1. What is non-surgical rhinoplasty
A new approach in cosmetic medicine
Non-surgical rhinoplasty is a cosmetic medical technique that improves the shape or contour of the nose by injecting a dermal filler into the nasal tissue without using a surgical scalpel [1]. In the US alone, over 2.7 million (DeVictor 2021) injection procedures were performed in 2019, and with low cost, short downtime, and the point that results are obtained immediately, demand is rapidly increasing worldwide [2]. This procedure is widely indicated for correcting a dorsal hump, adding height to the radix, adjusting the height or angle of the tip, and even correcting minute deformities after surgical rhinoplasty [3, 4].
The main preparations used
As injection materials, hyaluronic acid, calcium hydroxyapatite, or autologous fat or cartilage may be used [1]. However, in the survey of one systematic review, hyaluronic acid was the most frequently used in 73.38% of all cases, followed by calcium hydroxyapatite at 12.44% (Williams 2020) [5]. Hyaluronic acid is a glycosaminoglycan component originally present in the human body, composed of alternating monosaccharides of d-glucuronic acid and N-acetyl-d-glucosamine [6]. Therefore, hypersensitivity reactions are unlikely to occur, and high safety is its characteristic [6]. In addition, it has the greatest advantage that the effect can be reversibly undone using the enzyme hyaluronidase, and because the incidence of adverse events is also low, it is recommended by many specialists as the first choice [6, 7].
2. The effect and satisfaction of 5,000 cases (Harb 2020)
The background of the largest-scale retrospective study
Regarding the effectiveness of non-surgical rhinoplasty using hyaluronic acid, a retrospective study of 5,000 cases by a single specialist—the largest scale ever—has been reported [8, 9]. This study targets treatments performed during the period from March 2016 to January 2019 [9]. The breakdown of patients was 4,702 women and 298 men, with a mean age of 27 [9]. The most common age group was 25 to 34, accounting for 52% (Harb 2020) of the total [9].
Indicated symptoms and specific procedure data
The most common indication for treatment was correction of a dorsal hump, amounting to 43.6% (about 44%) of the total [8, 10]. Next, deformity correction after surgery was 20.0%, tip droop 14.7%, contour indistinctness 8.7%, asymmetry seen from the front 7.0%, and a bulbous nose 6.0% [10]. The mean procedure time was short, at 12 minutes, completed in as little as 5 minutes and at most 25 minutes [11]. The mean amount of hyaluronic acid injected per patient was 0.72 ml, with a range of 0.30 ml to 2.40 ml [11]. In addition, the pain score reported by patients immediately after the procedure was a mean of 2 (Harb 2020) on a 10-point scale—very low—confirming that the physical burden on patients is minimal [11].
Extremely high patient satisfaction
Among these 5,000 cases, only 3 patients (0.06%) clearly expressed dissatisfaction with the procedure result [12]. Furthermore, when dissolution with hyaluronidase was proposed to these 3 (Harb 2020) to return them to the pre-procedure nose shape, all of them declined it [12]. In addition, in another systematic review of 1,600 cases, the overall satisfaction recorded an extremely high figure of 94.94% [13]. In the same study, while the short-term satisfaction within 6 months after the procedure was 95.19%, the long-term satisfaction after 6 months was 89.58%, and although a statistically significant difference was seen (p value = 0.017), it still shows that about 90% (Williams 2020) of patients are satisfied with the result over a long period [13].
📊 HA rhinoplasty proportions by indicated symptom (Harb 2020 / 5,000 cases)
Source: Harb et al. 2020 (single-operator, 5,000-case retrospective study)
3. Duration
The properties of hyaluronic acid in the nasal region
Generally, the effect from hyaluronic acid injection is temporary, but injection into the nose tends to be absorbed more slowly and the effect tends to last longer compared with other parts of the face [14]. Expert consensus points out that hyaluronic acid injected into specific parts of the nose may have an effect lasting up to 2 to 3 years (Trevidic 2022) [14]. In addition, according to the analysis of a large-scale systematic review, the general period during which the best aesthetic result is maintained is estimated to be about 6 months to 1 year (Williams 2020) [15]. In a survey using patient self-reported rating scales (FLO-11, etc.), a good effect was maintained for 150 days (10.1097_DSS 2020) in 50% (10.1097_DSS 2020) or more of subjects, and it is concluded that generally a notable cosmetic effect lasts for 4 months (10.1097_DSS 2020) to 6 months (10.1097_DSS 2020) [16, 17].
The course and retreatment in long-term follow-up
In the clinical data of 5,000 cases, patients were informed that the guideline for the duration of the effect was 9 months to 12 months [18]. As the actual course, at the 12-month point about 32% of patients visited for re-evaluation, and many of them received retreatment [18]. Furthermore, patients who visited and received retreatment at the 18-month point were 5% [18]. A point of note is that even 12 months after treatment, the shape of the nose had not completely returned to the pre-treatment state, and a soft contour was often observed to be maintained [19]. The product itself is a cross-linked hyaluronic acid designed with the intent of 12 months (Harb 2020) of persistence, but it is generally thought that the clinical effect, while gradually declining, persists over the long term beyond this period [19].
