Patients with previous laminectomies are very difficult to trial due to the extensive epidural scarring. While it is possible to go ventral to the cord and come back dorsal above the scar, this is seldom well tolerated by patients. I prefer to use an open trial technique where I perform a laminectomy immediately above the scar and bring the leads in from a tuoy needle below. That way I can close the wound and then pull the leads at a later date as a typical trial. If the patients goes perm I can insert the paddle at the new laminectomy site with little difficulty if done within a couple of weeks.