I have been advised that such a clinical presentation is very unusual, but not unknown. Thank you very much. Arachnoiditis is inflammation and subsequent scarring in and around nerve roots as they exit the spinal cord, occurring after back surgery. It is an extremely difficult condition to treat. Although acute inflammation affecting so many roots so quickly is unusual, it is indeed not unheard of, and may be the lower extremity equivalent of a condition known as Parsonage-Turner syndrome, or acute brachial plexitis, or neuralgic amyotrophy, particularly if you end up having wasting or atrophy of leg muscles.
Surgery is a common trigger for the former disorder.
A test called an EMG can assess the severity of the ongoing damage to affected nerve roots. If you are interested in a second opinion at the Cleveland Clinic, I would suggest that you see both a neurologist and a neurosurgeon. I would recommend Drs. Shields or Levin or Pioro on the neurology end and Dr. Ian Kalfas, our chief spinal neurosurgeon, on the neurosurgery end of things. If your symptoms are as severe as you describe, as aggressive and expedient a diagnosis and attempts at treatment should be made, especialy on the off chance that this may be another, more treatble condition than arachnoiditis.