Mononeuropathies: A Practical Approach to Diagnosis and Treatment

Dr. Simran Singh Basi MD, FRCPC, CSCN Diplomate (EMG) February 28, 2018 Faculty/Presenter Disclosure

• Faculty: Dr. Simran Singh Basi • Relationships with commercial interests: – Grants: Allergan Inc. – Consulting Agreement: Allergan Inc. Disclosure of Commercial Support

• Allergan Inc. (unrestricted educational grant) • Allergan Inc. (spasticity consulting agreement)

This presentation has not received financial support from Allergan Inc. nor will any of the treatments discussed deal with Allergan Inc. products. Mitigating Potential Bias

• The information in this presentation is based on recent information that is peer reviewed and all the recommendations involving clinical medicine are based on evidence that is accepted within the profession; and all scientific research referred to, reported or used in the presentation in support or justification of patient care recommendations conforms to the generally accepted standards. Objectives

• Formulate a differential diagnosis for common mononeuropathies • Understand the basics of electrodiagnostic testing • Rationalize an approach to treatment Agenda

• General Approach to Neuromuscular Disorders • Median Mononeuropathy • Ulnar Mononeuropathy • Radial Mononeuropathy • Peroneal Mononeuropathy General DDx for Mononeuropathies

• UMN – Brain – Spinal Cord • LMN – Motor or Sensory Neuronopathy – – – – Mononeuropathy – NMJ – Myopathy Electrodiagnostic Testing

• Nerve Conduction Studies – Demyelination – Axonopathy • Needle Electromyography – Muscle pathology patterns • Neuropathic • NMJ • Myopathic

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• 30 yo M with 3 month history of right hand paresthesias and mild weakness. Works as a mechanic. Difficulty sleeping at night time due to hand symptoms that awaken him from sleep. Otherwise healthy. Entrapment Points: • Ligament of Struthers (ligament connecting bone spur to medial epicondyle) • Lacertus Fibrosis (Bicipital aponeurosis thickening attaching biceps to radius bone) • Sublimis Ridge or Pronator Teres (FDS fascia or two heads of pronator teres) • AIN Syndrome • Carpal Tunnel http://www.bing.com/images/search?view=detailV2&ccid=NTvN9z%2fg&id=BD1B73D1EA724 10146DE70FF51E4689A5F260529&thid=OIP.NTvN9z_giBZZ7eA_pMtdNAEsEs&q=ligament+of+ struther&simid=607986625495699220&selectedIndex=0

http://www.bing.com/images/search?view=detailV2&ccid=o0BqM3tt&id=A0423722BCEF328CC953E16C6 C49D7E4179BDD79&thid=OIP.o0BqM3ttbbwV2GquHsdi9AEsCG&q=lacertus+fibrosis&simid=6080285014 13856674&selectedIndex=7 Carpal Tunnel Contents: – FDS (4 tendons) – FDP (4 tendons) – FPL – Median Nerve Causes of CTS: (if non-dominant hand most involved, likely not idiopathic) – Idiopathic (repetitive activity, occupational) (female, dominant hand) – Tunnel Volume Changes: • Hypothyroid • DM2 • Renal Failure • Mass (Tumor, Hematoma) • Pregnancy • Bony Changes: Fracture (Colles), OA • RA tenosynovitis • CHF • Amyloidosis http://www.bing.com/images/search?q=carpal+tunnel&view=detailv2&&id=A2FF2A98C15CDD37DD8072 9CF03663B1079795ED&selectedIndex=20&ccid=D0iivs%2by&simid=608038461102689588&thid=OIP.M0f 48a2becfb2adf9dad20be7111aba5bo0 CTS

Classification: • Mild CTS: Sensory abnormality • Moderate CTS: Sensory + Motor abnormality • Severe CTS: Sensory + Motor + Muscle Atrophy

DDx CTS

• UMN: – CNS lesion (seizure, migraine, TIA/stroke of lateral thalamus + internal capsule) • UMN signs • LMN – C6/C7 Radiculopathy • Neck pain, abnormal reflexes (biceps, brachioradialis, triceps) – Brachial Plexopathy (Upper/Middle Trunk, Lateral Cord) • Widespread Motor and Sensory abnormality – Proximal Median Nerve Lesion • Palmar Cutaneous Affected • Proximal median nerve muscles affected

EDx Role in CTS

• Assess DDx • Classify Severity of CTS – Mild: sensory nerves only – Moderate: motor + sensory nerves – Severe: EMG changes in median nerve palm muscles CTS Rx

