Ultrasound is a common imaging technique that employs high frequency sound waves to create images of organs and other internal structures of the body. These images provide valuable information of underlying pathology of the tissues and assists with diagnosis and planning the treatment of a particular condition. Ultrasound provides a clear view of the organs, tendons, muscles or joints and any associated disorders.
Ultrasound is generally complimentary to other imaging techniques, and is similar to MRI in that both imaging tests use non-ionizing radiation to create pictures.
Ultrasound guided injection is a minimally invasive procedure used for treating various musculoskeletal painful conditions such as tendonitis, bursitis and neuritis or to perform cyst aspiration.
It is also an excellent tool for guiding the placement of needles for both diagnostic as well as therapeutic purposes.
Injection of a pain medication in combination with a local anesthetic directly to the site of injury helps to relieve pain. The advanced imaging of ultrasound provides high resolution images that enable the physician to precisely locate the injections deep into the target tissue without harming surrounding tissues.
The advantages of ultrasound imaging compared to other imaging techniques include the following:
- No patient exposure to ionizing radiation.
- No additional contrast administration is required.
- Able to assess tendons, ligaments and muscles under high resolution.
- Provides direct visualization of the area being treated.
- Ensures accurate placement of the needle to targeted areas.
The indications for diagnostic ultrasound imaging technique include the following:
- Diagnose conditions such as tendon/ligament tears, inflamed bursa, joint fluid and cysts.
- Assess painful pops and snaps that occur during movement
- Deliver diagnostic injections to specific targets including joints and tendon sheaths or bursa.
- Help guide needle placement during needle aspirations or injections for patients with challenging anatomical variations or people taking blood-thinning medications.
- Aspiration of a ganglion cyst.
- Guide needles in percutaneous therapy for the treatment of calcific tendonitis.
How do I know if an ultrasound-guided injection is right for me?
The most common ultrasound-guided injection is used to treat inflammation in or around a joint, which may or may not be related to osteoarthritis. In this scenario, a combination of steroid and anesthetic is injected into the joint to reduce pain and inflammation. Similarly, Dr. Carpenter also performs steroid injections along an inflamed tendon for the treatment of tendinitis. Common examples include iliopsoas bursa injections, as well as greater trochanteric bursa injections.
Alternatively, an injection of viscous fluid known as hyaluronan is also performed in the setting of osteoarthritis, and the purpose of this injection is to aid in lubrication of the joint. Examples of these injectable compounds include Synvisc and Hylagan.
In select cases, your referring physician may prescribe an injection of a short-acting anesthetic into the joint, and this is a useful diagnostic exam to determine whether the pain you are experiencing is being generated by the joint itself.
Dr. Carpenter also performs anesthetic and steroid injections along nerves in patients experiencing symptoms attributable to peripheral neuritis, as well as aspiration of joints, popliteal (Baker) cysts, and hematomas.
If you are a patient suffering from calcific tendinitis, there is also an established ultrasound-guided procedure known as barbotage, which is more effective than steroid injection alone. During this procedure, a small needle is guided into the calcium deposit(s), and the after the administration of anesthetic, the calcium is then punctured with the needle tip, and lavaged with sterile saline. The purpose of this procedure is to break up and aspirate as much of the calcium as possible, in order to prevent additional inflammation.
The procedure is used for diagnostic as well as therapeutic purposes. Anti-inflammatory medications such as corticosteroids and hyaluronans are the most commonly used medications to relieve pain, inflammation and swelling or to stimulate synovial fluid production to improve lubrication.
At the time of the procedure, you will have a chance to meet with Dr. Carpenter to discuss the procedure, and have all your questions answered. You will then be positioned on the ultrasound bed, and Dr. Carpenter will first perform an ultrasound evaluation of the injection site, and place a small mark on the skin.
Using ultrasound, Dr. Carpenter will then advance a small needle into the anatomic location of interest, and confirm the correct position of the needle tip by injecting a small volume of anesthetic. Once placement is confirmed, the therapeutic portion of the injection will be completed. The needle will then be removed, and a small bandaged will be applied, which should be kept clean, dry, and intact for 24 hours following the procedure.
In general, most ultrasound-guided procedures take approximately 15 minutes, although some procedures may occasionally take longer.
Experience during and after the procedure
Ultrasound examinations are painless and easily tolerated by most patients. Activity limitations following a therapeutic activity are tailored to the procedure performed, however, most patients are able to drive themselves home following the procedure.
There are limitations to the depth that sound waves can penetrate, as well as limitations to the depth that a needle can be advanced. Therefore, deeper structures, especially in larger patients, may not be easily treated through ultrasound-guided intervention.
Knee joint injection technique
Knee joint injections are frequently used for knee conditions such as osteoarthritis, baker’s cyst or knee bursitis.
During the administration of the injection the patient will be positioned lying down and clear water based conducting gel is applied over the targeted site. The gel is used for transmission of the sound waves to deeper structures. The doctor moves the hand held transducer over the targeted area to provide images of internal structures. Under the guidance of ultrasound the doctor inserts the needle into the skin to reach the targeted location. The procedure can be used for injecting medications or to aspirate fluid from the affected tissue.
Ultrasound guided injection is a relatively safe and painless procedure. Some of the associated complications include bleeding at the site of insertion, and injury to adjacent structures. Patients can resume their normal activities immediately after the completion of the procedure.