What Is The Treatment For Achalasia?

My mother in law has been treated with Botox for difficulty swallowing for the last few years. Her doctor is suggesting she find someone who treats this condition more frequently that he does. I am not sure of her diagnosis but it sounds like she may have Achalasia. We are looking for doctors who are specialist in this disease. She lives in Cheraw, SC. She is 87 years old and has no other medical problems.