I had a herniated l5- s1 in 2011 and the sciatic pain is gone now. but since last week i feel tingling and numbness in the middle toe of my left feet. is this due to herniated disc?

Recurrent herniation: It is certainly possible that you may have had a recurrence of the disc herniation, which could be causing numbness/tingling now instead of pain. If the symptoms have been present for only a short time, it would be reasonable just to observe, but if the symptoms persist or worsen you should see a physician.

Radiculopathy: An l5-s1 disc herniation can cause this condition by causing irritation to the nerves that travel from the back to the foot. Morton's neuroma is another condition which can cause numbness in one toe.

Sciatica: It is possible, however, it is unlikely if no longer having pain in the lower back. If the pain in the lower back resolved just recently then i feel it is quite possible. Check with your md for other possibilities like diabetes or vitamin deficiencies. Hope you feel well soon.

Something Else: Numbness to a middle toe is usually due to a neuroma. See podiatrist and can diagnose it with examination.