Over the last several years the use of ultrasound in sports and orthopedic medicine has grown rapidly. When most people think of ultrasound in medicine, they immediately think of Obstetricians looking at growing babies in the uterus with fetal ultrasounds, or cardiologists doing echocardiograms to assess the heart. But cutting-edge sports medicine physicians are starting to use ultrasound both to help diagnose injuries and to guide injections to make them more accurate and effective.
At New Pain Solutions we use musculoskeletal ultrasound (MSKUS) to help diagnose injuries to muscles, ligaments, and joints. Dr. James Robies has over 136 hours of training in MSKUS.
DIAGNOSTIC MUSCULOSKELETAL ULTRASOUND
ADVANTAGES OF DIAGNOSTIC MSKUS
MSKUS has many significant advantages over x-rays, MRI, and CT scans. These include:
- Better resolution of soft tissue than MRI
- Convenient in-office service; no need to go to another facility
- No exposure to ionizing radiation
- No claustrophobia
- The ability to perform a dynamic or "live" study; we can see the injured area move and look for evidence of injury
- More cost-effective
- Ability to see inflammation
- Ability to guide injections
MSKUS has been shown to be equal to or even better than MRI for looking at the rotor cuff. Also, MSKUS allows the physician to look for signs of joint instability, unlike x-rays or MRI.
For example, look at the image to the right. This shows a normal appearing supraspinatus tendon, one of the muscles of the rotator cuff. The tendon has a uniform smooth appearance, the overlying bursa has no fluid and the bursa walls are not thickened, and the cortex of the humeral head is smooth. (Note the scale to the right of the image, indicating depth in centimeters.)
Now look at the image to the left of an abnormal rotator cuff. The tears in the supraspinatus tendon are clearly visible. There is also subtle loss of the normal convex curve of the upper surface of the tendon and overlying bursa, further indicating a tear in the tendon. In addition, there is some thickening of the bursal walls, suggesting a chronic irritation, consistent with tendinosis and bursitis.
PITFALLS OF MSKUS
WHAT CAN MSKUS NOT DO?
While MSKUS has many great advantages, there are some restrictions, including:
- Unlike MRI, ultrasound cannot penetrate bone to "see" inside joints, so cartilage and joint surfaces are not visualized as well.
- MSKUS is generally not as good as x-rays at looking at bones.
- Performing and interpreting MSKUS takes a LOT of training and practice, more than x-rays and MRI. Therefore not many physicians do it.
One of the great advantages of MSKUS is the ability to use ultrasound to help the physician guide the needle when performing injections. While many injections traditionally are performed "blind," without the help of guidance, studies have shown the poor accuracy rate of blind injections. Performing injections under ultrasound guidance helps ensure accurate needle placement and medication delivery. This improves both patient comfort and treatment efficacy. It also helps avoid placing the needle in nearby dangerous structures such as nerves, blood vessels, or other organs.
For example, a recent study looked at the accuracy of hip joint injections done with ultrasound guidance. Ultrasound had a 97% accuracy rate. When comparing injections given into the piriformis muscle (a muscle deep in the buttocks that sits on top of the sciatic nerve) between ultrasound and fluoroscopy ("live" x-ray), one study showed that ultrasound guidance achieved a 95% accuracy rate, whereas fluoroscopy was accurate only 30% of the time in guiding the needle correctly.
At New Pain Solutions, we have extensive experience with ultrasound guidance, and we perform almost all of our injections under ultrasound.
LIVE IMAGE X-RAY
Fluoroscopy is a study of moving body structures - similar to an x-ray "movie." A continuous x-ray beam is passed through the body part being examined, and is transmitted to a TV-like monitor so that the body part and its motion can be seen in detail.
Fluoroscopy is used in many types of examinations and procedures, such as barium x-rays, cardiac catheterization, and placement of intravenous (IV) catheters (hollow tubes inserted into veins or arteries). In barium x-rays, fluoroscopy allows the physician to see the movement of the intestines as the barium moves through them. In cardiac catheterization, fluoroscopy enables the physician to see the flow of blood through the coronary arteries in order to evaluate the presence of arterial blockages. For intravenous catheter insertion, fluoroscopy assists the physician in guiding the catheter into a specific location inside the body.
HOW IS FLUOROSCOPY PERFORMED?
Fluoroscopy may be part of an examination or procedure that is done on either an outpatient or inpatient basis. The specific type of procedure or examination being done will determine whether any preparation prior to the procedure is required.
HOW DO YOU PREPARE FOR IT?
Preparation varies depending on the type of test. The contrast agent which allows the image to be viewed when x-rayed will be introduced into the body via swallowing, injection or an enema. Your doctor will give you specific instructions prior to your procedure.
Your physician should notify you of any pre-procedure instructions. Although each hospital may have specific protocols in place and specific examinations and procedures may differ, fluoroscopy procedures generally follow this process:
- An intravenous (IV) line is started in the patient's hand or arm.
- The patient is positioned on the x-ray table.
- For procedures that require catheter insertion, such as cardiac catheterization or catheter placement, an additional line insertion site may be used in the groin, elbow, or other site.
- A special x-ray scanner is used to produce the fluoroscopic images of the body structure being examined or treated.
- A dye or contrast substance may be injected into the IV line in order to better visualize the structure being studied.
EXAMPLES OF FLUOROSCOPY
The type of care required after the procedure will depend on the type of procedure done. Certain procedures, such as cardiac catheterization, will require a recovery period of several hours with immobilization of the leg or arm where the cardiac catheter was inserted. Other procedures may require less time for recovery. The physician will give more specific instructions related to care after the examination or procedure.