Ultrasound Guided Injections in the Musculoskeletal System - HD

Introduction

My name is Ron Adler.

I am a professor of radiology at New York University in Midtown Manhattan.

I work at a place called the Center for Musculoskeletal Care, which is part of the NYU Medical Center.

It's a dedicated outpatient orthopedic hospital or outpatient center.

What I'm gonna be talking about today is ultrasound guided interventions in the musculoskeletal system.

We're gonna start out with some background information and a few technical considerations.

Talk about some basics, what musculoskeletal anatomy looks like on ultrasound.

And then basically, by way of a series of clinical examples, show you the types of injections that we do.

Utility of Ultrasound

Of course, the utility of ultrasound is that allows excellent depiction of the soft tissues, tendons, muscles, and so forth.

It's tomographic, which means we have stereotactic placement of the needle in real time.

And of course, the real time aspect of ultrasound.

Perhaps one of the most important things 'cause it allows us to do continuous monitoring during needle placement, as well as follows the distribution of the injected material or aspirated material.

There is a contrast effect that we're gonna talk about in a few minutes that also can be beneficial when we do ultrasound guided interventions.

And also importantly, because ultrasound is not subject to things like susceptibility artifact or streak artifact that we would have an MRI or computer tomography.

It doesn't at all interfere with our ability to see soft tissues overlying orthopedic instrumentation.

And because of that, we can do a variety of procedures in patients who have who've had previous orthopedic procedures.

Technical Considerations

The important things is that you have a good sense of the equipment you're using.

The scanning techniques for musculoskeletal ultrasound imaging, how to optimize your imaging, and what optimal transducer do you optimally choose for any given procedure.

Knowledge of the sonographic anatomy is also very important when you're doing these types of procedures.

Sonographic Anatomy Basics

Let's talk about some basics to begin with.

Just to remind you that an ultrasound tendons appear echogenic and fibrillar as opposed to the low signal intensity appearance that we're used to seeing when we're looking at a magnetic resonance imaging.

And because of this fibrillary architecture that we see in tendons, tendons display a property known as anisotropy.

And what I mean by that is when the beam insulates perpendicular to the long axis of the tendon, the tendon will appear to be fairly bright or echogenic.

Whereas if it insulates at some angle, and it could be as little as five degrees, the tendon becomes progressively hypoechoic.

Now, this is important in interventions because if we're doing tendon sheath injections, we don't want to falsely interpret hypoechoic tendon is being fluid.

Since we don't want to, we wanna avoid doing an intratendinous injection.

So in as such, anisotropy is something we always need to be aware of when we're doing these types of procedures.

Muscles

Muscle alternatively to tendons tends to be hypoechoic.

We see a back sort of a hypoechoic background with the interspersed with these fine linear echogenic structures corresponding to the fiber adipose connective tissue as opposed to the intermediate signal intensity structure that we see when we're looking at the magnetic resonance imaging.

Bones and Joints

Bones, bones and joints.

Bones are strong specular reflectors that have posterior acoustic shadowing the junction of smoothly articulating surfaces.

We see as in depicted in this MCP joint or in this hip joint below, we may see a thin hypoechoic layer overlying the cortical surface corresponding to articular cartilage.

We may see presence of intraarticular fat or capsule, which generally appears echogenic on ultrasound.

So this is in the case of an MCP joint.

This is in the case of a hip joint where we have overlying echogenic capsule.

A little bit of fibrocartilage over here, which tends to appear echogenic and a thin hypoechoic layer overlying the articular surface of the femoral head.

Nerves

Nerves appears when we look at them in cross-section, look I sort of liken them to a cluster of grapes.

They, we see the hypoechoic fascicles separated by internal epineurium, which is the connective tissue, loose connective tissue that surrounds the nerve fascicles.

And they're surrounded by a hyperechoic layer called the outer epineurium that gives rise to that sort of echogenic layer.

And if we turn our transducer 90 degrees, so we're looking at the nerve in long axis, we see these hypofascial sort of elongated, and some people have likened this to a tram track appearance.

Ultrasound Guided Intervention Techniques

Now, the principle of doing ultrasound guided interventions, at least in my experience, we prefer to use a free hand technique where the object is to make the needle appear as a strong specular reflector.

One of the advances that we have is oftentimes metal has a characteristic strong reverberation artifact.

As we see in this needle over here, we want to optimally choose our needle position.

So I usually put a small offset in the skin relative to where the transducer is positioned, so we can see the needle as much as possible as a specular reflector, as is indicated here.

Just as in any other type of interventional procedure, we're gonna use the sterile technique.

So we're gonna have our tray set up ideally with sterile gel, sterile drapes, and so on, so that we can do the procedure sterilely.

Axis Approaches

Okay? By manner of I would like to introduce a little bit of nomenclature before we go on, you're gonna hear me use the term long axis and short axis, and I want to define what I mean by that.

So by long axis, I mean where the needle's going parallel to the long axis of either a joint or tendon.

