Regional Quiz #3

Question 0

In response to a Sciatic nerve block, what is the interpretation if you make contact with the bone but you do not get a local twitch of the gluteus muscle, what is the problem and what action should you take?

Answer 0

The needle is inserted close to the caudal aspect of the iliac bone or the lateral aspect of the sacrum. The problem is caused by needle insertion to superior or medial. You should redirect needle slightly laterally and more caudally.

Question 1

In response to a Sciatic nerve block, what is the interpretation if you get a local twitch of the gluteus muscle, what is the problem and what action should you take?

Answer 1

Your needle is too shallow, so you are getting direct stimulation of the gluteus muscle and so you should continue advancing the needle.

Question 2

In response to a Sciatic nerve block, what is the interpretation if you make contact with the bone and you get sciatic twitches? What should be your response if this happens?

Answer 2

Because the needle was inserted too laterally(towards the hip joint), or medially(towards the ischial bone), the needle missed the sciatic plane and has hit either the hip joint(too lateral) or the ischial bone(too medially). You should withdraw the needle and redirect either slightly laterally or medially 5-10 degrees.

Question 3

In response to a Sciatic nerve block, what is the interpretation if you get a local twitch of the hamstring muscle, what is the problem and what action should you take?

Answer 3

There is no problem, you should accept and inject as the hamstring is within the sciatic nerve sheath at this level. What is being elicited by a hamstring twitch is stimulation of the main trunk of the sciatic nerve.

Question 4

In response to a Sciatic nerve block, what is the interpretation if your needle is inserted really deep(10 cm) but you have not elicited any twitches and you have not hit bone? What should you do next?

Answer 4

Due to inferior needle placement, the needle has passed through the sciatic notch. You should withdraw the needle and redirect slightly laterally or cephalic.

Question 5

In response to a Sciatic nerve block, what is the interpretation if you get paraesthesia of the genital organs, what is the problem and what action should you take?

Answer 5

The problem is too inferior or medially needle placement. The needle is stimulating the inferior root of the sacral plexus(pudendal nerve). You should withdraw and redirect slightly more laterally or cephalic.

Question 6

What are the acceptable twitches for a successful sciatic nerve block? At what mA is it acceptable to accept and inject?

Answer 6

hamstring, calf, foot or toes;

ceasing between 0.2 - 0.5 mA

Question 7

What are two local anesthesia agents used for sciatic nerve blocks?

Answer 7

0. 5% bupivacaine

0. 5% ropivacaine

Question 8

For a Sciatic nerve block, what is the onset, duration of anesthesia and duration of analgesia of 0.5% Ropivacaine?

Answer 8

Onset 15-20 minutes
Duration of anesthesia 6-12 hours
Duration of analgesia 6-24 hours

Question 9

For a Sciatic Nerve Block, what is the onset, duration of anesthesia and duration of analgesia of 0.5% Bupivacaine?

Answer 9

Onset 15-30 minutes
Duration of anesthesia 8-16 hours
Duration of analgesia 10-48 hours

Question 10

What 7 muscles are affected by the tibial nerve?

Answer 10

• biceps femoris
• semitendinosus
• adductor magnus
• popliteus
• gastrocnemius
• soleus
• flexors of the foot

Question 11

What motions are elicited when the tibial nerve is stimulated?

Answer 11

• knee extension
• plantar flexion
• toe flexion

Question 12

Where are 5 areas where sensations are elicited by the tibial nerve?

Answer 12

• heel
• sole of foot
• hip
• knee
• ankle

Question 13

What 5 muscles are affected by the peroneal nerve?

Answer 13

• biceps femoris
• peroneus longus
• peroneus brevis
• extensors of the foot
• extensors of the toes

Question 14

What motions are elicited when the peroneal nerve is stimulated?

Answer 14

• knee flexion

- foot flexion

Question 15

Where are 4 areas where sensations are elicited by the peroneal nerve?

Answer 15

• anterior leg
• dorsum of the foot
• knee
• ankle

Question 16

Stimulation of the femoral gives you knee _____?

Answer 16

Knee extension

Question 17

Stimulation of the sciatic nerve gives you knee _____?

Answer 17

Knee flexion

Question 18

What segments of the tibial nerve is responsible for muscle motion and sensation?

Answer 18

L4-L5,S1-S3

Question 19

What segments of the peroneal nerve is responsible for muscle motion and sensation?

