Transmastoid endoscopic-assisted Eustachian tube packing after translabyrinthine tumor resection: A cadaveric feasibility study

Hypothesis: Endoscopically assisted packing of the Eustachian tube (ET) will improve visualization of the protympanic space compared with standard techniques with the microscope. Background: Postoperative cerebrospinal fluid (CSF) leakage after translabyrinthine tumor resection remains a problem. Current techniques of packing the ET are limited by inadequate visualization. The objective of this study is to demonstrate the feasibility and usefulness of transmastoid endoscopic-assisted ET packing during translabyrinthine tumor resection. Methods: Eight human cadaveric temporal bone dissections were performed on four heads to test the visualization that could be obtained of the ET orifice with an endoscope via transmastoid-facial recess approach. The incus body and incus buttress were removed, the aditus ad antrum enlarged, and tensor tympani muscle was cut. The scope was placed where the incus buttress had previously resided. The ET orifice was visualized and subsequently packed. Results: In all eight temporal bones, the endoscope was successfully able to visualize the ET orifice, with improved visualization of the orifice compared with standard techniques. Surgical technique and potential pitfalls are discussed. Conclusions: The transmastoid endoscopic approach for packing the ET improves visualization of the ET orifice. Packing under direct visualization provided greater reassurance that the material entered the true ET lumen as opposed to a false passage. The technique can be performed without any significant changes to standard surgical technique, allowing for a fast and accurate closure of the ET orifice and has application in potentially decreasing postoperative CSF leak rates.