This item caught my eye because my pilot son, who is in his 40s, has been suffering from the same problem.
I'm not a 'quack' nor wish to step on their toes but I suggested he has a look at 'Treat your own back' a book by Robin MacKenzie, as I believe sciatica often starts with low back pain. The author, if still alive, is a Kiwi ,highly respected for his work as a physiologist.