• Nuances and complexity of PI assessments and concepts discussion by a senior IME.

    5 October at 20:42 from atlas

    26 October 2017.

    The terms impairment and disability are often used interchangeably by medical and case management staff, but they are different.Medico-legally they are different however.

    Impairment is a loss, loss of use , or derangement of any body part, organ system, or organ function (page 2 AMA 5).Impairment in AMA 5 and 6 no longer is defined as a condition which interferes with an individual's ability to perform ADLs; this concept reflects an impairment rating.Not all impairments interfere with ADL.However, an impairment that interferes with an individual's ability to perform a listed ADL (AMA 5 table 1-2) , generally is of sufficient severity to meet an impairment rating.

    The interested reader may refer to page 2 of textbook 'Master the AMA Guides V th : A Medical and Legal Translation to the guides to the Evaluation of Permanent Impairment, Fifth Edition' ( Linda Cocchiarella - co-editor of AMA5 and Stephen J Lord) published by the American Medical Association 2001:

    ' Not all impairments interfere with ADL.These are not ratable impairments.Only impairments that interfere with ADL qualify for an impairment rating based on the Guides. Such impairments are ratable in terms of a percentage loss of the whole person'

    It is important for an IME to remember that only impairments that interfere with ADL qualify for an impairment rating i.e.. the impairment is ratable based on the AMA Guides.The AMA guides are a consensus driven attempt to quantify WPI that is due to anatomical and functional losses into a percentage HOWEVER this impairment estimate is only datable when there is interference with ADLs. The inquisitive  reader may ponder why an IME  determined  DRE III after a lumbar discectomy with 10% baseline with no interference with ADLs  are reported by the claimant ! This is clarified BOTH in the AMA5 Guides and in the accompanying tet 'Master the AMA Guides fifth: A Medical and Legal Transition to the Guides to the Evaluation of Permanent Impairment, Fifth Edition' ( Linda Cocchiarella and Stephen J Lord, 2001, American Medical Association)on page 204:

    'When determining what end of the range to use, determine whether the condition and its impact on ADLis consistent with that condition, or if the impairment has led to worse functioning. If ADL are more severely impacted than expected for the condition, use the upper end of the scale.If pain is disproportionate for the condition, use the pain chapter for determining whether a qualitative and additional amount (1-3 %) should be COMBINED with the DRE or ROM rating'

    Thus the AMA Guides give a clear direction in increasing impairment rating from the baseline -lower- rate to the higher rate due to ' Impact on ADLs' The Guides do not state that the baseline when used means there is NO impact on ADLs BUT that with more severe impact than 'expected' the baseline may be increased , with however no clear guidelines on how this  adjustment can be quantified.

     This appears inconsistent with the Guides' intent - measure anatomical and functional loss (impairment) and ONLY rate when interference with ADLs to make it a 'ratable impairment' BUT as  stated above a baseline score that can be increased by virtue of more severe impact on ADLs does not mean the baseline has no ADL impact, as this would be inconsistent with the Guides intent which is to provide a numerical PI estimate that reflect impact on ADLs.The reader would be reminded that these are guides that are consensus driven and after for example a lumbar discectomy there is generally interference with ADLs -the claimant may not report any But the Guides are a consensus driven tool and estimate what would be associated with each clinical condition.

    Strictly applying the 'no ADL=-no ratable PI' intent of the Guides is not advised in many jurisdictions which use the AMA Guides as the substratum for their WPI assessment guides for the above reasons.

     In Queensland and New South Wales for example the workers' compensation schemes use AMA 5 and in the above example there is ADDITION of % for 'Impact of ADL'  of 0-3 %  (  Section 4.33  to 4.35 NSW WC  Guidelines evaluation of permanent impairment) from the AMA 5 derived baseline in the  published guidelines of application of AMA 5. These are 1% yard/garden/sport/recreation; 2% home care and 3 % self-care.The referred to state guidelines advise the reader that' an assessment of the effect of the injury on ADLs is not soley dependent on self-reporting , but is an assessment based on all clinical findings and other reports'(4.33).Thus the examiner may reject the claimant's reports of inability to garden for example if the IME can find no clinical basis for same. 

    These state modifications to the AMA5 Guides in respect to Impact of ADLs is CONSISTENT with the instructions in the Guides (and supplementary text book) BUT actually gives specific numerical guidance to the assessor between choosing 0,1, 2 or 3 %.

