Richard1954

In 1999, any degenerative disc disease that involved the sciatic nerve would be rated as one issue.   In my case my sciatic nerve damage resulted in dropfoot and I was awarded a K award for the drop foot but I was not awarded anything for the sciatic nerve damage because at that time the VA considered it part and parcel of the back injury.
It wasn't until years later that the va changed the rating guidelines and started to award a separate rating for sciatic nerve damage,  in cases that involved back injuries.
You do  not have a CUE, because at the time of  your 2000 rating the rules and rating guidelines were different than they are now. 
Why did they change the rating guidelines... simply because changing the guidelines resulted in lower ratings because under the new rules bed rest must be prescribed for a specific period  of time, the longer the bed rest the higher the rating, in our time ,  most doctors do not prescribe bed rest. At they same time they started to allow for separate ratings for the nerve problems caused by the back injury. The end result was a lower rating for the back, and low rating for the nerve, unless the nerve was damaged so bad it caused drop foot.  Lower ratings make it harder to reach a 100% scheduler rating.