So the typical example of that, for instance, will be the hip where I'm scanning longitudinally across the joint and my needle's going in the plane of the transducer.

So it's going in what I would consider the long axis of the joint as indicated in this injection below.

And typical examples of that would be hip injections and shoulder injections as we'll see in a few minutes.

But what I mean by short axis on the alternatively, is perpendicular to the long axis of a structure.

And the typical example of that is doing a retrocalcaneal bursa injection.

So in this example over here, you can see this is the Achilles tendon and long axis, what I'm doing is I'm scanning in short axis across the tendon, and I'm visualizing the needle as it comes in perpendicular to the tendon.

So since it's coming in perpendicular to the tendon, I refer to that as a short axis technique.

And this is what this would look like on ultrasound.

You see the tendon in cross section above, and you see the needle coming in in long axis, just the way we're visualizing here in this corresponding image.

And again, most importantly, we're always observing things in real time.

And so here's a long axis approach to hip injection, and you're gonna see we're gonna see distension of the joint capsule, and we see the presence of microbubbles going to the non-dependent surface.

So there's some internal contrast that we have just by virtue of what we inject.

'cause invariably there's small amount of air bubbles in the contained mixture.

Contrast Effects

Now, contrast can be from injecting microbubbles, but it can also be from the injectate itself.

So this is an example of injection of a tendon sheath in the dorsal aspect of the ankle.

And you'll see that there are echoes generated just by virtue of the therapeutic mixture.

And this has to do with the fact that many of us use this particulate suspension such as triamcinolone, a depomedrol, which when placed in an aqueous medium automatically produces an inherent contrast effect.

And we've estimated this to be as much as 20 dB increased contrast.

So what I mean by that is we'll see in the next example.

This was actually some work that we did a few years ago where we just simply looked at a cyst phantom.

And here you can see an anechoic cyst.

And this is the background over here.

And what happened is when we injected this mixture of steroid in anesthetic solutions, so it became sort of a suspension, as soon as you inject, you get this significant contrast effect.

And as you would expect since this particulate substrate that we're injecting, it will settle out over time.

And so you expect to see a gravitational effect.

So with time, you actually see a settling effect that occurs just simply by virtue of gravity.

And we in fact, looked at this a little bit more quantitatively.

So if this top line represents the background, and this upper line represents a lower half of the cyst, and this lower part here represents the upper part of the cyst, you notice that the contrast settles more rapidly in the upper part of the cysts, where it's taking a little bit more time in the bottom 50% of the cyst, as you would expect since we were not only losing contrast material, but we're also gaining it from the upper half.

And then eventually it falls off fairly dramatically once we've lost the contribution from the upper half of the cyst phantom.

So it's exactly what you would expect if we were seeing a gravitational effect due to settling of a contrast.

Types of Injections and Aspirations

Now there's a wide variety of types of injections and aspirations that we do in this table on the list.

This is by all means, not all inclusive, but gives you a pretty good idea of the kinds of things that we do fairly typically in our practice.

Joints: Small to Medium Joints

Now, let's start by talking about joints.

And we'll start with small to medium joints.

And these are basically the small joints of the ankle and foot, hands, wrist, and elbow.

Much of the time what we're gonna be injecting is a smaller amount of steroid.

I typically use something on the order of 10 to 20 milligrams of triamcinolone or methylprednisolone.

Sometimes with the upper extremity in particular where cosmesis becomes important, we'll use something that's more rapidly absorbed, such as celestone, because those types of steroids are less apt to produce depigmentation or skin atrophy.

We generally will use a short axis approach, a 25 gauge needle as satisfactory for virtually all these injections.

And we use a high frequency linear transducer.

So this would be the example of injecting how we would place our transducer for looking at the first MTP joint.

So that's what we'll do is our typical example of a short axis approach.

So here's this here in this image in the right lower corner, we see how the transducer would be positioned if we were doing a first MTP joint injection.

This will be a short axis approach.

So here we have the first metatarsal, the proximal phalanx.

There is actually a small joint body situated in the dorsal recess of the joint.

And then when I'm placing my needle in short axis 'cause of how I'm scanning along the long axis of the joint, you can only see the needle in cross section.

So you see a little echogenic focus with a strong reverberation artifact.

So we know that's the needle placement, and that's simply a joint body.

And then what we do is we perform our injection, and you can see the distension of the dorsal recess is indicated over here, and possibly some level echoes due to the contrast material that contrast effect that we spoke about a few minutes ago.

This is what this would look in real time.

So we have our needle in cross-section, and you can see the contrast effect from the injected steroid anesthetic mixture coming in.

We see the distension of the dorsal capsule.

So looking in real time, you have a nice for sure that you're getting intraarticular as well as you're nicely distending the joint.

We could apply the same principle to other small joints.

This is a base of thumb injection.

This is the first carpometacarpal joint.

This is the trapezium articulating with proximal first metacarpal.

