Microinjection Technique: A Novel and Comprehensive Approach for Nose Reshaping with Hyaluronic Acid Fillers

J Clin Aesthet Dermatol. 2024;17(5):43–47.

by Cemre Busra Turk, MD; Bugra Burc Dagtas, MD; Neslihan Fisek Izci, MD; and Gonca Gokdemir, MD

Dr. Turk is with the Wellman Center for Photomedicine at Massachusetts General Hospital in Boston, Massachusetts, and Department of Dermatology at Harvard Medical School in Boston, Massachusetts. Dr. Dagtas is with the University of Health Sciences at the Istanbul Training and Research Hospital and Dermatology Clinic in Istanbul, Turkey. Dr. Izci is with the Faculty of Medicine and Department of Dermatology at Bahcesehir University in Istanbul, Turkey. Dr. Gokdemir is with Prof. Dr. Gonca Gokdemir Clinic in Istanbul, Turkey.

FUNDING: No funding was provided for this article.

DISCLOSURES: The authors have no conflicts of interest relevant to the contents of this article. 

ABSTRACT: Nose reshaping with hyaluronic acid (HA) fillers, also known as medical rhinoplasty, is an increasingly popular, minimally invasive aesthetic procedure. As the demand for nasal reshaping continues to rise, it is essential to develop safe and efficient injection techniques and assess satisfaction to ensure optimal outcomes and patient-centered care.

Objective. This study aims to evaluate patient and physician satisfaction with hyaluronic acid filler applications using microinjection technique for nasal reshaping.

Methods. The study included healthy adult patients who underwent medical rhinoplasty with the same HA filler using the microinjection technique. Patient satisfaction levels were evaluated at one and six months after the last injection using the Global Patient Satisfaction Scale (GPSS). Additionally, an independent dermatologist conducted a clinical evaluation for each patient by comparing before and after clinical pictures, using the Aesthetic Improvement Scale (AIS). Any side effects were recorded during each session and follow-up period for six months.

Results. A total of 40 patients (37 women and 3 men) participated in the study. The most frequently targeted anatomical areas for filler injections were the nasal tip (100%), columella (100%), nasal prominence (100%), nasal dorsum (85%), and nasal root (82.5%). Injections distal to the nasolabial fold (NFL) were performed in 2.5 percent of patients. Patients expressed high satisfaction with the results at both one and six months after the procedure (mean GPSS, respectively; 4.65 and 4.47). Similarly, clinicians reported satisfaction with outcomes at the same time points (mean AIS, respectively; 1.7 and 1.4). Apart from mild pain during the procedure and transient erythema afterward, no side effects were recorded.

Conclusion. Medical rhinoplasty with HA fillers using the microinjection technique is an effective and reliable procedure. This technique provides safe and aesthetically pleasing results from both patient and dermatologist perspectives, making it a favorable option for nasal reshaping with HA dermal fillers.

KEYWORDS: Dermal filler, hyaluronic acid fillers, medical rhinoplasty, nose reshaping, filler techniques

Introduction

Rhinoplasty operations are one of the most common cosmetic surgery procedures globally. However, non-surgical (medical) nose reshaping treatments have recently become popular. Nose reshaping using filler injections are more economical than rhinoplasty operations, the recovery time is shorter than surgery, and the results are seen immediately.¹ Although hyaluronic acid (HA) fillers are mostly preferred for the nasal region, there are also studies on semi-permanent (such as calcium hydroxyl apatite or polycaprolactone) or permanent filler (polymethylmethacrylate) applications in the literature.² The main goal of these procedures is to camouflage the arch structure, correct deformities, or support depressed areas on the nasal dorsum, providing alar type projection, correcting the nasolabial angle, and correcting deformities.³ However, the nasal area is the most dangerous filler injection site considering the rates of vascular complications. Therefore, injections in this specific area should be performed by experienced physicians with a strong knowledge of anatomy.³

