@brycek112
Did they say what is causing your DDD at such a young age? Did you have an accident or play sports that caused serious compression of your L4-L5 disc? Were you told you have a congenitally narrow spinal canal?

I am 55 and just had L3-L5 decompression and fusion surgery in August 2024 due to severe central spinal canal stenosis, DDD and neurogenic claudication. You could not even see my spinal canal/cord on MRI because it was so severely compressed by disc bulge plus arthritis bone growth. Many symptoms are improved while in the healing process. There is some restriction in movement but I was restricted before due to pain. My L4 vertebrae was slipping over L5 (spondylolisthesis) so they needed to use hardware to stabilize my spine to prevent movement and support fusion plus they removed lamina bone to give space for spinal cord.

Depending on the cause of your DDD and compression of L4-L5 disc, disc replacement may be okay but if you have instability in your spine, the fusion would help to limit the movement which could cause issues with a disc replacement (may slip/move again requiring another surgery). It would be good to ask both surgeons questions as to pros and cons and maybe get a 3rd opinion one you get more answers and information. Have you seen neurosurgeons or orthopedic spine specialists? I had my surgery done by an orthopedic surgeon ( he also did my cervical spine surgery).