Mainstay Medical is a Irish medical device company that develops and commercializes an implantable restorative neurostimulation system (ReActiv8) to treat people with disabling chronic low back pain. Mainstay Medical is commercializing their therapy in the US, Australia, Germany and the UK.

The ReActiv8 therapy activates the key stabilizing muscle of the low back, the multifidus. Stimulation electrodes are placed adjacent to medial branch nerves and an implanted pulse generator device delivers electrical pulses in 30-minute sessions, twice-daily.

In 2024, Gilde invested in Mainstay Medical to bolster the company’s ongoing commercial expansion, generate additional clinical evidence, and enhance reimbursement coverage, aiming to propel advancements in the field of mechanical chronic low back pain.