@MurFer - IJV compression can have multiple causes. The most common one is the IJV being compressed between the styloid process & the C1 vertebra. Sometimes the styloid is more at fault & others it’s more due to he position of C1. In the former case, a styloidecotmy is enough to allow the IJV to decompress, In the latter case, even if the styloid is removed, C1 will still be pressing into the IJV enough to disallow it to open. In that case, either C1 needs to be shaved a little or the OJV needs to be moved away from C1. Other causes of compression that can be in addition to or instead of the styloid/C1 scenario are compression by a nerve, muscle, other vascular or soft tissue. Those scenarios are also somewhat common.
Did Dr. Osborne discuss with you what he’d do to decompress your IJVs if he does your surgery(ies)? We do have at least one member who had IJV decompression done by Dr. Osborne. I don’t remember who it is at the moment though.