Regional Quiz #3 Flashcards
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?
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.
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?
Your needle is too shallow, so you are getting direct stimulation of the gluteus muscle and so you should continue advancing the needle.
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?
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.
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?
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.
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?
Due to inferior needle placement, the needle has passed through the sciatic notch. You should withdraw the needle and redirect slightly laterally or cephalic.
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?
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.
What are the acceptable twitches for a successful sciatic nerve block? At what mA is it acceptable to accept and inject?
hamstring, calf, foot or toes;
ceasing between 0.2 - 0.5 mA
What are two local anesthesia agents used for sciatic nerve blocks?
- 5% bupivacaine
0. 5% ropivacaine
For a Sciatic nerve block, what is the onset, duration of anesthesia and duration of analgesia of 0.5% Ropivacaine?
Onset 15-20 minutes
Duration of anesthesia 6-12 hours
Duration of analgesia 6-24 hours
For a Sciatic Nerve Block, what is the onset, duration of anesthesia and duration of analgesia of 0.5% Bupivacaine?
Onset 15-30 minutes
Duration of anesthesia 8-16 hours
Duration of analgesia 10-48 hours
What 7 muscles are affected by the tibial nerve?
- biceps femoris
- semitendinosus
- adductor magnus
- popliteus
- gastrocnemius
- soleus
- flexors of the foot
What motions are elicited when the tibial nerve is stimulated?
- knee extension
- plantar flexion
- toe flexion
Where are 5 areas where sensations are elicited by the tibial nerve?
- heel
- sole of foot
- hip
- knee
- ankle
What 5 muscles are affected by the peroneal nerve?
- biceps femoris
- peroneus longus
- peroneus brevis
- extensors of the foot
- extensors of the toes
What motions are elicited when the peroneal nerve is stimulated?
- knee flexion
- foot flexion
Where are 4 areas where sensations are elicited by the peroneal nerve?
- anterior leg
- dorsum of the foot
- knee
- ankle
Stimulation of the femoral gives you knee _____?
Knee extension
Stimulation of the sciatic nerve gives you knee _____?
Knee flexion
What segments of the tibial nerve is responsible for muscle motion and sensation?
L4-L5,S1-S3
What segments of the peroneal nerve is responsible for muscle motion and sensation?
L4-L5,S1-S2
What is the largest peripheral nerve in the body?
The sciatic nerve
What nerve roots form the sacral plexus?
Ventral Rami of L4, L5 -S1-S3
What is the origination of the tibial nerve?
L4, L5, S1-S3
What is the origination of the common peroneal nerve?
L4, L5, S1 and S2
Which is most lateral, the common peroneal nerve or the tibial nerve?
The common peroneal nerve
Whats the indication for a sciatic nerve block?
Lower limb surgery