Shawn Jorgensen, MD Jeff Strakowski, MD Jeff Strommen, MD

Introduction Discuss role of US vs EMG in focal peripheral neuropathies (FPN) Discuss role of US vs EMG in focal peripheral neuropathies (FPN) Examine literature to determine roles in specific FPN Examine literature to determine roles in specific FPN CTS CTS Ulnar neuropathy at the elbow Ulnar neuropathy at the elbow Fibular neuropathies Fibular neuropathies Less common Less common

GoalsGoals Attendees should, after this course: Attendees should, after this course: Have an evidence-based approach to ordering EDX, US, or both in specific FPN Have an evidence-based approach to ordering EDX, US, or both in specific FPN

GoalsGoals Attendees should, after this course: Attendees should, after this course: Have an evidence-based approach to ordering EDX, US, or both in specific FPN Have an evidence-based approach to ordering EDX, US, or both in specific FPN Ideally, be able to answer these three questions for any FPN Ideally, be able to answer these three questions for any FPN 1. Which test should be the primary test 1. Which test should be the primary test 2. Under what circumstances the primary test would change 2. Under what circumstances the primary test would change 3. Under what circumstances the secondary test should be added 3. Under what circumstances the secondary test should be added

Why discuss US? 1. Which test should be the primary test for all FPN? 1. Which test should be the primary test for all FPN? EDX is clearly superior to MRI and satisfactory for all FPN EDX is clearly superior to MRI and satisfactory for all FPN 2. Under what circumstances would the primary test change? 2. Under what circumstances would the primary test change? MRI only when EDX impossible MRI only when EDX impossible 3. Under what circumstances should the secondary test be added? 3. Under what circumstances should the secondary test be added? Very few MRI when EDX non-diagnostic Very few MRI when EDX non-diagnostic US experimental US experimental

Why discuss US? US is valid and reliable (Cartwright 2013) US is valid and reliable (Cartwright 2013)

Why discuss US? 1. Which test should be the primary test for all FPN? 1. Which test should be the primary test for all FPN? EDX is clearly superior to MRI and satisfactory for all FPN EDX is clearly superior to MRI and satisfactory for all FPN 2. Under what circumstances would the primary test change? 2. Under what circumstances would the primary test change? MRI only when EDX impossible MRI only when EDX impossible 3. Under what circumstances should the secondary test be added? 3. Under what circumstances should the secondary test be added? Very few Very few MRI when EDX non-diagnostic MRI when EDX non-diagnostic US experimental US experimental US valid and reliable

Why discuss US? MRI is in the past MRI is in the past US is superior to MRI and is changing the role of imaging in FPN US is superior to MRI and is changing the role of imaging in FPN Greater sensitivity (93% vs. 67%), equal specificity, better at multifocal lesions than MRI (Zaidman 2013) Greater sensitivity (93% vs. 67%), equal specificity, better at multifocal lesions than MRI (Zaidman 2013)

Why discuss US? 1. Which test should be the primary test for all FPN? 1. Which test should be the primary test for all FPN? EDX is clearly superior to MRI and satisfactory for all FPN EDX is clearly superior to MRI and satisfactory for all FPN 2. Under what circumstances would the primary test change? 2. Under what circumstances would the primary test change? MRI only when EDX impossible MRI only when EDX impossible 3. Under what circumstances should the secondary test be added? 3. Under what circumstances should the secondary test be added? Very few Very few MRI when EDX non-diagnostic MRI when EDX non-diagnostic US valid and reliable US valid and reliable ??? - US when EDX non-diagnostic US only when EDX impossible EDX is clearly superior to US and satisfactory for all FPN

Why discuss US? 1. Which test should be the primary test for all FPN? 1. Which test should be the primary test for all FPN? EDX is clearly superior to US and satisfactory for all FPN EDX is clearly superior to US and satisfactory for all FPN 2. Under what circumstances would the primary test change? 2. Under what circumstances would the primary test change? US only when EDX impossible US only when EDX impossible 3. Under what circumstances should the secondary test be added? 3. Under what circumstances should the secondary test be added? Very few Very few ??? - US when EDX non-diagnostic ??? - US when EDX non-diagnostic US valid and reliable US valid and reliable EDX is clearly superior to US but not perfect for all FPN

Why discuss US? US may be offered for diagnosis of CTS (Cartwright 2012 AANEM position statement) US may be offered for diagnosis of CTS (Cartwright 2012 AANEM position statement)

