Tips to Help Hand Surgeons and Therapists Do Their Own Ultrasound Examinations

INTRODUCTION Many hand surgeons and hand therapists could benefit from adding “ultrasound vision” to their physical examination when they see patients. Most have access to ultrasound probes but have not tried to use them. We created this article and its videos to help them get started. DOING YOUR OWN ULTRASOUND EXAMINATION IS EASY BECAUSE YOU KNOW THE ANATOMY Just pick up an ultrasound probe and start. Practice by looking inside your own hand. It is very similar to taking your own mini Carm x-rays of hands and fingers. You are used to looking at bones with x-ray. Now you can see tendons, ligaments, joints,1,2 nerves, blood vessels, and muscles3 just as easily, without radiation.4 (See Video 1 [online], which shows how and why all hand surgeons and therapists will soon do their own ultrasound examinations.) {"href":"Single Video Player","role":"media-player-id","content-type":"play-in-place","position":"float","orientation":"portrait","label":"Video 1","caption":"shows how and why all hand surgeons and therapists will soon do their own ultrasound examinations.","object-id":[{"pub-id-type":"doi","id":""},{"pub-id-type":"other","content-type":"media-stream-id","id":"1_3ahl2k3u"},{"pub-id-type":"other","content-type":"media-source","id":"Kaltura"}]} ALWAYS START BY FINDING THE BONE It is easy because bones are hard, so they are white. The bones are at the bottom of the screen where they stop ultrasound waves. The more solid the structure, the more white it is. Liquid, like pus, blood, or a ganglion cyst, is black. Fat and tumors are different shades of gray. After you find the bone, ask the patient to move the tendons. You will see the tendons move above the bone. As you tilt your probe backward and forward a little, the tendons become more clear when the probe is perpendicular to the tendon fibers, and less clear when you are not at a 90-degree angle. The median and the ulnar nerve do not change in clarity when you tilt the probe, which is one way to know they are nerves. Once you recognize the tendons and nerves, you can easily figure out the rest because you know your anatomy! Veins are black (liquid), round structures that disappear when you press on them. Arteries are black, round structures that pulsate and become colorful when you press on the color Doppler button of the ultrasound machine. The waves that go around thin needles and wood slivers make an “echo” pattern underneath the wood or needle, which makes them even easier to recognize (Video 1 [online]). KEEP YOUR PROBE MOVING TO MAKE STILL PICTURES A MOVIE Ultrasound sees a slice of anatomy the width of a credit card, like a single slice of a computed tomography scan. You need to keep your probe moving back and forth, side to side, turning it longitudinally and transversely to appreciate the 3-dimensional anatomy it allows you to see, like looking through multiple computed tomography slices. Use all your fingers or use both hands to stabilize the probe over the finger or hand you are examining so you do not slide off target. THE VIEW IS ALWAYS BETTER FROM THE TOP OF THE HILL If you keep your probe on the top of a mountain of gel, 5 mm or more thick, with or without a booster, you will see the inside structures much better than if you are pressing the probe right on the skin with a very thin layer of gel. (See Video 2 [online], which shows how and why to examine the hand and fingers with the ultrasound probe sitting on a mountain of gel for a better view of the structures, as well as how to make an ultrasound probe booster which keeps a mountain of gel between the skin and the probe, even with a moving finger under the probe.) You can easily build yourself a booster to keep a thick layer of gel between the probe and the skin. We show how to do this in Video 2 [online]. {"href":"Single Video Player","role":"media-player-id","content-type":"play-in-place","position":"float","orientation":"portrait","label":"Video 2","caption":"shows how and why to examine the hand and fingers with the ultrasound probe sitting on a mountain of gel for a better view of the structures, as well as how to make an ultrasound probe booster which keeps a mountain of gel between the skin and the probe, even with a moving finger under the probe.","object-id":[{"pub-id-type":"doi","id":""},{"pub-id-type":"other","content-type":"media-stream-id","id":"1_ld5t45pi"},{"pub-id-type":"other","content-type":"media-source","id":"Kaltura"}]} LOOK AT THE NORMAL HAND FIRST Most patients come in with a normal hand to compare with the hand that has abnormalities. Start by looking