In order to obtain a coordinated result, the subunit principle in rhinoplasty was proposed by Burget and Menick.10 It was concluded that if more than 50% of one aesthetic subunit was involved, then the optimal choice would be removing the leftover and reconstruct the whole subunit, including all three lamellae.11 For the same reason, total or subtotal nasal reconstruction is considered when the defect is large and encompasses two or more nasal subunits.
The paramedian forehead flap has been the first choice and golden standard for nasal reconstruction so far. It provides esthetically satisfying skin color and texture to match surrounding tissue. The flap is well-vascularized and could be applied to smokers, considering that the blood supply of forehead tissue derived from the supratrochlear artery and other collateral arteries, which compose a complex vascular network with abundant nourishment.12,13 For this reason, the paramedian forehead flap was put forward by Millard as a two-stage procedure based on unilateral vascular pedicle to obtain a more effective length, smaller rotation angle and more applicable pedicle.14-16 The forehead flap surgery is generally safe to perform and anticoagulation therapy is not needed.17
The remaining problem is that forehead tissue contains 4 layers: skin, subcutaneous fat, the frontalis muscle and a thin layer of areolar tissue, which makes all forehead flaps thicker than normal nasal tissue and hard to form an ideal 3D shape.18,19 Menick18,20 preferred to perform a modified 3-stage forehead flap to overcome this problem. However, it may not be suitable for East Asian patients because of racial characteristics. Different from Caucasians, the skin of East Asians mainly pertains to Fitzpatrick skin type Ⅲ to Ⅳ with a higher risk of keloids and hypertrophic scars.21-24 It is thicker with dense ligamentous attachments, greater amount of melanin and contains more collagen, which results in a higher tendency to develop hyperpigmentation and scar formation.5,25,26 Hsiao et al24 therefore advocated some refinements based on the subunit principles in nasal reconstruction for ethnic Asian patients. Radovan27 first presented his technique of chest skin expansion at the Annual Meeting of American Society of Plastic and Reconstructive Surgeons. Not long after that, this technique was applied to nasal reconstruction and repairment of other units on the head for apparent advantages.28-31 The application of tissue expansion efficiently helps to solve this problem as the donor site can be totally free of tension and easy to close primarily, creating a minimum scar line following this modality.19 It can also thin the terminal branch of the flap to 1.2-2 mm so that the flap would perfectly match native nasal skin and might be folded to reconstruct inner lining or perform some other manipulations.32 Therefore, tissue expansion of the forehead flap provides abundant bulk of tissue for reconstruction, which is also supple, well-vascularized, easy to operate on and donor-site protective, especially for Chinese or East Asian patients.
Here, we extensively used expanded paramedian forehead flap in all total nasal reconstruction and 50% of half nasal reconstruction out of its attractive advantages and special consideration for Chinese patients. This flap was categorized by Wang et al33 as Type Ⅱ flap and the expander was suggested to be inserted submuscularly for safety concerns. The volume of the expanders we used was mostly 150ml. The volume of fluid injection was approximately twice the volume of the expander. Expansion often proceeded once a week, with 30-40ml fluid injected each time. Subsequent surgery was performed about 1 month after the final expansion to help stabilize forehead tissue. There is no need to dissect the pedicle after elevation of the flap because it is long enough and the size of the flap can be rather adaptive.33 Lu et al34 agreed with the priority of expanded forehead flap when dealing with non-Caucasian patients’ defects in consideration of hairline and the tendency to scar, which was in accord with our view. Pinto et al35 treasured the expanded forehead flap as well and claimed that it was their gold standard to provide external skin coverage in nasal reconstructions. Limitations of this technique include a prolonged surgical procedure, inconvenience in daily life and an embarrassing appearance with the expander implanted inside. However, the awkward situation could be evaded well through careful negotiation and planning with patients prior to the expansion procedure. According to other researches, patients may also encounter kinds of problems or complications, such as infection, extrusion, wound dehiscence and ruptures.36 The prevention of infection could be managed with an algorithm put forward by Dong et al.37 Nevertheless, we did not observe any complications directly related to the transferred flap, like necrosis or infection, except for two cases of leakage during the gradual process of tissue expansion. Radwan et al38 attributed the occurrence of leakage to 3 reasons: (1) inadvertent puncture of the tubing or the prosthesis; (2) improper securing of the connector; (3) use of an appropriate needle into the injection port. Thus, it was recommended that the tubing be trimmed, the connector be well protected and injections be completed at varied locations with a small needle. Our experience suggested that replacing the leaky expander with a more suitable one in time could figure out this problem effectively without any sequelae and do no harm to the final result. The forehead has been argued as one of the expander locations with the lowest incidence of overall complications, hence the extra injury that might occur to patients treated by expanded forehead flap is minimized.36,39
The racial features of Asian patients not only highlight the use of expanded forehead flap, but are also concerned with the donor site selection of cartilage grafts needed for structural support. In our series, 10 of 13 needed cartilage grafts for structural reconstruction, which provide reliable support to prevent the inner lining and outer envelope from collapsing especially for full-thickness defects. Donor sites include the ear and costal region. Cartilage from the remnant septum has been taken as another important source of grafts by doctors in view of its outstanding physical properties and harvesting convenience4,40-42, while we recognized it as an inappropriate choice for Chinese patients. Unlike Caucasians, the septal cartilage of Asian people is weak and scarce, especially when an extensive defect affects the cartilaginous septum, which necessitates the use of the auricular and costal cartilage.43,44 In our series, auricular cartilage was mainly used for ala, nasal tip and columellar reconstruction. Costal cartilage was designed as a three-dimensional strut to support the nasal tip, columellar, ala or dorsum and reinforce the nasal septum. It was as well treasured by our Chinese counterparts because the costal cartilage was satisfying in both quantity and quality, particularly when a large cartilaginous defect occurred.34,45 The intrinsic curve and suppleness of conchal cartilage make it the first choice to design alar batten grafts or replace lateral cartilage, while the prominent stiffness and abundance of costal cartilage are ideal to play the role as a central support element or dorsal onlay graft.46-48 Sannier et al49 also preferred to use ipsilateral conchal bowl cartilage and suggested the exploitation of costochondral cartilage when cartilage was in great demand.
