Mel.
I've not had a 'Sural'. (I have had the Skin Punch Biopsy)
I've read about it on these BB's for 8 years.
IMHO, the results (not the Dx, but the after affects) can be worse than the PN and that can not be fixed - ever !
More pain, More suffering!

The consensus is that the test results, more than 50% of the time,
only confirm the previous diagnoses.

I'd get detailed info on that Dr's claim that 70 out of 100 get 'fixed'.
How? Why? Which, when, where, who, .......DUH !!
(For some reason, some surgeons just love to do Sural's.
I think they need the practical experience....or maybe it's a good way to pay the Country Club's annual fees....who knows?
They just gotta do 'em..damn the damage done to the patient)

I would not take the risk unless I'd had a 2nd, & 3rd opinion on it,
from a PN neurologist - specialist. Not just a neurosurgeon.