Besides injectors, injection technique is also crucial for safe injection in the nasal area. Injection using a thick needle, aspiration before injecting the fillers, using a cannula, or deep injections just above the bone surface (i.e., the area without vascular structure) may be preferred for safer applications. However, even using these measures, there is still a risk for vascular complications in this area. The chosen filler material and its properties are also important and adjustable factors for better results. It is safer to use fillers that do not have much tissue invasion, have weak hydrophilic properties, and are not resistant to hyaluronidase.⁴

Due to the popularity and regional risks of nose reshaping with HA filler, it is essential to better understand the expectations of patients and improve injection techniques for safer applications and better outcomes. The present study endeavors to offer a comprehensive analysis of the outcomes of nose reshaping performed with HA fillers using the microinjection method, with a particular emphasis on the perspectives of both the patient and the injector. Through an in-depth discussion of the findings, this work aims to shed light on this technique’s potential benefits and limitations in optimizing nose reshaping using HA fillers.

Methods

Clinical study design and ethics. This study was a single-center and retrospective study with a prospective clinical registry, evaluating patient and injector satisfaction rates on nose reshaping with HA filler using a microinjection technique. Ethical approval was obtained from the Clinical Research Ethics Committee of Bahcesehir University. 

Forty patients who underwent nasal filler application at our clinic between June 2022 and November 2022 were included in the study. Pregnant or breastfeeding women and/or those with autoimmune diseases or active dermatological conditions, such as herpes, acne, or rosacea, were excluded from the study. All patients provided written informed consent for the filler injection, with details of the procedure explained to them beforehand. The demographic characteristics of the patients were recorded. Before and after the procedure, patients’ photographs were taken from the frontal and profile views.

Injection technique. Each injection was administered by the same physician with the same filler: an HA filler containing 20mg/mL HA (Restylane®-lidocaine; Galderma, Lausanne, Switzerland). A topical anesthetic was applied to the nasal area followed by a 20-minute wait period prior to commencing the procedure. After the target region was numbed, it was cleaned with an antiseptic solution to start the procedure.

Five areas in the nasal region were injected with HA filler according to the patient’s needs: radix, nasal dorsum, nasal tip, columellar area, and alar base. The microinjection technique involves administering a maximum of 0.05- 0.02 cc of HA at each injection point using a suitable applicator within the appropriate plane based on the region being treated. For the radix, nasal dorsum, and nasal tip, subdermal/intradermal planes were chosen with applications utilizing a 0.5mL, 30 G insulin syringe. For the columella, injections were administered in the subcutaneous plane, while for the nasal spine, they were delivered perpendicularly to the periosteum, both utilizing a 29G needle (Figure 1). Injections were performed using a 29G needle for the subcutaneous columellar and bony nasal spine areas. A 0.5mL 30G insulin syringe was used for the other regions. The subdermal and intradermal planes were used for the injections on the radix, nasal dorsum, and/or nasal tip. A follow-up visit was set 2 to 3 weeks after the initial injection, and additional applications were performed at that session as needed. A maximum of 0.5cc of filler was used per session.

Assessment of the effectiveness of filler application. The global patient satisfaction scale (GPSS), which is a five-point Likert scale, was used to evaluate the patients’ contentment levels one and six months after the last injection visit. The numbers and meanings were as stated, respectively, 1=not satisfied at all, 2=slightly satisfied, 3=moderately satisfied, 4=quite satisfied, 5=very satisfied. An independent dermatologist scored the results at the same time points using the Aesthetic Improvement Scale (AIS) on the photographs taken of the patients. The scale was another five-point Likert scale, as follows: +2=very good, +1=good, 0=no change, -1=poor, and -2=very poor. 

Statistical analysis. Analysis was performed with the SPSS (Statistical Package for Social Science) version 23.0 program. The results were evaluated within the 95 percent confidence interval, and p<0.05 values were considered statistically significant. 

