Browse the corpus

Shoulder pain is a common patient complaint encountered both by primary care physicians and orthopedic surgeons. Many shoulder structures can account for the clinical presentation of shoulder pain, and the diagnosis can be challenging. Clinicians often use a combination of physical examination, clinical history, and imaging to establish a diagnosis; however, sometimes, the diagnosis remains in question. An ultrasound-guided injection can aid in these cases providing clinical information and often therapeutic benefit. This activity reviews the indications, potential complications, and the method for performing an ultrasound-guided biceps tendon sheath injection. Objectives: Review shoulder anatomy with a focus on the biceps tendon. Outline the clinical presentation of patients with biceps tendinosis or superior labral tear. Identify the indications for ultrasound-guided biceps injection. Summarize the procedure for ultrasound-guided biceps tendon injection. Access free multiple choice questions on this topic.

Ultrasound is well-suited for clinical practice given its affordability, portability, and lack of radiation exposure during image acquisition. These features allow clinicians from almost any specialty the ability to perform image-guided evaluations and interventions.[1][2][3][4][5] Radiologists are uniquely suited to perform these evaluations and procedures, given their extensive training, knowledge of human anatomy, and understanding of the varied anatomical appearances across multiple imaging modalities.[6] Part of a radiologist’s training involves understanding medical physics, including how medical images are obtained. In ultrasound, the sonographer or physician utilizes a transducer to interrogate the area of interest. Within the transducer are piezoelectric crystals that vibrate when exposed to an alternating current. These vibrations generate sound waves transmitted into the patient’s soft tissues via a layer of ultrasound gel. The sound waves then interact with the tissue and are ultimately reflected to the transducer. Once the sound waves return to the transducer, they are converted back into an electric current. The computer then calculates the time interval between when the sound wave was initially generated and when the transducer received it to determine the location (depth) of the tissue that reflected the sound wave. When planning a procedure, one must consider the type of transducer that yields the highest quality images. There are a variety of transducers that can be used with varied frequencies and shapes. In general, higher-frequency transducers are used for imaging more superficial structures, as they offer better resolution. However, the higher-frequency sound wave is more easily attenuated and has a decreased ability to penetrate tissue, limiting its use in the evaluation of deeper structures. For deeper structures or larger patients, one might choose a lower frequency or curved transducer. When imaging small body parts, such as a finger, a small transducer (hockey stick) may help.

When planning a procedure, one must consider the type of transducer that yields the highest quality images. There are a variety of transducers that can be used with varied frequencies and shapes. In general, higher-frequency transducers are used for imaging more superficial structures, as they offer better resolution. However, the higher-frequency sound wave is more easily attenuated and has a decreased ability to penetrate tissue, limiting its use in the evaluation of deeper structures. For deeper structures or larger patients, one might choose a lower frequency or curved transducer. When imaging small body parts, such as a finger, a small transducer (hockey stick) may help. Image guidance for procedures includes ultrasound, fluoroscopy, computed tomography, and, in some cases, magnetic resonance imaging (MRI). In general, ultrasound is particularly helpful in guiding soft tissue procedures such as therapeutic tendon sheath injection, soft tissue biopsy, and cyst or abscess aspiration/drainage.[1][7] Ultrasound, computed tomography, and fluoroscopy guidance can be used for both joint aspiration and therapeutic injection. The chosen modality may depend on availability, user expertise, the body part to be treated, and the patient's body habitus. Advantages of ultrasound include the absence of ionizing radiation and direct, real-time visualization of the needle and surrounding soft tissues during the procedure. During fluoroscopic guidance, the needle is intermittently imaged, and its position is assessed only relative to the associated osseous structures. The involved soft-tissue structures must be inferred from anatomical knowledge. Also, fluoroscopy often requires a contrast agent to verify needle placement, whereas ultrasound allows direct visualization of the needle position. Computed tomography is useful for biopsy of osseous structures or therapeutic injection of deep anatomic structures, which can be difficult to visualize with ultrasound or palpate on physical examination.[7][8][9][10]

Potential complications include pain, infection, bleeding, damage to nearby structures, allergic reaction, and non-therapeutic results. Complications specific to steroid use include septic arthritis, post-injection flare, local tissue atrophy, skin discoloration, tendon rupture, cartilage damage, avascular necrosis, flushing, and increased blood glucose level. If inadvertently injected intravascularly, there can be severe CNS and cardiac effects, particularly with insoluble, particulate formulations such as triamcinolone, which can embolize and lead to stroke.[18] As mentioned previously, the maximum safe dose of lidocaine in the ultrasound is 300 mg or 30 ml of 1% lidocaine. Above this threshold, there is a risk of CNS, cardiac, and skeletal muscle toxicity. Local anesthetics are toxic to chondrocytes in both animal studies and in vitro studies using human chondrocytes; bupivacaine is the most chondrotoxic, and ropivacaine the least. Lidocaine is most often used because it is the least expensive and most readily available.[20][21]

As mentioned above, shoulder pain is often multifactorial in etiology. Often, the radiologist and orthopedist work together to determine the underlying cause of a patient’s pain. A patient typically presents initially to their primary care provider, and if clinically indicated, they may be referred to an orthopedic specialist for further evaluation. Considering the patient’s history and physical exam findings, further evaluation with diagnostic imaging is sometimes indicated to evaluate for underlying pathology. It is not uncommon for imaging evaluation, such as MRI, to demonstrate multiple abnormalities, any of which could be causing the patient’s pain. In these cases, it can help perform a diagnostic and sometimes therapeutic injection to help clarify the clinical significance of the imaging findings. If a patient experiences pain relief after a targeted injection, it can be inferred that the treated area was a pain generator. Alternatively, if the patient does not have pain relief, one can infer that this area was not a pain generator. The patient’s response is clinically important as it can guide what surgical procedures, if any, may be offered for symptomatic relief. It can also help a patient avoid unnecessary surgical procedures. Orthopedic nurses set up the procedure, assist during the procedure, and provide patient instruction. Physical therapy may be needed to assist with post-procedure recovery exercises and to strengthen the muscles around the shoulder joint. These disciplines need to function as an interprofessional team to achieve optimal patient outcomes from this procedure.