Radiculopathy Flashcards

Question

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

Answer 1

Lumbar 62-90% L5 S1 Thoracic < 2% Cervical 5-36% of all radiculopathies

Answer 2

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

Answer 3

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

Answer 4

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)

Answer 5

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)

Answer 6

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.

Answer 7

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.

Answer 8

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

Answer 9

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

Answer 10

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)

Answer 11

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

Answer 12

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

Answer 13

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

Answer 14

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

Answer 15

ongoing denervation chronic denervation chronic If radiculopathy causes axonal damage, wallerian degeneration causes distal axon death. Neuropathic MUAPs = chronic denervation with subsequent reinnervation

Answer 16

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

Answer 17

Occurs proximally-to-distally Reinnervation begins after denervation Can be seen months to years after injury Results in neuropathic units