First of all, keep in mind that I am unable to diagnose you because I am unable to examine you, this forum is for educational purposes. Cavernous hemangiomas are rare vascular malformations that can occur at any place in the nervous system including the spinal cord. They occur intra and extra dural (inside and outside the lining of the spinal cord), and more rarely intramedullary (inside the cord). These lesions are most commonly located in the thoracic cord (middle segment) with the cervical cord being next most common. Patients generally present with pain, which can then follow a progressive course of weakness and/or numbness if the lesion expands (bleeds). Treatment consist of complete surgical excision using microsurgical techniques, and these surgeries do have a good outcome when done in major hospitals (although your exact risk is largely dependent on your lesion, which I am not able to examine). The cost of such a procedure is dependent on many variables, and I would suggest that you speak with a financial counselor (available at all major hospitals). A 30% risks of paralysis does seem unreasonable, and I would a least seek a second opinion. I would recommend that you see a neurosugeon and bring your MRI scans for him/her to examine. Until then, there are a number of neuropathic pain medications that may be helpful that include Lyrica, Neurontin, Cymbalta, Maprotiline, Desipriamine, etc. (discuss these with your neurologist).
I hope this has been helpful.