean 7 cottonoids (range: 0-18) corresponding to mean 0.56 mg (range: 0-1.44). No major cardiovascular adverse effects were assessed. Only 2 intraoperative hypertensive events were recorded. One sensorineural hearing loss was observed in a case of cholesteatoma involving the stapes; no facial palsy occurred during the study period. CONCLUSION: The combined use of local injection and topical epinephrine is a safe and effective strategy to control bleeding in exclusive EES, when used within the dilutions and quantities reported in this study.