Cumulative Trauma Disorder

&

Upper Extremity Conditions

Cumulative Trauma DisorderCumulative Trauma DisorderDefinitionDefinition

Mechanical Events Leading to the Alteration of Tissue Homeostasis– Typically through prolonged exposure– Overexertion– Excessive Movements– Awkward or Irregular Postures

Cumulative Trauma DisorderCumulative Trauma DisorderScopeScope

Hipprocates

Affections

“What occupation does he follow?”

Ramazzini17th Century Manuscript

Diseases of Workers

Cumulative Trauma DisorderCumulative Trauma DisorderScopeScope

Increasing prevalence of disorders Not new clinical syndromes Major concern

– Industry– Insurance Carriers– Health-care Providers– State and Federal Government

Not solely a product of the modern technology

Cumulative Trauma DisorderCumulative Trauma DisorderScopeScope

Despite the proliferation of keyboards in modern life (i.e. computers) there has been no increase of CTS. The incidence remains at ~5%

Cumulative Trauma DisorderCumulative Trauma DisorderScopeScope

CTD not important to the medical treatment of the patient except perhaps to recommend activity modification

Legally, this delineation may generate:– Adversary– Expense– Vitriolic Emotions

Cumulative Trauma DisorderCumulative Trauma DisorderScopeScope

US Bureau of Statistics

List of new occupational illnesses associated with repetitive trauma– 1980: 23,300– 1983: 26,000– 1984: 34,700

Cumulative Trauma DisorderCumulative Trauma DisorderCausationCausation

Cumulative trauma disorders due to performance of repetitive tasks account for more than 50% of all occupational illnesses in the United States today

Rempel 1992

Cumulative Trauma DisorderCumulative Trauma DisorderCausationCausation

Cumulative trauma disorders are frequently responsible for the development of occupational neuropathy

Zimmerman 1992

Carpal Tunnel Syndrome & Typing

Cumulative Trauma DisorderCumulative Trauma DisorderCausationCausation

All such statistics must be viewed cautiously, as this tends to represent the reporting of conditions, not an actual delineation of the conditions as etiologically bound (caused by) to the exposure.

Does having a condition prove causation?

Cumulative Trauma DisorderCumulative Trauma DisorderCausationCausation

Ergo Proctor Ergo Semper– Subsequence does not prove ConsequenceMerely having the problem or

symptoms manifest themselves during work hours does not automatically mean the problem arose out of and in the course and scope of one’s employment and thus be deemed as compensable.

Cumulative Trauma DisorderCumulative Trauma DisorderCausation: Which came first, the chicken or the eggCausation: Which came first, the chicken or the egg

Cumulative Trauma DisorderCumulative Trauma DisorderCausationCausation

Are epidemiologic surveys identifying diseases or merely cataloging complaints?

And if the disease is diagnosed, is there a causal link, an exacerbating link to the work exposure, or merely an enhanced awareness of the condition?

What about confounding variables?

Cumulative Trauma DisorderCumulative Trauma DisorderCausationCausation

Has the exposure even been quantified?

How much repetition? How much force

Most assessments are qualitative at best.

Compare the modern keyboard to the old typewriters prior to even the electric typewriter

Cumulative Trauma DisorderCumulative Trauma DisorderComorbiditiesComorbidities

Age Gender Smoking Weight Disease

– Diabetes– Hypothyroid

Avocational Pursuits

Conditioning– Exercise increases

joint laxity ergo diminishes risk of injury

Psychosocial– Job Satisfaction

– Marital issues

Cumulative Trauma DisorderCumulative Trauma DisorderScope: Turkey ProcessorsScope: Turkey Processors

This is an area of medical controversy, the intensity of which as demonstrated by the five days of medical evidence I heard would be worthy of medieval theology. For which, I am none the wiser.