This is what this would look like in a radiograph that you see in this image in the right lower corner.

And so let's see what this injection will look like.

So here's our baseline image over here.

Here's the trapezium.

Here's the base of the first metacarpal.

And this is placing my needle in short axis.

So you can see a little bit of reverberation artifact from where the needle's in position below the joint capsule, which is situated over here.

And then what we're gonna do is do our injection.

So we're gonna see the distension of the dorsal capsule as we see over here filled with the fluid.

And you see that contrast effect that we spoke about earlier, so that now we have a successful injection of the base of the thumb.

Joints: Hip and Shoulder

Typical injections that we do for long axis are the hip in the shoulder.

This is probably one of the more bread and butter injections we do fairly often.

We use generally use a larger amount of steroids, something on the order of 40 to 80 milligrams depending on the specific indication.

Use we'll use a spinal needle.

Generally we use 22 gauge for the majority of the injections that we do in a long axis approach, as I mentioned earlier, and the patient.

And depending on patient body habitus, we will use either a curvilinear or sometimes we need to use a sector transducer in order to see deeply enough.

So this is what this would typically look like if we were doing a hip injection.

You basically want to direct your needle to the femoral head neck junction right over here, since the capsule becomes a little more redundant distally.

So this is sort of the sweet spot, if you will, and it's a fairly broad target to aim for.

Once we place our needle in, you're gonna go in obliquely.

You can see the needle relatively well as a specular reflector.

You'll feel when you hit the cortex of the bone.

You can do a little test injection, make sure you get a field, a little microbubbles, a little fluid there with some anesthetic.

And then you know your intraarticular.

Then you can do your injection.

And you're gonna look for distension of the joint capsule.

You may see if there are microbubbles, they may go to the non-dependent surface of the joint, as we saw earlier in one of the video clips.

And in this case, the microbubbles are actually outlining this anterior labrum.

And sometimes that can actually give you a little bit of a contrast effect as well, and actually even show some potential labral pathology.

Glenohumeral joint injections we do with the patient decubitus.

The patient is lying on their side, so the shoulder is up, transducer is positioned posteriorly along the shoulder.

The needle comes sort of deep to the transducer, deep to the infraspinatus tendon and joint capsule.

This is what this would look like if we when we position the patient.

And so this is what this will look like on a real time examination.

Here's the infraspinatus muscle belly, a thin echogenic capsule, the hypoechoic articular cartilage.

I like to place my needle tangential deep to the capsule, and I find that to be the easiest type of way to do these injections.

And then what we're gonna see as we had before, we're gonna see the as we're doing the injection, there'll be distension of the dorsal recess.

And you may see low level echoes flowing away from the needle tip corresponding to the contrast effect due to the fact that it's a suspension that we're injecting now.

Bursa and Tendon Sheaths

Bursa tendon sheaths, those are the synovial lined structures that we see throughout the musculoskeletal system.

We can categorize them as either deep or superficial.

The typical deep bursa that we're asked to inject or aspirate or Baker cyst or iliopsoas.

So bursa generally we'll use a spinal needle.

The approach may be a little bit more variable depending on which way we optimally see the cyst.

Although short axis is probably the one I tend to use more often.

Again, the transducer will vary depending on patient body habitus.

And as will the amount of steroids.

The superficial bursa, the typical example of that we saw before is a retrocalcaneal bursa or most tendon sheaths.

We can do these largely with a 25 gauge needle in a short axis approach, using a high frequency linear transducer, and generally a small amounts of steroids similar to what we would use in a small joint.

Deep Bursa: Baker's Cyst

So this is a typical Baker cyst.

This is seen in short axis, the needle head of the gastrocnemius muscles over here.

Gastrocnemius is over here.

This is the cyst that we see usually nicely distended this way.

Here's my needle situated within the cyst.

And then what we're gonna do is aspirate the cyst.

And so here's the collapsed cyst that we would see collapse during real time when we're observing in real time.

And I usually like to leave a little bit of fluid in there so I can see the needle tip still.

And then what I'll generally do is I'll put a small amount of steroid and anesthetic in there.

Deep Bursa: Iliopsoas Bursa

Iliopsoas bursa.

Oftentimes we're more in a position to inject these.

We rather than aspirate them because patients may have chronic groin pain due to stretching the tendon if they've had previous arthroscopic surgery or if they have an indwelling prosthesis.

So I would say probably greater than 90% of the time we're actually looking to find the bursa, rather to aspirate it.

Just to get you familiar with the anatomy, we generally look for the tendon at the level of the iliopectineal eminence of the hip.

You see the femoral head, you see it as a if you're looking at an MR, it'll be sort of an elliptical low signal intensity structure right by the femoral head neck head junction with the acetabulum on ultrasound.

Where we see is the echogenic reflector corresponding to that iliopectineal eminence.

The femoral head is over here.

This is the capsule.

And you see this elliptical echogenic area corresponding to iliopsoas tendon overlying iliopsoas muscle.

