Hey Christine,
Curious if you have tried additional sessions with this patient? Occasionally, you will get that sensation with ENS due to proximity to sensory nerves. So my first thought would be was it just coincidence. There is a relationship between the neurology of the gut/belly with legs and lower lumbar so there is a possible connection there but I would want to see if you moved the needles to a slightly different location in the same area if she had the same response.
Nick
