introduction to occupational medicine...ama guides to the evaluation of permanent impairment sixth...

IMPAIRMENT RATINGS

Bruce W. Randolph, MD, MPH

Assistant Professor

University of Arkansas for Medical Sciences

Preventive Occupational Environmental Medicine Clinic

Disclosures

I have no disclosures or conflicts of interest to reveal.

Objectives:

I. Understand the purpose and scope of an

Impairment Evaluation and Impairment Rating.

II. Understand how Impairment Ratings are derived.

III. Understand why two physicians may render

different impairment ratings for the same injury.

AMA Guides to the Evaluation of

Permanent Impairment Published by the American Medical Association

1958 - 1st Article published the

Journal of the American Medical

Association (JAMA).

“A Guide to the Evaluation of

Permanent Impairment of the

Extremities and Back”.


Permanent Impairment Published by the American Medical Association

1958 – 1970 : Over the next 12 years,

12 additional articles were published

in JAMA.


Permanent Impairment

1971- First Edition

1st Published in book form (Compendium of the 13 Guides)

Standardized an objective approach to

evaluating medical impairments.



The Guides are revised periodically:

Current scientific research

Evolving medical evidence

Clinical knowledge and judgment

Correct deficiencies and respond to criticism



1984 - Second Edition

1988 - Third Edition – Pie charts for

range of motion (ROM) impairment

evaluation of the upper extremities

1990 - Third Edition (Revised)



Fourth Edition (1993):

Diagnosis Related Estimates (DRE) or “Injury

Model” to evaluation of spinal injuries

Pain Chapter was introduced



Fifth Edition (2000):

Refined the Pain Chapter

Modified the DRE method

Expanded the ROM method for spinal

impairment evaluations.


Permanent Impairment Sixth Edition (2007):

A “paradigm shift” to the assessment of impairment

Simplified

Adopts a contemporary model of disablement based on the International Classification of Functioning, Disability, and Health (ICF)

Functionally based

Diagnosed based with diagnoses being evidenced based

Internally consistent

Arkansas Workers Compensation Commission

RULE 099.34 - IMPAIRMENT RATING GUIDE

(Adopted July 1, 1994; revised June 9, 1995, effective July 1, 1995)

“The purpose of Rule 34 is to establish an

impairment rating guide to be used in the

assessment of anatomical impairment.”


RULE 099.34 - IMPAIRMENT RATING GUIDE (Adopted July 1, 1994; revised June 9, 1995, effective July 1, 1995)

To accomplish this purpose, the Arkansas

Workers’ Compensation Commission adopted

the Guides to the Evaluation of Permanent

Impairment (4th ed. 1993).


RULE 099.34 - IMPAIRMENT RATING GUIDE (Adopted July 1, 1994; revised June 9, 1995, effective July 1, 1995)

“Exclusive of any sections which refer to pain

and exclusive of straight leg raising tests or

range of motion tests when making physical or

anatomical impairment ratings to the spine.”


“Objective findings” are those findings which

cannot come under the voluntary control of

the patient.

When determining physical or anatomical

impairment, cannot consider complaints of

pain


“For the purpose of making physical or

anatomical impairment ratings to the spine,

straight leg raising tests or range of motion

tests shall not be considered objective

findings.”


“Medical opinions addressing

compensability and permanent

impairment must be stated within a

reasonable degree of medical certainty.”


Permanent Impairment, 4th Edition

AMA Guides, 4th Edition

“Provides a standard framework and method of

analysis through which physicians can

evaluate, report on, and communicate

information about the impairment of any

human organ system”


“The Guides can help provide consistent

and reliable acquisition, analysis,

communication, and utilization of

medical information”


“The major objective of the Guides is to define

the assessment and reporting of medical

impairments so that physicians can collect,

describe, and analyze information about

impairments in accordance with a single set of

standards”.