Results

Forty patients (37 female, 3 male) participated in this study. The mean age was 36.1±1.7 (minimum: 18, maximum: 62). The anatomical areas where fillers were injected were, in order to frequency, nasal tip (100%), columella (100%), nasal prominence (100%), nasal dorsum (85%), nasal root (82.5%), distal to the nasolabial fold (NFL) (2.5%). The total filler amounts utilized were as follows: nasal tip, 0.15cc; columella, 0.05cc; dorsum and radix, 0.2cc; and nasal spine, 0.1cc.

The sole patient requiring an injection in the distal NFL expressed concerns about the width of their nasal wings and a noticeable depression at the nasal tip when smiling. Three of the patients sought a filler treatment for revision after surgical rhinoplasty. Complaints of these patients included deviation on the nasal dorsum (66.6%), depression on the nasal dorsum (33.3%), and asymmetrical ala nasi (33.3%).

Throughout the six-month follow-up period, all subjects expressed satisfaction with the results (Figure 2). After one month, the independent dermatologist reported that 97 percent of the aesthetic outcomes were “good” or “very good,” decreasing slightly to 77.5 percent after six months (Figure 3). Figures 4 to 6 show before and six months after HA filler treatment in the subjects who reported being “very satisfied” with the outcomes.

The mean GPSS score was 4.65 (min=3, max=5), and the AIS score was 1.70 (min=0, max=2) after the first month of the procedure. These two scores were positively correlated (r=0.55). Although there was a weak positive monotonic relationship between age and AIS, the relationship between age and GPSS scores was nearly negligible (r= 0.19; 0.05, respectively) at that time.

After six months of the filler application, the mean GPSS score was 4.47 (min=2, max=5), and the AIS score was 1.42 (min=-1, max=2) after the first month of the procedure. These two scores were positively correlated (r=0.65). Although patient age has a weak negative correlation with AIS, it was not associated with GPSS scores (r=-0.24; 0.05, respectively).

There was a statistically significant decrease in AIS scores between the 1st and 6th months (p=0.002), while GPSS scores tended to be more self-consistent during the same period (p=0.17).

Other than pain during the procedures, there were no adverse events or complications during the procedure, and transient erythema afterward. 

Discussion

This study reports the outcomes of nose reshaping using HA fillers, specifically employing the microinjection method in 40 patients, targeting the nasal region. The most frequently targeted anatomical areas for filler injection were the nasal tip, columella, and nasal prominence, accounting for 100 percent of cases, followed by the nasal dorsum and nasal root. Only 2.5 percent of patients required filler application distal to the NFL. Both patient satisfaction scores and dermatologist-assessed aesthetic outcomes were high. Over the six-month follow-up period, patients and injectors reported positive results, suggesting that hyaluronic acid fillers are a viable option for patients seeking non-surgical or minor nasal enhancements.

The first nasal reshaping with dermal fillers began in 1885 using bovine collagen, and the first hyaluronic acid filler application was reported in a pilot study by Han et al in 2006.^5,6 There are various studies in the literature detailing nasal filler applications using different techniques and products. The most commonly applied filler products are hyaluronic acids. There are fewer studies performed with the biostimulatory calcium hydroxylapatite fillers and permanent applications using polymethyl methacrylate.^2,6 

Vascular complications, one of the most severe risks associated with dermal filler applications, occur most frequently in the nasal area. Due to anatomical complexity and potential risks, readily degradable fillers are considered safer for applications on the nasal region, while permanent fillers carry a significant risk.⁷ Existing literature contains minimal studies on permanent filler applications in the nasal area, underscoring the need for experienced physicians to perform such procedures for enhanced safety and control.² Biostimulatory fillers, such as calcium hydroxylapatite, have also been investigated for nasal reshaping, but their use necessitates high expertise.^8,9 Therefore, in line with the existing literature,⁹ we advocate the use of HA fillers to reduce the risk of superficial injections when shaping the nasal tip.

