SPINE RATINGS: RANGE OF MOTION METHOD
There are two methods for rating Spine injuries using the AMA Guides. The more commonly used is the Diagnosis Related Estimate (DRE) Method. With this method, the physician simply selects the impairment category (1-5) which best represents the applicant’s impairment. Each category has a percentage range. The physician then selects a percentage within the range. The most commonly selected category is Category II, which has a range of 5-8%.
The second, and more complex method is the Range of Motion Method. This is used when the symptoms are not the result of a specific injury or involve more than one level within a single spinal region (L3 & L4 for example). The Range of Motion descriptor is a misnomer as the method is actually composed of three elements (range of motion, nerve deficit & specific disorders). The Range of Motion element is measured by loss of spinal motion. For the Lumbar Spine, this includes flexion, extension, right lateral bending and left lateral bending (pages 407 & 409). Each diminished motion equates to a whole person impairment percentage (WPI). The percentages are then added together for a final figure for the Range of Motion element.
Calculating Nerve Deficit involves a two part procedure. The physician provides a grade level of nerve function for the various nerves involved. The scale is from 0-5, with 0 representing complete loss of function, while 5 represents no loss. After selecting the grade level, the physician selects an impairment percentage within the grade and multiplies the percentage by the total value of the involved nerve. For instance, applicant has a Grade 4 Sensory Loss at L-3. Physician selects a 25% impairment percentage within the Grade 4 range (1-25%). The 25% figure is multiplied by the maximum value of the nerve (5%). The resulting product is 1.25, which rounds to 1% WPI. Nerve Deficit is found in Tables 15-15 through 15-18 on page 424 of the Guides.
The final element is Specific Disorders found in Table 15-7 on page 404. The table is composed of four major categories and several subcategories. Each subcategory item is assigned a WPI percentage. For example, an Unoperated Disk with Residuals (lumbar spine) merits a 5% WPI (category II, item B).
The final impairments for each of the three elements (range of motion, nerve deficit, specific disorders) are then combined using the Combined Values Chart (page 604). The resulting figure is then adjusted for Future Earnings Capacity, Age and Occupation.