@upnort I have read your other posts and you are in a difficult place with no answers and the possibility of things getting so much worse in the future. Your neurosurgeon is the best one to answer your questions about the risk and details of the biopsy procedure as well as recovery afterward. From what you posted before the risks included paralysis which makes sense if nerve tissue is removed. The spinal cord does not heal easily from injury. Dr. Mohamed Bydon (spine neurosurgeon at Mayo) is researching spinal cord regeneration and stem cells and has had some initial success.
https://www.mayoclinic.org/biographies/bydon-mohamad-m-d/bio-20147826
You might ask your neurosurgeon if they have consulted Dr. Bydon about what treatment could be done if the biopsy causes damage to the spinal cord and loss of function. That may be tough to answer since they don't know the cause of the lesion or if it is cancerous. It it was me, I would want an opinion from Dr. Bydon. I found this link about his research area and it mentioned genetic testing for disease. Has anyone done genetic testing that may lead to a clue?
Here is the link: https://www.mayo.edu/research/labs/neuro-informatics/research-activities/genetics-spine-disease-spinal-regeneration
https://www.mayo.edu/research/labs/neuro-informatics/research-activities/spinal-cord-injury
If you go to this Mayo News Network link, there is a spinal cord injury patient story about Dr. Bydon and a video.
https://newsnetwork.mayoclinic.org/discussion/case-report-stem-cells-a-step-toward-improving-motor-sensory-function-after-spinal-cord-injury/
Do you have someone to help you at home? Being a primary caregiver is difficult enough by itself and further complicated by your own health issues. These are very difficult decisions as to what to do, and there may not be other members who have had similar experiences because of the rarity of the condition. You are right to ask the question, even if all we can do is lend a caring listening ear. I hope you get some answers without loss of function and ability.

Jennifer