Why discuss US? 1. Which test should be the primary test for all FPN? 1. Which test should be the primary test for all FPN? EDX is clearly superior to US but not perfect for all FPN EDX is clearly superior to US but not perfect for all FPN 2. Under what circumstances would the primary test change? 2. Under what circumstances would the primary test change? US only when EDX impossible US only when EDX impossible 3. Under what circumstances should the secondary test be added? 3. Under what circumstances should the secondary test be added? Very few Very few ??? - US when EDX non-diagnostic ??? - US when EDX non-diagnostic US valid and reliable US valid and reliable EDX may be superior to US but not perfect for all FPN ??? ??? - US possibly in all patients? ??? - Many or all

Why discuss US? US adds value to the diagnosis of CTS (Cartwright 2013 AANEM position statement) US adds value to the diagnosis of CTS (Cartwright 2013 AANEM position statement)

Why discuss US? 1. Which test should be the primary test for all FPN? 1. Which test should be the primary test for all FPN? EDX may be superior to US but not perfect for all FPN EDX may be superior to US but not perfect for all FPN 2. Under what circumstances would the primary test change? 2. Under what circumstances would the primary test change? ??? ??? 3. Under what circumstances should the secondary test be added? 3. Under what circumstances should the secondary test be added? ??? - Many or all ??? - Many or all ??? - US possibly in all patients ??? - US possibly in all patients Specific indications Specific indications ??? - US when EDX is non-diagnostic ??? - US when EDX is non-diagnostic ??? - Failed intervention ??? - Failed intervention ??? - Unilateral CTS ??? - Unilateral CTS ??? - In the setting of trauma ??? - In the setting of trauma ??? US possibly in all patients bifid MN / PMA can alter tx

Why discuss US? 1. Which test should be the primary test for all FPN? 1. Which test should be the primary test for all FPN? EDX may be superior to US but not perfect for all FPN EDX may be superior to US but not perfect for all FPN 2. Under what circumstances would the primary test change? 2. Under what circumstances would the primary test change? ??? ??? 3. Under what circumstances should the secondary test be added? 3. Under what circumstances should the secondary test be added? ??? - Many or all ??? - Many or all ??? - US possibly in all patients bifid MN / PMA can alter tx ??? - US possibly in all patients bifid MN / PMA can alter tx Specific indications Specific indications ??? - US when EDX is non-diagnostic ??? - US when EDX is non-diagnostic ??? - Failed intervention ??? - Failed intervention ??? - Unilateral CTS ??? - Unilateral CTS ??? - In the setting of trauma ??? - In the setting of trauma ???

Ultrasound for nerves 101 Excellent anatomic detail Excellent anatomic detail Can measure Can measure size size shape shape doppler flow doppler flow echogenicity echogenicity mobility mobility Cross sectional area (CSA) is the only measurement with statistical utility currently Cross sectional area (CSA) is the only measurement with statistical utility currently

1. Which test should be 1 st line for most circumstances? 1. Which test should be 1 st line for most circumstances? Systematic evidence-based medicine criteria for a useful diagnostic test (Frybeck 1991) Systematic evidence-based medicine criteria for a useful diagnostic test (Frybeck 1991) 1. Valid and reliable 1. Valid and reliable 2. Accurate 2. Accurate 3. Changes the diagnosis 3. Changes the diagnosis 4. Changes the treatment plan 4. Changes the treatment plan 5. Improves patient outcomes 5. Improves patient outcomes 6. Good cost-benefit profile 6. Good cost-benefit profile Carpal Tunnel Syndrome: EMG vs. US

What do we want a test for focal peripheral neuropathies to do? What do we want a test for focal peripheral neuropathies to do? 1. Diagnose/exclude CTS 1. Diagnose/exclude CTS 2. Rule out the other likely diagnoses 2. Rule out the other likely diagnoses 3. Assess severity 3. Assess severity 4. Establish timing of injury 4. Establish timing of injury 5. Determine etiology 5. Determine etiology 6. Determine prognosis 6. Determine prognosis 7. Guide treatment 7. Guide treatment Carpal Tunnel Syndrome: EMG vs. US

