The ASA Relative Value Guide reports that "Any procedure around the head, neck, or shoulder girdle, requiring field avoidance or an procedure requiring a position other than supine or lithotomy, has a minimum Base Value of 5 regardless of any lesser base value assigned to such procedure in the body of the Relative Value Guide". Page xi
An example of this would be: ankle tendon repair CPT 27658 which crosses to 01470 with a base unit of 3. This procedure is commonly (not always) done in the prone position. If indeed, your anesthesia provider documented the prone position, that is acceptable to bump the BV to 5.....no modifier necessary.
Many times during ENT surgery the "table is turned"......meaning the OR table is unlocked and turned 45,90,maybe 180 degrees......getting our providers to specifically document the number of degrees will only strengthen their case for the additional base units. Communicate with your providers......."Please help me understand what you mean by this, Dr. X"
Detailed documentation can only help your cause, especially when you find it necessary to appeal.