US Guided Nerve Blocks of Upper Extremity in the 21st Century: New Techniques and Management - SD

Introduction

My name is Dr. Kho Gandhi. I'm from Thomas Jefferson University in Philadelphia, Pennsylvania.

I am an assistant professor of anesthesiology and director of Regional Anesthesia.

Today I'll be talking about ultrasound guided nerve blocks of upper extremity.

My presentation today, I will be talking about benefits of regional anesthesiology.

Specially I will talk about nerve stimulation and ultrasound guidance in localizing peripheral nerves.

And the common upper extremity blocks that I'll talk about is intra scaling supraclavicular infraclavicular and axillary nerves.

And I will also talk about management of continuous catheter for peripheral nerve blocks.

Benefits of Regional Anesthesia

Regional anesthesia has gained a lot of attention in the last 10 years due to the advancement in ultrasound technology.

Now we are able to visualize peripheral nerves with ultrasound and able to block these nerves for anesthesia purposes.

And some studies have shown that outcomes may be better with regional anesthesia.

Evidence from Studies

So where is the evidence? HUD and colleagues first published in 2005 in anesthesiology, that patients who have upper extremity surgery such as rotator cuff surgery have better outcomes.

And those outcomes are these patients are able to bypass pacu.

They are able to have less pain when you compare these patients to general anesthesia.

They require few treatment of pain and have less nausea, vomiting, and have faster ambulation, and are able to have faster intake of solids and fluids as well as go home quickly so that they do not spend a lot of time in the hospital setting.

And this serves as an advantage to the hospital system as well as the patients.

Brian Feld also published in 2005, that patients who have upper extremity catheters have better mobility.

They have better elevation of their shoulder, and better range of motion in terms of elevation and external rotation when you compare to patients who have catheters versus patients who do not have catheters.

And this better mobility gives patients a faster rehabilitation.

Summary of Advantages

To summarize, the advantages of regional anesthesia are such that you have a greater recovery profile.

Patients have less pain, less nausea, vomiting, faster intake of fluids, faster ambulation, and faster discharge.

Modalities for Localizing Peripheral Nerves

Now, there are two forms of modalities used to localize peripheral nerves.

The older way of doing this was to use nerve stimulation to actually locate the nerve.

Now with ultrasound, we're able to actually visualize our needle when we go about blocking the nerves.

Nerve Stimulation

Nerve stimulation uses a technology where we send electricity to the peripheral nerve, which in return gives us a stimulus, a motor response, giving us an indication that we are close to the nerve.

Whenever a current is less than 2.2 milligrams, that may indicate that your needle may be too close to the nerve and may actually be intradural.

So that is something that we need to worry about.

However, nerve stimulation does not give us a reliable indicator of intravascular needle placement.

Ultrasound Guidance

The ultrasound probes that we need for regional anesthesia are we need linear or a convex probes.

The linear probes are great for superficial nerves.

While the convex are great for low frequency, convex offers the advantage of low frequency, which are what gives us the advantage of visualizing deeper peripheral nerves.

Nerve root needles can be advanced with an ultrasound probe within the in plain approach, which allows you to visualize the needle in terms of the longitudinal access so that you know where your needle is traveling.

The adder plane technique allows us to use the needle in the perpendicular, allows us to place the needle perpendicular to the transducer.

This sometimes does not allow us the ability to track the needle and for beginners, an in implant approach is sometimes better when doing peripheral nerve blocks.

Benefits of Ultrasound

So the benefits of ultrasound technology is that it reduces time to perform blocks, and this have all been shown in literature.

Use of ultrasound improves efficacy of nerve blocks, reduce onset time.

We are able to minimize the amount of drugs that we use and be able to visualize the local anesthetic spread, and we can also minimize vascular puncture and needle passes.

Disadvantages of Ultrasound

Some of the disadvantages of ultrasound that we have seen in regional anesthesia is that it does require some training and technology is expensive sometimes.

We, it requires assistance from nursing to assist us in nerve block.

And we still do not have advanced technology in ultrasound to make us be able to visualize intravesicular needle placement or intradural needle placement.