We see overlying that.

And the pectineus muscle is somewhat more medial.

So let's see what this injection will look like.

We come with a short axis approach.

I use a 22 gauge spinal needle.

And what I'm gonna do is come in laterally the neurovascular structures are situated medially.

So this way we avoid those structures.

So here's my needle coming in laterally go.

I tend to go just deep to the tendon.

I aim for the iliopectineal eminence.

And what you're gonna do is you're gonna do a test injection with some anesthetic.

And what I find helpful is that once you hit bone, you may wanna pull the needle back a little bit, feel look to feel that release.

And when you feel the release, you'll notice in real time, you're gonna start distending the bursa.

And once you start distending the bursa you're in right location, you can switch in and start putting your cortisone as I've done over here.

And this is that contrast effect that we see actually is a swirling phenomenon as we're doing the therapeutic injection itself.

The other scenario, of course, is aspirating the cyst.

And I tend to see this more often in patients that have indwelling hardware.

So here's an MR of a patient with an arthroplasty, the susceptibility artifact due to the metallic hip replacement.

You see this large collection that's complex over here in this axial image corresponding to a large distended iliopsoas bursa.

Here's a corresponding coronal image showing that bursa, and you can really see these are can be quite complex on MR.

What's good about ultrasound is that as I mentioned before, is the orthopedic hardware doesn't interfere with the ability to see the overlying soft tissues.

So here's the sagittal image on MR or that area.

You have all the susceptibility artifact that's something that can somewhat obscure the bursa corresponding ultrasound.

We have no difficulty this this is the metallic component with the reverberation artifact.

But notice how nicely we see this overlying bursa, as well as noticing the degree of complexity.

So sometimes we actually get a better sense of the complexity of the cyst on ultrasound than we can with MR, because we can much more easily see the fluid components.

Now the important thing to recognize, particularly with a large iliopsoas, is that sometimes you have displacement of the femoral nerve.

So it's important to remember what nerves look like.

This is actually the femoral nerve, which is displaced by mass effect.

So you wanna make sure if you're coming in here to a short axis approach, you wanna see that nerve so that you're not inadvertently sticking the nerve.

In this case, we saw the nerve very well, so we placed our needle underneath it to get to the various cystic components of the bursa that we can subsequently aspirate and then inject with the therapeutic mixture.

Superficial Bursa: Retrocalcaneal Bursa

We spoke before about the superficial bursa, and a typical example of that is a deep retrocalcaneal bursa.

So this is a short axis approach.

This is the Achilles tendon in cross section.

Here's the calcaneus.

I'm gonna advance my needle in short axis.

So the way my transducer's position, it's gonna you're actually gonna see the needle as a long axis structure going to whatever little bit of fluid you have.

If you don't see fluid, you're gonna go right where the tendon inserts on the calcaneus, you're gonna do a test injection with lidocaine, and usually you can find the bursa.

And once you find the bursa, you can put a little bit of lidocaine in there, give you a little bit of fluid standoff, and then you can put in your therapeutic mixture.

And as you inject the therapeutic mixture, you're gonna again see that contrast effect.

So this is what this would look like in short axis, if I was scanning along the long axis of the needle, if I turned my transducer along the long axis of the tendon, we're gonna see what we would expect to see in terms of the cross-section of the needle with that corresponding reverberation artifact situated within a distended retrocalcaneal bursa.

Tendon Sheath Injections

We use the same principle for other types of tendon sheath.

This is a long head of biceps tendon sheath injection, and we find that for distended biceps tendon sheaths, it's fairly simple just to scan over immediately over the long head of the biceps tendon sheath scan anteriorly come in from a lateral approach.

And since we see the fluid fairly well, we can avoid the tendon, thereby avoiding doing a intratendinous injection as I've indicated in this next image here.

And we can aspirate whatever fluid we see and then do our therapeutic injection as we did here.

And you see that contrast effect nicely distending the bicipital tendon sheath.

Now, what happens if the sheath is not well distended?

Well no situations we tend to go or find it more convenient to go directly into the rotator interval.

The rotator interval is actually surrounded by a pulley corresponding due to the coracohumeral ligament going superiorly and the superior glenohumeral ligament going inferiorly.

And what I find helpful to do is place the needle just between those structures adjacent to the tendon.

Do a test injection with lidocaine.

If it's going in easily, you have enough back pressure from the injection that it'll fill both the bicipital tendon sheath as well as fill the rotator interval.

This is what this approach would look like with the patient recumbent and externally rotated.

Now this is on an ultrasound.

Basically, when you're going in the rotator interval, you wanna find the tendon here, usually situated between two soft tissue structures.

This coracohumeral ligament above superior glenohumeral ligament below.

You're gonna go right to the margin, do a test injection, make sure it's smooth, flowing smoothly, and you're not getting intratendinous.

And once you do that, you can do your injection.

And this is this particular patient we scanned over the biceps tendon sheath after doing the injection.

