Ultrasound of Hernias

What is a Hernia?

A hernia is a protrusion of a viscous or part of a viscous through an opening or weakness in a wall.

In my experience, these patients may present with a bulge, but they often present with vague pain and they can be a diagnostic dilemma.

Anatomy

This is the anatomy we're going to deal with. This is the right groin, rectus abdominis muscle. Inguinal ligament. This is the inguinal canal. It's fairly short, two to three inches. Spermatic cord runs through the inguinal canal. Pubic symphysis is right here, femoral artery and vein.

We're gonna use these anatomic structures to find our way as we look for a hernia.

These are the layers of the abdominal wall. Simplified. Peritoneum is deep skin is here, and this transverse fascia turns out to be pretty important because hernias in the transverse fascia. The main deep layer are what lead to hernias.

This is the testicle headed south to get into the scrotum where it's a little cooler. Most of us don't remember when this happened. A few people may, I don't know. I'm sure the women don't.

The ovary, of course, doesn't go down the inguinal canal. The inguinal canal, and this is supposed to be this spermatic cord. The green thing is the inguinal canal in a female is smaller than in a male.

This is Hesselbach's triangle demarcated by the inguinal ligament, the rectus abdominis and the inferior epigastric artery. You're gonna have to find the inferior epigastric artery as you look for these hernias.

Why is that? Because the inferior epigastric artery marks the deep ring or opening to the inguinal canal, which is right here. You can't actually see that opening, but you've gotta try to find it.

If you look from the side, this is supposed to go, but it maybe it's not going to. Let's see. Nope, it's not gonna go. This testicle will slide down, slide through the muscular layers and wind up in the scrotum.

Here's the pubic symphysis. In a female inguinal canal is depicted here and the female has a round ligament of the uterus that runs through the canal, but it's much harder to find than the spermatic cord in a male.

Mostly we're gonna talk about males because males get most of the hernias.

Types of Hernias

The quick version, and I'm gonna go over and over this. We're gonna repeat this five or six times in the next 30 minutes.

You're gonna look for a femoral hernia. First they tend to lie medial to the femoral vein and then move from superior to inferior. In a worst case situation, the femoral hernia will wind up in the woman's medial thigh. I say woman, because these are almost all females. The femoral hernia, the incidence of it is related to the number of pregnancies.

Indirect hernia moves from the anterior inferior iliac spine to the symphysis pubis. It's a congenital thing where the deep ring is open a little bit. It is in males, mostly it the hernia slides anterior to the spermatic cord. These tend to strangulate. They can occur in females, but and they're more common than a direct hernia. In females, these are called indirect hernias. The surgeons named them because when they opened the surgical field, the hernia came into the surgical field indirectly from above.

The direct hernia is from medial and behind the cord, so it tends to move posterior to anterior. Comes straight toward your transducer. When you're looking in the groin, it's tends to be an older males, sometimes called an old man's hernia. Doesn't tend to strangulate. They often reduce when the patient is lying supine on the table. Not common at all. In females, I've seen one or two in females, but they are not common in females.

Spigelian hernia moves posterior anterior, just like that direct hernia. It's at the linea semilunaris along the edge of the rectus abdominis can occur anywhere along that line. I'll show you that line on a diagram in a minute. There's no strangulation of Spigelian.

The umbilical hernia, we'll talk about, that's almost all females, once again related to pregnancy. They may strangulate and they may not be exactly in the umbilicus. I'm gonna show you how to get a good look at the retro umbilical area.

Femoral Hernia

Femoral hernia comes through the femoral ring, which is the entrance to the femoral canal that's medial to the femoral vein. It's 20% of hernias in females, about 5% in males. It's usually just above the saphenous merger with the femoral vein and medial to the vein. There's a risk of strangulation goes into the medial thigh. A woman can wind up with a big lump in the medial thigh and contains fat and or bowel.

Here it is depicted on the diagram. Saphenous vein coming up and in femoral hernia is sticking here. Femoral hernia is always below the inguinal ligament. And here is a little bitty femoral hernia. This is the femoral vein, femoral artery and a little bitty piece of fat sticking down alongside the femoral vein.

I look at these first because if I don't look at them first, I forget to do them. They're important enough that I think they need to be, you need to look for them initially with your exam.