In addition to the safety profile, HA fillers may provide aesthetically pleasing outcomes when carefully selected with appropriate attributes. Especially when injecting in small, areas such as the nose, HA fillers with high viscosity, low water retention, and minimal tissue invasion should be chosen. Selecting fillers with excessive water retention may lead to enlargement over time and suboptimal aesthetic outcomes. Consequently, the majority of HA fillers employed in studies are of high viscosity, promoting a well-defined nasal shaping.^10–13

In this work, we exclusively used hyaluronic acid fillers produced with Non-Animal Stabilized Hyaluronic Acid (NASHA) technology, containing 20mg/mL HA, possessing attributes of high viscosity, minimal tissue invasion, and weak water retention. The primary purpose of the filler injections in the nasal area was shaping rather than volumizing, as the application area was generally small. The fillers selected for this area should have a high viscosity and a low tissue invasion. Comparably, Wang et al¹⁴ employed a similar filler product, Restylane®-Lyft by Galderma, Lausanne, Switzerland, focusing on patients of East Asian heritage.Their findings demonstrate success in using this filler for nasal enhancement, addressing specific aesthetic concerns such as nasal width and tip depression during facial expressions like smiling. Although there are a few nose reshaping studies that used Restylane®-lidocaine in the literature, they included fewer subjects than our study.¹⁵ In this work, we present 40 patients with satisfactory results.

To address the potential vascular complications and to provide a safer application, different injection techniques have been reported.¹⁶ Although performing with a cannula is relatively safe, the risk of vascular incidents remains.¹⁷ According to the literature, injections on the nasal midline are safer. However, there is a risk of migration of the filler in supra-bone injections to the radix and nasal dorsum, and it can easily be displaced. In our study, we applied microinjections on the radix and nasal dorsum, either subcutaneously or intradermally. In particular, small amounts (not exceeding 0.05cc per injection point) were slowly injected with low pressure. After each injection, the color change on the skin was evaluated and massaged. For the nasal tip, a slight subcision was performed using a 27G needle before the injection, and then the HA was injected in the subdermal plane. Perpendicular injections onto the bone require more filler to achieve the desired projection, which may cause enlargement of the nasal tip with an unpleasant appearance. Therefore, we applied a maximum of 0.05cc HA at each injection point and called this a microinjection technique. 

Importantly, in our study, the filler application procedures were well-tolerated, with no reported adverse events or complications, except for mild pain during the procedure and transient erythema afterward. Moreover, the microinjection technique provided good clinical results from the perspective of both the patient and the physician. Overall, both patients and injectors report similar levels of satisfaction and effectiveness regarding the treatment outcomes. Although physician satisfaction was relatively low in older patients and decreased over time, patient satisfaction was favorable in all ages during the six months. These findings demonstrate the safety and efficacy of HA fillers with microinjection technique in achieving aesthetically pleasing outcomes for patients undergoing medical rhinoplasty.

Limitations. Our work needs to be interpreted under some limitations. First, it was designed as a retrospective analysis of prospective, open-label applications. A double-blinded, randomized, controlled study would have provided a more robust design. However, considering we present a pilot study on an innovative technique instead of comparing fillers or injection techniques, our preliminary data may help evaluate the microinjection technique. Additionally, the study lacked objectively measurable endpoints like morphometric calculations. Nonetheless, the assessment of minimally invasive aesthetic outcomes from the patients’ perspectives can offer a comprehensive understanding. The inclusion of physician and subject standpoints in our fundamental data using well-established scales enhances the validity of our findings. Finally, our results represent an appraisal six months after the procedure, which may be considered as relatively early to assess long-term results, prompting the need for further investigation into the microinjection technique’s sustained effects.

Conclusion

Our study demonstrates that nose reshaping with HA fillers employing a microinjection method is a safe and effective option for patients seeking nasal enhancements. The use of HA fillers with specific attributes, such as high viscosity and low water retention, contributes to aesthetically pleasing outcomes. The microinjection technique, injections of a maximum of 0.05cc HA at each point within the right plane depending on the region, yields favorable clinical results, with high satisfaction rates among patients and physicians alike. While our study presents promising preliminary data, future research with more robust designs and longer follow-up periods is warranted to consolidate the microinjection technique’s efficacy and long-term benefits in nasal reshaping procedures.

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