Radial Sound (Shockwave) Therapy Resolves Delayed-onset Nodules Following Injection of Hyaluronic Acid Dermal Filler: A Case Study

J Clin Aesthet Dermatol. 2021;14(12 Suppl 1):S15–S17

by Laura Ostezan, MD, and Jenna Peck, RN, MSN, WHNP-BC

Dr. Ostezan is a board-certified dermatologist who practices aesthetic dermatology in Reno, Nevada. Ms. Peck is an advanced practice, board-certified Womens’ Health Nurse Practitioner and Aesthetic Medicine Specialist who practices cosmetic medicine in Gardnerville, Nevada.

FUNDING: No funding was provided for the preparation of this article.

DISCLOSURES: Assistance with manuscript preparation was provided by Lynda Seminara, CMPP, of ClearView Medical Communications, LLC, and was funded by a publication grant from Allergan (now AbbVie). Allergan (AbbVie) had no role in the design or conduct of the research.

ABSTRACT: Delayed-onset nodules, a potential complication of injectable hyaluronic acid (HA) fillers, can be distressing to both patient and clinician. Current treatment options, including oral corticosteroids and antibiotics, have potential side effects and may be ineffective or contraindicated in some patients. Hyaluronidase is an enzyme used to degrade HA fillers. Although it is generally effective for resolving such nodules, it can interfere with the favorable aesthetic effects of filler treatment. This report describes a novel and successful method of treating delayed-onset nodules in facial tissue. Radial sound (shockwave) therapy was used to treat multiple delayed-onset facial nodules in two patients following HA filler injection. Substantial improvement was observed in both patients after the initial 10-minute session, and all nodules resolved fully by the third or fourth treatment. There were no side effects or downtime. Patients were satisfied with the results, particularly because the aesthetic effects of the HA filler were maintained. 

KEYWORDS: hyaluronic acid, dermal filler, delayed-onset nodules, shockwave therapy, radial sound treatment 

Augmentation of soft tissue by injection of hyaluronic acid (HA)-based dermal filler is a commonly performed aesthetic procedure. It is frequently used to address loss of facial volume, atrophic scarring, and facial asymmetry. Although the procedure is generally considered safe, complications do occur, such as the development of delayed-onset nodules. These nodules can be infectious and related to bacterial contamination, but most likely result from an immunologic stimulus or trigger,1 such as viral infection, trauma, dental procedures, or facial injury.1 In a recent retrospective study of 4,500 patients,1 delayed-onset nodules occurred in up to one percent of patients a median of four months after treatment with Vycross® fillers (Allergan, Irvine, California); however, the incidence rate is lower (0.25%) for non-Vycross fillers.1 

Delayed-onset nodules are transient in nature and usually resolve without incident within six weeks.1 However, delayed-onset nodules can be uncomfortable and distressing to patients, and treatment is desired in such cases. Current options for managing delayed-onset nodules, including antibiotics and corticosteroids, may be undesirable to patients and practitioners due to potential side effects or may be contraindicated or ineffective in some patients. As such, more invasive procedures, such as surgical excision, may be required. Hyaluronidase is an enzyme that can be used to degrade the filler, but it is costly and may increase risk of spreading infection, if nodules are related to bacterial contamination.2 Moreover, the degradation properties of hyaluronidase can interfere with the aesthetic effects of the HA filler. Hence, an effective noninvasive treatment modality would be a welcomed addition to the available treatment options for delayed-onset nodules following HA injection.

Radial sound (shockwave) technology (RST) has been employed in the treatment of soft-tissue injuries, such as tendinitis, fasciitis, and panniculitis, for several years.3-7 More recently, RST has been used in aesthetic practice to reduce cellulite.8-10 An author of the present report (J.P.) has successfully used RST technology (ZWave®; Zimmer, Neu-Ulm, Germany) to treat postradiofrequency lipolysis. Favorable results prompted the current case study to evaluate the effects of RST on delay-onset nodules caused by HA filler injections. Herein is a summary of the initial experience using RST to treat noninfectious delayed-onset nodules caused by HA filler injections. The authors emphasize that this treatment should not be administered to patients suspected of having bacterial biofilm or other potentially infectious nodules. 

