If you search up a dermatome map, you will see the areas most likely to be affected by L 3/4 problems. You should know, however, that there can be a fair amount of uncertainty because of the various ways and places a disk or other spinal anatomy may impinge on a nerve.
I have already had a laminectomy at l3-4 around 8 years ago, then I had a fusion on L4-5 with hardware on 6/30/04. The problems from the disc at 4-5 are very much improved, but I developed severe lt hip pain and pain across my thigh. I have a CT scan on Friday to see what is going on..But I am wondering if the fusion caused pressure on the already surgically altered L3-4 and that is what is now happening. The doctors office said they are to see me right after my ct scan and to bring my films straight over..That makes me very nervous.