@dablues It would be worth calling the other Mayo Campuses to see if your insurance is accepted. It can be different between them. You might have a wait to get into Mayo, and they have to review your case and accept you. I was told it might be a 3 month wait, and I got in sooner after a month because of a cancellation. It was worth it to me to travel to Mayo and they don't waste your time. They get all their testing done right away and you have an answer usually within a week.

Doctors have to look for a differential diagnosis for things like MS or ALS that can be confused with a spine problem because they need to know with certainty what is causing the pain. Clearly from your other post, you do have a multilevel cervical issue with significant impingement of nerves that exit the spine in the foramen (nerve roots). That might be part just of the issues and there could be something else causing overlapping symptoms. According to my neurologist, MS would show some changes in the brain imaging, and the EMG nerve conduction tests would show some malfunction in conduction of signal in the nerves.

You might ask for imaging in the rest of your spine too to rule out a spine related cause there since you have leg pain. I had Mayo do MRIs of my thoracic and lumbar spine so I had a complete picture. What makes this confusing (if it is a spine issue) is that nerve root compression causes pain that follows a specific dermatome map, but spinal cord compression can also cause pain, but it doesn't follow a map. It can be anywhere, and that may depend on how you move your head or neck and the spinal cord should move and float freely inside the spinal canal and that can change where the cord may be touching bad discs or bone spurs (osteophytes). The spinal cord is a huge bundle of all the nerve pathways for everything in the body and when one part of it gets compressed, it's hard to know where that is happening. You can also have a situation where the spinal cord gets touched in multiple places because of the bulging discs and osteophytes and it can cause pain in an unsuspected place like in the legs, and that leg pain can be generated by spinal cord compression in the neck (funicular pain). The dermatome map for leg pain, if caused by compression of nerve roots would be from the lumbar spine which I didn't have, but I did have a bulging lumbar disc. It cracks on rotation and that did change some sciatic pain and stop it temporarily when I still had cord compression before my surgery. I had pain all over my body in every dermatome. That is what confused a bunch of surgeons in my case and because they didn't understand it, they wouldn't help me. If I keep my core strength up and maintain good posture, I avoid leg pains altogether. Having spine surgery that freed the cervical spinal cord resolved all the pain I was getting everywhere in my body from the compression in my neck. There are also some pelvic syndromes that can cause sciatic pain from nerve compression and misalignment that are not spine related. I have had pelvis tightness also create some sciatic pain, and my physical therapist has been able to resolve that, and what happens is that it pulls on the spine and throws the pelvis out of normal alignment and compresses nerves that pass through overly tight muscles.

Your doctors should be able to tell you why you have your symptoms and be able to connect that to what they see on imaging and tests. That is where in my case, they got it wrong. The spine surgery on my neck at C5/C6 completely resolved my leg and body pain, as well as the problems walking with an uneven gait.

Here are a couple links with information and the literature I found that described cases similar to mine.
https://www.ncbi.nlm.nih.gov/pubmed/20938789
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3111492/
This is a Spine Health link that explains "funicular pain". I'm glad to see they have updated this as this was not explained at the time of my surgery. https://www.spine-health.com/conditions/neck-pain/types-neck-pain

This explains pelvis alignment issues. https://trainingandrehabilitation.com/identify-treat-lumbar-plexus-compression-syndrome-lpcs/

This explains dermatome maps and where the nerve pathways go. https://www.healthline.com/health/dermatome#dermatomes-list