Over the last six years, more than 20,000 patients have been implanted with the Sprint PNS system to manage acute or chronic pain, SPR Therapeutics Inc. reported. The 20,000th patient was treated for low back and leg pain with the Sprint Extensa XT system, which like the company’s other systems is implanted for 60 days in a minimally invasive surgery. The system uses percutaneous peripheral nerve stimulation (PNS) to recondition the central nervous system to provide long-term, significant relief from pain.