1. Diagnose/exclude CTS - reliably 1. Diagnose/exclude CTS - reliably Electrodiagnostics Electrodiagnostics Test-retest reliabilityGOOD Test-retest reliabilityGOOD CSI Spearman rho 0.95 (Lew 2000) CSI Spearman rho 0.95 (Lew 2000) Inter-rater reliabilityPOOR Inter-rater reliabilityPOOR Large enough to limit clinical trials (Dyck 2013) Large enough to limit clinical trials (Dyck 2013) Reference values BEST Reference values BEST Standardization of practiceAVERAGE Standardization of practiceAVERAGE Identify dynamic pathologyWORST Identify dynamic pathologyWORST Use side-to-side comparisonBEST Use side-to-side comparisonBEST Quality assurance Quality assurance Operators ABEMBEST Operators ABEMBEST Laboratories AANEMGOOD Laboratories AANEMGOOD Carpal Tunnel Syndrome: EMG vs. US

1. Diagnose/exclude CTS - reliably 1. Diagnose/exclude CTS - reliably Ultrasound Ultrasound Test-retest reliabilityBEST Test-retest reliabilityBEST Coefficient >=0.98 (Cartwright 2013) Coefficient >=0.98 (Cartwright 2013) Inter-rater reliabilityBEST Inter-rater reliabilityBEST P

1. Diagnose/exclude CTS EMG-negative 1. Diagnose/exclude CTS EMG-negative Ultrasound GOOD Ultrasound GOOD Normal EDX Normal EDX With sx of CTS 30.5% had a CSA>10.5mm 2 With sx of CTS 30.5% had a CSA>10.5mm 2 Controls without sx of CTS 3.3% had a CSA>10.5mm 2 (Koyuncuoglu 2005) Controls without sx of CTS 3.3% had a CSA>10.5mm 2 (Koyuncuoglu 2005) Carpal Tunnel Syndrome: EMG vs. US

2. Rule out other likely diagnoses - neurological 2. Rule out other likely diagnoses - neurological ElectrodiagnosticsBEST ElectrodiagnosticsBEST Series of failed carpal tunnel release ultimate diagnosis (Witt 2000) Series of failed carpal tunnel release ultimate diagnosis (Witt 2000) Polyneuropathy (2/12) Polyneuropathy (2/12) Cervical radiculopathy (1/12) Cervical radiculopathy (1/12) Motor neuron disease (4/12) Motor neuron disease (4/12) Spondylotic myelopathy (1/12) Spondylotic myelopathy (1/12) Syringomyelia (1/12) Syringomyelia (1/12) Multiple sclerosis (2/12) Multiple sclerosis (2/12) TEST OF CHOICE Carpal Tunnel Syndrome: EMG vs. US

2. Rule out other likely diagnoses - neurological 2. Rule out other likely diagnoses - neurological UltrasoundPOOR UltrasoundPOOR Cervical radiculopathy Cervical radiculopathy Brachial plexopathy Brachial plexopathy Ulnar neuropathy Ulnar neuropathy Proximal median neuropathy Proximal median neuropathy Polyneuropathy Polyneuropathy Carpal Tunnel Syndrome: EMG vs. US

2. Rule out other likely diagnoses - MSK 2. Rule out other likely diagnoses - MSK ElectrodiagnosticsWORST ElectrodiagnosticsWORST Carpal Tunnel Syndrome: EMG vs. US

2. Rule out other likely diagnoses - MSK 2. Rule out other likely diagnoses - MSK UltrasoundBEST UltrasoundBEST Tenosynovitis Tenosynovitis Trigger finger Trigger finger Synovitis Synovitis Ganglion cysts Ganglion cysts Carpal Tunnel Syndrome: EMG vs. US TEST OF CHOICE / ALTERNATE

3. Establish timing of injury 3. Establish timing of injury ElectrodiagnosticsBEST ElectrodiagnosticsBEST Needle EMG Needle EMG Size of fibrillation potentials Size of fibrillation potentials Size of motor unit action potentials (MUAP) Size of motor unit action potentials (MUAP) Carpal Tunnel Syndrome: EMG vs. US

3. Establish timing of injury 3. Establish timing of injury UltrasoundWORST UltrasoundWORST Carpal Tunnel Syndrome: EMG vs. US

4. Assess severity 4. Assess severity Electrodiagnostics Electrodiagnostics Electrophysiologic rating scales Electrophysiologic rating scales Steven scale Steven scale Canterbury scale Canterbury scale Combined sensory index (CSI) Combined sensory index (CSI) Carpal Tunnel Syndrome: EMG vs. US

