Upper extremity nerve block

Question 1

Compared to bupivicane, ropivicaine ability to provide differential block sensory in epipotent doses is better or worse? Also compare the duration of action of these two

Answer 1

It has been suggested that ropivacaine provides more profound sensory than motor block as compared with bupivacaine, and ropivacaine has also been shown to have a slightly shorter duration of action as compared with bupivacaine

Question 2

What dose of clonidine can be added to peripheral nerve blocks? What does clonidine do when used as an additive?

Answer 2

Clonidine is an α2-agonist that has been shown to provide prolongation of peripheral nerve blocks when used in doses between 10 and 150 μg.18,19 This prolongation is more sensory than motor in nature and provides a relatively small increase in duration of bupivacaine when compared with the shorter-acting local anesthetics such as lidocaine and mepivacaine.18,19 The “ideal” dose has not been conclusively demonstrated; however, with increasing dosages, there are increasing side effects.19 Most notable are hypotension, bradycardia, sedation, and low body temperature

Question 3

What nerve roots comprise the brachial plexus?

Answer 3

The brachial plexus is derived primarily from the cervical nerve roots of C5, C6, C7, C8, and T1, although there are variable contributions from C4 and T2 as well

Question 4

Which muscles do the nerve roots emerge from?

Answer 4

Anterior and middle scalene

Question 5

At what anatomical landmark do the brachial plexus trucks start to form the divisions?

Answer 5

at the level of the clavicle

Question 6

At what anatomical landmark do the brachial plexus divisions start to form cords?

Answer 6

Once the brachial plexus passes under the clavicle, at the lateral border of the first rib, the divisions combine to form the medial, posterior, and lateral cords around the subclavian artery

Question 7

Please draw out the brachial plexus.

Question 8

From which nerve roots does the deep cervical plexus arise from?

Answer 8

r origins from the anterior rami of C2, C3, and C4

Question 9

From which nerve roots does the superficial cervical plexus arise from?

Answer 9

origins from the anterior rami of C2, C3, and C4

Question 10

Where do the superificial and deep cervical plexus live?

Answer 10

lie directly under the sternocleidomastoid muscle

Question 11

What does the superficial cervical plexus give sensory innervation to?

Answer 11

It is the superficial plexus that innervates the skin of the neck, posterior head, and superior shoulder

Question 12

What landmarks would you look for to do a superficial cervical plexus block?

Answer 12

To block the superficial cervical plexus, asking the patient to lift their head should identify the lateral border of the sternocleidomastoid muscle. The midpoint of this border should be marked. The needle should then be advanced approximately 1 cm deep to the sternocleidomastoid muscle. It then can be withdrawn slightly and then redirected superior and inferior along the lateral border of the sternocleidomastoid muscle

Question 13

What landmarks should you look for when performing an interscalene block?

Answer 13

The interscalene groove may be palpated by moving one’s fingers posterior and laterally from the lateral edge of the sternocleidomastoid muscle at the level of the cricoid cartilage

Question 14

Describe how to perform an interscalene block using nerve stimulation.

Answer 14

a needle is advanced in the interscalene groove at a 45-degree angle caudad and slightly posterior. A contraction of the shoulder or arm should be elicited if using nerve stimulation or a paresthesia over one of the dermatomes of the plexus if using only a blunted needle

Question 15

Where does the phrenic nerve lie around the area when performing an interscalene block?

Answer 15

The Also the phrenic nerve lies on the anterior border of the anterior scalene muscle

Question 16

What nerve distribution does the interscalene block usually miss?

Answer 16

when performed correctly, the interscalene block should spare the ulnar distribution; thus it is not an appropriate block for surgeries distal to the elbow

Question 17

What are major risks of performing the interscalene block?

Answer 17

The interscalene block also carries an almost certain risk of transient ipsilateral diaphragm paralysis and thus should be avoided in patients whose respiratory mechanics are depleted to such an extent that the loss of diaphragm mechanics would cause them respiratory distress. There is also a risk of ipsilateral Horner syndrome (ptosis, miosis, anhidrosis). There is also a small risk of injection into the vertebral artery or the intrathecal space; thus equipment for emergent airway management should be readily available when performing this block

Question 18

Describe the plumb bob technique of performing a supraclavicular block

Answer 18

The “plumb bob” or vertical technique is another landmark technique that was developed as a way to simplify the anatomical landmarks needed for the block. Once again the patient should turn his or her head away from the side being blocked and be in the supine position. The patient should be asked to raise his or her head off of the pillow in order to identify the insertion point of the lateral sternocleidomastoid muscle with the clavicle. The needle should be inserted directly superior to the clavicle at this point; however, unlike the classic approach, the needle will now be directed perpendicularly to plain of the floor. A paresthesia or nerve twitch of the fingers should be elicited. If neither of these end points is achieved on the first pass, but the first rib is contacted, you may walk along the rib in an anterior-posterior direction. The needle should never be directed medially in order to avoid puncturing of the pleura.

Question 19

Describe the coracoid landmark technique for performing an infraclavicular block

Answer 19

The coracoid technique requires the coracoid process being palpated and marked. The insertion site will be 2 cm caudad and 2 cm medial to that mark at the coracoid process (Fig. 49-21). The needle should be directed posterior until a nerve twitch or the muscles of the hand or a paresthesia is elicited, which should occur at a depth of 4 to 5 cm

Question 20

How can you do a landmark technique for the radial nerve distal to the other brachial plexus blocks

Answer 20

With conventional landmark techniques, the radial nerve is approached in the antecubital fossa. A line should be drawn between the 2 epicondyles. The biceps tendon should be identified. The needle insertion site should be inserted 1.5 to 2 cm lateral to the biceps tendon along the line connecting the 2 epicondyles, and 3 to 5 mL of <!--This node is not processed by any templates: dx-->local anesthetic should be injected in a “fan” lateral to medial

Question 21

Describe the approach of a landmark technique for the median nerve around the elbow area.

Answer 21

A line should be drawn between the 2 epicondyles. The traditional landmark technique requires the identification of the brachial artery by palpation or Doppler ultrasound. Once the brachial artery has been identified on the intercondylar line, 3 to 5 mL of <!--This node is not processed by any templates: dx-->local anesthetic should be injected medial to the brachial artery pulse. A paresthesia or nerve stimulation of wrist flexors should be the end point before injection, although an injection in a fan pattern may be effective

Question 22

Please review cutaneous innervation of the upper extremity with Netter