Evidence-Based Nasal Analysis for Rhinoplasty

The 10-7-5 Method

Íris M. Brito, MD; Yash Avashia, MD; Rod J. Rohrich, MD

Disclosures

Plast Reconstr Surg Glob Open. 2020;8(2):e2632 

In This Article

Frontal View (10 Key Areas)

Facial Proportions

Several definitions of aesthetic ideals, relationships, ratios, and angles, have been described in detail including sex, ethnic, and age-specific characteristics.[2–6] Analysis of facial skeletal morphology and cephalometric headplates by Ricketts,[4] life-size photography and soft-tissue response to skeletal alterations in rhinoplasty by Guyuron,[5,6] and nasofacial ratios and relations by Rohrich et al[2,7] provided golden proportions for bone and skin components to define accurately rhinoplasty aesthetic goals. It is also helpful to detect facial disharmonies that can influence the surgical outcome. Adjunctive procedures addressing the facial skeleton such as orthognathic surgery, and careful attention to skin thickness, are important features to consider in rhinoplasty and facial balance.[2,4–7] Evaluation of the patient should include static and dynamic views, to identify possible dynamic changes of the nose and upper lip while smiling.[2,3,7] Examples of application of nasofacial analysis are the facial golden proportions (3 similar distances: trichion-to-eye, nose-to-chin, and eye-to-mouth)[4] and ratios (equivalent horizontal thirds: hairline-to-brows, brows-to-nasal base, and nasal base-to-menton; vertical fifths: limits adjacent to the most lateral projection of the head, the lateral canthi, and the medial canthi).[7]

Skin Type/Quality

The rhinoplasty surgeon should recognize the diverse anatomical variations that define ideal aesthetics across cultures or ethnic backgrounds.[8] White patients (Fitzpatrick type 1–3) are characterized by thin skin and facial proportions with equally spaced vertical fifths and horizontal thirds (Figure 4).[8] African noses commonly have thicker sebaceous skin; wider vertical middle fifth, and shorter height of the horizontal middle third.[8] Asian patients typically have relatively thick skin; wider middle fifth distance, and upper and middle thirds larger than the lower third.[8]

Figure 4.

Caucasian nose. Adapted with permission from Plast Reconstr Surg 2019;143:1179e–1188e.

Skin thickness can be a major factor affecting rhinoplasty outcomes.[2,9,10] Thin skin may show reconstructed nasal frame imperfections; however, nasal shape definition is more easily achieved.[2,9,10] A thicker skin can camouflage minor imperfections, but reduces the surface contour definition, due to prolonged edema and inflammation that can lead to scaring and unfavorable aesthetics.[2,9,10] Nasal skin is thickest at the radix and nasal tip and thinner at the rhinion and columella.[9,10] Thick skin at the tip and columella was associated with poorer rhinoplasty outcomes.[10]

Symmetry and Nasal Deviation

Nasal deviation is commonly associated with facial asymmetries (nose tends to deviate away from face wider side).[11] Correction of a deviated nose on an asymmetric face aim to obtain nasal symmetry and center the nose on a line between the mid glabella and the mid cupid's bow.[11] The deviated nose is an osseocartilaginous unit in which all components may play a role, and both functional and aesthetic problems must be addressed.[12,13] Different classification systems exist for nasal deviation.[12,13] Rohrich et al[12] described 3 basic types: caudal septal deviations (septal tilt, C-shaped and S-shaped), concave dorsal deformities (C-shaped, reverse C-shaped), and concave/convex dorsal deformities (S-shaped with bony pyramid deviation).[13] Guyuron et al reported 6 types of septal deviations: septal tilt (40%), C-shape anteroposterior (32%), C-shape cephalocaudal (4%), S-shape anteroposterior (9%), S-shape cephalocaudal (1%), and localized deviation or spurs (14%).[14] Correction may require diverse steps: open approach with wide exposure and release of septum deforming forces, straightening the septum and maintaining an adequate dorsal and caudal strut, restoring long-term support, reducing the hypertrophied turbinates, and adequate osteotomies.[12,13] Cartilage scoring and spreader grafts were also recommended.[14]