Canterbury Scale (Bland 2000) Canterbury Scale (Bland 2000) 0 NORMAL 0 NORMAL no neurophysiological abnormality no neurophysiological abnormality 1 VERY MILD 1 VERY MILD detected only in two sensitive tests (inching, palm/wrist median/ulnar comparison, ringdiff) detected only in two sensitive tests (inching, palm/wrist median/ulnar comparison, ringdiff) 2 MILD 2 MILD index finger CV 6.5ms motor latency >6.5ms 6 EXTREMELY SEVERE 6 EXTREMELY SEVERE motor amplitude

4. Assess severity 4. Assess severity Electrodiagnostics correlates with surgical outcome Electrodiagnostics correlates with surgical outcome Yes - Combined sensory index (Malladi 2010) Yes - Combined sensory index (Malladi 2010) Normal (4.6 - 54% complete resolution of sx Absent 37% complete resolution of sx Absent 37% complete resolution of sx Carpal Tunnel Syndrome: EMG vs. US

4. Assess severity 4. Assess severity Ultrasound correlation with EDX severity Ultrasound correlation with EDX severity No correlation (Bland reference, Mhoon 2012, Mohammadi 2010, Kaymak 2008) No correlation (Bland reference, Mhoon 2012, Mohammadi 2010, Kaymak 2008) Correlation (Karadag 2010, ?Lee 2005, Bayrak 2007, Padua 2008, Ziswiler 2005) Correlation (Karadag 2010, ?Lee 2005, Bayrak 2007, Padua 2008, Ziswiler 2005) Carpal Tunnel Syndrome: EMG vs. US

4. Assess severity 4. Assess severity ElectrodiagnosticsGOOD ElectrodiagnosticsGOOD Carpal Tunnel Syndrome: EMG vs. US

4. Assess severity 4. Assess severity Ultrasound POOR Ultrasound POOR Carpal Tunnel Syndrome: EMG vs. US

5. Determines etiology 5. Determines etiology ElectrodiagnosticsWORST ElectrodiagnosticsWORST Carpal Tunnel Syndrome: EMG vs. US

5. Determines etiology 5. Determines etiology UltrasoundBEST UltrasoundBEST In patients with CTS In patients with CTS Ganglion 25% in unilateral CTS, 7% bilateral by US (Nakamichi 1993, Buchberger 1991) Ganglion 25% in unilateral CTS, 7% bilateral by US (Nakamichi 1993, Buchberger 1991) Tenosynovitis 10% in CTS by US, confirmed in surgery (Buchberger 1991) Tenosynovitis 10% in CTS by US, confirmed in surgery (Buchberger 1991) Fatty tissue on the floor of CT 7% in CTS by US, confirmed in surgery (Buchberger 1991) Fatty tissue on the floor of CT 7% in CTS by US, confirmed in surgery (Buchberger 1991) Intrusive FDS 7% in CTS by US (Buchberger 1991) Intrusive FDS 7% in CTS by US (Buchberger 1991) Instrusive lumbricals 22% (Touborg-Jensen 1970) Instrusive lumbricals 22% (Touborg-Jensen 1970) Fracture Fracture Dislocation Dislocation Carpal Tunnel Syndrome: EMG vs. US

5. Determines etiology 5. Determines etiology UltrasoundBEST UltrasoundBEST Determining causation Determining causation Test can potentially detect abnormality Test can potentially detect abnormality Increased incidence in CT than in normals (association) Increased incidence in CT than in normals (association) ? Treating improving symptoms or other disease marker (causation) ? Treating improving symptoms or other disease marker (causation) Carpal Tunnel Syndrome: EMG vs. US

6. Determines prognosis 6. Determines prognosis Electrodiagnostic Electrodiagnostic Carpal Tunnel Syndrome: EMG vs. US

6. Determines prognosis 6. Determines prognosis US US Carpal Tunnel Syndrome: EMG vs. US

7. Change treatment 7. Change treatment A. By severity (and presumed natural history) A. By severity (and presumed natural history) B. By etiology (and treatments specific to that cause) B. By etiology (and treatments specific to that cause) Carpal Tunnel Syndrome: EMG vs. US

7. Change treatment 7. Change treatment Electrodiagnostics GOOD Electrodiagnostics GOOD A. By severity (and presumed natural history) A. By severity (and presumed natural history) This does not tell you whether a patient should have surgery or not! This does not tell you whether a patient should have surgery or not! Mild - probably shouldnt Mild - probably shouldnt Doesnt compare outcomes with or without surgery, just surgery with different severities Doesnt compare outcomes with or without surgery, just surgery with different severities B. By etiology (and treatments specific to that cause) B. By etiology (and treatments specific to that cause) none none Carpal Tunnel Syndrome: EMG vs. US