Senior British Judge 1994

Cumulative Trauma DisorderCumulative Trauma DisorderHistory: LegalHistory: Legal

Exposure: causal vs exacerbatory vs awareness No uniformity in categorizing occupational

conditions

Liability of an industrial carrier may vary

Adding to the confusion is the poor, yet evolving evidence as to causation of diagnoses

Cumulative Trauma DisorderCumulative Trauma DisorderDefinitionsDefinitions

Synonyms– Repetitive motion disease– Repetition strain disorder/ injury (RSI)– Upper limb syndrome– Shoulder-arm syndrome– Overuse syndrome– Work related disorder– Cervico-brachial syndromes

Cumulative Trauma DisorderCumulative Trauma DisorderDefinitions: DescriptiveDefinitions: Descriptive

Overuse Syndrome– Activity induced aches and pains – Alleviated by:

Periods of Rest Activity Modification

– Effects may be transient or permanent– Concept of metaplasia

Cumulative Trauma DisorderCumulative Trauma DisorderDefinitions: MalignedDefinitions: Maligned

Repetitive Strain Injury (RSI) – Implies causation– Usurped by popular usage and the media – Ascribed to the Americans– Australian Experience

Illuminates the foibles of applying medical and legal principles to poorly defined terms and processes

Cumulative Trauma DisorderCumulative Trauma DisorderDefinitions: MalignedDefinitions: Maligned

Repetitive Strain Injury (RSI) RSI represents a psychosomatic disorder

associated with psychological, social, or economic issues

Millender 1992

Repetitive Strain InjuryRepetitive Strain InjuryHistory: AustraliaHistory: Australia

Epidemic of 1980s Occupational Arm

Pain Attributed to rapid,

repetitious use– Initially on a keyboard

Repetitive Strain InjuryRepetitive Strain InjuryHistory: AustraliaHistory: Australia

Collection of Symptoms Affecting the Upper extremity– Weakness– Paresthesias– Swelling– Pain

Pain, while often consistent in a given patient, is not consistent among patients

Repetitive Strain InjuryRepetitive Strain InjuryHistory: AustraliaHistory: Australia

Pain, while often consistent in a given patient, is not consistent among patients

– No primary objective findings except tenderness

– Does not conform to any known:Neurologic pathwaysAnatomic structuresPathophysiologic pattern

Repetitive Strain Injury Repetitive Strain Injury History: AustraliaHistory: Australia

Affected– Young to middle

aged– Predominantly

female– Occupations

Low-paying Monotonous Low prestige

Repetitive Strain InjuryRepetitive Strain InjuryHistory: AustraliaHistory: Australia

Clinical studies are negative:– Biochemistry

Hematology– Radiography

Thermography Bone scan

– Electromyography– Histopathology

Biopsies

Repetitive Strain InjuryRepetitive Strain InjuryHistory: AustraliaHistory: Australia

Fails to respond to:– Rest– Splinting– Physical therapy– Anti-inflammatory

medications– Surgery

Repetitive Strain InjuryRepetitive Strain InjuryHistory: AustraliaHistory: Australia

Lack of clinical evidence

Epidemic spreads Complicity of:

– Physicians– Lawyers– Employers– Government

Repetitive Strain InjuryRepetitive Strain Injury History: AustraliaHistory: Australia

Epidemic spreads: Industries with no change for decades in manual tasks and productivity

– Data Processors– Process Workers– Typists– Clerks– Cashiers– Bank Tellers– Musicians– Packers– Machinists

Repetitive Strain InjuryRepetitive Strain InjuryHistory: AustraliaHistory: Australia

Initially attributed to rapid, repetitious use a keyboard:– Keystroke Occuptation Incidence– Lowest Telephonists 34 %– Low Clerks 28 %– Highest Keyboardists 3.4%

Cumulative Trauma DisorderCumulative Trauma Disorder PsychologyPsychology

Australia disavows RSIClaims disappear

Industry created around RSI disintegrates

Cumulative Trauma DisorderCumulative Trauma DisorderPsychologyPsychology

Repetitive Strain Injury (RSI) RSI represents a psychosomatic disorder

associated with psychological, social, or economic issues

Millender 1992

Cumulative Trauma DisorderCumulative Trauma Disorder DiagnosisDiagnosis

When Delineating between Factitious, Psychological, & Organic Syndromes

Caution:

What’s the difference between God and a doctor?