“ Two physicians, following the methods

of the Guides to evaluate the same

patient, should report similar results and

reach similar conclusions”


“ If two physicians who examine a patient

and use the methods of the Guides do

not obtain similar results and reach

similar conclusions, the book can be

used to resolve the discrepancies.”


“If the clinical findings are fully

described, any knowledgeable observer

may check the findings with the Guide

criteria”

Basic Principles AMA Guides, 4th Edition

The Guides only apply to permanent impairments

Permanent impairments are adverse conditions that

are stable and unlikely to change

Evaluating the magnitude of these impairments is the

purview of the physician

Determining disability is usually not the physician’s

responsibility

Basic Principles – continued AMA Guides, 4th Edition

Impairment: the loss, loss of use, or

derangement of any body part, system, or

function.

Disability: a decrease in, or the loss or absence

of, the capacity of an individual to meet :

personal, social, or occupational demands

statutory or regulatory requirements.


Permanent impairments are evaluated in

terms of how they affect the patient’s

daily activities including occupation.

Activities of Daily Living AMA Guides, 4th Edition

Self care and personal hygiene

Eating and preparing food

Communication

Speaking and Writing

Maintaining one’s posture

Activities of Daily Living AMA Guides, 4th Edition

Standing, walking, and sitting

Caring for the home and personal finances

Traveling and moving about

Recreational and social activities

Work activities


“An impairment percentage represents

an informed estimate of the degree to

which an individual’s capacity to carry

out daily activities has been diminished.”


“The impairment percentage derived by

using Guides criteria represent estimates

rather than precise determination.”

Impairment AMA Guides, 4th Edition

An alteration of an individual’s health status

A deviation from normal in a body part or

organ system and its functioning

Conditions that interfere with an individual’s

“activities of daily living”

The loss, loss of use, or derangement of any

body part, system, or function

Permanent Impairment AMA Guides, 4th Edition

Impairment that has become static or well

stabilized with or without medical treatment

and is not likely to remit despite medical

treatment

Impairment is unlikely to change substantially

and by more than 3% in the next year with or

without medical treatment.

Impairment Rating AMA Guides, 4th Edition

Analyzing data accumulated in the course of

an impairment evaluation

Comparing those data with Guides criteria to

estimate the extent of impairment

Impairment ratings prepared according to

Guides criteria are estimates of impairment


“The impairment estimate or rating is

simply a number..….it does not convey

any information about the person or the

impact of the impairment on the person’s

capacity to meet personal, social, or

occupational demands.”


It is not an estimate of disability – “an

alteration of an individual’s capacity to

meet personal, social, or occupational

demands, or statutory or regulatory

requirements, because of an

impairment.”


“ It must be emphasized and clearly

understood that impairment percentages

derived according to Guides criteria

should not be used to make direct

financial awards or direct estimates of

disabilities.”


“The primary purpose of the Guides is to

rate impairment to assist adjudicators

and others in determining the financial

compensation to be awarded to

individuals who, as a result of injury or

illness, have suffered measurable

physical and/or psychological loss.”

Rules for Evaluation AMA Guides, 4th Edition

Estimate the extent of the patient’s primary

impairment or impairing condition - the

condition that seems to be of most concern to

the patient

Assess the current state of the impairment

according to the criteria in the Guides

The estimate should be based on current

findings and evidence


“Physician must use clinical skills and

judgment is assessing whether or not the

results of measurements or tests are

plausible and related to the impairment

being evaluated”


“The physician’s judgment, experience,

training, skills, and thoroughness in

examining the patient and applying the

findings to Guides criteria will be factors

in estimating the degree of the patient’s

impairment”


“95% to100% whole person impairment is

considered to represent almost total

impairment, a state that is approaching

death”


Measurements should be consistent between two

trained observers or examiners

Two measurements made by the same examiner may

be expected to lie within 10% of each other

Final estimated whole person impairment percent

may be rounded to the nearer of the two nearest

values ending in 0 or 5.


