Has the surgeon given a reason why there is now a bilateral foot drop when there was not prior to the surgery? Once might expect swelling, haematoma etc. Could also be poor surgery. I would hassle for the reason and perhaps see if nerve conduction tests are available to monitor the situation.

It is true this can happen post surgery and it does usually resolve over time (could be 12-18 months though) but there are many reasons for this and one would want to rule out anything that could be corrected by going in again now to sort it out. Is there a post OP Wikipedia reference-linkMRI?

p.s. Where is the Location "Anon"?