This is the biceps tendon here, and you see the contrast effect from the nicely distended bicipital tendon sheath.

And in fact, you see echoes also going into the rotator interval.

And actually, it's very helpful to inject both these structures since both are implicated with patients in patients with bicipital tendinosis.

The same principle applies to other tendon sheath injections throughout the musculoskeletal system.

This is a posterior tibialis tendon sheath injection.

We I usually put the patient decubitus so that the medial side is up, and usually I go inframalleolar because oftentimes there's a small amount of fluid that you can go.

And if you have fluid, that's always a helpful thing to target.

If not, basically you're gonna place your needle into the where the expected location of the tendon sheath is, and you're gonna try to make a tendon sheath effusion initially with anesthetic, and then you're gonna do your therapeutic mixture, inject your therapeutic mixture.

So here's my needle coming in.

There's actually a little bit of fluid distending the tendon sheath here.

And after I do my injection, you're gonna see the contrast effect as the fluid is going in.

And then once we're done, we're gonna have nice distension of the tendon sheath, both in short axis here, as well as we're seeing in a long axis here.

And you can see the tendon margins very nicely.

So you get sort of a little bit of a sonographic effect by virtue of doing the injection as well.

De Quervain's tendonitis is a stenosing tendonitis that we see in the first dorsal compartment.

The issue that we have here is we both have the tendonitis, we tendinosis, and we have a thickened retinaculum.

So what I find helpful to do is to use a short axis approach.

Again, we tend to go distal to the retinaculum, oftentimes where there's a little bit of tendon sheath effusion.

This is what this would look like when we're setting the patient up again, we're gonna go, it's gonna be a short axis approach relative to the tendon location and the structures you want to be able to see.

And one of the advantages of ultrasound is you avoid the radial artery.

There's a cephalic vein as well as recurrent branch of the radial nerve.

And those structures are all can be seen on realtime examination so that you can avoid them when you do these injections.

And what I find particularly helpful is to go just distal to the extensor retinaculum in the first dorsal compartment.

And you can oftentimes see the radial artery as it courses into the snuff box.

And then you can avoid it very easily and place your needle aware of there's a little bit of fluid, or do a test injection as you need to, to distend the tendon sheath.

And once we've done that, and these are these two abductor pollicis longus tendons, we have nice distension of the tendon sheath.

The one caveat I would mention here is that occasionally you may have an intervening septum separating out these two structures.

Usually it's not difficult diagnostically to distinguish that there's a septum there.

So you may have to do one injection and potentially advance your needle to get into the other tendon sheath for the two tendons that occupy the first dorsal compartment.

Now, another type of injection that we do fairly often in our practice is the flexor hallucis longus tendon sheath injection.

Now these you typically see these in patients who do a lot of plantar flexion.

So ballet dancers are one particular group that we see often in our practice.

And they tend to do hyper plantar flexion and they're predisposed to get these posterior impingement syndromes, and they get they can get a stenosing tenosynovitis, similar to what we see in a De Quervain's patient.

And basically, this is where we're going posterior to the talus and calcaneus.

There's this retinaculum and right in this sulcus over here is where we often see tendinosis because of this constriction due to the retinaculum.

And this is the approach we would take.

Now because of the way the neurovascular bundle is situated, I'll usually scan medially and come in lateral to the Achilles tendon.

So let's see what that looks like anatomically.

So here's an MR, which shows the posterior sulcus of the talus and the flexor hallucis longus tendon.

My transducer is situated along the medial aspect of the ankle.

The Achilles tendon is situated over here.

I can see the neurovascular bundle over here.

And you can see the advantage of coming lateral to the Achilles tendon is that you can come in to the where the tendon's located, you can avoid the neurovascular structures.

And you see you still see the needle nicely as a specular reflector.

So this is what the corresponding anatomy looks like.

An ultrasound.

Here's the tendon, the neurovascular structures.

Achilles tendon is situated around over here.

And once we place our needle in laterally, we place it usually along the sulcus deep to the tendon.

We're gonna again do a test injection with 1% lidocaine, and we're gonna see distension of the tendon sheath.

And that's what we're looking for when we're doing these examinations.

You also I can't help but stress the feeling that when you're doing the injection, it feels almost like injecting a joint, so it should go in fairly easily.

Ganglion Cysts

Ganglion cysts are those cysts that we see.

Oftentimes the dorsal aspect of the wrist as well as the foot and ankle, although they can be anywhere in the musculoskeletal system, they're filled with this clear gelatinous material.

They can be very hard to palpation on physical examination.

So the needle and approach will vary depending on how the cyst is oriented and how thick the material is.

Sometimes you need to go in with a fairly large bore needle.

But sometimes you I've actually treated these with as little as a 22 gauge needle.

So it can be quite variable depending on how tenacious the material is you're injecting.

This was an example of a dorsal ganglion cyst of the talonavicular joint in which we took a dorsal approach.

And here's our needle coming into the cyst.

