The breakdown of L4-5 only 2 years after your L5-S1 ALIF is quite unusual. I would think there was some preexisting degeneration of L4-5 prior to the surgery.
I am unclear what “partial osseous fusion” means. There might be a solid fusion but different radiologists have different meanings for this phrase. I will assume you have a solid fusion at L5-S1.
You still have continued stenosis at L5-S1 (“central canal narrowing”) but the radiologist did not use a modifier (moderate, severe) to indicate the amount of narrowing. This by the way is common with an ALIF as the anterior approach generally does not do a good job of posterior decompression. Your continued symptoms could be from the continued narrowing.
Your symptoms need to be correlated to the disorders found on your MRI. See the section “https://neckandback.com/conditions/how-to-describe-your-history-and-symptoms-of-lower-back-and-leg-pain/” to desire your symptoms.
Dr. Corenman
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.