Marty reported around noon today, Monday, April 13:
that the operation "will not be any cutting surgery, just a fine needle aspiration biopsy in my trachea". It is considered low risk procedure, although he will be under general anesthesia. The operation will also be in the morning...he will check in 7 or 7:30am and procedure begins at 8am.
Marty plans to stay all day at hospital until he is fully recovered, and his couchsurfing family in Houston will drive him to and from.
He also reports that the surgeon, a male doctor named Georgie Eapen, thinks it's likely mucous and this biopsy is the least elaborate way to make absolutely sure whether it's mucous or not.