How To Treat Sciatica Pain Between The Ankle And Knees?

Age 78yrs,Height 5ft.5inches,Weight 63kg,. pain of sciatica in the right leg between ankle and knee and more in the middle of both. spine nerve is pressed between Ls3 and Ls4 and also in Ls4 and Ls5.pain while standing a minute or two and pain increases while walking for 5 minutes.can sit only at a particlar height of the seat,got physiotherapy done from 3 places for 3 months.getting worse.doing some excercises at home but no relief.suggest a permanent solution. mri shows degeneration of spinal bones.