Arachnoiditis can cause local pain but typically causes leg symptoms and many times arachnoiditis is an incidental finding (not generating symptoms). Rhizotomies and facet injections would treat lower back pain (LBP) generated by the facets which has nothing to do with arachnoiditis. This assumes that your LBP is the only symptom and is only facet generated (not typical).
I would start over with a new spine surgeon and obtain new imaging studies (MRI) as you might have something undiagnosed yet to treat.
Dr. Corenman