Can nerve root block distinguish between PN and a cause related to nerve root ?
 

So for 12 months I have had excruciating pain in my right foot. MRIs showed there was nothing wrong with the foot itself - my GP then thought it might be a peripheral neuropathy but two neurologists said this was not the case. I then saw a pain specialist who said that the cause was in my back as a lumbar MRI showed an L5 S1 disc herniation. I had a series of four nerve blocks/ steroid injections into L5 S1 and three of these relieved the foot pain completely ( temporarily). It came back and last week I had a discectomy on L5S1 but this has done nothing for the foot pain - it is still there as strong as ever. My question is : were they on the right track saying the source was in the nerve root ( as evidenced by the success of the nerve blocks) or could this pain have a local cause in the foot itself ??
I have never heard of anyone getting peripheral neuropathy in just one foot have you ?
Does the success of the nerve root blocks 100% confirm that the cause is in the nerve root or could a nerve root block stop pain that has a source elsewhere ( eg related to prripheral neuropathy)???
I am very confused as to what the success of a nerve root block actually shows ??
Thoughts please !
Many thanks.