The three phases of calcific tendinitis. (Reprinted with permission from Philip Peng Education Series)
Uhthoff and Loehr described three distinct stages in the disease process, namely, the precalcific, calcific, and postcalcific stages (Fig. 26.1). Depending on the phase of disease, the imaging appearance and physical consistency of the calcification differ significantly as do patient symptoms. The calcific stage consists of three phases: formative, resting, and resorptive.
The formative and resting phases are long-lasting asymptomatic stages (hard calcific phases) but may be associated with varying degrees of pain at rest or with movement. Many patients are asymptomatic if they are not large enough to induce impingement syndrome. These calcifications tend to be well circumscribed and discrete when examined radiographically and often produce significant acoustic shadowing by ultrasound scan (Fig. 26.2). It is difficult to aspirate the calcifications in these two phases because the calcifications are quite hard and chalklike. Most common indication of lavage at this stage is calcification over 1 cm in diameter, which commonly causes impingement syndrome.
The resorptive phase is the last phase in the calcific stage (soft or liquid calcium phase) and is the most symptomatic. Shedding of calcium crystals into the adjacent subacromial bursa may result in severe acute pain and restricted range of motion. This phase typically lasts for 2 weeks or longer. These calcifications appear ill-defined or well defined, but the opacity is homogeneous and less dense over hard calcific phase on radiographs, producing little or no acoustic shadowing by ultrasonography (Fig. 26.3). When aspirated, these calcified deposits typically are soft with toothpaste-like consistency. This stage is the most common indication for ultrasound-guided intervention.
Successful aspiration may not be possible in cases when the calcifications appear striated or small and diffusely scattered. In these cases, these calcifications can be grounded gently with the needle tip by rotating the syringe by fenestration technique.
Fenestration means the surgical creation of a new opening in a body part. For calcific tendinosis, new opening can be made by repeated needling procedure to stimulate natural absorption. This mechanical perturbation of the deposit is hypothesized to stimulate cell-mediated resorption. There is evidence in the surgical literature to support that calcific deposits need not be removed completely to achieve successful outcomes.
Patient with painful arc and with radiologic evidence of calcium deposit in the tendon is usually the candidate. If the calcified tendinosis is noticed in patient with no symptoms, it is better to leave it alone as the procedure can cause pain. Dystrophic calcification is not included in the entity of calcific tendinosis and not a candidate for this procedure. This occurs in degenerative tissue and does not heal spontaneously. This is in contrast to the calcific tendinosis, which occurs in healthy tissue, is cell-mediated, and is self-limiting.
Ultrasound Scan and Procedure
Supine or oblique supine position for subscapularis and supraspinous lesion opposite the affected side
Lateral decubitus position for infraspinatus lesion
Probe: Linear 6–12 MHz
26G 1.5 inch needle for local anesthetic infiltration
18G 1.5 inch needle for calcium barbotage
24G 3.5 inch needle for release of calcium plug obstructing the 18G needle or fragment the hard calcium before lavage
Several 5 mL lock syringes
3 mL 1% lidocaine for irrigation (for filling in the several 5 mL syringes)
3 mL lidocaine with 1 mL dexamethasone
Approach: In-plane approach
One-Needle Barbotage Technique
First, identify the symptomatic calcification through full ultrasound examination. Place the transducer along the long axis of maximum calcium cavity (Fig. 26.4a). Target is the center of calcium cavity. Following skin infiltration with local anesthetic, advance the 18G needle until its tip is placed in the center of the calcification. Do not relocate or adjust the needle after inserting the needle in the calcium cavity. You have only one chance to insert the needle.
After bending the distal part of 6-cm-long 24G needle, pass the needle through into the lumen of 18G needle as a stylet for release of calcium plug obstructing the needle (Fig. 26.4b).