God knows he’s not a doctor

Cumulative Trauma DisorderCumulative Trauma Disorder Psychologic CorrelatesPsychologic Correlates

Back Pain &

Work Incapacity

– A belief by patients that their work had injured their backs

– Job dissatisfaction

Magora

Nachemson

Bigos

Cumulative Trauma DisorderCumulative Trauma Disorder Low Back PainLow Back Pain

85% – Affects adult population

Miss 1 day of work

5% – Source of pain identified

50% – Patients receive surgical

intervention

Cumulative Trauma DisorderCumulative Trauma Disorder Making a DiagnosisMaking a Diagnosis

Clearly defined & distinguishable subjective clinical symptoms

Reproducible, objective physical findings

Recognizable pathologic findings

Response to accepted and proven forms of effective physical treatments

Cumulative Trauma DisorderCumulative Trauma Disorder Playing GodPlaying God

Avoid labels– Terms like CTD, RSI

suggest mechanisms but are not diagnoses

Cumulative Trauma DisorderCumulative Trauma Disorder Playing GodPlaying God

Avoid labels– Terms like CTD, RSI

suggest mechanisms but are not diagnoses

– Inappropriate use of terms invalidate otherwise defined processes

Fibromyalgia – A defined syndrome– Specific diagnostic

criterion– Widespread use

Aches Fatigue

– Connotation Psychiatric Factitious disorder

Cumulative Trauma DisorderCumulative Trauma DisorderPlaying GodPlaying God

Avoid labels– Terms like CTD, RSI

suggest mechanisms but are not diagnoses

– Inappropriate use of terms invalidate otherwise defined processes

Pain is a recognized diagnosis, use it

ICD-9-CM– 729.5 Pain in Limb– Includes:

Arm pain Finger pain Leg pain Foot pain

Cumulative Trauma DisorderCumulative Trauma Disorder EvidenceEvidence

Let’s review specific diagnoses

Adding to the confusion is the poor, yet evolving evidence as to causation of diagnoses

Cumulative Trauma DisorderCumulative Trauma Disorder

“There can be little doubt that in patients who develop (this condition) use of the hand will be painful…but there is no clinical evidence to support the view that the use of the hand alters the natural history of the condition in any way whatsoever, though the symptoms are clearly relieved by rest…highly-repetitive work should be avoided (to) simply diminish symptomatology.

Kay NR. De Quervain’s disease. Changing pathology or changing perception? J Hand Surg Br 2000; 25:65-69

Cumulative Trauma DisorderCumulative Trauma DisorderDiagnosesDiagnoses

Nerves: Peripheral Entrapment

– Carpal Tunnel Syndrome– Cubital Tunnel Syndrome– Thoracic Outlet Syndrome

Tendons– Trigger Digits– de Quervain’s Tendonitis

Skin– Blisters– Calluses

Muscles (Enthesopathy)– Lateral Epicondylitis

(Tennis Elbow)– Shoulder Impingement

(Rotator Cuff Disease) Joint & Bone

– Arthritis– Stress Fractures– Ganglions

Vascular– White Finger Syndrome

Cumulative Trauma DisorderCumulative Trauma Disorder Analyzing Occupational Risk FactorsAnalyzing Occupational Risk Factors

Combination of Risk Factors (Load & Rate)– Force & Repetition– Force & Posture

VibrationHighly Repetitive Work

– Alone or in Combination with other factors– Cycle time of less than 30 seconds or more than 50% of

the cycle time involved in performing fundamentally the same activity

Cumulative Trauma DisorderCumulative Trauma Disorder Analyzing Occupational Risk FactorsAnalyzing Occupational Risk Factors

Forceful Work– 4 kg (but most jobs without effective technique to assess

actual grip force)

Awkward Postures– Posturing more than 45°

Keyboard Activities Cold Environment Length of Employment Tool Size & Weight

Cumulative Trauma DisorderCumulative Trauma DisorderContributory Factors in the Work PlaceContributory Factors in the Work Place

Psychomotor Skills (coordination)

– Not identified as a risk factor

Cumulative Trauma DisorderCumulative Trauma DisorderEvidenceEvidence

The scientist often uses literature as the drunk uses a light post

Cumulative Trauma DisorderCumulative Trauma DisorderEvidenceEvidence

The scientist often uses literature as the drunk uses a light post

More often for support than for illumination

Cumulative Trauma DisorderCumulative Trauma DisorderEvidenceEvidence

AMA Guides to the Evaluation of Disease & Injury Causation 2nd Edition

Melhorn, Ackerman, Talmage, Hyman

Cumulative Trauma DisorderCumulative Trauma Disorder Useful Research TermsUseful Research Terms

“Typical results are shown…”– The best results are shown

Cumulative Trauma DisorderCumulative Trauma DisorderDiseases Caused by ExposureDiseases Caused by Exposure