4. Complication risk (SR + meta-analysis)
The overall risk based on systematic reviews
Non-surgical rhinoplasty is considered highly safe, but the risk of complications is not zero. In a comprehensive systematic review and meta-analysis of 8,604 cases, the overall incidence of adverse events (complications) was calculated to be 2.52% [20]. Even when case reports were excluded and it was limited to cohort studies only, the incidence of adverse events was 2.34% (DeVictor 2021) [21]. In addition, in another review of 1,600 cases, the complication incidence within cohort studies remained at a low level of 1.63% (26 cases (Williams 2020)) [22].
Details of mild and serious complications
- Mild complications: The most common complications in the meta-analysis were mild, with bruising accounting for 1.58% (136 cases) and hematoma 0.13% (11 cases (DeVictor 2021)) [20, 23].
- Serious complications: Although extremely rare in frequency, serious complications have also been reported. Vascular occlusion 0.35% (30 cases), vision loss 0.09% (8 cases), skin necrosis 0.08% (7 cases), and infection 0.07% (6 cases) occurred [20, 23]. In addition, nodule formation in 6 cases, asymmetry in 5 cases, granuloma in 2 cases, telangiectasia in 1 case, blepharoptosis in 1 case, and anaphylaxis in 1 case (DeVictor 2021) were reported [23]. Moreover, from an extensive literature survey, a total of 65 cases (Williams 2020) of serious vascular events, including 30 cases of skin necrosis and 33 cases of visual impairment, were identified [24].
Risk comparison between preparations (hyaluronic acid vs. CaHA)
Through the meta-analysis, it was found that the complication risk differs greatly depending on the type of preparation injected. The complication incidence of 6,385 cases using hyaluronic acid was 3.12% (199 cases) [25]. In contrast, in the 63 cases using calcium hydroxyapatite (CaHA), the complication incidence was markedly higher at 19.05% (12 cases (DeVictor 2021)), and many of the serious cases such as skin necrosis and permanent vision loss were related to the use of CaHA [25, 26].
Safety data of a single facility with 5,000 cases (Harb 2020)
In the single-facility study of 5,000 cases, intraoperative bleeding was seen in 11.1% (559 people) and immediate postoperative bruising in 2% (100 people) [27]. The most-to-be-watched signs of arterial occlusion were confirmed in 0.48% (24 people), with the sites of occurrence being the tip in 16 people, the dorsum in 6 people, and the radix in 2 people [27]. Of these, 14 people recovered naturally with massage and warm compresses, and the remaining 10 people immediately received a procedure injecting 1,500 IU of hyaluronidase and recovered completely without sequelae [27]. The final skin necrosis was kept to 0.06% (3 people) and infection to 0.04% (2 people (Harb 2020)), showing that prompt response firmly ensures safety [8, 28, 29].
5. Comparison with surgery
The merits and risks of surgical rhinoplasty
Surgical rhinoplasty (surgery) is the absolute gold standard for performing functional and aesthetic reconstruction of the nose [3]. However, the surgical approach has demerits such as high cost, the need for general anesthesia, and long-term downtime [30, 31]. Furthermore, the risk of prolonged postoperative edema or bruising, and irreversible complication risks such as iatrogenic deformity and functional deficits from destruction of the nasal valve, cannot be ignored either [30].
The merits and limits of the non-surgical approach
By contrast, the non-surgical approach using hyaluronic acid and the like has the strong advantage that downtime is extremely short and the result can be visually confirmed almost immediately after the procedure [4]. Especially in correcting minute asymmetry or over-resection after surgery, it is an excellent option for patients who refuse reoperation [31]. In fact, in the 5,000-case study as well, 20.0% (Harb 2020) of the total was for the purpose of correction after surgery [10].
On the other hand, non-surgical reshaping has clear limits. Because hyaluronic acid cannot change the bone framework of the nose itself, it is impossible to fundamentally correct a severely deviated (crooked) nose, an extremely large hump, a markedly bulbous nose, and so on [32]. In addition, because the effect is temporary, periodic re-injection every 1 to 2 years (Williams 2020) is needed to maintain it [33]. Moreover, when injecting into a nose after surgery, caution is needed regarding the point that the injection space is limited by the presence of scar tissue from past surgery and the decrease in skin extensibility, raising the risk of vascular insufficiency [34, 35].
