What could cause facet joint degeneration?

Hello doctor,

I currently take Gabapentin for my back pain, Tylenol and Tizanidine, Warfarin for blood clots, and Simvastatin for a CVA that I had six years back. My report is as follows.

Degenerative intervertebral disc and facet changes are noted at the lower lumbar levels. Findings are most prominent at L5-S1, where a bulging disc with a superimposed left subarticular disc protrusion and mild facet arthropathy results in mild central spinal canal stenosis, significant effacement of left lateral recesses with mass effect upon the transiting left S1 nerve root, and mild bilateral neural foraminal narrowing.

Clinical information: 48-year-old patient with back pain that radiates to the left lower extremity.

Technique: Noncontrast MRI lumbar spine was performed.

Findings: Sagittal images included from T11 through S3.

Height and AP alignment of visualized vertebral bodies are preserved.

Bone marrow signal intensity is normal.

Normal imaging appearance of perivertebral soft tissues.

The CONUS is seen at the L1-L2 level. The size and signal intensity of visualized distal spinal cord is normal.

Normal imaging appearance of cauda equina nerve roots.

At L5-S1, a bulging disc with a left subarticular disc protrusion and mild facet arthropathy results in mild central spinal canal stenosis, significant effacement of left lateral recesses with mass effect upon the left S1 nerve root (better seen on image 7 of series 301 as well as image 60 of series 501) and mild bilateral neural foraminal narrowing.

At L4-L5 eccentric left bulging disc and mild bilateral facet

arthropathy with mildly prominent ligamentum flavum results in mild effacement of the ventral aspect of the thecal sac and mild bilateral neural foraminal narrowing.

Kindly help me to understand this report.