This is another one, a larger one. This is fat. Here's the vein over here, the femoral vein. This fat is poking down into the thigh alongside the femoral vein. This doesn't reduce completely. It doesn't go back up into the up into the pelvis completely. This is a pretty important hernia and should be repaired.

Indirect Hernia

Indirect hernia enters the deep ring of the inguinal canal, which is marked by the inferior epigastric artery. It extends from the peritoneal cavity into the deep ring down the inguinal canal. It may not go very far down the inguinal canal, however, these are often congenital because of the patent canal. They're usually on the right more than the left.

Why would that be? Because the left testicle usually goes down first. If you're male, look at yourself and you will find that your left testicle is usually lower. If you're a female, look at somebody else.

Fat and or bowel can go all the way to the scrotum with these, I used to teach that if you had bowel in the scrotum, that usually meant an indirect hernia. I'm gonna show you a counter example of that in a minute.

The neck is at the deep ring. That's kind of where everything gets caught. This lies anterior to the spermatic cord, if you can see it.

Here is the inguinal canal and the light brown. Here's the hernia sac coming down the inguinal canal. It's coming from lateral superior toward the pubic symphysis. I usually line my transducer up along this inguinal canal and you will see this hernia come sliding down. It may go all the way to the scrotum.

This is looking at it from the side, it comes down the inguinal canal. It heads this way and it's because that this ring, this deep ring is congenitally large. Here, here's one coming down the canal, there was a little fluid in the canal. A lot of times you will have fluid as an indicator that there's something going on in there. It's coming from lateral to medial.

Here's one that's just barely sticking down the canal. Watch it again. It comes in right here. Just keep watching. It comes right down. This one I would say is not as risky as the one, as the first one I showed you.

Here's a static image of one, and this would be the deep ring right here. Most of the time that you can't see this, let's see if we can get this one to play. Okay, sorry, this, there's a big hernia here, but I can't show it to you.

Sherry Telford at Wash U in St. Louis taught me a different technique than finding that inferior epigastric artery. What Sherry does is goes to the near the pubic symphysis, goes transverse on the pelvis and finds the spermatic cord. You're just lateral and above the penis. Then once you find the spermatic cord, you can follow that up to the, to you follow it over to where it crosses the femoral artery in vein. Then you're finding the deep ring.

This might be easier than finding the inferior epigastric artery. I still find the inferior epigastric artery if I can. But I do use Sherry's technique when I can't find it. I think some people have a clotted off inferior epigastric artery. A very hypoplastic one. It just makes it hard to find and especially obese people.

This is a spermatic cord and this would be kind of what you're looking for, these striations.

Direct Hernia

Direct hernia, it's an old man's hernia. It's less common in females, almost vanishingly rare in females. It's poor coverage of a conjoined tendon, which is a combination of internal oblique muscle transverses abdominis muscle and transverses abdominis.

It's a tear in the transverse fascia, which I showed you early on in the talk. These usually have a wide broad neck and they are reducible so that when the patient is supine you the hernia may fall back in. You've gotta look for these a little bit. This tends to occur over in this territory. Hesselbach triangle.

I look here, I go over next to the rectus abdominis muscle because this is where they usually are. Slide up and down a little bit. I'll start to see tissues moving around. This is what's happening. You're tearing this transverse fascia, which is the red line here.

Sometimes these will poke through multiple layers of the muscle and will taking a bleak course and wind up in very funny positions. Here's one pokes right out toward your transducer. It pokes directly toward your transducer. It's a direct hernia. No rush to have these repaired in general. Don't tend to strangulate. This one's fat.

Here's another one's poking straight at you, third one. I bet the fourth one isn't gonna play, which makes me sad because I just did this one last week and it's a good one. The tech came into me and said I can't find anything. She was looking too far laterally in Hesselbach triangle. I came in and found a hernia that was right here.

An occasional direct hernia may lead to bowel in the scrotum. I just told you that usually when there's bowel in the scrotum, it's an indirect, but what happens is the hernia sac penetrates the back wall of the canal. This is a sagittal set of images or sagittal depiction. If the skin is out here, here's our anterior abdominal wall, here's the inguinal canal. The direct hernia pokes through the back wall of the canal and can actually get in the canal. Then will the bowel and or fat will slide all the way to the scrotum.

