In the Guides to the Evaluation of Permanent Impairment, 4th Edition, spinal injuries are rated using the Injury Model. Range of motion measurements of the spine lack adequate validity and reliability to serve as a basis for rating impairment. This rationale is verified in the following articles.
Lumbar spine range of motion as a measure of physical and functional impairment: an investigation of validity.
Nattrass CL, Nitschke JE, Disler PB, Chou MJ, Ooi KT. Clin Rehabil. 1999;13:211–8.
Objective: To investigate the validity of the spinal range of motion models outlined in the second and fourth editions of the American Medical Association Guides to the Evaluation of Permanent Impairment for assessing the percentage impairment in chronic low back pain patients.
Design: Cross-sectional validation study.
Setting: Outpatient department in the Rehabilitation Medicine Unit.