Risk of Hearing Loss from Playing the Saxophone
The eustachian tube emanates from a location that is very close to the entry of the sinuses. And, any irritation that causes swelling in the eustachian tube area will frequently also cause sinus problems- both are lined with mucous membranes that are easy to irritate. But, other than that, forceful blowing through the eustachian tube will not either damage the eustachian tube or the mucous membrane lining the sinuses.
There is no evidence that bone conducted sound (either through a reed or holding a violin box tightly to one's jaw) will be a culprit in hearing loss. The frequency of best transduction by bone conduction is at 2000 Hz and it takes 40 dB SPL to vibrate the skull to audibility- and much greater for lower and higher frequencies. Even sustained bone conducted intensities of 120 dB SPL will be far below 85 dB by the time it reaches the inner ear.
A final comment about hearing loss and loud music, there is also no evidence that someone who already has a permanent sensori-neural hearing loss is any more (or less) susceptible to future hearing loss from loud music (or noise). As such, individuals with hearing loss should take the same precautions to protect their hearing as those with normal hearing (i.e. limit exposure intensity and duration and using hearing protection).