     AMA 5 Guides and the  supplementary transition text  along  with ABIME training materials do advise the IME to consider clinical matters in their decisions regarding the AMA 5 published rages for a particular DRE Category and this MAY include ADLs. The AMA Guides attempt to measure effect on ADLs - the IME may refine WPI ( or state DPI ) using  clinical assessment  and other documentary evidence relating to Impact of ADLs and Effects of Surgery.The state guidelines  at 4.33 to 4.35 give advice on using clinical assessment as well as history and direct numerically on the impact of ADL adjustment from the baseline up to addition of 3 %.  AMA5 and the state guidelines are in agreement with the state guides providing specific guidance on BOTH what to consider AND the numeric ratings. 4.33 - 4.35 must be carefully read.

     The AMA guides are able to be used as a consensus driven base guide with jurisdictional variations as discussed and exemplified above.

     The astute reader may conclude that both are 'guides' and the  guides in various  international jurisdictions do make adjustments to the AMA Guides as the state determines in areas.The various jurisdictions make other adjustments to AMA 5 for example not using ROM methodology and combining further WPI due to the Effects of Surgery.

    Such examples of  modifications or adjustments are 'impact on ADLs' (section 4.33 to 4.35 WC NSW and GEPI Qld for example) and other areas as well e.g.. 'Effect of surgery' ( 4.37 , Table 4-2) , which allow for additional % impairment to be COMBINED ( using AMA combination tables)to baseline AMA 5 (with ADL adjustments) .

     The state guides clearly state the basis for modification of AMA 5 derived WPI % AMA5 tables 15-3 to 15-5 , pages 384,389 and 392) do not adequately account for the effect of surgery on the impairment rating for certain disorders of the spine'. The additions in Table 4.2 (Effects of surgery) are COMBINED with AMA5 derived WPI in the various tables with ADDITION of impact of ADL 0-3%.

    ADLs include(i):Self-care & personal hygiene(ii);Communication,(iii)Physical Activity of standing, sitting, walking, climbing stairs;(v) Sensory function;(vi)Nonspecialised hand activities,(vii)Travel, (viii)Sexual function & (ix)Sleep ( page 4, table 1-2 AMA 5: ADLs). 

    The reader and student of impairment assessment will note that impairment percentages or ratings are consensus- derived estimates that reflect the severity of the medical condition and the degree  to which the impairment decreases an individual's ability to perform common activities of daily living(ADL) EXCLUDING work.

    Impairment ratings were designed to reflect functional limitations and  not disability.Impairment ratings and percentages listed in the AMA Guides estimate the impact on the individual's overall ability to perform activities of daily living, excluding work (page 4, AMA 5).

    They are NOT intended for use as a direct determinant of work disability( AMA 5, page 5, para 1 and 2).

    Disability is variously defined. In AMA 5 defines it as an alteration of an individual's capacity to meet personal, social, or occupational demands or statutory or regulatory requirements because of an impairment( AMA 5, page 8). The impairment evaluation is only one aspect of disability determination and an IME must take into account many other factors and have a detailed understanding of the job requirements. In many jurisdictions the opinion of an OT and Occupational Physician may be required to accurately assess work capacity and work disability. figure 1-1 on page 8 AMA 5 may help with this important concept.

    Only impairments that interfere with ADL qualify for an impairment rating based on the AMA Guides.

    Impairment assessment includes both anatomic and functional loss, with some body systems emphasising one area.

    Impairments do NOT necessarily lead to disability or functional limitations;the relationships between these terms are not linear but bidirectional.

    Disabilty is an alteration of an individual's capacity to meet personal, social, or occupational demands or statutory or regulatory requirements because of an impairment.Impairment ratings should NOT be used as direct estimates of disability UNLESS the impairment results in no more interference with personal, social or occupational demands than is already considered in the anatomic or functional loss implicit in the impairment rating. 


    In worker's compensation schemes , disability traditionally refers to the loss of income-earning capacity caused by an impairment.If an impairment is not rateable, it usually means that no disability exists, since a ratable impairment is usually a legal requirement for calculating disability.

    Despite limitations, WPI % s estimate the impact of the impairment on the individual's ability to perform ADL%s are Combined from multiple regional body impairments using the Combined values Chart(not arithmetically!).all regional impairments are converted to a WPI rating. A 0% impairment rating indicates that an impairment MAy be present , but that impairment does NOT impact on he ability to perform ADL.A 90-100% WPI indicates a very severe organ or body system impairment requiring the individual to be fully dependent on others for self-care, approaching death(page 5 AMA 5).

    Assessors who assess disability need to understand the impairment , its impact on ADL, and the interaction with the environment (work or social) for which the referrer has requested as the setting for the disability determination.

    Under AMA 5 ,some disability claims will be nullified because of AMA 5's non-ratable impairments(those that are recognisable anatomical losses that do NOT interfere with ANY ADL.).