Case Reports

Patient 1. Patient 1 was a 75-year-old woman who had received HA fillers five years earlier without incident. Her recent treatments included injections of an HA gel filler into her cheeks and mid-face (Juvéderm® Voluma™, Allergan, Bridgewater, New Jersey) and her perioral rhytids (Juvéderm Vobella™). There were no immediate post-injection complications.

Three months later, the patient presented to our clinic with five circumoral nodules located in her right and left oral commissures and upper lip. The nodules were not visible but could be detected by palpation; each was approximately one centimeter in diameter. The patient reported that the nodules felt “hot and tight” under the skin. She also reported to have experienced an upper respiratory infection two weeks before the nodules appeared, but was afebrile upon presentation, with no systemic signs of infection; thus, an infectious etiology was not suspected in regard to the nodules. The decision was made (with the patient’s consent) to use RST to attempt to break up the nodules. 

RST settings were 80mJ/10Hz×2500 pulses per cheek and 1,000 pulses over the upper lip. A sterile gel served as the gliding agent. Before treating the upper lip, caution was taken not to disturb the patient’s teeth by covering them with folded gauze and holding the lip outward with gloved fingers. The patient reported no discomfort from treatment at these low settings. 

Immediately after the first treatment, lasting 10 minutes, the patient stated that the nodules felt “less tight” and were “less hot and uncomfortable.” Immediately post-procedure, the nodules felt smaller and softer on palpation.The patient agreed to return for three additional sessions over the next two weeks and to delay treatment with hyaluronidase or oral corticosteroids. After the fourth RST treatment, the nodules had resolved completely, and the aesthetic effects of the HA filler were maintained. The patient was satisfied with the results and reported no downtime or side effects related to the RST therapy. Treatment with hyalyronidase or corticosteroids was not required.

Patient 2. Patient 2 was a 58-year-old woman who had received HA fillers injections multiple times previously without incident or complication. Four months prior to presentation, the patient received HA gel filler injections to her cheeks (Juvéderm Voluma) followed, two months later, by injections to her oral commisures, marionette lines, and mandible (Juvéderm Ultra XC). Two months following her last injections, the patient returned to her injector with multiple 2- to 4cm nodules, described by the injector as “indurated but nontender and palpable in the exact areas” where the HA fillers had been injected. The patient was prescribed a 15-day course of prednisone (20mg/d) and was administered 2mL of hyaluronidase (Hylenex® USP U/mL; Halozyme, San Diego, California), which was injected into the nodules. This treatment regimen achieved a small reduction in the size of the nodules, but failed resolve them in a satisfactory manner. The patient was then referred to our clinic for treatment, where she agreed to undergo RST therapy. 

Our examination revealed five nodules, 1 to 2cm in diameter, among the right and left oral commissures and upper lip. The patient’s history included severe acute bronchitis and aggravation of environmental allergies shortly before the nodules appeared. 

The treatment settings were modified (from those used in Patient 1) to 60mJ/6Hz × 2500 pulses per area as a precautionary measure to avoid damaging her teeth, particularly because all affected areas were circumoral. Immediately after the first treatment, lasting 10 minutes, the patient reported that she could no longer feel some nodules and that the nodules she could still feel were smaller and softer. Examination confirmed that the remaining nodules were smaller and softer to palpation, and that two nodules in her left oral commissure had fully resolved. 

To reduce travel time for Patient 2, who lived some distance from our clinic, subsequent treatments were performed on a weekly basis. The same settings were used for the subsequent sessions. During Treatments 2 and 3, a small quantity of hyaluronidase 0.45mL was injected into a persistent nodule in the patient’s left upper lip, not to completely degrade the filler but to aid its dispersion. One month after the third treatment, all nodules had resolved completely, and the aesthetic effects of the filler were retained. The patient was satisfied with the results and reported no downtime or side effects related to RST therapy. 


The etiology of delayed-onset nodules remains unclear, but evidence suggests that such nodules are immune-mediated (i.e, caused by a triggering event1), as was likely the case in both of our patients. As such, careful attention should be paid to aseptic technique and patient selection when administering HA filler injections.11,12 If delayed-onset nodules develop, RST therapy may offer an effective alternative to the currently available treatment options. RST is already used in many dermatology and aesthetic medical practices, rendering it affordable and readily accessible as a potential treatment option for noninfectious delayed-onset nodules resulting from HA injections. Larger-scale, controlled studies are required to support our findings. 


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