These are very confusing. Does it matter if you figure out what's direct and indirect? Nope. Doesn't matter. I've spent a lot of time telling you what direct and indirect are, but a decent surgeon can make the incision and take it from there.

I've talked to multiple of our surgeons about whether or not they really needed to know and they say, no, we can deal with it either way. It's the same incision. You don't really have to tell us, but you number one, I think you should know because you need to be conversant in these so you don't look like an idiot. Number two, it kind of gives you an indication of how urgent it is that the patient have this repaired.

Spigelian Hernia

Spigelian hernia along that border between the rectus abdominis and the oblique musculature. There's a defect in the aponeurosis of the internal oblique and the transversus abdominis muscles. It's usually in the lower abdomen. I usually don't go very high in the abdomen looking for these unless the patient has symptoms higher in the abdomen.

These occur up here. They actually are along the path of the inferior epigastric artery. As I said earlier, they can go all the way up.

Umbilical Hernia

The umbilical hernia at the umbilical ring, they can increase in size with age and with more pregnancies. The hernia moves posterior to anterior, just like the direct hernia. They may occur because the round ligament, the obliterated umbilical vein doesn't reinforce the umbilical ring properly. Or maybe it's because of late midgut return to the abdomen.

Most adults have a para umbilical hernia, which is a centimeter or two from the very center of the umbilicus. That's due to weak musculature, weak linea alba.

Para umbilical hernias need to be repaired.

How do you do an umbilical hernia? 'cause they can be a little bit challenging. You stick your transducer on the umbilicus and you run into a bunch of gas that's trapped in the umbilicus. What do you do? I fill the umbilicus with gel and I start tapping the umbilicus and I try to get the air bubbles out and I tap some more, I put more gel in. I keep tapping. If I still can't see, then I move obliquely and go from the side. Usually, by doing one of these two techniques, I can get a good shot of what's behind the umbilicus.

Here is one here. This is a widened neck umbilical hernia that does not reduce. Looks like mostly fat, maybe all fat in here. There's the sac. Here's the defect. This is rectus abdominis muscle over here on the sides. Here's a narrow neck umbilical hernia with the sac.

Causes and Associations

Causes and associations. The indirect have a congenital component. All of them are associated with a collagen abnormality. If you have an abnormal ratio of type three immature collagen to type one mature collagen, you have an increased propensity to get these hernias.

There is an association with aortic aneurysms. I don't jump up and look at an aortic look for an aortic aneurysm. When I find a hernia, one could argue that you should do that, but I've just decided not to do it.

Other associations include cigarette smoking. I almost always ask the patient, are you a cigarette smoker? Ehlers-Danlos and various other things, including obesity, poor conditioning and ascites. Anything that will distend the abdomen.

The femorals, as I said, are associated with pregnancies.

Examination Technique

Here we go. Here's my technique. Start on your femoral artery and vein slide up. I start low and I come up, proximally become superiorly. When I find the saphenous vein coming into the femoral vein, I stop and have the patient Valsalva position number one. I'll maybe move one centimeter above one centimeter or below. Have the patient Valsalva. Again, look around. If you have a femoral hernia, it will be coming down the leg.

Position number two, I will slide on up the femoral artery and vein until I see the inferior epigastric artery come off and go medially. The inferior epigastric artery is the only big vessel going medially. The other big vessels go laterally, find that inferior epigastric artery. Have them Valsalva. The indirect hernia will come down this inguinal canal and it will slide toward the pubic symphysis as though we're gonna try to get to the scrotum, which is what it is trying to get to.

Then I slide over to position number three into Hesselbach triangle. I'll move all around this triangle and have the patient Valsalva. I will work my way along the edge of the rectus abdominis in three or four different positions and look for movement of tissues. It's usually pretty easy to pick these up. These are really common. This is the most common I do.

Worldwide, it said the indirect hernia is the more common type of hernia, but I think that includes pediatric patients. In an adult population, most of 'em we're gonna be directs.

Then just slide right on up along the edge of the rectus abdominis and look for a Spigelian, 1, 2, 3, 4. Theoretically, you ought to be able to do it in two minutes. In practicality, you can't because many of these people are obese and you have trouble finding some of these landmarks.

