Mistakes We Make: MSK

Transcription

1 Mistakes We Make: MSK Ali Naraghi Division of Musculoskeletal Radiology Joint Department of Medical Imaging University of Toronto

2 Outline Extent of the problem in MSK Types of mistakes Sources of error Fractures Tumors Strategies to reduce incidence of such mistakes

3 What is the average miss rate for fractures of the axial and appendicular skeleton on radiographs? a) 0-2% b) 2.1-4% c) 4.1-6% d) 6.1-8% e) %

4 What is the average miss rate for fractures of the axial and appendicular skeleton on radiographs? a) 0-2% b) 2.1-4% c) 4.1-6% d) 6.1-8% e) %

5 Errors in MSK Radiology Error rates in radiology 30% of abnormal studies Overall rate of 3-4% Most commonly radiographs > CT False negatives > false positives No 1 mistake: missed diagnosis >80% missed fractures Brady et al 2012 Guly et al 2001

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7 Study N Setting Miss Rate Vles All trauma 1.3% Juhl Orthopedic OP 2.2% Wei ER 3.7% Pehle Major trauma 4.9% Houshian Major trauma 8.1% Brooks Major trauma 22.2% Janjua All trauma 39% Pfeifer R et al 2008

8 Litigation and Fractures American College of Emergency Physicians Missed fractures largest source of malpractice US insurance data 10-20% of all malpractice related to missed fractures Reasons: 60% failure to order appropriate test 40% interpretative error (x-rays >> CT) Kachalla et al 2007

9 Types of Mistakes Perceptual errors (70-80%) Scanning error Recognition error Interpretive errors (20-30%) Decision making error Misclassification Measurement errors Communication errors Renfrew et al 1992 Robinson et al 1997

10 Perceptual Errors Fatigue Time of day: Increased missed fractures 8pm-2am Duration of workday: Increase in missed fractures end of shift Distractions Conspicuity of imaging finding 40-70% of missed fractures subtle but visible Hallas et al 2006 Krupinski et al 2010

11 Subtlety of Findings Function of the pathology and the complexity of anatomy Overlapping structures Flatbones Permeative lesions Fractures Carpal bones Midfoot Sacrum Acetabulum Stress fractures

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13 Where is the abnormality? a) Right ilium b) Sacrum c) Left ilium d) Right hip e) Left hip

14 Where is the abnormality? a) Right ilium b) Sacrum c) Left ilium d) Right hip e) Left hip

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21 Sources of Error Lack of clinical information Lack of prior images / reports Dependence on prior reports Satisfaction of search Corner findings Lack of knowledge Training Not attributing enough significance Technical considerations

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23 What is the diagnosis? a) Trauma b) Inflammatory arthritis c) Septic arthritis d) Crystal arthropathy e) None of the above

24 What is the diagnosis? a) Trauma b) Inflammatory arthritis c) Septic arthritis d) Crystal arthropathy e) None of the above

25 Acute pseudogout Septic Arthritis Rheumatoid Arthritis

26 Clinical Details Helps with: Localization Differential diagnosis Decrease error rate 6-11% improvement for fractures No change in accuracy but reduced variability Tudor et al1997 Swensson et al 1985 Aideyan et al 1995

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29 Previous Imaging Hardware Tumor assessment

30 Previous Imaging Hardware Tumor assessment

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32 Satisfaction of Search Abnormality not reported as discovery of another abnormality has satisfied the goal of the search Reduced accuracy for other fractures after identifying the first fracture The more major the initial fracture, the more likely to miss other fractures Ashman et al 2000 Berbaum et al 2001 & 2012

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38 Corner Findings Corner of image Other organs Scout / localizers

39 Corner Findings Corner of image Other organs Scout / localizers

40 Corner Findings Corner of image Other organs Scout / localizers

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42 Extraosseous Incidental Findings Common Radiographs CT MRI Many represent simple cysts / benign pathologies Liver, kidney, adenexal May need further characterization

43 What is the incidence of significant extraspinal / extraosseous findings (requiring follow-up investigation) on lumbar spine MRI? a) 0-4% b) 4.1-8% c) % d) % e) %

44 What is the incidence of significant extraspinal / extraosseous findings (requiring follow-up investigation) on lumbar spine MRI? a) 0-4% b) 4.1-8% c) % d) % e) %

45 Extraosseous Incidental Findings Lumbar spine MRI 3000 examinations 68.7% extraosseous findings 57.4% minor /not clinically significant 8.7% requiring further investigation 2.5% major 51% lympadenopathy 20% genitourinary lesions 15% aortic aneurysms 10% colorectal Of the major findings 60-90% missed prospectively Quattrocchi et al 2013

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50 Technical Considerations Poor Technique Too few view Incomplete coverage Artifacts Wrong protocol Limitation of technique Technique not sensitive enough Technique perceived to be insensitive

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53 Hip Fractures Need for further imaging depends on clinical Bone scan vs CT vs MRI CT and MRI positive in 36-46% of patients with negative x-rays and clinical suspicion # Occult hip fractures CT may miss 20% of # s seen on MRI Depends on local resources Frihagen et al 2005 Lubovsky et al 2005 Hakkarinen et al 2012 Gill et al 2013

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59 Conclusion Suspend every doctor who makes an error today and the error rates tomorrow will be exactly the same BMJ 2001;322:247-8

60 Conclusion Imaging protocols Systematic analysis Be aware of your blind spots Double reporting Clinical details and previous studies Regular dialogue with clinicians Reviewing errors