Vibration & White Finger SyndromeStress Fractures (esp. Metatarsals)Blisters, calluses

Cumulative Trauma DisorderCumulative Trauma Disorder Useful Research TermsUseful Research Terms

“It has long been known…”– I didn’t look up the original references

“Typing causes Carpal Tunnel Syndrome”

Cumulative Trauma DisorderCumulative Trauma DisorderCarpal Tunnel SyndromeCarpal Tunnel Syndrome

Risk Factor EvidenceCombination of Risk Factors Strong Risk Evidence

– Meat packing, poultry packing, automotive industry

Vibration Low Risk Evidence– But laboratory studies support this claim

Highly Repetitive Work Strong Risk Evidence– But must define repetition

Forceful Work Strong Risk EvidenceAwkward Postures Low Risk Evidence

Cumulative Trauma DisorderCumulative Trauma DisorderCarpal Tunnel SyndromeCarpal Tunnel Syndrome

Risk Factor EvidenceKeyboard Activities No Risk EvidenceCold Environment No Risk EvidenceLength of Employment No Risk EvidenceJob Satisfaction Some Risk Evidence

Cumulative Trauma DisorderCumulative Trauma DisorderCarpal Tunnel SyndromeCarpal Tunnel Syndrome

Risk Factor EvidenceAge: Very Strong Evidence

– Commonly Seen in 4th DecadeWeight: Very Strong Evidence

– Correlated (BMI > 30)Disease: Very Strong Evidence

Diabetes Rheumatoid Arthritis Hypothyroid ESRD

Gender: Very Strong Evidence– 3:1 Female to Male

Cumulative Trauma DisorderCumulative Trauma DisorderCarpal Tunnel SyndromeCarpal Tunnel Syndrome

Risk Factor EvidenceBiopsychosocial Factors: Very Strong EvidenceSmoking: Low Risk EvidenceWrist Size: Some Risk EvidenceNonoccupational Activities: Some Risk EvidenceHand Dominance: No Risk Evidence

– Consider this lack of correlation in light of arguments associating CTS with use. Further, since people awaken at night with symptoms, is sleep a cause?

Cumulative Trauma DisorderCumulative Trauma DisorderUseful Research TermsUseful Research Terms

“It is clear that much additional work will be required before a complete understanding of the phenomenon occurs..”

I don’t understand it

Cumulative Trauma DisorderCumulative Trauma DisorderCubital Tunnel SyndromeCubital Tunnel Syndrome

Risk Factor EvidenceAge: Strong Risk Evidence

– 6th decade, and increases with each decade of lifeWeight: Low Risk EvidenceDisease: Some Risk EvidenceGender: Some Risk EvidenceBiopsychosocial Factors:* No Risk EvidenceSmoking: Some Risk EvidenceHand Dominance: No Risk Evidence

Cumulative Trauma DisorderCumulative Trauma DisorderCubital Tunnel SyndromeCubital Tunnel Syndrome

Risk Factor EvidenceCombination of Risk Factors Some Risk EvidenceVibration No Risk EvidenceHighly Repetitive Work No Risk EvidenceForceful Work No Risk EvidenceAwkward Postures No Risk EvidenceKeyboard Activities No Risk EvidenceCold Environment No Risk EvidenceLength of Employment No Risk Evidence

Cumulative Trauma DisorderCumulative Trauma Disorder Useful Research TermsUseful Research Terms

“While it has not been possible to provide definitive answers to these questions…”

An unsuccessful experiment, but I still hope to get it published

Cumulative Trauma DisorderCumulative Trauma Disorderde Quervain’sde Quervain’s

Age: Strong EvidenceGender: Strong Evidence

– 5:1 Female ratio

Role of New mother’s disease

Cumulative Trauma DisorderCumulative Trauma Disorderde Quervainde Quervain

Risk Factor EvidenceCombination of Risk Factors Some Risk Evidence*Vibration No Risk EvidenceHighly Repetitive Work Some Risk Evidence*Forceful Work Some Risk EvidenceAwkward Postures Low Risk EvidenceKeyboard Activities Low Risk EvidenceCold Environment No Risk EvidenceLength of Employment No Risk Evidence

Cumulative Trauma DisorderCumulative Trauma Disorder Useful Research TermsUseful Research Terms

“Time and time again…”

