Abstract
Evaluators who use the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Sixth Edition, should understand the significant changes that have occurred (as well as the Clarifications and Corrections) in impairment ratings for disorders of the cervical spine, thoracic spine, lumbar spine, and pelvis. The new methodology is an expansion of the Diagnosis-related estimates (DRE) method used in the fifth edition, but the criteria for defining impairment are revised, and the impairment value within a class is refined by information related to functional status, physical examination findings, and the results of clinical testing. Because current medical evidence does not support range-of-motion (ROM) measurements of the spine as a reliable indicator of specific pathology or permanent functional status, ROM is no longer used as a basis for defining impairment. The DRE method should standardize and simplify the rating process, improve validity, and provide a more uniform methodology. Table 1 shows examples of spinal injury impairment rating (according to region of the spine and category, with comments about the diagnosis and the resulting class assignment); Table 2 shows examples of spine impairment by region of the spine, class, diagnosis, and associated whole person impairment ratings form the sixth and fifth editions of the AMA Guides.
Numerical pre-clinical testing in hard tissue surgery