Comparison and Combined Use

And when you compare nerve stimulation to ultrasound, there's really no benefits of ultrasound, and I feel that the best way to utilize both of these techniques is to use a nerve stimulation in conjunction with ultrasound technology.

Equipment for Nerve Blocks

The equipment that's needed when you do nerve blocks are ultrasound machine, nerve stimulator, as well as local anesthetic and a stimulating needle with some sterile equipment such as sterile gauges and some iodine or chlorhexidine for prepping the skin.

Common Upper Extremity Blocks

Some of the common blocks of upper extremity that we conduct in a hospital setting are intra scaling brachial plexus block, which are great for shoulder arthroscopy, rotator cuff surgery, or anything that is above the elbow.

His supraclavicular block gives us a adequate anesthesia or analgesia of the lower arm, so anything that is below the elbow hand such as for AV fistula or orthopedic surgeries.

And for clavicular axillary blocks are also function similar to supraclavicular block and provide good anesthesia analgesia of the hand and forearm.

Anatomy of the Brachial Plexus

So to review some of the anatomy of the brachial plexus of the upper extremity, the brachial plexus is derived from C five, C six, C seven, C eight and T one of nerve roots.

These nerve roots pass between the anterior scaling and middle scaling muscles.

Whenever you do an intra scaling nerve block, you are blocking the nerve roots of the brachial plexus.

The roots then form and combine to become the trunks and the divisions of the brachial plexus at the level of the clavicle or below the clavicle.

When you do a supraclavicular nerve block, you're actually blocking the trunks and the divisions of the brachial plexus.

The divisions then form the cords, the cords form at the level of below the clavicle.

When you conduct an infraclavicular nerve block, the cord, there are three cords, the lateral cord, the middle cord, and the posterior cord.

And these cords give rise to the distal, the terminal nerve roots of the hand and the forearm.

This diagram again, demonstrates the brachial plexus, and I would like to highlight that the phrenic nerve is very close to the roots of the brachial plexus.

So when you do an intra scaling nerve block, you have a hundred percent paralysis of the phrenic nerve.

Also It is mandatory that when you do a block for shoulder surgery, you want to do an intra scaling nerve block because the suprascapular nerve comes very high off before the trunks, so that if you were to do a supraclavicular nerve block, you may not be able to block the suprascapular nerve.

Therefore, giving inadequate analgesia of the shoulder joint,

this is a dermatomal distribution of the upper extremity.

Your upper extremity is derived from the brachial plexus dermatomal layers.

One nerve that is not covered in the upper extremity by the brachial plexus is the intercostal brachial nerve.

The intercostal brachial nerve is actually derived from the T two.

So anytime you do a nerve block for upper extremity shoulder surgery, you will not be able to block the intercostal brachial nerve.

Patients may still have pain in the ax.

Interscalene Nerve Block

To talk specifically about intra scaling nerve block, the probe is placed transverse in the neck.

And what you actually visualize are the anterior scaling muscle and the middle scaling muscle between the two muscles are the hypoechoic nerve roots, which demonstrate your C five, C six, and C seven nerve root.

If your probe is placed more medial to this structures, you may actually be able to see the vertebral artery, which below C six can be visualized.

Above C six.

This vertebral artery enters the intervertebral foramen, and you are unable to visualize this artery.

So whenever doing nerve blocks below the C six, it precautions should be practiced so that your needle is not advancing to the vertebral artery.

This is a illustration video of how one goes about doing a intra scaling nerve block.

As you scan the neck, you could see the nerve roots, which are hypoechoic between the anterior and the middle scaling muscle and the nerve roots.

Then go to the supraclavicular area, which lie above the subclavian artery.

Again, this is the same illustration, starting from above the clavicle, you are able to visualize the plexus above the subclavian artery at the supraclavicular area, which actually is the divisions or the trunks.

And as you scan patients superiorly, you could see the nerve roots being formed between the anterior and the middle scaling muscle.

Now this video demonstrate how a single injection rascal nerve block is conducted.

