I can share my experience! I inquired about colostomy a few years ago. The colorectal surgeon told me that surgery would not eliminate the symptoms of IBS. There would still be gas, pain, C and D, only it would be going into a bag instead of a toilet. He told me that any surgeon who would do such a radical surgery for IBS would be, in his opinion, unethical.
However, if your primary condition is chronic and extreme C, this could be an option. I believe there are a few posters here who have had this experience and I'm sure they will respond!