 Both cadaveric and clinical studies where done. Cadaveric studies revealed no evidence of fractures to the cartilaginous or bony lumen, and no damage to the internal carotid artery. Several clinical studies and many others that confirm the safety of eustachian tube balloon dilation and consider it as a potential solution for chronic eustachian tube dysfunction. A systematic review preformed in 2014 showed no adverse outcomes in 103 patients who had undergone balloon dilation of the Eustachian tube. Another more recent systematic review in 2016 that included nine prospective studies, describing 713 eustachian tube balloon dilations in 474 patients confirm the safety of eustachian tube balloon dilation. 