I've not had a mandiblectomy so I'm not much help on that front - however I did want to welcome you and suggest as others have to educate yourself about the disease and procedures here - if you have questions there is usually at least one person who's gone through something similar - who could try and explain. Do find out why they are removing some of your mandible. It's important at you have confidence as to why.

Best of luck - and do bri g something to communicate with when you go in - and if you can have someone advocate for you - even better,

Take care