Here we go again. 1, 2, 3, 4 femoral down here. Slide up, find the inferior epigastric artery. Look there. Slide over medially. Look for the direct slide up. Look for a Spigelian. This is just the same thing I said, but written in words. I'm not gonna go into it, Do it supine and do it standing. If you don't do that, you're gonna miss 'em.

Why is that? Because these patients tend to be deconditioned, tend to be obese. They don't have good muscle tone in the rectus abdominis muscles or in their oblique muscles. They can't generate enough pressure when you have them Valsalva, to really push that hernia sac out, you've gotta do them supine and standing.

I recommend start supine because you can find the anatomic landmarks easier. When they stand them up, the anatomic landmarks tend to disappear. There's often a big pannus hanging out and but once you have found the anatomic landmarks, supine, you usually have a pretty good idea of where they are when they're standing.

Then have them push with the patient in the standing position.

Today, after doing these for multiple years, I have about 30 sonographers that I work with. I will tell you that the sonographer comes in. The first thing I say is, did you stand them up? After years of doing this, I probably have a standup rate of about 60%. You gotta stand them up.

I send residents in so that my sequence is sonographer does it. I tell the resident to go do it and then I go do it. Unless it's a really a good resident and he can find the hernia easy and I, but I say to the resident, did you stand them up? I'm about 80% with the residents. But you've gotta do them standing, 1, 2, 3, 4 on the femoral vein below the inguinal ligament at the inferior epigastric artery come medial and then slide up.

Vascular Anatomy

This is just a little vascular anatomy to help you out. As you come up the femoral artery, you'll start to see vessels of one big vessel come off the superficial iliac circumflex. It goes laterally. Second big vessel comes up deep circumflex, iliac goes laterally. The third vessel is inferior epigastric artery. It goes medial. Don't be surprised when you see these two and know that you haven't gone high enough yet. 1, 2, 3, 4. Stand them up.

Terminology

Terminology, the neck of the hernia is the narrow part where it penetrates through the fascial plane. It's where the defect is. There's a sac, a peritoneal sac that holds the contents of the hernia. You need to figure out if there's bowel and or fat within the hernia sac. That's really important. If there's bowel in there, it's gonna get operated on much quicker. If there's just fat in there, it's not really, not really much urgency.

Strangulated means that the contents of the sac or ischemia, you really can't tell this based on your color Doppler or power Doppler. I don't try to tell 'em if it's ischemic. That's something based on symptoms. The urgency of surgery based on clinical factors and incarcerated hernia cannot be reduced.

You need to tell them, can this hernia reduce? Does it reduce spontaneously? I'll push around with the transducer a little bit, but I really don't push hard trying to reduce these. Reducible versus non reducible is determined incarcerated.

Other Hernias

Incisional Hernia

Other hernias, incisional and an incisional at a c-section scar. I've worked my way along the incision, the scar from the incision, I go trend, I go perpendicular to it and then I go parallel to it and I stand them up. These usually occur from a breakdown of deep layer of sutures. You have trouble seeing the fascial planes because of the surgical scar. But you can find these pretty easily most of the time 'cause the scar is marking the spot for you.

Sports Hernia

The other thing I'm gonna talk about is athletic, a pubic or a sports hernia. A sports hernia is not really a hernia in most people's lexicon. It's quite a confusing entity, has a confusing literature. There's a Radiographics article in 2008 that's pretty good. That mainly covers MRI. There's a review paper last year in skeletal radiology that covers the various entities that can give you pain in the lower mid abdomen, which is where it is.

It's pain around the pubic symphysis. It's often athletes, it's often soccer players who do a lot of crossover. Leg movements, cornerbacks in football, sometimes basketball players. It's rectus abdominis, adductor longus, tendinopathy, maybe occasionally an inguinal ligament tear. I've not seen that myself. Osteitis pubis at the bone of the pubic symphysis. A stress response or fracture at the pubic symphysis and tendinopathy of the short adductors. Your adductor brevis and adductor longus.

