Surgery for diverticulitis is done because it is a disease. Spasms are not a disease nor is IBS. Have you tried consulting with one of the premier GI centers in the country? I'm not sure where you live but getting a 2nd opinion at the Cleveland Clinic or the Mayo in MN might be something to consider.
dx proctitis in 1987
dx UC in 1991, was stable until 1998
1998 started prednisone, asacol, pentasa, nortriptylene, ativan, 6MP, rowasa enemas and suppositories, hydrocortisone enemas, tried the SCD diet, being a vegetarian, omega 3s, flax, pranic healing, yoga, acupuncture, probiotics
2000 lost all my B-12 stores and became anemic
2001 opted for j-pouch surgery- now living life med-free