Radiculopathy Flashcards

1
Q

Radiculopathy is most commonly caused by compression of _____ or _____

A

nerve root, or disc herniation

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2
Q

What are the different degenerative changes of the spine (3)

A
  1. osteophytes
  2. facet hypertrophy
  3. ligamentous hypertrophy

also disc herniation or less commonly, trauma (root avulsion)

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3
Q

____ is the cutaneous area supplied by one sensory nerve root level

A

dermatome

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4
Q

Long thoracic nerve supplies which muscle

A

serratus anterior

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5
Q

subscapular nerve supplies which 2 muscles

A

teres major
subscapularis

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6
Q

which muscle does the lateral pectoral nerve supply?

A

pectoralis major

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7
Q

which two muscles does the axillary nerve supply

A

deltoid
teres major

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8
Q

what muscle does the dorsal scapular nerve supply

A

rhomboids

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9
Q

____ All the muscles that are innervated by a single ventral root

A

myotome

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10
Q

name the types of herniation:

A

Central

Paramedian (Lateral recess): subarticular (anterior SAP)

Foraminal (Far lateral): between pedicles

Extraforaminal: lateral to pedicle

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11
Q

Lateral herniation: compresses ____

Medial herniation compresses the _____

A

Lateral herniation: compresses the lower nerve root (radiculopathy)
Medi1al herniation: compresses the spinal cord (myelopathy)

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12
Q

midline herniaion compresses the

parasagittal herniation compresses the

far lateral herniation compresses the

A

Midline herniation: compresses the traversing nerve roots and/or cauda equina (L4-5 disc bulge = L5/S1/S2 radiculopathy)

Parasagittal herniation: compresses the traversing nerve root (L4-5 disc bulge = L5)

Far lateral herniation: compresses the exiting nerve root (L4-5 disc bulge = L4)

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13
Q

Most common location for disc herniation

type?

which nerve root?

A

posterolateral disc herniation

L4-5 disc herniation = L5 radiculopathy

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14
Q

Nerve root:

Pain location: paraspinal muscles, superior shoulder

Sensory disturbance: neck

Weakness: diaphragm, nuchal muscles, strap muscles

Reflex change: None

A

C3-4

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15
Q

Nerve root:
Pain location: neck shoulder, anterior arm

Sensory disturbance: shoulder

Weakness: deltoid, SS/IS, rhomboids, biceps, brachoradiolis

Reflex change: Biceps, BR

A

C5

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16
Q

Root:

Pain Location: neck, shoulder, anterior upper arm, extending to antecubital fossa

Sensory disturbance: Thumb, index finger, radial forearm

Weakness: deltoid, SS, IS, biceps, BR, PT, FCR, ECR

Reflex change:

A

Biceps, BR

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17
Q

all muscles are innervated by atleast 2 root levels except:

A

rhomboids C5

18
Q

Root:

Pain Location: neck, shoulder, dorsum of forearm

Sensory disturbance: middle finger

Weakness: triceps, lats, PT, FCR, ECR

Reflex change: Triceps

A

C7

19
Q

Root:

Pain Location: neck, shoulder, ulnar forearm

Sensory disturbance: ring, little fingers, hypothenar eminence

Weakness: intrinsic hand muscles, finger extensors, finger flexors

Reflex change: none

A

C8

20
Q

Root:

Pain Location: neck, shoulder, ulnar arm

Sensory disturbance: ulnar forearm

Weakness: intrinsic hand muscles (horners syndrome)

Reflex change: none

A

T1

21
Q

Root:

Pain Location: anterior thigh, groin

Sensory disturbance: anterior thigh

Weakness: iliopsoas, adductors, quads

Reflex change: knee

A

L3

22
Q

Root:

Pain Location: anterior thigh

Sensory disturbance: medial calf, medial foot

Weakness: quads, adductors (iliopsoas)

Reflex change: knee

A

L4

23
Q

Root:

Pain Location: Posteriolateral thigh and calf, extending into great toe and dorsum of foot

Sensory disturbance: dorsum of foot, great toe, lateral calf

Weakness: tib ant, tib posterior, ext hallucis longus, peronei, gluteus medius, TFL

Reflex change: None

A

L5

24
Q

Root:

Pain Location: posterolateral thigh and calf, extending into lateral toes and heel

Sensory disturbance: lateral foot, posterior calf, sole of foot

Weakness: gastroc-soleus, hamstrings, gluteus maximus

Reflex change: ankle

A

S1

25
Q

What is the most common radiculopathy?
1. with percentage
2nd most common?

A

Lumbar 62-90%

L5
S1

Thoracic < 2%

Cervical 5-36% of all radiculopathies

26
Q

What are the most common cervical radiculopathies?

A

C7: 70%
C6: 19-25%
C8: 4-10%
C5: 2%

27
Q

What are the elecrodiagnostic criteria for radiculopathy? (3)

which gives definitive diagnosis?