And then after we finish aspirating it, you see the cyst is collapsed.

Now this is a fairly simple situation where actually probably could have been done clinically as opposed to under ultrasound guidance.

The situation in which we really play a significant role is more the occult ganglion cyst, which is difficult to palpate, but these can be quite symptomatic.

And these are often occur in the dorsal aspect of the wrist of the dorsal scapholunate ligament.

This little cyst over here, for instance, was quite symptomatic for this patient, and was difficult to palpate.

But here's my needle come in actually using a long axis approach in this case into the center of the cyst.

We lavage it aspirated and usually what I'll do is I'll fenestrate the cyst afterwards to break up the wall and leave a little bit of cortisone.

And these patients, I'll typically use celestone as opposed to something like triamcinolone or depomedrol.

Parameniscal Cysts

Parameniscal parameniscal cysts or cysts that we see typically situated around the knee, the shoulder or the hip.

In the shoulder in particular they can be symptomatic 'cause they can cause a compressive neuropathy of the suprascapular nerve in the knee.

They cause pain more because of mechanical properties against adjacent structures.

We almost invariably associated with a fibrocartilaginous tear, although don't necessarily have to be, and the approach will be variable, depending again how the cyst is oriented.

So here's a this was a case of a parameniscal cyst that we have over here in a G medial meniscal tear.

This is an extended field of view image showing that cyst.

And then the and I'm imaging the cyst in short axis.

And you can see my needle coming in over here.

One of the things about these cysts is it can have a fair amount of echogenic debris within them.

So you may not be able to aspirate them completely, but at least you have a better sense of what you can and can't do, which is one of the again one of the features that's very helpful with ultrasound.

'cause I think you get a better sense of what the cyst contents are really like.

And this is after injecting.

This is the contrast effect of the appearance of microbubbles.

This is an example of a suprascapular cyst corresponding fluid sensitive sequence on a MR.

This is a coronal image showing this large suprascapular cyst and a branch of the suprascapular nerve usually passes right in this area.

And these patients can be quite symptomatic due to developing a compressive neuropathy.

Here's my needle coming and using a long axis approach to this supraspinatus muscle belly to get into the cyst.

And again, these are fairly easily approached under ultrasound guidance.

This is another supras.

This is another type of paralabral cyst.

This is in the posterior aspect of the shoulder, so called spinoglenoid notch on MR.

We're looking posteriorly.

So this is this notch that we see over here.

This is the infraspinatus situated above it.

On ultrasound I'm gonna look for this depression in the bone, the humeral head's over here.

And this is the cyst over here.

And as indicated by the asterisk.

And here's my needle tip that we place in the cyst.

We come into a sort of a long axis approach along the posterior aspect of the shoulder into the cyst.

And then here's the contrast effect.

So we know for sure that we're that our needle situated within the cyst and that contrast.

So that contrast effect is very reassuring to know that we in fact are in the right location.

We're gonna do our aspiration and injection.

Neuromas

Now, there are a variety of other types of injections that we do.

I've listed several here, neuromas perineural intratendinous muscle injections and so forth.

Let's briefly speak about several of these.

Neuromas are the so-called reactive pseudotumors that we have in our feet.

They form in the interdigital about the interdigital nerves, most commonly between the second and the second and third web spaces on ultrasound.

They appear hypoechoic over here.

We may see a thickened nerve going into them.

They're fairly characteristic, relatively easy to diagnose under ultrasound.

And what I'll generally do is place my needle.

You can go through either a dorsal or a plantar approach into the neuroma, use a 25 gauge needle, a similar to a similar amount of steroid as you would with a small joint injection.

And what you typically see is the needle placed here.

And you get that sort of contrast effect that we spoke about earlier, where the entire neuroma will brighten up as you do your injection.

And you also frequently will fill an associated intermetatarsal bursa at the time of the injection, which is not a bad thing because it gives the steroid keeps the steroids sort of in a contained space.

And these patients do quite well.

I would say about 80% of them actually get very good therapeutic relief.

This was a 19-year-old that had a neuroma the superficial peroneal nerve that were asked to do a therapeutic injection on see whether or not they would respond to potential nerve ablation.

And you see it as a small hypoechoic nodule.

Again, this is a this case this is a post-surgical neuroma and our needle's coming down to where the neuroma is located.

We're gonna inject in and around it, and you can see all the surrounding steroids.

So we basically go in into it as well as doing a perineural injection as well.

Perineural Injections

Carpal tunnel syndrome as in other peripheral nerve abnormalities are also areas that we're asked to look at.

I won't spend much time on it other than say that we see the median nerve very well on the superficial aspect of the carpal tunnel.

There are various criteria out there for diagnosing abnormality of the nerve.

We see it very well and can do this diagnosis fairly easily on ultrasound.

What I generally do is take a short axis approach in these patients, placed my needle through the flexor carpi radialis below the epineurium, which is the echogenic tissue surrounding the nerve for if you remember.

