Differentiating Cervical Radiculopathy and Peripheral Neuropathy. Adam P. Smith, MD

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1 Differentiating Cervical Radiculopathy and Peripheral Neuropathy Adam P. Smith, MD

2 I have no financial, personal, or professional conflicts of interest to report

3 Radiculopathy versus Neuropathy Radiculopathy Usually involves one spinal nerve root distribution following myotomal and dermatomal patterns Pathology often proximal (disc or osteophyte) Neuropathy Usually involves one peripheral nerve branch Pathology often entrapment distally Double Crush phenomenon Rare Both radiculopathy and neuropathy present

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5 Key Features of Differentiation Neurologic examination Neurologic examination Neurologic examination Supplement exam with tests Willie Sutton

6 Roots versus Branches Roots C 5 C 6 C 7 C 8 T 1 Branches Musculocutaneous (C 5,6,7 ) Axillary (C 5,6 ) Radial (C 5,6,7,8, T 1 ) Median (C 5,6,7,8 ) Ulnar (C 8, T 1 ) Abundant overlap between motor and sensory distributions

7 C 8 versus Ulnar nerve- Motor C 8 spinal nerve root Present in ulnar, median, and radial peripheral nerve branches Myotome based Weakness in muscles of one spinal root but multiple peripheral nerve branches, so usually partial or incomplete Atrophy rare (unless long-standing) Fasciculations rare (visible motion of muscle) C 8 palsy will cause some weakness in nearly all intrinsic hand muscles, including those innervated by median nerve

8 C 8 versus Ulnar nerve- Motor Ulnar nerve (C 8 and T 1 ) Muscle based Weakness usually complete Worse with use and better with rest Atrophy early Fasciculations common Innervates: 1 ½ muscles in forearm (flexor carpis ulnaris and flexor digitorum profundus 3 & 4) Majority of hand intrinsic muscles, except LOAF (median)

9 Sensory Exam Branches Roots Sensory distribution of spinal nerve roots overlap Sensory distribution of peripheral nerve branches are very discrete

10 C 8 versus Ulnar nerve- Sensory C 8 Dermatome based Sensation to entire ring finger affected (and pinky finger) Total sensory loss virtually never occurs

11 C 8 versus Ulnar nerve- Sensory Ulnar nerve (C 8 and T 1 ) Sensation to only ulnar half of ring finger affected (and pinky finger)

12 Reflexes Radiculopathy Appropriate DTRs depressed or absent early Neuropathy Rare reflex changes Depends on location of entrapment

13 Radiculopathy Pain Common history of neck pain (abrupt-disc, slow-osteophyte) Occasional radiation into suboccipital area and interscapular area Pain down arm in spinal nerve root distribution Leaning head away from affected side and neck traction may improve pain May worsen with valsalva Neuropathy Rarely neck or radicular pain Pain may be distal near joint (entrapment often proximal to joint) Depends on entrapment Carpal tunnel- Pain predominant symptom early in course Cubital tunnel- Pain may or may not be present

14 Maneuvers/ Signs Spurling s test Radiculopathy Tinel s test Phalen s test Neuropathy Clawing Froment s Wartenberg s Neuropathy

15 Electrodiagnostic Studies Radiculopathy NCS usually normal Usually sensory normal Motor may be abnormal EMG quite sensitive Single motor axon can innervate many muscle fibers, the loss of only a few axons can produce detectable EMG changes Fibrillations of muscles at rest supplied by spinal nerve root Not seen until >3-4 weeks after compression Denervation ipsi paraspinal muscles Posterior rami ( sensory ) innervates paraspinal muscles» Can only be compressed in foramen

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17 Electrodiagnostic Studies Neuropathy Conduction delay often at site of compression Absence of denervation in posterior myotomes (paraspinal muscles) EMG usually normal

18 Imaging Radiculopathy MRI or CT myelogram Require clinical and electrodiagnostic correlation Nearly 28% of asymptomatic adults >40yo have abnormal imaging Neuropathy Rarely useful

19 Most Crucial Differentiations Difference in distribution of motor and sensory deficits Neuropathy has weakened muscles and disturbed sensation solely within distribution of one peripheral nerve branch Discrete Lack of neck and radicular pain in neuropathy Neuropathy has absence of denervation in posterior myotomes Frequent presence of Tinel s sign at point of entrapment or compression

20 Case Examples

21 Case Example 45yo male with neck pain radiating into right arm, right deltoid/bicep weakness, and numbness in right thumb and index finger No reflex abnormality + Spurling s test to the right

