I am unclear as to the meaning of 85-90% union. Does this mean complete union or “you are almost there” type of union? This can make a big difference. Use of BMP with increased pain in my practice means a new MRI is warranted to look for the “BMPoma”.
You have not had a SNRB of the L5 root on the left yet. In my practice, that would be the next step along with an MRI. If the patient would get great relief, I would focus more on the L5 root than the SI joint. Again- if good relief (depending upon the MRI findings), I would consider removing the instrumentation and exploring the nerve root before considering fusion of the SI joint.
If the SNRB gave no relief or the MRI demonstrated no compression or adhesions of the L5 root, then I would consider a fusion of the SI joint.
Donald Corenman, MD, DC is a highly-regarded spine surgeon, considered an expert in the area of neck and back pain. Trained as both a Medical Doctor and Doctor of Chiropractic, Dr. Corenman earned academic appointments as Clinical Assistant Professor and Assistant Professor of Orthopaedic Surgery at the University of Colorado Health Sciences Center, and his research on spine surgery and rehabilitation has resulted in the publication of multiple peer-reviewed articles and two books.