    As stated above in most cases an IME is  tasked with deterring WPI ( or DPI) using the relevant state /federal  or motor accident authority guides and these guides do make recommendations on the application of certain tables and methodologies (e.g. no ROM but only DRE) AND on adjustments including ADLs and Effects on surgery which may appear to be 'doubling up' on the derived values listed in the AMA Guides HOWEVER the AMA Guides are being used as the substratum and are able to be adjusted depending on jurisdictional recommendations/guides to IME. 

    The various state workers ' compensation , federal Comcare and motor accident authority guidelines are used by IMEs in APPLYING the AMA Guides. The reader should refer to these legislated guidelines on the use an application of the AMA Guides as they are complex and do vary in jurisdictions.

    The concept of EXCLUDING work or complex social or recreational activities was developed during the initial creation of The Guides and its impairment ratings in 1958."Evaluation (rating) of permanent impairment is an appraisal of the nature and extent of the patient's illness or injury as it affects his personal efficiency in the activities of daily living.These activities are self-care,normal living postures, ambulation, elevation, travelling and non-specialised hand activities.It is not and never can be the duty of physicians to evaluate the social and economic effects of permanent impairment."

    It is very complex indeed.A disability award also accounts for the anatomic or functional loss measured by the impairment.Common phrases used in worker's compensation are" disability in excess of impairment" and "disability inclusive of impairment."

    Aggravation refers to a factor(s) that ALTERS the course or progression of the medical impairment. (AMA 5 page 599).Aggravation is a legal concept as well as a medical one.Aggravation may be a form of subsequent causation that also requires apportionment.Aggravation is associated with a permanent change in anatomical structure and the individual does NOT return to their pre-aggravation status.

    Exacerbation is a transient worsening of a prior condition by an injury or illness, with the expectation that the situation will eventually return to baseline or pre-worsening level.

    Various insurers will have Guidelines in their Spinal protocols that determine whether surgical intervention will be covered by the insurer and this may involve current concepts (AMA 6) of aggravation and exacerbation with reference often to whether the proposed surgery is to treat structural changes cause by the event or injury , or whether the proposed surgery is operating on changes pre-existent to the incident that may have been exacerbated by the incident. different jurisdictions have differing Spinal Surgical Approval guidelines ,which may , or may not rely on what the surgeon is operating ion and what caused it-the injury OR pre-existing degeneration.

    The terms 'aggravation' and 'exacerbation' may not always be used interchangeably-certainly AMA 6 makes the differences crystal clear.

    In Texas, for example, an aggravation that leads to a permanent worsening of an underlying or pre-exisyting condition may be a compensable, work-related injury.An exacerbation , however, is interpreted as a temporary worsening of symptoms, such as pain, that does not change an individual's underlying medical condition.An exacerbation alone may not always be compensable , even if it caused by work.This is the situation in AMA 4 &5.

    When giving opinions around the issue of causation, it is important for physicians to be aware of such jurisdictional nuances.

    'Aggravation' and 'exacerbation ' ARE different! The interested reader should refer to each edition of the AMA guides and  AMA 6 page 25, para 9:

    ' Exacerbation does not equal aggravation'.

    It is incumbent on the insurer  in a particular jurisdiction ( not the assessor or the AMA Guides)to document a set of Guidelines for assessors to use in respect of approving or disapproving the separate matter (rather than MMI or PI) requests for surgery in Workman injury cases-having regard to the current concepts of aggravation being a permanent change and exacerbation temporary OR using  the 'test 'of whether the changes being operated on were caused by the injury(essentially either a new injury OR an aggravation of pre-existing change causing a new structural permanent change or alteration of structure that will likely be permanent OR a different set of criteria , in writing.

    The comments and opinions stated herein are soley those of the author and IMEs are advised to seek and follow their own advices and training as IME assessors.

    The author is a senior Brisbane Neurosurgeon (MB BS 1st Class Honours 1980 UQ) who holds 6 Fellowships in Surgery and was honoured to be elevated to the status of Master CIME after 3 examinations and training requirements over 3 years by the American Board of Independent Medical Examiners(ABIME) in May 2017.He is a senior clinical OSCE examiner RACs, advisor surgical mortality QASM RACS, Member RACS Academy of Surgical Educators(MASE) , Chairman MAC Sunnybank Private Hospital (Healthscope) and Honorary Adjunct Clinical Assistant Professor.

    Qualifications and Memberships: MCIME, MB BS ( 1st Class Honours, 1980 UQ), FRACS, FRCS(ENG, Edin, Ireland, Glasgow) and FACS(USA), MAPS, MNSA, MNSQ , MASE


    Patients always follow your treating doctor's advice.

    27 October 2017.


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