Hi nomad9988 .....
Perhaps someone can lead us to a study on this. However, with the number of patients who are never included in a study, it would not be completely reliable as to how common facial involvement might be.
As you state, there are tons of factors to consider: size, exact place of the growing tumor, type of tumor (sticky, completely encapsulated, etc.), etc. Then there is the overall health of the patient, type of treatment or not, skill of the treating physician/surgeon, etc.
In today's world, the treating physicians have the knowledge of many more years of their own experience, as well as the experience of other treating docs, to draw on who have treated acoustic neuroma. This is why we stress the importance of choosing a physician with vast experience in treating specifically acoustic neuroma. This greatly minimizes the chance of facial involvement for those patients seeking treatment.
In my case, I chose my physicians very carefully. I had no facial nerve involvement before or after my first surgery. I had extremely minimal facial weakness for a few weeks following my second surgery (only discernible when smiling very broadly). No issues whatsoever now.
Clarice