I have seen it twice before

Cumulative Trauma DisorderCumulative Trauma DisorderTrigger FingerTrigger Finger

Age: Commonly Seen in 6th DecadeDisease: Increased Prevalence

Diabetes Hypothyroid

Gender: 4:1 Female to Male

Cumulative Trauma DisorderCumulative Trauma DisorderTrigger FingerTrigger Finger

Risk Factor EvidenceCombination of Risk Factors Some Risk EvidenceVibration Some Risk EvidenceHighly Repetitive Work Low Risk EvidenceForceful Work Low Risk EvidenceAwkward Postures Low Risk EvidenceKeyboard Activities No Risk EvidenceCold Environment No Risk EvidenceLength of Employment No Risk Evidence

Cumulative Trauma DisorderCumulative Trauma Disorder Useful Research TermsUseful Research Terms

“Three of the samples were chosen for detailed study…”

Since it didn’t work, maybe I can prove my point with selection bias and by eliminating any contrarian data

Cumulative Trauma DisorderCumulative Trauma DisorderTriangular Fibrocartilage Complex (TFCC)Triangular Fibrocartilage Complex (TFCC)

Risk Factor EvidenceCombination of Risk Factors No Risk EvidenceVibration No Risk EvidenceHighly Repetitive Work No Risk EvidenceForceful Work No Risk EvidenceAwkward Postures No Risk EvidenceKeyboard Activities No Risk EvidenceCold Environment No Risk EvidenceLength of Employment No Risk Evidence

Cumulative Trauma DisorderCumulative Trauma DisorderTriangular Fibrocartilage Complex (TFCC)Triangular Fibrocartilage Complex (TFCC)

Risk Factor EvidenceAge Strong Risk EvidenceAnatomy Strong Risk Evidence

Mechanism of Injury

– Traumatic vs Degenerative Twisting Palmar Rotation (i.e. fall)

– Ulnar Impaction

Cumulative Trauma DisorderCumulative Trauma Disorder Useful Research TermsUseful Research Terms

“A definite trend is evident…”– These data are practically meaningless

Cumulative Trauma DisorderCumulative Trauma DisorderLateral Epicondylitis (Tennis Elbow)Lateral Epicondylitis (Tennis Elbow)

Risk Factor EvidenceCombination of Risk Factors Strong Risk EvidenceVibration No Risk EvidenceHighly Repetitive Work No Risk EvidenceForceful Work Low Risk EvidenceAwkward Postures Low Risk EvidenceKeyboard Activities No Risk EvidenceCold Environment No Risk EvidenceLength of Employment No Risk Evidence

Cumulative Trauma DisorderCumulative Trauma DisorderLateral Epicondylitis (Tennis Elbow)Lateral Epicondylitis (Tennis Elbow)

Age: Commonly Seen in 4th Decade– Had it not been for the exposure, condition

would not have occurred

Repetition/ Lifting: CorrelatedBut consider vocational & avocational

activities

Cumulative Trauma DisorderCumulative Trauma Disorder Useful Research TermsUseful Research Terms

“It is clear that much additional work will be required before a complete understanding of the phenomenon occurs…”

I don’t understand any of it

Cumulative Trauma DisorderCumulative Trauma DisorderRotator CuffRotator Cuff

Age: Commonly Seen in 4th DecadeRepetition: Overhead lifting

Cumulative Trauma DisorderCumulative Trauma Disorder Useful Research TermsUseful Research Terms

“A careful analysis of available data…”

I lost three pages of information when I spill my beer

Cumulative Trauma DisorderCumulative Trauma DisorderCMC ArthritisCMC Arthritis

Risk Factor EvidenceAge: Very Strong Evidence

– Commonly Seen in 3rd-5thth DecadeWeight: Some EvidenceDisease: No EvidenceGender: Very Strong Evidence

– 4:1 Female to Male

– Peri- / post- menopausal correlation– 40% of all women

Hand Dominance No Evidence

Cumulative Trauma DisorderCumulative Trauma DisorderCMC ArthritisCMC Arthritis

Risk Factor EvidenceCombination of Risk Factors No Risk EvidenceVibration No Risk EvidenceHighly Repetitive Work No Risk EvidenceForceful Work No Risk EvidenceAwkward Postures Some Risk EvidenceKeyboard Activities No Risk EvidenceCold Environment No Risk EvidenceLength of Employment No Risk Evidence

