1 Department of Rehabilitation Medicine, University of Washington, 4225 Roosevelt Way NE, 4th floor, Seattle, WA 98105, USA. Electronic address: jimrob@uw.edu.
2 Department of Rehabilitation Medicine, University of Washington, Seattle Spine & Sports Medicine, 3213 Eastlake Avenue E, Suite A, Seattle, WA, 98102, USA. Electronic address: vsingh@seattlespine.com.