Territory Insurance Conference, resilient future A/Prof Peter Steadman, Medilaw Consultant...

Territory Insurance Conference, resilient future

A/Prof Peter Steadman, Medilaw Consultant Orthopaedic Surgeon

WHICH TEST IS BEST?

Learn about different medical investigations

TerritoryInsurance Conferenceresilient future


What are we trying to achieve with a test?

1. Identify pathology – ‘What is wrong?’2. Pathology related to symptoms – ‘Is the

pathology the case of the complaint?’

• Would seem straightforward …

Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon

29/10/2015


Results complicated by –

1. Each test is specific for a particular

circumstance

‘you wouldn’t measure speed with a

thermometer’

2. Test results are affected by – • Variation of normal • Pre-existing conditions• Interpretation Dr Peter Steadman, Medilaw Consultant Orthopaedic

Surgeon29/10/2015


Plan for today

• Summary of tests available • What is normal?• Pre-existing conditions • Interpretation


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Common ‘imaging’ modalities


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Ultrasound

Radiography

Multislice CT

MRI

Bone scan

Nerve conduction studies

Subcutaneous Tendon Joints Ligaments Muscles Bone Intervertebral discs Nerve Blood vessels

All advantages / disadvantages


Types of imaging


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• Investigations

Radiographs / X-ray

Ultrasound

CT

MRI

Bone scan



Plain radiography – in spine

• Used frequently and often inappropriately

• X-ray for ‘Red Flags’ or severe symptoms lasting more than 6

weeks

• Degenerative changes shown well but often don’t correlate with

symptoms

• High radiation dose – ovary dose equivalent to a large number of

CXR’s

• Soft tissue structures not imaged

• XS dimension of spinal canal not assessedDr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon 29/10/2015


Types of imaging

• Investigations

Radiographs / X-ray

Ultrasound

CT

MRI

Bone scan



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Calcific deposit – shoulders

Rotator cuff tears – shoulders


Subacromial impingement Dynamic ultrasound


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Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon 29/10/2015

Types of imaging

• Investigations

Radiographs / X-ray

Ultrasound

CT

MRI

Bone scan




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Types of imaging

• Investigations

Radiographs / X-ray

Ultrasound

CT

MRI

Bone scan


Calcific deposit – shouldersAchilles tendinopathy



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Subacromial Bursitis A bursal effusion may be seen with ongoing impingement alone but should always alert the reader to the likelihood of a full thickness supraspinatus tear.

A: Bursal effusion, supraspinatus tendinosis and impingementB : Bursal effusion, bursal surface partial thickness tear of supraspinatus tendon by a subacromial spur

Coronal T2 with fat saturation

A B



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Types of imaging

• Investigations

Radiographs / X-ray

Ultrasound

CT

MRI

Bone scan


Tibial stress fracture Neck of femur fracture



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Types of imaging

• Investigations

Radiographs / X-ray

Ultrasound

CT

MRI

Bone Scan




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Types of imaging

• Investigations

Radiographs / X-ray

Ultrasound

CT

MRI

Bone Scan


Left ulnar nerve neuropathy (conduction problem in ulnar nerve)



The choice of test depends on :- HISTORY and EXAMINATION – which leads to:-

1. The pathology or problem suspected

2. The type of tissue or anatomy involved

Potentially a range of tests on the same region to define / exclude different pathology

Example: Investigation of ‘ankle pain’

- X-ray – fracture/arthritis- Ultrasound – ligament damage- CT scan – to look for small bone defects in joint - MRI – tendon pathology / soft tissues- bone scan – to look for stress fracture- nerve conduction studies – to rule out nerve compression at the ankle


Imaging guided procedures

• Nerve root block• Epidural injection• Joint injection• Facet joint injection• Medial branch block / RF Ablation

• Used to confirm Dx and relieve acute and chronic

pain


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To determine if the result of a test is significant we need to know what is ‘normal’

1.Normal variation with population at any single age

2.Variation over time (expected age related changes)


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Normal bell curve The normal distribution, also called the Gaussian distribution, is an important family of continuous probability distributions, applicable in many fields. Each member of the family may be defined by two parameters, location and scale: the mean ("average", μ) and variance (standard deviation squared) σ2, respectively. The standard normal distribution is the normal distribution with a mean of zero and a variance of one (the red curves in the plots to the right). Carl Friedrich Gauss became associated with this set of distributions when he analyzed astronomical data using them, and defined the equation of its probability density function. It is often called the bell curve because the graph of its probability density resembles a bell.

The importance of the normal distribution as a model of quantitative phenomena in the natural and behavioral sciences is due to the central limit theorem. Many psychological measurements and physical phenomena (like noise) can be approximated well by the normal distribution. While the mechanisms underlying these phenomena are often unknown, the use of the normal model can be theoretically justified by assuming that many small, independent effects are additively contributing to each observation.


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Ageing tissues

• Collagen – strength of issues


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Ageing issues

• Bone – reduced density – osteoporosis


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Ageing issues

• Bone – reduced density – osteoporosis


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Greater risk of fracture in the older worker


‘Degeneration’ – Normal

Degenerative change – we all have it

Common terms –

‘Wear and tear’ – has implicationsTendinosisTendinopathyDegenerationArthritisArthrosis Spine – intervertebral disc disease

– disc desiccation



‘Degeneration’

Incidence of rotator cuff tear in asymptomatic individuals:


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Minagawa H, Yamamoto N, Abe H (2013). "Prevalence of symptomatic and asymptomatic rotator cuff tears in the general population: From mass-screening in one village". Journal of Orthopaedic 10 (1): 8–12.


