With recovery it is hard to say what will come back first. This is depending where actually the injury has taken place, which nerves have been severed the most. An Wikipedia reference-linkMRI after the actual surgery could tell the most because it would show (in principle) which nerves have been affected. You could think also as followed: e.g. S2 supplies dermatomes, muscles and alike. the further away the less likely a full recovery. having said this a problem arises again because one doesn't know when a nerve is affected which part is affected. when a 1 fibre is damaged as much as a 4 fibre the 1 fibre will most likely have a better chance to recover (less complex). The longer a fibre is the less likely it is to recover. I try to point out that it is all very complex and therefor unpredictable.