A

Abnormal findings in two or more muscles that receive innervation from the same root, preferably via different peripheral nerves

Normal findings directly above and below the affected root level

Definitive Diagnosis: paraspinal involvement

28
Q

what is the protocol for assessing radiculopathy

A

1 At least 1 motor and 1 sensory NCS in most relevant area
(If abnormal, or if polyneuropathy suspected, further evaluation should be performed of either ipsilateral or contralateral limbs to define the cause of the abnormality)

2 Examine at least 5 muscle of involved limb

3 Examine at least 1 muscle innervated by each root level
- Examine 1 or 2 additional muscles innervated by the suspected root and a different peripheral nerve
- Demonstrate normal muscles above and below the involved root

4 Examine paraspinal muscles (except for sacral radiculopathies or prior posterior spine surgery)

29
Q

Which is the deepest paraspinal muscle?

a. semispinalis
b. multifidus
c. longissimus
d. spinalis

why is it tested during radiculopathy exams

A

b multifidus

Considered by some as the only paraspinal muscle one to have monosegmental innervation but overlap likely exists

Abnormalities are not pathognomotic of radiculopathy

other disorders can cause paraspinal abnormalities (diabetes, motor neuron disease, local muscle trauma, etc)

30
Q

on radic study, if needle EMG abnormal, what should you do next? (2)

A

If needle EMG abnormal, needle 1 or more contralateral muscles

Perform median F-waves and compare with contralateral side if necessary

Option 1: to exclude bilateral radiculopathy, or to differentiate b/t radiculopathy and polyneuropathy, motor neuron disease, etc.

31
Q

what are the typical findings on sensory and motor NCS for radic?

A

sensory - normal

motor: Usually normal unless severe axonal loss leads to reduction in amplitude

SNAPs normal b/c continuity b/t peripheral nerve and cell body (DRG) remains intact… so Wallerian degeneration does not occur

Disc herniation proximal to the dorsal root ganglion results in sparing of the continuity between the distal sensory nerve fibers (to digits) and the cell body within the dorsal root ganglion.

32
Q

H reflex for S1 radiculopathy;

Significant if
- latency difference > _____
- Amplitude difference if > _____

Relevance:
Sensitivity:
Specificity:

A

Significant if:
- Latency difference > 1.0-1.8ms

  • Amplitude difference > 50%

Relevance:
- Sensitivity: 36.4% if absent, 18.2% if asymmetric

  • Specificity: 91% if absent, 100% if asymmetric

So helpful if positive due to high specificity

33
Q

Why are F-waves so low in sensitivities

A

Sensitivity low b/c:
Only assess motor fibers
Affected portion of pathway is so small compared with total pathway being assessed, abnormalities may be obscured
The muscle tested also contains motor axons derived from more than one root, so any slowing may be masked by normal conduction along fibers traversing the unaffected root. I.e., the shortest latency (which is what is measured) may just represent the healthy axons

specificity is anywhere between 62-95.5 depending upon study

34
Q

Needle EMG for lumbosacral radiculopathy:

Sensitivity:
Specificity:
PPV:
NNV:

A

Sensitivity: 29-92%
Specificity: 37-100%
PPV: 66-100
NNV: 33-66

Research results vary depending upon ‘gold standard’ used (MRI, surgical visualization, history, exam, etc)

Sensitivity goes way up if there is weakness (motor involvement) on exam

Sensitivity goes up with more muscles tested (to a certain point)

35
Q

Needle EMG for cervical radiculopathy:

Sensitivity:
Correlation with radiological findings:

A

Sensitivity (moderate): 50-71%
Correlation with radiological findings (high specificity): 65-85%

36
Q

The study of paraspinals improves ______

Limitations:
- Sensitivity:
- Specificity:

A

Improves localization

Limitations:
Sensitivity: 50-66%
Specificity: 85-90%

Localization: suggests lesion proximal to plexus

  • Can occur in normal aging/asymptomatic patients
  • Should not be used as sole criteria for diagnosis
  • Cannot exclude radic if findings are absent
37
Q

What are three factors affecting EMG findings?

A

Muscle sample selection
Timing
Type of fibers involved (sensory, motor, both)

38
Q

what is the goal for muscle selection for EMG (radic study)

A

find 2 muscles innervated by the same root level but different peripheral nerve while demonstrating that the level above and below are normal

39
Q

PSW/Fibs indicate _____

CRD indicate ____

Neuropathic MUAPs indicate ____

A

ongoing denervation

chronic denervation

chronic

If radiculopathy causes axonal damage, wallerian degeneration causes distal axon death.

Neuropathic MUAPs = chronic denervation with subsequent reinnervation

40
Q

What will you see on EMG during denervation process?

1 week

3 weeks

5-6 weeks

A

1 week
- Reduced recruitment (can be seen immediately)
- Paraspinals with PSWs and fibs

3 weeks
- Proximal limb muscles with PSWs and fibs

5-6 weeks
- Distal limb muscles with PSWs and fibs

  • Proximal-to-distal sequence
41
Q

Reinnervation occurs ____ direction

begins after _____

Can be seen ______ after injury

Results in ____ units

A

Occurs proximally-to-distally

Reinnervation begins after denervation

Can be seen months to years after injury

Results in neuropathic units