at the normal hand when you are beginning, or if there are preexisting hand deformities. Then, look at the side that has a problem. The differences become obvious quickly. Many patients love watching their ultrasound hand examination with a guided tour just as some enjoy seeing ultrasound images of a baby in a pregnant woman. HOSPITALS ARE FILLED WITH ULTRASOUND MACHINES. JUST PICK UP A PROBE AND USE IT! The higher the frequency, the better the view for hand structures. Twenty megahertz is ideal, but lower frequency probes can still get a great view with a booster. You can buy ultrasound probes that work with your phone. Someday, all hand surgeons and therapists will have an ultrasound probe for their telephone like cardiologists have a stethoscope. JUST TAKE A QUICK LOOK BEFORE YOU TAKE OUT ANY LUMP OR REPAIR A TENDON If you do this every time, you will get faster quickly. You will learn something from every case. You will quickly recognize if a lump is solid (gray) or liquid (black). If it is liquid, you may want to aspirate it. The ultrasound probe will let you see the tip of your needle in the center of the liquid as you aspirate. With cut tendons, you can easily find the location of the proximal end of the cut or ruptured tendon by asking the patient to move it (previously published videos help hand surgeons and therapists do their own flexor tendon ultrasound5). You can see the distal cut tendon stump move by passively moving the finger. Once you know where the 2 tendon ends are, you can make shorter incisions for fewer adhesions and less tenolysis, especially for flexor repair in the finger. When the profundus stops moving, any therapist or surgeon can just take a quick ultrasound look and see whether the repaired flexor is ruptured (needing surgery) or just stuck in scar (treat with a relative motion extension splint). HOW TO SEE NEEDLES, GLASS, OR WOOD SLIVERS Needles, glass, and wood slivers are hard (white). (See Video 3 [online], which shows a second way to build an ultrasound booster, and more examples of a thick layer of gel helping to see small objects like a sliver of glass 2 mm below the skin of the distal phalanx of a finger.) {"href":"Single Video Player","role":"media-player-id","content-type":"play-in-place","position":"float","orientation":"portrait","label":"Video 3","caption":"shows a second way to build an ultrasound booster, and more examples of a thick layer of gel helping to see small objects like a sliver of glass 2 mm below the skin of the distal phalanx of a finger.","object-id":[{"pub-id-type":"doi","id":""},{"pub-id-type":"other","content-type":"media-stream-id","id":"1_c6vfvrv7"},{"pub-id-type":"other","content-type":"media-source","id":"Kaltura"}]} USE YOUR ULTRASOUND PROBE LIKE YOUR EXAMINING FINGER You can press gently with the probe to find the tender spot. When you find it, you can add more gel to get your probe off the skin, magnify the pathological view, and stop causing pain. WITH FRESH INJURIES, EXAMINE THE HAND IN THE BOTTOM OF A BOWL OF WATER Place your probe in an examination glove with gel in it to maintain probe contact with the surrounding water. The water separates your probe from the freshly wounded hand to avoid pain during the examination. The water also magnifies the ultrasound signal. (See Video 4 [online], which shows longitudinal and cross-section anatomy of a finger with a thick layer of gel ultrasound accompanied with illustrations, and more tips for ultrasound examination such as examining the freshly injured hand in a bowl of water for a better view and less pain.) {"href":"Single Video Player","role":"media-player-id","content-type":"play-in-place","position":"float","orientation":"portrait","label":"Video 4","caption":"shows longitudinal and cross-section anatomy of a finger with a thick layer of gel ultrasound accompanied with illustrations, and more tips for ultrasound examination such as examining the freshly injured hand in a bowl of water for a better view and less pain.","object-id":[{"pub-id-type":"doi","id":""},{"pub-id-type":"other","content-type":"media-stream-id","id":"1_8t5jkdot"},{"pub-id-type":"other","content-type":"media-source","id":"Kaltura"}]} CONCLUSIONS This article and its videos may be helpful to empower surgeons and therapists to simply pick up an ultrasound probe and start looking at tendons, nerves, ligaments, masses, inflammation, and other pathology inside of hands and fingers. DISCLOSURES Dr. Lalonde receives royalties from Thieme book publishers and as a consultant for ASSI instruments. The other authors have no financial interest to declare in relation to the content of this article.