1. Education: avoid wrist flexion/repetitive activities if possible 2. Modify work environment + proper ergonomics 3. Resting Wrist-Hand Orthosis qhs with 0-5 deg of wrist extension (MILD CTS) 4. Pharmacologic: - NSAIDs, diuretics, thyroid replacement - CSI into carpal tunnel (MODERATE CTS) + still use wrist splint 5. Surgery: Release of transverse carpal ligament (SEVERE CTS or failed non-surgical) http://www.bing.com/images/search?view=detailV2&ccid=giD3mtdU&id=D43366F47AB011B31F1BF3D0E BF2C266867D1FE6&thid=OIP.giD3mtdUxEmEg63SoHJv6gD6D6&q=carpal+tunnel+brace&simid=60801768 6688697272&selectedIndex=5 Case 2

• 40 yo M with 3 month history of right hand weakness and numbness of digits 4&5. Dropping objects due to weakness.

Entrapment Points: (from proximal to distal) • Arcade of Struthers (fascial band connecting brachialis to triceps) • Ulnar Groove – proximal to medial epicondyle • Cubital Tunnel Syndrome – distal to medial epicondyle • Guyon’s Canal http://www.bing.com/images/search?view=detailV2&ccid=UpbSWRG8&id=732E74B5C9B5B50B9EA452EC00866A5EEFE9 0EA9&thid=OIP.UpbSWRG8W7jFY530xetbIgEsEs&q=arcade+of+struthers&simid=607992427981049532&selectedIndex=0 at the Elbow (UNE) a) Ulnar Groove (located just proximal to medial epicondyle) b) Cubital Tunnel Syndrome (bordered by medial epicondyle, olecranon and overlying FCU aponeurosis) ~ 3 cm distal to medial epicondyle

http://www.bing.com/images/search?q=cubital+tunnel&view=detailv2&&id=0AF3FC16CF69DF6D2EB6FBBFB1DEEC9230 EC1CEF&selectedIndex=1&ccid=N41sHujv&simid=607998732654019557&thid=OIP.M378d6c1ee8ef2b5a7b4e6140d0007 b61o0 UNE

• Causes: • Chronic Mechanical Compression • Ganglion • Tumor • Excessive cubital valgus angulation • Accessory muscle (anconeous epitrochlearis)

DDx in UNE

• UMN: – CNS lesion (seizure, migraine, TIA/stroke of lateral thalamus + internal capsule) • UMN signs • LMN – Motor Neuron • No sensory symptoms – C8/T1 Radiculopathy • Neck pain with radicular features – Brachial Plexopathy (Lower Trunk, Medial Cord) • Weak hand muscles • Abnormal MABC (medial antebrachial cutaneous nerve) – Distal Ulnar Nerve Lesion (ulnar neuropathy at wrist) • Normal DUC and PUC

EDx Role in UNE

• Assess DDx • Localize entrapment site with inching studies • Characterize pathology – Demyelinating – Axonopathy Next Steps

• Ultrasound or MRI of elbow to look for causative pathology UNE Rx

1. Education: • Ulnar nerve hygiene practices • Avoid leaning on elbow • Avoid excessive elbow flexion for prolonged period • Cubital tunnel splint or pediatric zimmer splint or a towel around elbow qhs 2. Hand-Finger Orthosis if ulnar claw hand develops 3. Surgical Ulnar Nerve Transposition or Nerve Release/Decompression

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• 30 yo M with 1 week history of . Patient was recently out of the country with his wife for their honeymoon. Radial Nerve Entrapment Sites: (proximal to distal) • Crutch Palsy (can also affect axillary and suprascapular nerve) • Spiral Groove • (intramuscular septum between Brachialis and BR) – NO weakness - just pain • PIN lesion/ Arcade of Frohse/ Supinator Syndrome (connective tissue of Supinator) • Wartenberg Syndrome (superficial radial nerve palsy) DDx in Wrist Drop

• UMN: – CNS lesion (seizure, migraine, TIA/stroke of lateral thalamus + internal capsule) • UMN signs • LMN – C6/C7 Radiculopathy • Neck pain, abnormal Triceps reflex – Brachial Plexopathy (Middle Trunk, Posterior Cord) • Weak Axillary Nerve muscles • Weak Thoracodorsal Nerve muscle (latissimus dorsi) – Radial Nerve Lesion • Spiral Groove • PIN lesion

EDx Role in Wrist Drop

• Assess DDx • Localize level of radial nerve lesion • Characterize Pathology – Demyelinating – Axonopathy

Radial Nerve Injury at Spiral Groove

• Caused by: – Compression – Humerus #

• Clinical: – Weakness and paresthesias in radial nerve below spiral groove (Triceps, Anconeus, Posterior cutaneous nerve of arm OK) – Paresthesias in lateral arm, posterior and superficial radial sensory nerve to dorsal lateral hand

http://www.bing.com/images/search?q=radial+nerve+spiral+groove&view=detailv2&&id=ED81C474C56599F89ED9855E 3911D97816BC332A&selectedIndex=0&ccid=PImVrBzI&simid=607989361033742170&thid=OIP.M3c8995ac1cc870d8d70 16dc8c7327b99o0 Q:

