33: Brachial Plexopathy

Question 1

What tumors could invade the brachial plexus?

Answer 1

Pancoast tumor;
lymphomas, breast cancer, lung cancer metastasize to lymph nodes;
lymphoma and leukemia infiltrate nerve;
Schwannomas and neurofibromas are primary nerve sheath tumors

Question 2

Which nerves are more frequently involved in neuralgic amyotrophy?

Answer 2

Suprascapular > long thoracic > AIN > axillary > musculocutaneous > PIN > radial (SLAAX)

Question 3

What can NA originate from?

Answer 3

Environmental factors (immune triggers), mechanical factors, genetic susceptibility

Question 4

What can come about after CABG or other chest surgery?

Answer 4

Brachial plexopathy affecting the lower trunk in particular

Question 5

Beyond what dose of radiation is it common to see radiation plexopathy?

Answer 5

5700 rads

Question 6

What are two risks of stimulating at Erb’s point or the axilla?

Answer 6

Risk of co-stimulation and not ensuring supramaximal stimulation

Question 7

How fast do myokymic bursts fire? What are their frequencies within bursts?

Answer 7

.5-2 secs;
20-70 Hz

Question 8

With NA, what can happen with axonal wipeout and subsequent reinnervation on EMG?

Answer 8

Small, short, polyphasic MUAP’s with reduced recruitment (nascent potentials)

Question 9

On U/S, what can be seen with the C6 foramen vs. the C7 foramen?

Answer 9

C6 has both anterior and posterior tubercles with a larger and broader groove relative to C5;
C7 only has the posterior tubercle basically

Question 10

Some U/S findings for NA?

Answer 10

1. Swelling without constriction
2. Swelling with incomplete constriction
3. Swelling with complete constriction
4. Fascicular entwinement