Real-time monitoring and quantitative analysis of PAG-mediated chemical cochleostomy using 1.06-µm swept-source optical coherence tomography.

Abstract

Traditional cochleostomy relies on mechanical drilling, which carries inherent risks of acoustic and thermal trauma. In this study, we performed a quantitative analysis of phosphoric acid gel (PAG)-mediated chemical cochleostomy in ex vivo mouse cochleae using a 1.06-µm swept-source optical coherence tomography (SS-OCT) system. The imaging results demonstrated that 1.06-µm OCT provides high contrast for visualizing internal anatomic features, such as the organ of Corti, and changes in cochlear architecture during the chemical etching process. Quantitative evaluation revealed a reduction in bony wall thickness and enhanced visibility of intracochlear conduits post-PAG-application. Notably, the PAG-mediated thinning mitigates signal attenuation by reducing scattering from the dense bony wall, thereby improving OCT imaging contrast of internal structures. Real-time M-mode OCT imaging successfully captured dynamic reaction kinetics, providing a reliable feedback mechanism for identifying the etching endpoint. These findings suggest that 1.06-µm SS-OCT is a feasible guidance tool for precise, hearing-preservation cochlear interventions.