Silverlady, I know you were hoping there'd be something totally definitive on your MRI, and this doesn't supply you with that answer, so it's not great news to you. However, let's break it down, because I think there is some real information embedded in here:

sacroiliac joints are patent. No sacral nerve root lesions or masses are appreciated. There is no visible presacral soft tissue mass." Impression was : Normal MRI of the sacrum. and.....
Okay, your sacrum is fine.

MRI of the lumbar and sacral spine: "L4-5Small 1-2 mm posterolateral bulges which do not enhance are present within each posterolateral region: however, they do not cause significant canal stenosis or neural foraminal encroachment.
So this part, about the sacrum itself says you've got a couple of bulges (are you over 40? we all have a couple of bulges) but they are not pushing on the nerves running up and down (no stenosis) and not pushing on nerves coming out (foraminal encroachment)

L5-S1: A 4mm paracentral disk protrusion with mild central canal stenosis and probable right S1 nerve root impingement."
This level might explain your pain. There's a disk pushing into the spinal canal which is pushing against the nerves running up and down (spinal stenosis), but they think the pressure is "mild". It looks like a disk is pressing on the S1 nerve coming out. S1 supplies numerous muscles including the gastrocnemius, gluteus maximus, and semimembranosus. It supplies sensation to the butt, and lateral foot (the part with the little toe).

So, what might the doctors do to see if your pain is from S1? Well, they might do an EMG to see if it's abnormal in the S1 distribution. Or, they could do a transforaminal epidural and shoot a bit of salt water onto S1 to see if it produces symptoms which are the same as the pain you have. I'm not sure what else they might do; perhaps others here do.

Did they do bending xrays to see if you have spondylolisthesis? That's when vertebrae, because of arthritis, slip out of position when you bend. The spinal cord doesn't have much "give" in it, so if a vertebrae slips forward, it pulls the cord tight, and that, over time, damages nerves and gives symptoms that are identical with peripheral neuropathy? I'd suggest you google on "cauda equina syndrome" and see if you have symptoms of this. (I had a spinal cyst, due to spondylolisthesis, and symptoms of both peripheral neuropathy and cauda equina syndrome, and was treated as if I had "sciatica" for over a year before the diagnosis was made.)

So, I know you were hoping for something more definitive, but I do think there is the possibility here that this disk is giving you symptoms. And that would be a fairly simple thing for treatment.

Here's a link on symptoms of S1 radiculopathy. You might want to compare yourself with them.
http://www.thamburaj.com/lumbar_disc_prolapse.htm

Here's spinal stenosis: http://www.spine-health.com/topics/c...is/sten01.html

Here's an animation of spondylolisthesis :


http://72.14.209.104/search?q=cache:...s&ct=clnk&cd=3

and something about it: http://www.spine-health.com/topics/c...d/degen01.html

There's no mention of your lumbar spine here....did they really only just look at the sacrum? I mean, if you're getting an MRI, why not just look around the entire area? Nothing on the lumbar spine at all?

If you haven't had lumbar spine films done lately, you might ask for them, with the bending films to look for spondylolisthesis.

Hope this helps; I think there might be folk on this board who know more about spinal issues than I do.

LizaJane
www.lizajane.org