The sciatic nerve syndrome is a diet problem. The nerve starts very close to the anus and you can guess what the problem is? Constipation. This is why most Nature Paths will state all diseases are constipation and names are given only becauase of the location of the constipation.
A really good chiropractor can also eventually cure the problem, it may take 1-2 months of regular treatments. The chiropractor is opening up channels and aiding flow which is a form of relieving constipation, etc.
To make a good guess one would have to know allot about a person, such as age, weight, dental metals, water source, food habits, etc. to determin the toxic load or just do the one cure, cures all program the old docs did and be done with it, I am sure the simple 14 day program done to the book would relieve it just fine at almost no cost as long as dental toxins is not the culprit.