Back pain affects 80% of Americans. Many times the only option to relieve pain is spinal surgery. There are no unproblematic options to monitor post-op progress. The gold standard is to take x-rays of each spinal movement, which cause a 50% increase in allowable radiation exposed to the annual 600,000 spinal surgeries. The non-invasive device measures angular rotation of spinal range of motion by 3 battery powered sensors, yields immediate results and can reduce evaluation costs by $5B/year.