As one of the most challenging tasks, reconstruction of the internal lining could be realized in various approaches.50 The application of different techniques, from the simplest split or full-thickness skin grafts to mucosal flaps, pedicled flaps and free flaps, are reviewed and concisely summarized by Philips4 along with their pros and cons. Unlike the viewpoint of Philips considering the turn-in pedicled flap far from being ideal, Thornton49 preferred the usage of forehead flap skin for turn-in lining, which corresponds with the experience of Noel et al.51 Weber and Wang52 proposed the reconstructive ladder and several principles in nasal-lining reconstruction to stratify reconstructive modalities from the least (secondary intention) to the most complex (free-tissue transfer). Flip scar flap, also known as hinge-over flap, is a turndown flap of the released scar53 and has been our first-place choice for the reconstruction of internal nasal lining according to the senior author’s experience. RFFF and nasolabial flap were also used when the residual skin tissue is not enough or not suitable. We recognized that mucosa tissue is the optimal choice for airway humidification, while the surgeons were not accustomed to endoscopic operation to replace nasal lining with mucosa. From our view, the use of flip scar flap did not result in any adverse consequence, as the postoperative evaluation showed. The selection of the internal lining is similar to that of our Chinese counterpart.54 Zenga55 argued that the hinge flaps had the greatest reach and vascularity, but they required a prolonged period of time between injury and repair. From our perspective, the average time needed to heal is generally acceptable. The use of titanium mesh for nonradiated patients with an extensively large mucosal defect was also approved by scholars, although we did not take this technique into account.55-57
The NOSE and ROE scores are commonly used to evaluate the outcome of rhinoplasty both aesthetically and functionally. In our series, the scores of both parts in the questionnaire were satisfying.9,58 The NOSE score mainly focus on the severity of nasal obstruction, and the ROE score includes 6 questions, measuring comprehensive attitudes of patients towards rhinoplasties. Our choice to use flip scar flap did not occlude the airway as some may suggest, and thus increase patients’ quality of life. The evaluation supports the extensive use of expanded forehead flap, together with flip scar flap to form internal lining.
As regards the continuous progress achieved in the area of rhinoplasty, advances in science and digital technology have benefited the nasal reconstruction surgery a lot. The application of 3D preoperative planning and templating in forehead flap nasal reconstruction has already been reported. Zeng et al59 scanned the patient’s 3D facial model including the nasal defect and got a normal 3D model with the highest similarity matched in a database. The normal model found by a personalized algorithm was then transformed into a 2D flattened one to help determine the scope and usage of the forehead flap, which is more reliable and precise than the conventional empirical approach depending on the surgeon’s personal experience and opinions only. Fishman et al60 also utilized a conformal “unwrap” tool to obtain an ideal 2D skin flap shape from the patient’s flattened 3D nasal geometry. The following printed layout could therefore be referenced and traced on the forehead for intraoperative use. Further studies are still needed to modify the flattening algorithm, improve the operating steps, and confirm the subjective and objective outcome of this computer-assisted design and manufacturing pipeline so that it could be applied more widely in nasal reconstruction. Moreover, 3D-printing technology can fabricate a 3D surgical template of the complex structure of patient’s normal nose, to guide the reconstruction visually61,62. Combined with the promising bio-engineered materials, 3D printing has also been explored and applied in the field of osteogenesis and chondrogenesis, like the regeneration of nasal and auricular cartilage, and its feasibility in regenerative medicine was demonstrated by trials63-66. The intricate anatomical structure of nose calls for the help of 3D printing together with bio-engineered materials to satisfy patients’ need for personalized medicine better. Taking the dynamic aesthetic into consideration may be another vital direction for improvement once capable technical assistance becomes available.
This study had several limitations. First, it is a retrospective study, and the sample size was constrained. It is also subject to limitations associated with retrospective design. The impact of COVID-19 pandemic prevented us from recalling patients distributed countrywide, to take pictures and conduct furtherer objective assessments by professional doctors.