And we're basically gonna look to do hydrodissection of the nerve away from the flexor retinaculum, as well as adjacent to the adjacent tendons.

So here's basically here's some of the perineural injected material after we've done our part of our hydrodissection.

And we're gonna eventually put in our therapeutic mixture after we do that.

Same principles can be applied to peripheral nerves anywhere.

And as is actually one of the more common things we're asked to do in our practice to do small peripheral nerve perineural injections, you're gonna find the nerve you've looked for the characteristic hypoechoic appearance with the surrounding epineurium place your needle adjacent to it.

I oftentimes go both above and below it, and you're gonna really look to do hydrodissection.

What I tend to use with these nerve blocks is not only celestone because you avoid the issues of depigmentation and atrophy tend to use a stronger anesthetic, something like 0.75% marcaine.

'cause you get a more significant nerve block.

And when you do that hydrodissection, you generally will dissect fluid and actually will run a long several centimeters along the nerve course.

So it you can find these nerve blocks actually work exceedingly well using this approach.

Intratendinous Injections

A few minutes.

Let's talk about for a few minutes.

Let's talk about intratendinous injections.

So tendinosis that's refractory to standard conservative treatments such as cortisone injections and physical therapy.

One method that's been used advocated to treat these patients or intratendinous fenestration.

And then or combining intratendinous fenestration with autologous blood and platelet rich components now was described initially in the literature by colleagues of mine.

This organization such as Dr. Nazarian is doing fenestration, where you simply place a needle into the tendon.

And this is a patient with a lateral epicondylosis.

And what you're doing is you're placing your needle and you're basically fenestrating causing bleeding response.

You place your needle all the way up to the bone, try to irritate the periosteum and that procedure helps produce bleeding and results in release of local growth factors that promote healing response.

Well, the next iteration of this, as you might guess, would be to try to put these growth factors in higher concentrations.

And we can do that either by directly injecting blood or even going one step further by taking the blood and spinning it down to remove the platelet rich component, in which case we're placing in high concentrations of growth factors.

So here's a patient with lateral epicondylosis in which we're gonna do a PRP injection.

And here's my needle again, we're gonna be fenestrating 'cause that works.

Well, and then we we're gonna be doing our injection.

And what you'll notice is when we're doing the injection, you have all these little microbubbles due to the little bit of gas that's probably within the injected material.

So this is a 61-year-old female runner with buttock pain who had a large tear in her hamstring tendon origin that we were asked to do a PRP in.

So here's my needle in the tendon as I'm doing fenestration.

And we're gonna do our PRP injection.

And this is her three months follow up.

You could see that the tear is significantly smaller and she was feeling significantly better.

This is actually a professional ballet dancer who had acute onset of pain during rehearsal.

And this coronal image this is a proton density imaging.

This is her peroneus brevis or peroneus longus below.

And you can see this some pathologic signal intensity within the peroneus brevis tendon.

If we look at the corresponding ultrasound, This is scanning again similar to the coronal plane.

This is all the peroneus brevis tendon, which is markedly enlarged with a longitudinal split tear.

Peroneus longus is situated below, so it's significantly smaller.

And so what we were asked to do is to do a PRP injection in this patient.

So this is in long axis.

So with my needle situated within the tendon as we're doing fenestration and injection, and this is a short axis, is the reverberation effect from the needle as is passing into the tendon.

And you can see the appearance of these little microbubbles as we're injecting the tendon.

And often these tendons with the surrounding tenosynovitis.

The injectate takes the path of least resistance.

So it may actually distend tendon sheath, which means it coats the entire length of the tendon, which is actually a good thing.

This is her at baseline.

This is an extended field of view image to show you her response.

This is her at four months later where the tendon looks still a little bit abnormal, but has much more normal morphology relative to what it looked like before.

She's clinically much better.

And she was able to begin dancing again at a higher level.

And she was one of the principal dancers of this company.

So that was quite significant in her case.

Calcific tendonitis, or tendinosis is an area where we have high hydroxyapatite calcium hydroxyapatite depositing within the tendon.

These can be quite painful lesions.

They almost appear as sort of pasty material.

We see them most often in the rotator cuff, but they can occur anywhere in the musculoskeletal system.

And so generally we were asked to treat these quite often 'cause ultrasound has been shown to be an excellent way to do this.

In our practice, we use a single needle technique where what we want to do is place the needle centrally within the calcification, do a series of lavage of sort of lavage technique, then eventually fenestrate and inject, do a therapeutic injection into the subacromial subdeltoid bursa.

So this is my needle placed within the calcification.

This is while I'm doing lavage and aspiration.

And you can see this becomes progressively filled with fluid.

So this is what this would look like in real time.

My needle's placed in the calcification here.

And you have this sort of fish mouth appearance as we're lavaging it.

And we usually go through several syringes, but initially we start out with the 1% lidocaine, and then eventually we move on to sterile saline.

And I've actually had as many as 10 to 15 syringes of calcium.