Answer 19

L4-L5,S1-S2

Question 20

What is the largest peripheral nerve in the body?

Answer 20

The sciatic nerve

Question 21

What nerve roots form the sacral plexus?

Answer 21

Ventral Rami of L4, L5 -S1-S3

Question 22

What is the origination of the tibial nerve?

Answer 22

L4, L5, S1-S3

Question 23

What is the origination of the common peroneal nerve?

Answer 23

L4, L5, S1 and S2

Question 24

Which is most lateral, the common peroneal nerve or the tibial nerve?

Answer 24

The common peroneal nerve

Question 25

Whats the indication for a sciatic nerve block?

Answer 25

Lower limb surgery

Question 26

What are 2 other blocks that the sciatic nerve block is often combined with as a supplement block?

Answer 26

1. Femoral block | 2. Psoas compartmental block

Question 27

What are 5 contraindications to a sciatic nerve block?

Answer 27

1. patient refusal 2. local infection at site of injection 3. coagulopathy 4. preexisting central or peripheral nervous system disorders 5. allergic to the local anesthesia

Question 28

How many nerves stem from the sacral plexus?

Answer 28

7 nerves, 6 collateral branches and 1 terminal branch which is the sciatic nerve. The sciatic nerve is the largest peripheral nerve in the body.

Question 29

What type of surgeries is the posterior approach of the sciatic good for?

Answer 29

knee, calf, Achilles tendon, ankle and foot

Question 30

What complimentary blocks used in conjunction with a block of the sciatic nerve can be used to block the entire leg?

Answer 30

Femoral block | Lumbar plexus block

Question 31

After a successful block of the leg, what can be some issues after surgery is over?

Answer 31

There will be an inability to move the affected leg/foot. The patient will also be unable to have knee flexion. They will probably need a knee brace, walking boot and crutches

Question 32

What position should the patient be in for a sciatic nerve block?

Answer 32

lateral decubitus with a slight tilt forward

Question 33

What is the technique for performing a sciatic nerve block?

Answer 33

sterilize area, insert needle perpendicular to the skin, set stimulator to 1.5 mA, first visible twitches will be the gluteal muscles, once twitches of the calf, foot or toes is elicited decrease current

Question 34

What are the 3 major landmarks that needs to be identified for a Sciatic Nerve Block?

Answer 34

1. Greater Trochanter 2. Posterior Superior Iliac Spine 3. Sacral Hiatus

Question 35

In what 2 instances should LA not be injected during a sciatic nerve block?

Answer 35

1. when patient complains of pain | 2. when an abnormally high amount of pressure is needed to inject

Question 36

What is a Popliteal nerve block used for?

Answer 36

To block Sciatic nerve, used for excellent anesthesia of the calf, tibia, fibula, ankle and foot

Question 37

What is a Popliteal nerve block usually utilized for?

Answer 37

For anesthesia/analgesia for surgeries involving the foot, ankle and the lower leg

Question 38

How long does a Lateral Popliteal block with 0.5 mg of Bupivacaine last as opposed to an Ankle block with 0.5 mg of Bupivacaine?

Answer 38

Lateral Popliteal block last 18 hours versus an Ankle block lasting about 6.2 hours

Question 39

What are 5 indications for a Popliteal block?

Answer 39

1. corrective foot surgery 2. foot debridement 3. saphenous vein stripping 4. repair of the Achilles tendon 5. foot/toe amputation

Question 40

How does the Popliteal nerve block differ from the Sciatic nerve block?

Answer 40

As opposed to the more distal Sciatic nerve block, the Popliteal fossa nerve block anesthetizes the distal leg to the hamstring muscles, allowing patients to retain knee flexion.

Question 41

What two nerve trunks make up the sciatic nerve bundle?

Answer 41

The tibial(medial) nerve and the common peroneal(lateral) nerve.

Question 42

Of the two nerve branches of the sciatica, which of the nerves is the larger of the two divisions?

Answer 42

the Tibial nerve

Question 43

What are the terminal branches of the common peroneal nerve?

Answer 43

The terminal branches of the Common Peroneal Nerve is the Deep and Superficial Peroneal Nerves.

Question 44

What nerves come from the Tibial nerve?

Answer 44

Medial Plantar Nerve Lateral Plantar Nerve Sural Nerve Posterior Tibia Nerve

Question 45

When the nerves of the Common Peroneal branches are stimulated what responses are elicited?

