Brief Answer:
Surgery look necessary.

Detailed Answer:
I read your question carefully and I understand your concern.

I also viewed the MRI image and it is true that there is involvement of the spinal cord which is compressed at more than one level. Of course that must be correlated with the findings on your doctor's physical examination where weakness and spasticity is a common finding.

The risks as your doctor has explained are present, spinal degenerative changes are a progressive disorder and there is the possibility that spinal cord compression will affect your motor function, balance and in advanced stages bladder function as well.
Apart from that the fact that you describe pain on both sides makes the possibility of nerve root compression possible as well (it can not be judged by that single image you have provided, I should view all axial sections - sections in horizontal plane).

So decision must be done by combining imaging findings and physical exam. If I were to judge based only on the imaging I would say surgery is necessary, if there are physical findings as well that reinforces that even more.

Of course every surgery carries some share of risks, but generally according to published studies, results in neck degenerative disease surgery are good, with improvement rates as high as 90% so you can feel positive about it, while neglecting surgery and leaving the compression advance could render the functional impairment irreversible.

I remain at your disposal for further questions.

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Brief Answer:
CSF not the issue.

Detailed Answer:
I imagine the distress you must be under, considering your activity limitation.

Regarding the CSF fluid issue, no, it is not a question of affecting cerebrospinal fluid circulation, while there is compression at certain anterior points it still circulates laterally, no concern on that regard. But it compresses the nerve pathways going from the brain to your muscles, hence you feel muscle weakness and tire easily.

One mechanism it could affect the brain is by compressing the arteries supplying with blood the posterior part of your brain (vertebral arteries) as they are in close relation with the vertebrae, if that is the case blood supply to the brain might be insufficient at times. I can't say whether that is the case in your case as that is evaluated by imaging of the neck vessels (Angio MRI or CT), I don't know whether you have had that.

I mentioned that just as a possibility though, as I said the compression seen on that MRI image is enough to explain your weakness and tiredness.

I hope to have been of help.

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