SAN FRANCISCO – After slowing growth starting in mid-2018 and a court battle with Boston Scientific Corp. that ended in a favorable resolution, 2019 was a much better year for pain neurostimulation player Nevro Corp., as it launched a major new product. So far, 2020 is looking up too. Its shares (NYSE:NVRO) gained 5% following a presentation at the J.P. Morgan (JPM) Healthcare Conference, where it preannounced 2019 revenues and offered 2020 guidance.