Has anyone experienced loss of movement after lumbar laminectomy?

Foot Drop. Any operation around the lumbar spinal canal can put nerve roots at risk. The most common levels are between l4/l5 and l5/s1. The nerves at these levels control calf muscles responsible for raising or lowering the toes and although new weakness or paralysis is not common, there will always be a small potential risk.
No. But that does not make it impossible. Any operation on the nerves can cause weakness. Loss of movement sounds like paralysis and that is exceedingly rare.