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23 Spurling s Test

24 C 5 C 6 Right Left

25 C 5-6

26 Neck pain and radiculopathy Key Factors Weakness in muscles supplied by same spinal nerve root (C 6 ), but different peripheral nerve branches (deltoid- axillary n., bicepmusculocutaneous n.) Sensory disturbance concordant with C 6 Reflexes normal Positive Spurling s test Concordant MRI

27 1.5cm

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29 C 6 C 5 C 6 C 5 C 5 C 6

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32 Case Example 64 yo female with diffuse neck pain Radiates bilateral arms No weakness or numbness Slightly hyperactive reflexes Negative Spurling s

33 C 5-6 C 5 C 6-7 C 6 C 7

34 Discography

35 Discography

36 Discography

37 Neck pain and radiculopathy into arms Key Factors Interscapular pain Cloward Disc herniations of lower cervical levels induced spasms of para-scapular muscles Motor/sensory exam not localizing Myelopathic with hyperactive reflexes Negative Spurling s Positive discogram Reproduced pain at levels and no pain at adjacent levels Concordant MRI

38 Anterior Cervical Discectomy and Fusion

39 C 5 C 6

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42 Case Example 58yo female with right lateral hand numbness, and weakness Pain thenar eminence, no neck/arm pain Weakness in opponens pollicis Numb in first 3 ½ digits No reflex abnormalities Negative Spurling s sign, +Phalen s/tinel s

43 Tinel s Test

44 Phalen s Test

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46 NCS Latency < 2.3 ms or difference <0.3ms demyelination Normal Abnormal Amplitude >15μV (ulnar) or >50μV (median) axonal Courtesy of Simon Oh, MD Colorado Neurology Specialists

47 Key Factors No neck pain or radiculopathy Pain present in hand Weakness in muscles supplied by one peripheral nerve branch Sensory deficit in one peripheral nerve More than 1 spinal root involved (C 6 and C 7 ) Reflexes normal Positive Tinel s and Phalen s Concordant NCS

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52 Case Example 60yo female with left hand numbness and weakness Weakness hand intrinsics Clawing present Left pinky weak adduction Numbness 4 th and medial 5 th digits Reflexes normal Mild neck pain without radiculopathy No hand pain 4 Issues Neck pain No radiculopathy, but DM Prior dx carpal tunnel Motor/sensory findings ulnar problem Negative Spurling s PMHx- Long standing poorly controlled diabetes History of left hand carpal tunnel release No symptom improvement

53 Wartenberg s Sign Ask patient to adduct fingers Pinky finger of affected hand cannot adduct Patient may notice pinky caught on pant pocket Ulnar innervated palmar interossei weak

54 Ulnar Clawing Ask patient to leave fingers at rest 4 th and 5 th metacarpal-phalangeal joints extend while interphalangeal joints slightly flex but are somewhat paralyzed Weak medial lumbricales and 3 rd /4 th flexor digitorum profundus (both ulnar innervated)

55 Froment s Sign Ask patient to adduct the thumb and index finger so the finger pads touch Patient flexes interphalangeal joint and finger tips touch Ulnar innervated adductor pollicis weak so ulnar/median innervated flexor pollicis brevis compensates

56 Testing flexor digitorum profundus 3 and 4

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58 Tinel s Test

59 C 4-5 C 5-6 C4 C 5 C 6-7 C 6 C 7 -T 1 C 7 T 1

60 Stimulate ulnar nerve transcutaneously and record EMG/NCS of abductor digiti minimi Across elbow Across wrist

61 NCS Decreased amplitude (>6mV) Conduction velocity delayed (>51m/sec) Courtesy of Simon Oh, MD Colorado Neurology Specialists

62 Key Factors Minimal neck pain, but no radiculopathy into arms 60 yo so very common symptom Weakness of hand intrinsics supplied by ulnar nerve only Maintained median nerve function Sensory loss in ulnar nerve distribution Radial half of ring finger spared- not C 8 palsy No reflex abnormalities No pain or numbness in median nerve distribution to suggest carpal tunnel syndrome Failed prior carpal tunnel release Negative Spurling, but +Tinel s test at elbow NCS concordant with ulnar neuropathy at elbow Non-concordant MRI with spinal root palsy

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64 Biceps m. Medial epicondyle Tricepts m. Olecrenon Biceps m. Proximal Distal Tricepts m. Ulnar nerve Medial epicondyle Olecrenon Two heads of flexor carpis ulnaris m.

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70 NCS Preoperative Postoperative Courtesy of Simon Oh, MD Colorado Neurology Specialists

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72 Preoperative Postoperative

73 Thank You