A patient is prepped, ultrasound probe is placed, and you could visualize the brachial plexus in the neck area.

You can also visualize the carotid artery, which is more medial.

A local is given To numb the skin.

And then a insulating needle, which is attached to a nerve stimulator, is advanced towards the brachial plexus.

Once you advance toward the brachial plexus, you'll stimulate the axillary artery or the axillary nerves, and you will get a stimulus of the hand at that point.

You should inject the local anesthetic supra.

Supraclavicular Nerve Block

Supraclavicular blocks are done at the level of the clavicle.

What you visualize on the ultrasound machine is the subclavian artery and the plexus is laterally and superiorly to the subclavian artery.

Below the subclavian artery is the first rib, which is a hyper e coic line.

And below that is a lung, which is a second.

Hypo pleura is second hypo hypoechoic line with a dense black coloration.

When you do a supraclavicular nerve block, you are actually blocking these supraclavicular, your blocking the divisions and the trunks of the brachial plexus.

Infraclavicular Nerve Block

Infraclavicular nerve blocks are done below the clavicle.

The ultrasound probe is placed perpendicular to the clavicle.

And what you visualize is the axillary artery, which has been derived from the subclavian artery.

And you are able to see three hyperopic dots, the lateral cord, the posterior cord, and the medial cord.

The lateral cord gives rise to the musco cutaneous nerve and the median nerve.

The posterior cord gives rise to the radial and the axillary nerve.

Meanwhile, the medial cord gives rise to the ulnar nerve and the median nerve.

The approximate position of the cords along the axillary artery varies from proximal to the distal area, and the proximity of the artery.

The cords are lined up together as they travel distally.

They dispersed throughout the circumference of the axillary artery.

This video illustrates how a brachial plexus nerve block is conducted.

You could visualize the cords, which may be difficult to be seen, but they're hyper coic dots around the axillary artery.

And you could also visualize the axillary vein above the artery are the pec minor and the pec major muscle In terms of anatomy.

The cords are actually situated outside of the ribcage, so there's very low chance of pneumothorax long as your needle is traveling laterally, the cords are located below the clavicle and medial to the OID process anterior to the scapula.

This, again, this diagram illustrates how the cords are visualized on the ultrasound machine.

They appear to be hyper coic in terms of their appearance, and they're situated around the axillary artery.

Studies have shown that when you do a nerve block of the cords of the brachial plexus, you don't need to block all three cords.

You could position your needle behind the axillary artery, inject your local anesthetic near the posterior cord by injecting your local anesthetic near the posterior cord.

The anesthetic will disperse medially as well as laterally and be able to give you good analgesia.

If you are threading a catheter here, you could thread the catheter in the position of the posterior cord, and the catheter will stay there and provide continuous analgesia.

Sometimes a double bubble sign has been described to give you an efficacy of your infraclavicular nerve block.

When you see a injection of local anesthetic inferior to the artery, the posterior cord is pushed more posteriorly, and that gives an indication that the nerve block will give you high probability of success.

So the actual advantage of infraclavicular nerve blocks are that they provide greater coverage.

There is no need for arm abduction.

There's very low risk of pneumothorax, and there's very low risk of phrenic nerve paralysis.

And I particularly like infraclavicular nerve blocks for continuous catheter fixation,

Axillary Nerve Block

Axillary nerve blocks, which have been done for a very long time via the transarterial approach before ultrasound guidance, are now very commonly practiced with the ultrasound guidance.

Because you actually can visualize the terminal nerves in the axi, you are able to visualize the radial nerve, which is posterior to the axillary artery, as well as the ulnar and the median artery, which are more superficial.

It is to be pointed out that the muscle cutaneous nerve has already come off the brachial plexus, so you may not be able to block the mus cutaneous nerve.

When you do an axillary nerve block, the ultrasound probe is placed perpendicular through the axi.

And this video illustrates how a axillary nerve block is conducted.

The patient's arm is abducted, And the transducer is placed on the medial aspect of the arm or the axilla.

