Is there an alternative to palatal expansion surgery in adults?

You can leave the crossbite untreated and only correct anterior crowding since your crowded front teeth are probably your main concern. The other option might be to use a NiTi palatal expander appliance that slowly pushes and tips your teeth instead of splitting a midpalatine suture.

Yes there is an alternative to palatal expansion in adults-  Damon braces, if utilized correctly, can develop the upper jaw of an adult and avoid the use of surgically assisted rapid palatal expansion in adults.   I would get a consult from a certified Damon braces provider which can be found at Damonbraces.com. I hope that helps!