territory insurance conference, resilient future a/prof peter steadman, medilaw consultant...
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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
Territory Insurance Conference, resilient 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
Territory Insurance Conference, resilient future
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
Territory Insurance Conference, resilient future
Plan for today
• Summary of tests available • What is normal?• Pre-existing conditions • Interpretation
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
Territory Insurance Conference, resilient future
Common ‘imaging’ modalities
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
Ultrasound
Radiography
Multislice CT
MRI
Bone scan
Nerve conduction studies
Subcutaneous Tendon Joints Ligaments Muscles Bone Intervertebral discs Nerve Blood vessels
All advantages / disadvantages
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Types of imaging
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
• Investigations
Radiographs / X-ray
Ultrasound
CT
MRI
Bone scan
Nerve conduction studies
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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
Territory Insurance Conference, resilient future
Types of imaging
• Investigations
Radiographs / X-ray
Ultrasound
CT
MRI
Bone scan
Nerve conduction studies
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
Calcific deposit – shoulders
Rotator cuff tears – shoulders
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Subacromial impingement Dynamic ultrasound
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
Territory Insurance Conference, resilient future
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon 29/10/2015
Types of imaging
• Investigations
Radiographs / X-ray
Ultrasound
CT
MRI
Bone scan
Nerve conduction studies
Territory Insurance Conference, resilient future
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
Types of imaging
• Investigations
Radiographs / X-ray
Ultrasound
CT
MRI
Bone scan
Nerve conduction studies
Calcific deposit – shouldersAchilles tendinopathy
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Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
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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Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
Types of imaging
• Investigations
Radiographs / X-ray
Ultrasound
CT
MRI
Bone scan
Nerve conduction studies
Tibial stress fracture Neck of femur fracture
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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
Nerve conduction studies
Territory Insurance Conference, resilient future
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
Types of imaging
• Investigations
Radiographs / X-ray
Ultrasound
CT
MRI
Bone Scan
Nerve conduction studies
Left ulnar nerve neuropathy (conduction problem in ulnar nerve)
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Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon 29/10/2015
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
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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
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
Territory Insurance Conference, resilient future
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)
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
Territory Insurance Conference, resilient future
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.
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
Territory Insurance Conference, resilient future
Ageing tissues
• Collagen – strength of issues
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
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Ageing issues
• Bone – reduced density – osteoporosis
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
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Ageing issues
• Bone – reduced density – osteoporosis
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
Greater risk of fracture in the older worker
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‘Degeneration’ – Normal
Degenerative change – we all have it
Common terms –
‘Wear and tear’ – has implicationsTendinosisTendinopathyDegenerationArthritisArthrosis Spine – intervertebral disc disease
– disc desiccation
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon 29/10/2015
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‘Degeneration’
Incidence of rotator cuff tear in asymptomatic individuals:
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
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.
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Pre-existing conditions
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
Asymptomatic – normal – degenerative – previous injury – recovered –
full function
Symptomatic – normal – degenerative– previous injury – symptoms –
reduced function
Increasing age
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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.
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon 29/10/2015
Territory Insurance Conference, resilient future
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
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
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Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon 29/10/2015
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
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Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon 29/10/2015
Pre–existing conditions: Tests
• MRI scans – Achilles tendon
• Can demonstrate pre-existing degenerative conditions
• Insertional and non-insertional tendinopathy
• May become painful after work related event
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Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon 29/10/2015
Pre–existing conditions: Tests
Tibialis
Posterior
Tendonitis
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Tennis elbow: Pre-existing?
• 35 year old manual worker• Severe pain lateral elbow
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon 29/10/2015
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• T2FS coronal• Severe tendinosis and partial tear of common
extensor origin i.e. ‘tennis elbow’
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon 29/10/2015
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Pre-existing conditions: Spine
• Common relationship with ‘injury’• Back pain common in population• Increases during working years
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon 29/10/2015
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Disc desiccation
• Uniform: normal consequence of ageing• Focal: associated with disc pathology
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
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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
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
Territory Insurance Conference, resilient future
Annual tear
• Radial, circumferential, transverse• 40% of asymptomatic individuals
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
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Annual tear
• Overcalled by radiologists• Discogram required if
‘discogenic pain’ suspected
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
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Annual tears with protrusion
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon 29/10/2015
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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
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon 29/10/2015
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Osteoarthritis of the lumbar spine
• Disc space narrowing
• Osteophyte formation
• Facet joint sclerosis and hypertrophy
• Spondylolisthesis
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
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Osteoarthritis of the lumbar spine
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon 29/10/2015
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Disc – osteophyte complex
• Common in lumbar and cervical spine
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon 29/10/2015
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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.
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
Territory Insurance Conference, resilient future
Pointers for: symptomatic age related degeneration
• Relationship of circumstances to symptoms
• Extent/mechanism of reported injury
• Lack of temporal relationship
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
Territory Insurance Conference, resilient future
Pointers for: symptomatic age related degeneration
• Relationship of circumstances to symptoms
• Extent/mechanism of reported injury
• Lack of temporal relationship
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
• Evidence of similar changes on the other side
• Record or history of progressive changes prior to the
injury
• Worsening symptoms despite cessation of activity
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Has the injury altered the pre-existing condition?
• Exacerbation• This is a re-occurrence or flare up generally
implying worsening of a condition temporarily.
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon 29/10/2015
• Aggravation • An aggravation is a circumstance or event that
permanently worsens a pre-existing or underlying condition.
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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.
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon 29/10/2015
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The spectrum of ongoing symptoms – is it injury related?
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon 29/10/2015
Claim – Ongoing Symptoms
Isolated injury
Aggravation of pre-existing
condition
Age related degeneratio
n
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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 Peter Steadman, Medilaw Consultant Orthopaedic Surgeon 29/10/2015
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Which report is best?
• 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 Peter Steadman, Medilaw Consultant Orthopaedic Surgeon 29/10/2015
Territory Insurance Conference, resilient future
Which report is best?
• 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
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon 29/10/2015
Territory Insurance Conference, resilient future
• Summary of tests available• What is normal?• Age related changes• Pre-existing conditions• Interpretation
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015
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Questions?
Dr Peter Steadman, Medilaw Consultant Orthopaedic Surgeon
29/10/2015