Aug 10, 2018· Year founded: This technique was founded in the early 1950s; however, one of Thompson’s understudies, Erik A. Chamberjian, DC, CCEP, FICPA, says that patents were not granted on Thompson’s drop devices until a few years later.Specifically, the Palmer-Thompson drop headpiece was patented in 1955 and a table with drops for dorsal, lumbar, and pelvic areas was patented in 1957.