Cumulative Trauma DisorderCumulative Trauma DisorderUseful Research TermsUseful Research Terms

“Correct within an order of magnitude…”

Wrong

Cumulative Trauma DisorderCumulative Trauma DisorderGanglionGanglion

Occupational Risk Factors: Insufficient evidence – Repetition: Causes cyst to enlarge, but no

evidence for causal link – Trauma: 5% of cyst

Age: Seen at any ageCommon process accounting for 50-70%

of finger/hand/wrist masses

Cumulative Trauma DisorderCumulative Trauma DisorderIndustrial vs. Occupational ExposuresIndustrial vs. Occupational Exposures

Cumulative Trauma DisorderCumulative Trauma DisorderCategorizationCategorization

Category 1: Diagnosis is easily established, good methods are available for treating the condition, and the prognosis for returning to work is good.

– Still, remember: Diagnosis does not equal etiology

Cumulative Trauma DisorderCumulative Trauma DisorderCategorizationCategorization

Category 2: Diagnosis is established, but neither nonsurgical nor surgical treatment is always successful in returning the patient to the original job.

– Injury may preclude the patient from being able to reestablish premorbid status

– Vocational Rehab– Job modification

Cumulative Trauma DisorderCumulative Trauma DisorderCategorizationCategorization

Category 3: The condition combines definite physical problems and additional non-medical issues.

– Factor 1: Chronic pain out of proportion to the disorder

– Factor 2: Manifestation of anger, frustration, and depression associated with the injury, as well as psychosocial or economic issues.

Cumulative Trauma DisorderCumulative Trauma DisorderCategorizationCategorization

Category 4: Diagnosis is unclear.

– Factor 1: Generalized, vague aching discomfort and no specific diagnosis can be made.

– Factor 2: Chronic fibromyalgia or other rheumatologic abnormalities.

– Factor 3: Repetitive strain injury.

Repetitive Strain Injury Repetitive Strain Injury History: Australia: PsychologyHistory: Australia: Psychology

Japanese cartoon triggers seizures in hundreds of children

December 17, 1997Web posted at: 4:15 a.m. EST (0915 GMT) TOKYO (CNN) -- The bright flashing lights of a popular TV cartoon became a serious matter Tuesday evening, when they triggered seizures in hundreds of Japanese children. In a national survey, the Tokyo fire department found that at least 618 children had suffered convulsions, vomiting, irritated eyes, and other symptoms after watching "Pokemon."

Cumulative Trauma DisorderCumulative Trauma DisorderDefinitions: DiagnosesDefinitions: Diagnoses

Shoulder-arm Syndrome

– Specific diagnosis—neuropathy of the brachial plexus.

– Diagnosis does not equal etiology

Cumulative Trauma DisorderCumulative Trauma DisorderEtiologic ClassificationsEtiologic Classifications

1. Pain caused by the work task

Rotator Cuff Tennis Elbow de Quervain’s

Note: These may be caused by work, but may also be pre-existing

Cumulative Trauma DisorderCumulative Trauma DisorderEtiologic ClassificationsEtiologic Classifications

1. Pain caused by the work task

2. Pain aggravated by but not caused by the work task

CMC Arthritis Post-Traumatic

Arthritis

Cumulative Trauma DisorderCumulative Trauma DisorderEtiologic ClassificationsEtiologic Classifications

1. Pain caused by the work task

2. Pain aggravated by but not caused by the work task.

3. Pain unrelated to the work task, but develops serendipiditously during work

Dupuytren’s Disease

Note: The contentious diagnosis of CTS may fall into group 1, 2, or 3.

Cumulative Trauma DisorderCumulative Trauma DisorderEtiologic ClassificationsEtiologic Classifications

1. Pain caused by the work task

2. Pain aggravated by but not caused by the work task.

3. Pain unrelated to the work task, but develops serendipiditously during work

4. Pain that is unrelated to the physical work task– Psychological stress – Patient’s personality

Cumulative Trauma DisorderCumulative Trauma DisorderEtiologic ClassificationsEtiologic Classifications

1. Pain caused by the work task

2. Pain aggravated by but not caused by the work task.

3. Pain unrelated to the work task, but develops serendipiditously during work

4. Pain that is unrelated to the physical work task

5. Pain that is unrelated to the work task in any way but is dishonestly attributed to it. – Didn’t happen at work – Factitious processes