7. Change treatment 7. Change treatment Ultrasound Ultrasound A. By severity (and presumed natural history) A. By severity (and presumed natural history) None None B. By etiology (and treatments specific to that cause) B. By etiology (and treatments specific to that cause) ?? ?? Carpal Tunnel Syndrome: EMG vs. US

7. Change treatment 7. Change treatment Ultrasound etiologies that may change txAVERAGE Ultrasound etiologies that may change txAVERAGE Any surgery relative contraindications Any surgery relative contraindications Tenosynovitis 6% injection probably favorable (Beekman 2003) Tenosynovitis 6% injection probably favorable (Beekman 2003) Thrombosed persistent median artery treated with thrombolysis? (Fumiere 2002, Bianchi book 465) Thrombosed persistent median artery treated with thrombolysis? (Fumiere 2002, Bianchi book 465) Endoscopic surgery relative contraindications Endoscopic surgery relative contraindications Space occupying lesion (Bianchi book 467) Space occupying lesion (Bianchi book 467) Ganglion cyst 25% unilateral (Nakamichi 1993) Ganglion cyst 25% unilateral (Nakamichi 1993) Persistent median artery 9% (Padua 2011) Persistent median artery 9% (Padua 2011) Bifid median nerve 9% (Padua 2011) Bifid median nerve 9% (Padua 2011) May have separate compartments requiring separate treatments (Ianicelli 2000, Szabo 1994, Amadio 1987) May have separate compartments requiring separate treatments (Ianicelli 2000, Szabo 1994, Amadio 1987) Carpal Tunnel Syndrome: EMG vs. US

Negatives of testing Negatives of testing Electrodiagnostics Electrodiagnostics Tolerability WORST Tolerability WORST SafetyBEST SafetyBEST Price AVERAGE Price AVERAGE 95908+95861 = ~$200 95908+95861 = ~$200 SpeedAVERAGE SpeedAVERAGE ~30 minutes ~30 minutes Readily available Readily available Equipment GOOD Equipment GOOD Competent operators GOOD Competent operators GOOD Carpal Tunnel Syndrome: EMG vs. US

Negatives of testing Negatives of testing Ultrasound Ultrasound TolerabilityBEST TolerabilityBEST SafetyBEST SafetyBEST Price GOOD Price GOOD 76881 = $114 76881 = $114 SpeedBEST SpeedBEST Full anterior wrist, forearm comparison = ~12 minutes Full anterior wrist, forearm comparison = ~12 minutes Readily available Readily available Equipment GOOD Equipment GOOD Competent operators WORST Competent operators WORST Carpal Tunnel Syndrome: EMG vs. US

USEDX GOODSensitivity BEST AVERAGESpecificityBEST BESTReliabilityBEST POORpost CTRAVERAGE GOODPolyneuropathy GOOD POOR (MSK) Rule out mimickers BEST (PN) POORTimingBEST POORSeverityGOOD BESTEtiologyWORST POORPrognosticateGOOD AVERAGEDirect treatmentGOOD

USEDX BESTTolerabilityWORST BESTSafetyBEST GOODExpense AVERAGE BESTSpeedAVERAGE POORAvailabilityGOOD

US as a screening tool US as a screening tool US should be used as a screen US should be used as a screen Screening test profile Screening test profile Tolerable Tolerable Safe Safe Quick Quick Cheap Cheap Can confirm borderline values with a gold standard tests Can confirm borderline values with a gold standard tests Carpal Tunnel Syndrome: EMG vs. US

US as a screening test US as a screening test TolerabilityBEST TolerabilityBEST SafetyBEST SafetyBEST Time (12 minutes)BEST Time (12 minutes)BEST Price ($114)GOOD Price ($114)GOOD Sensitivity (65-97%)GOOD Sensitivity (65-97%)GOOD Specificity (72-97%)AVERAGE Specificity (72-97%)AVERAGE SeverityWORST SeverityWORST EtiologyBEST EtiologyBEST Rule out mimickersPOOR Rule out mimickersPOOR PrognosisPOOR PrognosisPOOR Direct TreatmentGOOD Direct TreatmentGOOD Carpal Tunnel Syndrome: EMG vs. US

Ringdiff =0.98 (Cartwright 2013) Coefficient >=0.98 (Cartwright 2013) Inter-rater reliabilityBEST Inter-rater reliabilityBEST P

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Shawn Jorgensen, MD Jeff Strakowski, MD Jeff Strommen, MD