AMA Guides, 5th Edition

“Philosophy, Purpose and Appropriate Use of the Guides” and “Practical Application of the Guides.”

The AMA Guides is a book used by doctors to assign percentage ratings to those who have suffered injuries.  The AMA Guides is a work in progress.  The rating system described by the Guides has been under development since 1958.  A series of articles first published in the Journal of the American Medical Association, between 1958 and August of 1970, became the basis of the first edition of the book form of the Guides.  The first edition was published in 1971.  The latest edition, the 5th edition, was published in November of 2000. 

The AMA Guides was assembled in response to the need for a standardized, objective rating system which would describe the amount of damage caused by various injuries and illnesses.  The rating systems described in the AMA Guides were developed by committees of experts.  The ratings described by the Guides have been adopted by workers compensation and injury compensation systems in most states of the United States and a number of other countries.  The percentage ratings are often used to determine the dollar compensation due to someone injured at work or in an accident.

The AMA Guides use a many “words-of-art.”  These are predefined terms generally accepted by the medical-legal community or codified by law. 

Impairment is a word-or-art defined as “a loss, loss of use, or derangement of any body part, organ system, or organ function.”  An impairment may be manifested objectively (a problem that can be seen or felt) or subjectively (a problem reported by a patient).  Impairment may lead to functional limitations or the inability to perform activities of daily living or ADL’s.  Impairment is not the same as disability.  An impairment rating may be used as the first step in determining the level of disability.  Impairment may refer to a region or to the whole body.

Normal refers to a range in a healthy functioning individual.  It varies by age, gender and environmental conditions.  A condition has reached maximum medical improvement (MMI) when it is unlikely to change within the next year with or without medical intervention.  “Impairment” becomes permanent once a condition has reached maximum medical improvement.  

Medical judgment is the informed opinion of a physician and is used to determine the level of impairment and other medical-legal issues.  A doctor is required, in California, to make determinations based on medical probability, which is whether something is “likely” to be true.

The AMA Guides is a set of guidelines.  It is not the law.  The recommendations are not “set in stone.”  Doctors may render opinions which stray from the recommendations of the Guides.  The doctor, whose opinions differ from those advised by the Guides, should explain his/her position.

“The Spine”

According the AMA Guides, spinal impairments can be rated only when a patient has reached maximal medical improvement.  There are two ways to rate spine injuries.  Doctors can use Diagnosis Related Estimates (DRE), or Range of Motion (ROM) models to rate spine injuries. 

Diagnosis Related Estimate Ratings

Diagnosis Related Estimates, or DRE’s, refer to specific conditions listed in the Guides.  Ratings should always be done the using DRE’s, unless there is a specific reason why the DRE’s do not apply.  Range of Motion based ratings are reserved for those cases which not covered by DRE’s or for diagnoses which are specifically excluded (for example,  multilevel fractures, multilevel radiculopathy, recurrent radiculopathy, and multilevel loss of structural integrity). Diagnosis Related Estimates are based only on objectives.  This system does not take into account aging, degenerative disease, or stated limitations.  Within each DRE grouping there is a range of 3%.  Examiners are expected to estimate the level of disability, within the 3% range for each category (for example, one can be a high, medium, or low category II).

Each of three regions of the spine (cervical, thoracic and lumbar) is considered separately by the AMA Guides.  If more than one level is rated, the ratings are estimated separately and combined using the multiple impairment tables.

Objectives

Objective findings recognized by the Guides include:

  • guarding or spasm;

  • loss of reflex(s);

  • decreased muscle circumference;

  • electrodiagnostic abnormalities;

  • non-verifiable root pain;

  • tension signs;

  • loss of bowel or bladder control;

  • bladder studies; and,

  • loss of structural integrity.

Loss of structural integrality is present if there has been a surgical fusion (or an attempted fusion).  It is present if flexion and extension films of the region show instability.

Translations which indicate instability:

  • cervical inter-segmental movement of more than 3.5 mm;

  • thoracic inter-segmental movement of more than 2.5 mm; or,

  • lumbar inter-segmental movement of more than 4.5 mm.

Cervical

The five DRE categories for the cervical spine are numbered I through VI.  The maximum disability is 38% a cervical injury.

Category I--0% impairment

  • No muscle guarding

  • No neurological changes

  • No alteration in motion segment integrity

  • No findings at the time of the examination

  • No fractures

Category II--5-8% impairment

  • Findings of muscle spasm, non-verifiable root pain,

  • History of radiculopathy  resolved without surgery, with a positive imaging study

  • Compression fracture < 25%

Category III--15-18% impairment

  • Radiculopathy at the time of evaluation

  • Surgery for radiculopathy

  • Compression fracture 25-50%

Category IV--25-28% impairment

  • Loss of motion segment integrity

  • Developmental fusion, Attempt at arthrodesis

  • Bilateral or multilevel radiculopathy

  • Compression fracture > 50%

Category V--35-38% impairment

  • Severe neurological involvement of the upper extremities

  • Compression fracture > 50% with unilateral neurological involvement

Thoracic

The five DRE categories for the thoracic spine are numbered I to VI.  The maximum disability is 28% for a thoracic injury.

