Objective: To evaluate the success rate of eustachian tube (ET) occlusion in subtotal petrosectomy relative to the occlusive material used and to the varying protympanum anatomy, by means of standardized alignment of the cochlea-carotid artery relation on computed tomography images.
Patients and methods: All cases of subtotal petrosectomy carried out by the same surgeon at a tertiary care referral center were retrospectively evaluated. Only cases with available computed tomography prior to second stage cochlear or middle ear implantation were included. The occlusive material was either muscle tissue or oxidized regenerated cellulose in combination with bone wax. On 3D multiplanar image reconstruction, the varying topographic interrelation of the cochlea and the petrous carotid artery was measured and categorized into two groups: detachment or overlapping.
Results: In 9 (31%) of the 29 included cases there was insufficient occlusion of the ET. In none of these cases was an infection of the fat filling in the obliterated cavity observed during the implantation procedure on second stage (average 10 months interval). The failure rate of both occlusion materials was almost the same (using muscle tissue, in 4 (33.3%) of 12 or oxidized regenerated cellulose, in 5 (29.4%) of 17 cases). It was also similar for both materials in each of the anatomic variation groups.
Conclusions: An incomplete occlusion of the ET alone does not appear to lead to an infection of the obliterated cavity. Autologous muscle tissue and oxidized regenerated cellulose had similar rates of ET occlusion failure. The topographical variance of the protympanum appears to have no direct influence on the success of the ET occlusion.
Keywords: carotid canal; eustachian tube; obliteration; occlusion; protympanum; subtotal petrosectomy.
© 2020 The Authors. Laryngoscope Investigative Otolaryngology published by Wiley Periodicals LLC on behalf of The Triological Society.