Pre-existing conditions


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Asymptomatic – normal – degenerative – previous injury – recovered –

full function

Symptomatic – normal – degenerative– previous injury – symptoms –

reduced function

Increasing age


Pre-existing conditions

• Why do we need to identify pre-existing conditions?• Determine causation / association of events• Determine treatment

• Prognosis, return to work and capacity• PI and apportionment

• pre-existing limitation of movement - subtract• ‘reasonable probability that impairment and

treatment greaterdue to pre-existing condition’ – AMA Guides, Ch. 1.




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Pre-existing conditions: Tests

• Radiograph of both knees – osteoarthritis

• Use of imaging of other limb to identify

arthritis in asymptomatic knee

• Symptomatic side therefore related to pre-existing condition



Pre–existing conditions: Tests

• MRI scan – knee pain

• Frequently reported with ‘meniscal tears’ after the development of pain

• Review of films demonstrate loss of articular cartilage, osteophytes, irregular bone

Importance of reviewing films




• MRI scans – Achilles tendon

• Can demonstrate pre-existing degenerative conditions

• Insertional and non-insertional tendinopathy

• May become painful after work related event




Tibialis

Posterior

Tendonitis


Tennis elbow: Pre-existing?

• 35 year old manual worker• Severe pain lateral elbow



• T2FS coronal• Severe tendinosis and partial tear of common

extensor origin i.e. ‘tennis elbow’



Pre-existing conditions: Spine

• Common relationship with ‘injury’• Back pain common in population• Increases during working years



Disc desiccation

• Uniform: normal consequence of ageing• Focal: associated with disc pathology


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Disc desiccation

• Seen normally with aging

• Not associated with pain without annular tear or disc

protrusion

• Occurs in the lower lumbar discs first

• Significant if seen in young patients less than 30

indicating premature disc degeneration


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Annual tear

• Radial, circumferential, transverse• 40% of asymptomatic individuals


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Annual tear

• Overcalled by radiologists• Discogram required if

‘discogenic pain’ suspected


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Annual tears with protrusion



Osteoarthritis of the lumbar spine

• Degenerative disc disease• Increased with age and trauma• Disc bulge, protrusion, sequestration

• Abnormal stresses on vertebral bodies and facet joints• Osteophytes, facet joint sclerosis and hypertrophy• Spinal canal stenosis• Foraminal stenosis• Degenerative spondylolisthesis




• Disc space narrowing

• Osteophyte formation

• Facet joint sclerosis and hypertrophy

• Spondylolisthesis


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Disc – osteophyte complex

• Common in lumbar and cervical spine



How does the pre-existing condition change?

1. Over time – ongoing age related degeneration2. As a result of injury or event

• Crucial to identifying causation and ‘work related injury’

• Causation is the "causal relationship between conduct and result". That is to say that causation provides a means of connecting conduct with a resulting effect, typically an injury.


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Pointers for: symptomatic age related degeneration

• Relationship of circumstances to symptoms

• Extent/mechanism of reported injury

• Lack of temporal relationship


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Pointers for: symptomatic age related degeneration

• Relationship of circumstances to symptoms

• Extent/mechanism of reported injury

• Lack of temporal relationship


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• Evidence of similar changes on the other side

• Record or history of progressive changes prior to the

injury

• Worsening symptoms despite cessation of activity


Has the injury altered the pre-existing condition?

• Exacerbation• This is a re-occurrence or flare up generally

implying worsening of a condition temporarily.


• Aggravation • An aggravation is a circumstance or event that

permanently worsens a pre-existing or underlying condition.


Aggravation / exacerbation: PI?

• Pre-existing condition:• Exacerbation – return of symptoms to baseline• Aggravation – persisting symptoms – PI

• Permanent impairment with apportionment to pre-existing

condition

‘reasonable probability that impairment and treatment

greater due

to pre-existing condition’ – AMA Guides, Ch.1.



The spectrum of ongoing symptoms – is it injury related?


Claim – Ongoing Symptoms

Isolated injury

Aggravation of pre-existing

condition

Age related degeneratio

n


Which report is best?

• Dr Kwik is a fast reader. Her turn-around time for reports averages 15 minutes. Her reports are brief with a paucity of differential diagnoses. When she flags pathology it is very likely to be present.

• Dr Thorough is not as fast. His turn-around time for reports averages 45 minutes. His reports are long and verbose. He meticulously lists all organs, regardless of whether pathology is suspected or absence of pathology in those organs is of clinical relevance.




• Dr Thorough presents long list of possibilities. He rarely comes down on a specific diagnosis.

• Dr Thorough almost never misses pathology. He picks up tiny lung cancers, subtle thyroid cancers and tiny bleeds in the brain.

• The problem with Dr Thorough is specificity. He often raises false alarms such as “questionable pneumonia,” “possible early appendicitis” and “subtle high density in the brain, small punctate haemorrhage not entirely excluded.”




• Dr Kwik – decisive – under-reporting – occasional miss –avoids over-investigation and unnecessary treatment

• Dr Thorough – comprehensive – never misses – leads to further tests and treatment of normal

• The review of films by the examining doctor is CRUCIAL



• Summary of tests available• What is normal?• Age related changes• Pre-existing conditions• Interpretation


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Questions?


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