“The impairment percentages shown in the

chapters that consider the various organ

systems make allowance for the pain that may

accompany the impairing conditions.”


“If an individual’s prosthesis or assistive

device can be removed or it use

eliminated relatively easily, the organ

system should be tested without the

device.”


“If the assistive device is not easily

removable, ….. the organ system’s

functioning should be evaluated with the

device in place.”


“If a patient declines therapy for a

permanent impairment, that decision

should neither decrease nor increase the

estimated percentage of the patient’s

impairment”.


“It should be understood that the Guides

does not and cannot provide answers

about every type and degree of

impairment”.


Causation

“A physical, chemical, or biologic factor

contributed to the occurrence of a

medical condition”


Aggravation

“A physical, chemical, or biologic factor, which

may or may not be work related, contributed to

the worsening of a preexisting medical

condition or infirmity is such a way that the

degree of permanent impairment increased by

more than 3%.”


Recurrence

“ A recurrence requires no identifiable incident

as a trigger to the medical condition in

question; rather, the patient has a resumption

of symptoms or signs that can be related to the

previously existing medical condition or

injury.”

Medical Assessment of Impairment AMA Guides, 4th Edition

Step One: Gather thorough and complete historical

information on the medical condition

Step Two: Analyze the history, clinical, laboratory, and

radiological findings to determine the nature and

extent of the impairment or dysfunction of the affected

body part or system.

Step Three: Compare the results of the analysis with

the criteria specified in the Guides for the particular

body part, system, or function.

Step One: Gather Information

Medical History

Physical Examination

Lab Tests and Diagnostic Procedures

Radiological Studies

Rehabilitation Evaluation

Medical Record Review

Medical History:

Onset and course of symptoms and condition

Findings on previous examination(s)

Treatments and response to treatments

Relevant occupational exposures or accidents

Current health status

Current medications

Past medical history

Medical Assessment of Impairment AMA Guides, 4th Edition

The strength of the medical support for

an impairment estimate (rating) depends

on the completeness and reliability of the

medical documentation.

Range of Motion AMA Guides, 4th Edition

“The tables of Chapter 3 are based on the active

range of motion, which is determined with the

patient’s full effort and cooperation”

“Evaluating the range of motion of an extremity or

spine of the spine is a valid method of estimating an

impairment”

“The result of such evaluations should be consistent

and concordant with the presence or absence of

pathologic signs and other medical evidence”



“Exclusive of any sections which refer to pain

and exclusive of straight leg raising tests or

range of motion tests when making physical or

anatomical impairment ratings to the spine.”


“…..the full range possible of active motion

should be carried out by the subject and

measured by the examiner.”

“The examiner may check the range of passive

motion, however in the Guides, the range of

active motion takes precedence”.


“Objective findings” are those findings which

cannot come under the voluntary control of the

patient.

When determining physical or anatomical

impairment, cannot consider complaints of

pain


“Range of motion measurements are

rounded to the nearest 10 degree.”

“The impairment percentages shown in

Chapter 3 make allowance for pain….”

The Spine AMA Guides, 4th Edition

Two approaches to estimating impairment:

“Injury Model” ( DRE – Diagnosis Related Estimate)

“Range of Motion Model” – not applicable in Arkansas

due to Rule 099.34.


The Injury Model relies on evidence of:

Neurologic deficits

Uncommon adverse structural changes, such as

fractures, dislocation, and loss of motion segment

integrity.”

“Surgery to treat an impairment does not modify the

original impairment”


Common Developmental Findings:

Spondylolysis – 7% of adults

Spondylolisthesis – 3% of adults

Herniated Disk without radiculopathy - >30% of adults

by age 40

Aging changes – 40% of adults after age 35

Impairment Ratings

Factors that may influence impairment rating:

Competence and experience of the examiner

Patient’s Personality

Financial Motives

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