Question
Hello, my father recently got into a motor vehicle accident. He was rear ended near the end of January and phisyotherapy has been on going roughly 3 times a week ever since. And after MRI the results say the following. We would just like to know what this means.
History - 54 year old Male, MVA
a non contrast MRI scan of the lumbar spine was obtained.
There are diffuse mild de-generative changes in the visualized lower thoracic spine and lumbar spine consitent with disc space narrowing, disc degeneration, osteophyte formation and facet and ligamentum flavum hypertrophy.

The L3-4 level shows minimal disc bulging
The l4-5 level shows a tiney central disc herniation without thecal sac or nerve root impingment
The l5-s1 level shows a tiny left central disc herniation abutting the left s1 nerve root. There is no evidence of nerve root impingment.
The t11-12 level also shows a tiny left central disc herniation without nerve root impingement. There is also evidence of multilevel minimal central spinal stenosis form L1-S1
Impression
mild diffuse dgenerative changes. L4-5 tiny central disc herniation. L5-s1 tiny left  central disc herniation. T11-12 tiny extruded left central disc herniation. No evidence of cord or nerve root impingement.

Answer
The MRI scan report essentially indicates that your father has some osteoarthritis (degenerative joint disease), degenerative disc disease, and multiple levels of disc herniations without the disc actually compressing the spinal nerves.

There is also narrowing of the central spinal canal, which is the area formed by the spinal column which contains the spinal cord.

It would be reasonable to assume that these findings are the results of the aging process and wear-and-tear on the spine.

For additional information on degenerative changes of the lumbar spine (low back) as well as spinal stenosis, you might find these brief article of interest:

http://www.aafp.org/afp/980415ap/alvarez.html

http://www.aafp.org/afp/990201ap/575.html

I hope that this answers your question.