You could visualize the axillary artery with the medial nerve, the radial nerve, and the ulnar nerve around the artery.

You could go about and inject local anesthetic to numb the skin and then place a stimulating needle towards each one of the terminal nerve roots.

You could see the stimulating needle approaching the terminal nerve roots of the brachial plexus.

And you could see the twitch, the medial nerve twitch, the radial nerve twitch and the ulnar nerve twitch.

You could inject local anesthetic close to those nerve roots.

You need as little as one cc of local anesthetic to block those nerve roots.

The musculo cutaneous nerve lies within the belly of the corco brachialis muscle.

Studies have shown that there is some variability in where you actually find the muscle cutaneous nerve.

Sometimes it is near the axillary artery.

It may be joint to the joint or fused to the medial nerve, or it may well be within the belly of the cortical brachialis muscle.

This nerve needs to be identified separately on the ultrasound, which is often not too far away from the axillary artery.

And the nerve could be blocked with local anesthetic to give you complete analgesia of the arm in addition to the axillary nerves that we have blocked.

In terms of looking at studies, these axillary nerve blocks have been done in the er for procedures for procedural pains.

You could actually block the distal nerve roots such as the radial, the arm, and the medial nerve roots for hand procedures in the emergency departments.

And this procedures have shown success when taught to the emergency department personnel,

you could actually visualize the ulnar nerve as well as the median nerve in the forearm and the radial nerve and block these nerves separately.

For any procedures that utilize hand

Local Anesthetics

In terms of local anesthetic, we can use a short acting local anesthetic such as two chloroprocaine or lidocaine.

Or you could use a extended version of local anesthetic such as ropivacaine and bupivacaine.

You could also utilize additives such as bar bicarb and epinephrine.

Typically for post-surgical pain, we utilize 0.5% ropivacaine, which gives you an onset duration of 15 to 20 hours in my clinical practice.

And the onset for these drugs are 15 to 20 minutes especially for the ropivacaine.

Continuous Nerve Blocks

Continuous nerve blocks are utilized for prolonged intraoperative anesthesia for and for postoperative pain control In the hospital setting, continuous nerve blocks have shown reduced opioid requirements, reduced side effects from opioid use, and they really have decreased incidence of hypotension compared to neuroaxial catheter.

Patients are also able to tolerate physical therapy with continuous catheters.

More recently, ambulatory peripheral nerve catheters are used in our hospital settings to send patients home with pain pumps.

And these pain catheters are pulled by the patients at home on post op day two or three.

And studies have shown that complications are not really increased with these procedures.

Catheter Techniques

In terms of catheter techniques, we utilize two he needles for stimulating catheters, which are used to localize the nerve.

A bolus is given and a catheter is inserted through the tubing needle, and placed in the vicinity of the peripheral nerve.

This video utilizes a continuous catheter for intra scaling nerve block.

This patient was to have a upper extremity rotator cuff surgery done.

A continuous catheter technique was used to localize the brachial plexus.

The tui needle is inserted in line with the ultrasound probe.

You could see the toothy needle approaching the brachial plexus when it approaches the brachial plexus.

Patient will have stimulation if a stimulate nerve stimulator is used and a bolus is given via the two he needle.

And subsequently a catheter is inserted in the vicinity of the brachial plexus.

The catheter can be visualized on the ultrasound machine, and the catheter is then secured to the skin in a secure fashion.

Since this catheter is very superficial and has a high rate of dislodgement, so a care must be used when removing a catheter and securing to the skin.

In terms of the type of local anesthetic to use through the continuous catheter, you can use 0.2% as well as 0.4%, keeping in mind that they function the same.

So it is optimal to utilize a lower concentration local anesthetic so that you have analgesia as well as less incidents of motor block.

Conclusion

In conclusion, the practice of regional anesthesia utilizes both nerve stimulation and ultrasound technology to increase accuracy, success, and safety of regional anesthesia.

The use of ultrasound machine for nerve blocks require extra level of training and resources and regional anesthesia with ultrasound technology has proven to improve outcomes after upper extremity surgery.

Thank you.