I had a discectomy at L4/L5 this past Feb due to disc herniation causing left sided foot drop. I had a tiny numb patch on left knee which resolved. A subsequent MRI in May shows severe L5 joint arthritis some stenosis and a 5 mm posterior residual disc bulge. Caudal nerves are not being bothered or touched. No nerve compression anywhere. I did not get good PT and my back got very very weak and started having double sided nerve irritation and sacral pain.

Fast forward to late October 2011. I went to emergency room because my entire butt went numb and some numbness in both legs. New MRI with contrast shows some scar tissue attaching to left L5 nerve root. The caudal nerves are safe and no signs of any impingement over there. The problem is I have patchy intermitent bilateral numb spots all over my legs and butt that comes and goes. I was good for 2 weeks after ER visit, overdid my walking yesterday and started getting some mild back pain and then the numb spots came back. The distribution can be anywhere, butt, external thigh, inside thigh. Not below knee though. Anybody with any words of wisdom as to what may be going on?

This numbness appears to come from scar tissue pressing on the nerve.