Answer 45

Dorsiflexion and Eversion

Question 46

When the nerves of the Tibial Nerve Branches are stimulated what response is elicited?

Answer 46

Plantar Flexion and Inversion

Question 47

What is the only sensory nerve below the knee?

Answer 47

Saphenous nerve

Question 48

What part of the leg does a Popliteal Block affect?

Answer 48

It provides anesthesia of the entire distal 2/3 of the lower extremity with the exception of the medial aspect of the leg which is supplied by the Saphenous nerve, a superficial terminal branch of the femoral nerve.

Question 49

What position should the patient be in for the Popliteal Nerve Block?

Answer 49

Prone, with the foot protruding off the bed in order to detect even the slightest movement

Question 50

What are the landmarks for the Popliteal Nerve Block?

Answer 50

Popliteal Fossa Crease Tendon of biceps femoris(laterally) Tendons of semitendinosus and semimebranous(medially)

Question 51

How many cm above the crease between the tendons should the needle be inserted when performing a Popliteal nerve block?

Answer 51

7 cm

Question 52

How many mls of LA should be injected with any peripheral nerve block?

Answer 52

30 - 40 mls, just don't go higher than the toxic threshold.

Question 53

What movement is elicited by stimulation of the Common Peroneal Nerve(CDE)?

Answer 53

Common Peroneal Nerve Dorsiflexion Eversion

Question 54

What movement will be elicited by stimulation of the Tibial nerve?

Answer 54

Tibial nerve Plantar flexion Inversion

Question 55

What length insulated needle is used to perform a Popliteal Nerve block?

Answer 55

50 mm short bevel

Question 56

What size insulated needle is used to perform a Sciatic Nerve block?

Answer 56

100 mm 21G short belved

Question 57

For a Popliteal Nerve Block, what is the onset time of 0.5% bupivacaine? What is the duration of anesthesia and analgesia?

Answer 57

Onset time 15 - 30 minutes Duration of anesthesia 5 - 15 hours Duration of analgesia 6 - 30 hours

Question 58

For a Popliteal Nerve Block, what is the onset time of 0.5 % Ropivacaine? What is the duration of anesthesia and analgesia?

Answer 58

Onset 5 - 30 minutes Duration of anesthesia 4 - 8 hours Duration of analgesia 5 - 12 hours

Question 59

When doing a Popliteal Nerve block, what is the problem when a local twitch of the biceps muscle is elicited? What is the interpretation and what is the corrective action?

Answer 59

Direct stimulation of the biceps femoris muscle is due to a too lateral placement of the needle. Withdrawal the needle and redirect more slightly medially(5 - 10 degrees).

Question 60

When doing a Popliteal Nerve block, what is the problem when a local twitch of the semitendinosus/membranous muscle is elicited? What is the interpretation and what is the corrective action?

Answer 60

It is a result of a direct stimulation of the semitendinosus/membranous muscles and is a result of too medial placement of the needle. You should withdraw the needle and redirect more slightly laterally(5 - 10 degrees).

Question 61

When doing a Popliteal Nerve block, what is the problem when a local twitch of the calf muscle is noted when neither toe or foot movement is elicited? What is the interpretation and what is the corrective action?

Answer 61

This is a result of stimulation of the muscle branches of the sciatic nerve. The problem is these muscles are often outside the sciatic sheath. One should disregard and continue advancing needle until twitches of the foot and toes is elicited.

Question 62

When doing a Popliteal Nerve block, what is the problem when you puncture the vascular? What is the interpretation and what is the corrective action?

Answer 62

Blood in the syringe indicates puncture of the popliteal vein or artery. The problem is too medial needle placement. The anesthesia provider should withdraw the needle and redirect more laterally.

Question 63

When doing a Popliteal Nerve block, what is the problem when the needle makes contact with bone? What is the interpretation and what is the corrective action?

Answer 63

The problem is too deep needle insertion. Either the nerve was missed or motor response was not appreciated and so the femur was hit by the needle. The needle should be withdrawn slowly and if no twitch is appreciated, the needle should be redirected.

Question 64

What is the most important complication of a Popliteal Nerve Block?

Answer 64

Avoid a combination of epinephrine in LA and application of a tourniquet over the injection site as it can lead to nerve ischemia.