6. Choosing a safe procedure
Anatomical knowledge and the characteristics of the Asian nose
Non-surgical rhinoplasty is a high-risk procedure that, one step wrong, invites catastrophic results such as blindness or skin necrosis [36]. Therefore, choosing an experienced physician well versed in the complex vascular anatomy of the nose is an absolute requirement [37]. The nose is composed of a 5-layer (DeVictor 2021) structure: skin, superficial fat layer, fibromuscular layer (SMAS), deep fat layer, and periosteum or perichondrium [38]. The blood supply is received from branches of the external carotid artery (the facial artery) and branches of the internal carotid artery (the dorsal nasal artery), and a technique to avoid mis-injection into these vascular networks is needed [39]. In addition, the Asian nose is classified as a mesorrhine nose, intermediate between Caucasian (leptorrhine) and African (platyrrhine) [40]. Choosing a physician who understands anatomical features such as a low, flat radix and dorsum and thick dermis and subcutaneous tissue at the tip directly leads to aesthetic success [40, 41].
Recommended injection techniques and the choice of device
As procedure standards to maximize safety, the following technical points can be cited.
- The depth of the injection layer: Because the majority of the major blood vessels run in the superficial layer, to minimize the risk of vascular damage, it is necessary to inject just above the deepest layer—the periosteum or perichondrium (the deep layer) [42].
- Low-pressure, micro-volume injection: To prevent bulk injection into a blood vessel, it is recommended to inject very slowly at low pressure, in micro-droplets of 0.1 ml or less per time (depending on the site, less than 0.02 ml (Harb 2020) to 0.05 ml (Trevidic 2022)) [43, 44].
- The choice of needle: Because there are reports of vascular occlusion even when using a blunt needle (cannula), specialists recommend using a very fine sharp needle such as 27-gauge or 30-gauge (Trevidic 2022) to inject precisely and at low pressure into the accurate layer [45, 46].
Prior assessment and emergency response (hyaluronidase)
Before the procedure, an assessment by a "pinch test" that pinches the nasal skin is always necessary [32]. If the skin is hard and cannot be pinched up from the bone or cartilage, accessing the correct injection layer is difficult, and because forcibly injecting carries a high risk of causing vascular damage from pressure, treatment should be forgone [32, 47]. Furthermore, the test of confirming the inside of the blood vessel by syringe aspiration before injection functions only about 53% (Trevidic 2022) of the time even in animal experiments, and is known not to be a completely reliable technique [48]. Therefore, to prepare for the unlikely event that signs of vascular occlusion such as skin pallor appear, it is indispensable to choose a clinic that always keeps an enzyme that can immediately dissolve hyaluronic acid (hyaluronidase) [7]. Animal experiments have shown that administering hyaluronidase within 4 hours (DeVictor 2021) of vascular damage may prevent skin necrosis, and this reversibility is the greatest safety reason for choosing hyaluronic acid [7, 49].
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7. Summary
Non-surgical rhinoplasty using hyaluronic acid is an excellent cosmetic treatment that can effectively improve the contour or height of the nose while avoiding the downtime and risks accompanying surgery [1, 50]. As a result of analyzing case data on the scale of thousands, the overall satisfaction reached about 95% (Williams 2020), proving that many patients are satisfied with the result over a long period [13]. The overall incidence of complications is also relatively low at 2.52% (DeVictor 2021), and by using the correct preparation (hyaluronic acid), the risk can be minimized [20, 25].
However, contrary to its convenience, it also has a high-risk side: once a serious complication such as vascular occlusion occurs, it invites irreparable situations such as skin necrosis or blindness [36]. Therefore, to finish this procedure safely and successfully, what is more important than anything is to choose a skilled specialist who deeply understands the Asian-specific anatomical structure of the nose and has the advanced technique to inject a micro-volume of hyaluronic acid at low pressure into the appropriate deep layer [37, 40, 42]. In addition, whether a medical system that can respond promptly with hyaluronidase in the unlikely event of an emergency is in place is also an essential condition for choosing a safe clinic [7].
References
- Williams L, Kidwai S, Mehta K, et al. Nonsurgical Rhinoplasty: A Systematic Review of Technique, Outcomes, and Complications. Plastic & Reconstructive Surgery. 2020 DOI
- Harb A, Brewster C. The Nonsurgical Rhinoplasty: A Retrospective Review of 5000 Treatments. Plastic & Reconstructive Surgery. 2020 DOI
- Trevidic P, Kim H, Harb A, et al. Consensus Recommendations on the Use of Hyaluronic Acid–Based Fillers for Nonsurgical Nasal Augmentation in Asian Patients. Plastic & Reconstructive Surgery. 2022 DOI
- DeVictor S, Ong A, Sherris D. Complications Secondary to Nonsurgical Rhinoplasty: A Systematic Review and Meta‐analysis. Otolaryngology–Head and Neck Surgery. 2021 DOI
The author of this article
Hiromitsu Nakamura Physician
Zetith Beauty Clinic Ginza / Osaka / Fukuoka
He has a track record of research presentations at domestic and international conferences in Japan and is also involved in technical guidance and education across the entire Zetith Beauty Clinic. Specializing in precise cosmetic medicine based on anatomical grounds, he pursues natural results tailored to each individual's bone structure and tissue.