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Quantitative Study of Bone Removal Region in Transcanal Endoscopic Approach to the Attic and Antrum Using a 70°
Masahiro Takahashi1, Masaomi Motegi1, Kazuhisa Yamamoto1
1Department of Otorhinolaryngology, Jikei University Faculty of Medicine, Tokyo, Japan.
Background:
Transcanal endoscopic ear surgery enables surgeons to operate with few blind areas, and using an angled endoscope expands its usefulness. We have previously reported the usefulness of a 70° endoscope in transcanal endoscopic ear surgery, but no quantitative study has been performed. We quantitatively clarified the difference between a microscope and various endoscopes in the bone removal region, especially a 70° endoscope, in the transcanal approach.
Methods:
A temporal bone model for ear surgery training was used to compare the use of a microscope, a 0° endoscope, a 30° endoscope, a 45°endoscope, and a 70° endoscope. The drilled mass during atticotomy or atticoantrostomy and the size of the reconstructed graft were measured when the formed pseudo-lesion was removed.
Results:
The amount of bone excision was 57% and the size of the reconstructed graft was 32% when using a 70° endoscope compared with the case of using a microscope, both of which were the smallest of the various endoscopes.
Conclusion:
It was quantitatively shown that using a 70° endoscope in transcanal endoscopic ear surgery reduced the bone removal region. We believe that a 70° endoscope is a useful tool for performing a minimally invasive and reliable surgery.