• How does wrist drop differ if spiral groove lesion vs PIN lesion? A:

• In PIN lesion, ECRL/ECRB preserved so will get some wrist extension laterally whereas spiral groove lesion has no wrist extension at all. Next Steps

• U/S or MRI to look for compressive lesion at spiral groove Rx of at Spiral Groove • 1. Education • 2. Physiotherapy for wrist extensor strengthening • 3. Wrist-Hand-Finger Orthosis • 4. Pain medication • 5. Surgical Intervention http://www.bing.com/images/search?view=detailV2&ccid=89rYw5JR&id=6DA7D0652C536C9FCE33C6280 727B9F6200318E6&thid=OIP.89rYw5JR- qY0iYiyHjqPowEsC1&q=radial+nerve+brace&simid=608029132778046337&selectedIndex=5 Case 4

• 40 yo male gardener with 4 weeks history of right foot drop. He is otherwise well. Unremarkable past medical history, no medications, unremarkable family history. DDx Foot Drop

• UMN: – CNS lesion (seizure, migraine, TIA/stroke of lateral thalamus + internal capsule) • UMN signs • LMN – L5 Radiculopathy • Back pain, abnormal hamstring reflex • Weak foot inversion, weak abductors – Lumbosacral Plexopathy • Widespread motor and sensory abnormality – Sciatic Nerve • Weak foot inversion, normal abductors – Common Peroneal Nerve • Lateral cutaneous nerve of the knee • Weak eversion – Deep Peroneal Nerve • Normal eversion – Polyneuropathy • ex. CMT – Tibialis Anterior Rupture • No sensory abnormality Peroneal Nerve Course: – Lateral Cutaneous Nerve of Knee (comes from common peroneal before it splits into superficial and deep) – provides sensation to lateral knee – Superficial Peroneal Branch – Deep Peroneal Branch EDx Role in Foot Drop

• Assess DDx • Localize Peroneal Nerve lesion • Characterize Pathology – Demyelinating – Axonal Loss Common Peroneal Neuropathy

• FIBULAR NECK most common site of nerve injury: – Trauma (fibular #) – Stretch (forcible ankle inversion) – Compression at fibular head: • 1. Cast • 2. Stockings • 3. Improper position during surgery – Occupational: • 1. Gardening • 2. Farmwork (squatting, kneeling) “Strawberry Picker’s Palsy” – Entrapment at Fibular Tunnel (between fibula and peroneus longus) – Mass Lesion (ganglia, tumors, Baker’s Cyst) – Miscellaneous (weight loss, habitual leg crossing, DM2) southfloridasportsmedicine.com Next Steps

• U/S or MRI to look for nerve irritation/mass lesion

Common Peroneal Neuropathy Rx

1. Education: avoid leg crossing, repetitive squatting 2. Lateral Knee padding 3. Ankle-Foot-Orthosis (posterior leaf spring) 4. Neuropathic Pain Medication 5. CSI 6. Surgical Intervention

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http://www.bing.com/images/search?view=detailV2&ccid=Y3GeBXNG&id=CD876D79BB737136F1980FEE7A72455B8FB05928&q=carpal+tunnel+syndrome+humor&simid=608028797659712487&selectedIndex=11 References

• Baima, J and L. Krivickas. Evaluation and treatment of peroneal neuropathy. Curr Rev Musculoskeletal Med. 2008 Jun; 1(2): 147-153. • Braddam RL. Physical Medicine and Rehabilitation 4th Edition. Elsevier Saunders. 2011. p. 171-257. • Caliandro, P, La Torre G, Padua R, Giannini F and L. Padua. Treatment of ulnar neuropathy at the elbow (UNE). Cochrane Library. November 15, 2016. • Cuccurullo SJ. Physical Medicine and Rehabilitation Board Review 3rd Edition. Demos Medical Publishing. 2015. p. 341-471. • Kothari MJ. Treatment of carpal tunnel syndrome. http://www.uptodate.com/home. • Lifchez S, Dzwierzynski and J. Sanger. Compression neuropathy of the radial nerve due to ganglion cysts. Hand. 2008 Jun; 3(2): 152-154. • Preston D and B. Shapiro. Electromyography and Neuromuscular Disorders 3rd Edition. Elsevier Saunders. 2013. p. 267-357. • Russell SM. Examination of Peripheral Nerve Injuries. Thieme. 2006. p. 1-108.