Category I--0% impairment

  • No muscle guarding

  • No neurological changes

  • No alteration in structural integrity

  • No findings at the time of the examination

  • No fractures

Category II--5-8% impairment

  • Findings of muscle spasm, non-verifiable root pain,

  • History of radiculopathy resolved without surgery, with a positive imaging study

  • Compression fracture < 25%

Category III--15-18% impairment

  • Lower extremity involvement

  • Radiculopathy at the time of the exam

  • Resolution of radiculopathy with surgery

  • Compression fracture 25-50%

Category IV--25-28% impairment

  • Loss of motion segment integrity

  • Multilevel radiculopathy

  • Compression fracture > 50%

Category V--35-38% impairment

  • Both Categories III and IV

  • Compression fracture > 50% with unilateral neurological involvement

Lumbar

The five DRE categories for the lumbar spine are numbered I to VI.  The maximum impairment is 28% for lumbar spine injuries.

Category I--0% impairment

  • No muscle guarding

  • No neurological changes

  • No alteration in motion segment integrity

  • No findings at the time of the examination

  • No fractures

Example:  no findings at the time of the examination, even if there were findings in the past.

Category II--5-8% impairment

  • Findings of muscle spasm, non-verifiable root pain,

  • History of radiculopathy resolved without surgery, with a positive imaging study

  • Compression fracture < 25%

Example:  minor findings on examination.

Category III--10-13% impairment

  • Radiculopathy with a positive imaging study

  • Surgery for radiculopathy, radiculopathy resolved or not.

  • Compression fracture 25-50%

Example:  radiculopathy at the time of the examination.

Category IV--20-23% impairment

  • Loss of motion segment integrity

  • Developmental fusion, attempt at arthrodesis

  • Compression fracture > 50%

Category V--25-28% impairment

  • Both Categories III and IV

  • Compression fracture >50% with unilateral neurological involvement

Range of Motion Ratings

Range of Motion or ROM disability ratings take subjectives into account, typically give higher ratings to older patients, are considered less reliable and do not work for all conditions.  The ROM system should be used when the DRE system does not apply.  It may be used in some cases when the evaluating physician feels it is more appropriate.  The Range of Motion system must be used in the following:

  • multilevel fractures;

  • multilevel radiculopathy (not degenerative disease);

  • recurrent radiculopathy; and,

  • multilevel loss of structural integrity.

To perform the ratings:

  • the patient must be disrobed;

  • women should have a chaperone;

Flexion and extension

  • place marks at the locations of each inclinometer, on occiput and T1 (for cervical), on T1 and T12 (for thoracic), or onT12 and S1 (for lumbar);

  • place inclinometers on the marks in the frontal plane and zero;

  • ask patient to bend forward as far as possible;

  • patient may support hands on knees if helpful;

  • record reading from both inclinometers;

  • repeat three times;

  • subtract the lower inclinometer reading from the upper to measure true flexion;

  • have patient return to zero position;

  • ask patient to bend backwards as far as possible;

  • record readings from both inclinometers;

  • repeat three times;

  • subtracting the lower inclinometer reading from the upper results in a measure of true lumbar extension; and,

  • refer to Table 15-12 for cervical impairment due to loss of flexion/extension, table 15-10 for thoracic flexion/extension, and table 15-8 to rate lumbar flexion/extension.

Lateral bending

  • place the inclinometers on the marks in the coronal plane and zero

  • ask the patient to bend to the right and then to the left

  • record reading from both inclinometers

  • refer to table 15-13 for cervical bending and table 15-9 for lumbar bending

  • take three measurements

  • all three should be within 10 % or 5 degrees of the mean

  • if not, obtain 3 more measurements

Total ROS rating

  • Refer to Table 15-7 and combine appropriate rating to rating for loss of range of motion

  • Refer to table 15-18 to determine any rating for neurological loss

  • 15-15 to determine magnitude of sensory loss

  • 15-16 to determine magnitude of motor loss

  • Combine values from ROM, Table 15-7 and Table 15-18

  • Combine impairment from all involved spinal areas 

Spinal cord injuries

Spinal cord injuries are rated using the neurology section.  Spinal cord injuries do not fit the spine section DRE and ROM models. See the following tables, and combine the totals using the multiple impairments table at the end of the book:

  • upper extremities injuries;

  • gait and station;

  • bladder;

  • anorectal;

  • sexual; and,

  • respiration.

 Forms for Cervical and Thoracic and Lumbar ratings can be obtained by clicking here.






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Last modified: 07/27/08