Ultrasound Offers Advantages in Musculoskeletal Disorders Diagnosis and Treatment

Recent advances in high-resolution ultrasound imaging present new opportunities for improving the care of patients with musculoskeletal injuries. Ultrasound uses sound waves to provide real-time, high-resolution images of tendons, ligaments, muscles, and nerves throughout the body.

Skilled practitioners in Mayo Clinic's Department of Physical Medicine and Rehabilitation and Sports Medicine Center now use musculoskeletal ultrasound to diagnose and treat a wide range of tendon, muscle and joint disorders.

Ultrasound as a Diagnostic Tool

Ultrasound offers several advantages over other available imaging tools such as live x-ray imaging (fluoroscopy), CT, and MRI.

Calcification in supraspinatus tendon

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"Ultrasound is a readily available and cost-effective imaging technique that can help us evaluate tendons, muscles, ligaments, and nerves with a resolution that equals or surpasses MRI," notes Jonathan T. Finnoff, D.O., of the Department of Physical Medicine and Rehabilitation and Sports Medicine Center. Ultrasound can also be performed live, allowing dynamic evaluation of ligaments and tendons, as well as guiding needles to target areas throughout the body. Finally, ultrasound does not use radiation and is therefore safe during pregnancy.

Ultrasound can be an effective tool for diagnosing problems in patients with difficult-to-evaluate conditions. For example, to determine whether a tendon tear is the source of a patient's ankle pain, the practitioner can use ultrasound to precisely inject anesthetic into the tendon sheath and assess the patient's response. This diagnostic injection can help differentiate incidental from symptomatic structural abnormalities.

Ultrasound can also help diagnose the source of painful movement-related snaps and pops. By evaluating patients dynamically while they demonstrate their symptoms, practitioners can identify unstable tendons, snapping calcifications within tendons, and other sources of motion-induced pain.

Common applications of diagnostic musculoskeletal ultrasound include:

• Identification of tendon or ligament tears, inflamed bursa, compressed nerves, cysts, and joint fluid.
• Evaluation of painful pops and snaps.
• Diagnostic injections into joints and tendon sheaths or around nerves.

Therapeutic ultrasound-guided procedures

In many cases, the use of ultrasound also allows the skilled practitioner to precisely and safely deliver therapies to the affected tissue. During ultrasound-guided injections or aspirations, practitioners can directly visualize the needle passing to the target. Direct visualization ensures accurate injectate placement and offers a greater margin of safety. Smaller needles may also be used, improving patient comfort and potentially reducing risk.

Applications for ultrasound-guided injections include:

• Needle placement into joints for aspiration or injection, particularly in patients with challenging anatomy, those on blood thinners, or those in whom a nonguided injection has failed.
• Injection into tendon sheaths or bursae.
• Aspiration and injection of ganglion cysts.
• Diagnostic or therapeutic nerve blocks, including carpal tunnel syndrome.
• Percutaneous treatment of calcific tendonitis.

Emerging and experimental applications

Mayo Clinic physiatrists are also using ultrasound to guide emerging therapies, including tendon fenestration (percutaneous tenotomy), and platelet-rich plasma (PRP) injections. "During tendon fenestration, the practitioner uses ultrasound to make multiple needle passes through areas of tendon degeneration to stimulate tissue healing," explains physical medicine and rehabilitation physician Jay Smith, M.D., who specializes in sports medicine and musculoskeletal ultrasound at Mayo Clinic in Rochester, Minn.

Treatment by lavage

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Used for more than a decade to facilitate the healing of difficult wounds, PRP is rich in growth factors linked to healing. Using ultrasound guidance, practitioners inject the PRP into the affected tendon, usually following a tendon fenestration procedure. "The fenestration breaks up the abnormal tissue, and then we inject the platelets into the prepared area to promote healing," explains Dr. Smith.

A team of Mayo Clinic researchers is now evaluating the efficacy of combining musculoskeletal ultrasound, PRP therapy, and tendon fenestration in patients with chronic tendon injuries. "We anticipate increasing use for ultrasound in the diagnosis of tendon, ligament, and other soft tissue disorders and in the delivery of biologic therapies to promote healing," note both Dr. Smith and Dr. Finnoff.