Surgical guiding enhancement of chronic otitis media using optical coherence tomography with the microscope

Surgery of chronic otitis media (COM) is a sensitive procedure, where the success rate crucially depends on the surgeon and the significant depth visibility of the surgical microscope. Additionally, videotapes have been frequently adapted for surgical guidance at operation theaters. While these approaches provide great views and assistance during the surgery, it has proven more challenging to derive morphological and volumetric information on subsurface layers of COM. To address this issue, an intra-surgical spectral-domain optical coherence tomography (OCT) microscope system with an extended working distance of 280 mm was developed, which has augmented reality on the ocular eyepiece of a surgical microscope for more effective visualization of morphological structures during mastoidectomy or tympanoplasty. The cross-sectional OCT images guide surgeons to more easily identify targeted regions by displaying depth direction information in real-Time during surgery. Three patients with COM participated in this study, and the lesion conditions of the temporal bone were observed with pre-operative computed tomography (CT) before the surgery. Moreover, pure tone audiogram examinations were performed to evaluate pre-and post-surgical conditions. The pure tone audiogram reveals that the operation was well performed based on the air-bone gap (ABG) reduction, and it can be confirmed that the hearing level was also improved. The success of the surgical procedure was confirmed through the intraoperative OCT images, and the post-examined audiogram results further confirmed the improvement of hearing. Hence, the integration of intra-surgical OCT and audiogram inspection methods revealed the potential merits of the proposed methodology.