This is a little anatomy. Rectus abdominis comes down, hooks onto the pubic symphysis. Your adductor longus comes off the bottom side of that. You get tendinopathy in these two. MRI in my opinion is better. I've had trouble with ultrasound, but I think because a lot of this, a lot of time the pathologies in these adductors down here below the pubic symphysis and in the pubic symphysis itself.

But this is a ultrasound attempt at it. What this was, was not tendinopathy of the rectus abdominis. This was an isotropy caused by my failure to have my transducer perpendicular. If you don't get your transducer perpendicular to the area you're interested in, you'll get dark bands and you'll fake yourself out. Maybe that's another reason I've had trouble with ultrasound in this.

Keep the transducer perpendicular. You can try the heel toe maneuver where you kind of rock the transducer, try to scan in multiple planes.

Complications of Repair

Complications of repair. You can get a recurrent hernia, you can get infection, and you get testicular ischemia. Post-op complications. The main one is urinary retention. These are all things that are not gonna concern us except or oras and infection. We need to be concerned about these and complications long term. A different author, ORAS and infection Seromas.

Testicular infarct. If a patient comes to you, a male patient and has had mesh placed in a hernia repair, stand them up and look at the do you don't have to stand 'em up. Look at the testicles. Do not ignore the testicles because I've had three dead testicles in the last year and this is a trip to the courtroom for the surgeon. Oftentimes this particular patient was 21 years old. He infarcted his testicle and it didn't concern him at all. Which was, that's a little bit odd in and of itself, I think.

Please look at the testicles if you're asked to look at a patient with pain post hernia repair.

If the repair is too tight, patients get neuralgia. They can get numb areas. If a patient complains of a numb penis, numb scrotum, a female complains of numb labia, the repair is probably too tight. You can oftentimes relieve the pain by flexing and produce the pain by extending the hip.

Systematic follow up, A very large series pain. The significance of pain for ultrasound, look for infection, recurrent hernia, the mesh will be in place. Patient will know if they have mesh. Try to work your way around the edges of the mesh. There are numerous papers that say that you can see the mesh and it's an echogenic line. I can see the mesh about 20% of the time, and I literally do five, six as many as eight of these a day.

I can tell you that once the mesh has been in there any significant amount of time, you're gonna have trouble seeing it. The mesh tends to just fold up and crinkle like a tissue at times. That means the mesh has failed or collapsed. Sometimes it can migrate away and be pretty far away. Most of the time I don't see hernias in the mesh.

Mesh is two types. You won't know what type your surgeon is using. This is about a half millimeter thick. This is the prolene mesh. I've looked at the surgical notes to see what kind of mesh they're using and they just say, we used mesh. They don't tell me what kind. This is almost never used. These are resorbable partial resorbable tissue substitutes.

This is a rent in the mesh back here. This is a hole right down the middle of the mesh and a big hernia that has recurred. 90-year-old female. This was not fixed. Again, this is another failure of mesh. This one has just buckled the mesh up here. I don't know if it was torn or exactly what happened without mesh.

Do the follow-up exam like you would for any other hernia if you think there's infection, look for edema or fluid, try to find mesh. If there's fluid around the mesh, the mesh has to come out. If there's fluid or edema superficially, the mesh can sometimes stay in. The infection can be treated with antibiotics.

There are oftentimes post hernia repair will be a little hernia sac left. This is a peritoneal sac left behind by the surgeon.

Other Inguinal Causes of Pain

Other inguinal causes of pain, endometriosis and varices. Endometrial glands could go down the inguinal canal and can be along the round ligament embedded in the wall of a hernia sac. The patient usually has pelvic endometriosis and can have a painful groin lump. Have a hypoechoic mass, sometimes cystic and sometimes it's blood flow that is taken from this paper in Radiographics in 2016. Little endometriosis and then varicosities.

These occur in pregnancy. The varicosities can go down the inguinal canal and can thrombosis and lead to pain. I consider these the equivalent of a varicose vein in a male, but you'll see a bunch of vessels around the in the inguinal canal.

References

The references, if you wanna read more about this, Tom Stavros and Cindy Rapp have a really nice paper in Ultrasound quarterly, which is the journal of this organization. In 2010, I did a paper in ultrasonography in ultrasound clinics in North America in 2014. If you wanna know about more about the inguinal canal, you can get it right there.

Thank you very much.