Welcome to our Pain Management Community - and please excuse my tardy response to your post. I've had some issues with our new format and posts don't always show for me on a timely basis. Sorry!
MRIs like many medical tests are filled with medical terms that are often confusing to non-medical ppl. Overall your MRI is showing signs of an aging spine. I know you're not very old - but your spine appears to be a few years ahead of your actual age, probably due to your DX (diagnosis) of Osteoarthritis.
Are you familiar with the spine? Here's a little Spine 101 to help you understand the terms and their significance. For location, functioning and naming the vertebrae is sectioned off - and beginning at the neck is the Cervical Spine. There are seven cervical vertebrae C1- C7. - Next are the twelve thoracic vertebrae T1 - T12. - Following those are the five lumbar vertebrae. Than there are five sacral vertebrae (S1-S5) which are fused in maturity, into one large bone the sacrum with no inter-vertebral discs. At the base of the sacrum is the Coccyx (tailbone) which also contains no discs.
Each vertebrae has it's own structure with cushioning discs between them. Facets joints are the "joints" of your spine allowing for motion. Each vertebra has two sets of facet joints. One pair faces upward (superior articular facet) and one downward (inferior articular facet). There is one joint on each side (right and left). Facet joints are hinge–like and link vertebrae together. They are located at the back of the spine (posterior).
Now back to your MRI. The "signal" the MRI is referring to is how well the MRI machine "sees" something - The image that the MRI creates looks black, white, and all shades of grey. This different shade is called "signal." High (or increased) signal is a white appearing shade, and low (or decreased) signal is a dark shade. The radiologist and physician use these signal characteristics to determine if the appearance in normal or abnormal. Signal abnormalities need to be interrupted by the medical professionals - the type of MRI used can also matter. Was it a T1 or T2 weighted MRI?
"There is some moderate decreased signal at the L3-4 and 4-5" Sometimes a decreased signal can mean a vertebral disc is drier than what's normal - which would interfere with it's ability to cushion and protect as well as it should. Sorry I don't have an exact meaning for you.
"At T11-12 disc there is mild bulging." At your T11- T12 vertebrae there is a disc that is bulging - discs should not bulge out of their normal space and this can cause varying degrees of discomfort.
"At L2-3 disc there is moderate generalized disc bulging with mild canal stenosis but there is no foraminal narrowing or disc protrusion." You've talked about the disc bulging - mild canal stenosis means there is some narrowing (mild) of your spinal canal, probably caused by the disc bulging. A foramen is an opening in a vertebra through which the nerve roots leave the spine.The MRI says that opening is not narrowed, indicating it's not compressing nerves. I don't like the term disc protrusion as it can have several meanings depending on the radiologist. Usually it means bulge.
"At L4-5 and 5-1 docs there is moderate bilateral facet joint arthritis but no protrusion or narrowing." This basically means normal aging. We spoke about the facet joints of the discs - this shows you have arthritis in those joints.
All in all your MRI does not show anything that looks like surgery to me. No need to get out the Samurai Swords! It says you have an aching low back - how severe your discomfort is - only you can tell us.
I hope I've helped. I know it's confusing. Please let me know if you would like more clarification - or if I've been of no help. I'll look forward to hearing from you again soon.