But these patients feel immensely better when you once you've done the procedure on them, the kind of material you get out is indicated over here.

This is a radiograph of some of this material and it's calcium hydroxyapatite.

So as you would expect, it's radiopaque with an x-ray.

Muscle Aspirations and Injections

Muscle aspirations are again the is another area that we're asked to aspirate in that infrequently, these are patients oftentimes high level athletes that have had muscle strain injuries.

There's no real definitive data out there to show benefit, although at least in our experience, and I think among many clinicians, it's felt to be beneficial in assisting their recovery.

But what I would say is that it's helpful to do it earlier rather than later.

'cause once these hematomas begin to organize, they can be fairly difficult.

So this was a 30-year-old professional baseball player, had a quadriceps strain grade two strain.

You could actually see this high signal intensity here within the rectus femoris corresponding to a small seroma corresponding ultrasound image.

Over here we see the my needle placed into the seroma.

We're gonna aspirate it.

And here's after aspirating the seroma.

And this actually this patient who was not rehabbing well, was able to return to practice within 24 hours following the aspiration.

So in his case, it actually made a significant result had a significant result.

Cortisone injections there were several case series out there that suggested potential benefit.

It's somewhat controversial.

The longest series was actually in NFL players.

This was reported in 13 years of experience injecting these patients with hamstring quadriceps and injuries or muscle injuries and their experience that these patients actually did quite well.

Some orthos suggest there can be negative effects due to the either diminished tensile strength from or weakening of the muscle from the steroid injected in the muscle, as well as promoting muscle atrophy.

So generally speaking, there's no consensus out there in the literature, although I would say that at least in my own experience these patients do fairly well.

So here's one such patient that had a hamstring injury that were asked to inject under ultrasound guidance with steroid.

And actually he returned to practice fairly rapidly.

So generally speaking well we will just reserve these for grade one to two strains.

If there's a well encapsulated seroma, we'll look to aspirate that first before we do the cortisone injection.

And what I tend to do is to confine myself to a rapidly absorb steroids.

Something like celestone or dexamethasone, both of which you usually reabsorbed extremely rapidly.

So you don't have the long-term deposition of steroid in there, which I think is what may promote the muscle atrophy.

And so this is what this will look like in this another patient over here.

He has a small seroma, we're gonna aspirate it.

And then we did our therapeutic injection.

Platelet rich plasma injections again are somewhat controversial in the muscle in muscle injuries.

There is strong supporting evidence that suggests that it works in vitro and in animal experiments.

There are some limited clinical results out there that shows the beneficial effects of it.

Although there's one of the there are some issues that need to be resolved as in addition to limited literature, there's no optimal method or frequency of doing these injections that has been purported in the literature.

What system it to use optimally is not exactly clear what the ideal post-injection therapy should be.

And also one of the growth factors that is something called TGF beta which actually promotes local fibrosis and actually predisposes this for scar formation.

And one of the problems with scar remodeling within muscle it actually produces sinus for the muscle to retear.

So that's one of the clinical concerns in using platelet-rich plasma in these patients.

Implant Complications

So finally, let's talk about implant complications.

There's a variety of complications where ultrasound can be very helpful.

And as I said before, the fact that there's indwelling hardware doesn't impede our ability to assess the overlying soft tissues.

So here's a 49-year-old female with groin pain and suspected iliopsoas tendinosis.

So we're asked to do a iliopsoas bursa injection on her.

Here's my needle coming in short axis.

There's a metallic component over here, which obviously does not impede our ability to see the tendon.

So I place my needle down to the iliopectineal eminence below the tendon.

I'm gonna do my test injection.

I'm distending the bursa over here.

You get a sense of how inhomogeneous this tendon is, because they have a little bit, it's getting through a little bit of a fluid standoff.

So it's a little more conspicuous now.

And then after I've done my injection, I'm looking in long axis, and you can see the this very inhomogeneous tendon with fluid sort of dissecting along it due to a with a successful injection.

And she did very well as a result of this.

This is a patient that were sent to us for joint injection.

The patient, if you look at the radiograph, there's extensive osteolysis.

The question is whether or not this was this was a septic or aseptic osteolysis.

And we usually will do a therapeutic aspiration in these patients.

So here's a long axis view showing a very sort of thickened in the pseudocapsule.

And there's some complex fluid over here.

This next image, you can see this is in the capsule.

This is my needle tip in the anterior recess of the joint.

And we actually withdrew 40 ccs of purulent material from the joint.

Summary

So in summary, we've seen a lot of examples where musculoskeletal ultrasound can be very helpful for performing guided injections.

The important things I wanna stress again is know the basic scan techniques.

Know the sonographic anatomy.

It's very important to know your equipment, how to optimize your images, as well as optimally choose your transducer for the approach you're gonna take.

And then plan your approach to ensure optimal needle visualization.

And I think if you do that, you'll find it to be very beneficial in your practice.

Thank you very much.