Dorsal Aesthetic Lines

Dorsal aesthetic lines were defined as originating on the supraorbital ridges, traversing medially along the glabellar area, converging at the medial canthal ligaments, diverging at the keystone area, and ending at the nasal tip.[15–17] Symmetry, width and definition should be accessed in every patient. Dorsal aesthetic lines width should match either the interphiltral distance or the tip-defining points width.[15] Male dorsum is wider and straighter, with less concavity at the superciliary ridges compared with women.[17] Component dorsal hump reduction is a reproducible 5-step technique to restore aesthetic and functional distortions of the dorsum: 1) separation of upper lateral cartilages from the septum, 2) incremental septal reduction, 3) dorsal bony reduction/rasping, 4) verification by palpation, and 5) final modifications (spreader grafts, suturing techniques, osteotomies).[15,16,18]

Bony Vault

The bony vault is composed of 3 distinct structures, the paired nasal bones and the perpendicular plate of the ethmoid.[19] Bony vault width, symmetry, and length of nasal bones are analyzed in frontal view. Bony base width should be 70%–80% of the alar base, typically equal to the intercanthal distance.[15,17] An open roof deformity (wide and flat bony vault) and width discrepancy between the bony vault and cartilaginous midvault may result from dorsal bony hump reduction.[19] Osteotomies are indicated to narrow wide bony vaults, close open-roof deformities and create symmetry by straightening deviated nasal bones.[15,17,19–21] External percutaneous lateral osteotomies provide a controlled fracture pattern with less intranasal trauma while minimizing associated morbidities of bleeding, edema, and ecchymosis.[15,20,21]

Midvault

The cartilaginous midvault include the paired upper lateral cartilages and the cartilaginous septum.[19,22] The keystone area represents a triangular region, union of the 6 distinct anatomical structures between the bony vault and the cartilaginous midvault.[19,22] Midvault width and deformities like the inverted-V or saddle-nose are identified in frontal view. The inverted-V deformity derives from midvault collapse due to over-resection of upper lateral cartilages (compared with the septum), creating a discrepancy between the bony and cartilaginous vaults that unmasks the caudal outline of the nasal bones.[15,19] Equalization of keystone width can be achieved by narrowing the bony vault (osteotomies), widening the midvault (tension spanning sutures, spreader grafts or autospreader flaps), or a combination of both.[19,22,23] Autospreader flaps adjust the height of upper lateral cartilages in a precise manner while preserving internal valve function.[24] In saddle deformity, a deficit in nasal dorsal support secondary to the loss of septal cartilage and/or nasal bone height exists.[25,26] Different reconstructive options were reported.[25,26]

Nasal Tip

The normal tip configuration (triangular and well-defined) should be distinguished from the bulbous tip (rounded and ill-defined) and the boxy tip (square and wide).[27] Anatomically, the nasal tip has an angle of divergence of 30 degrees, the domal arc a width of 4 mm or less, and a distance between the tip-defining points of 5–6 mm.[27] It can be broad and less defined in men. The boxy tip may result of an increased angle of divergence (>30 degrees), a widened domal arc (>4 mm), or a combination of the 2.[27] Excess infratip lobule projection (normal nostril apices coincide with the infratip lobule midpoint) is often the result of deformities of the middle crus and lower lateral cartilage.[28] The excess classification is divided into intrinsic (ie, long middle crus, wide middle crus, lower lateral malposition, and combinations) and extrinsic causes (ie, prominent septum).[28] A pinched tip with overprojected infratip lobule may result from an abnormal rotational orientation of the lateral crus with the caudal edge below the cranial edge.[28] Different management algorithms were proposed to treat these conditions.[27,28]

Alar Rims

The alar rim's ideal shape resembles a gull in flight.[8] Alar rim deformities, such as retraction, notching, collapse, and asymmetry, are common problems in rhinoplasty patients.[29] Excessive elevation of the alar rim is considered alar retraction, and a sharp angle within the ovular lateral contour is alar notching, which can extend cephalically and is sometimes referred to as a parenthesis deformity or ball tip.[29] Alar collapse is defined by a loss of support along the anterior portion of the alar rim resulting in a concavity, and it may be static, dynamic, or both.[29] Alar contour grafts have become an ideal method for controlling alar shape and improve aesthetic outcomes.[29]

Alar Base

Alar base width ideally approximates the intercanthal distance, one-fifth of the face width, or 70% of nasal height.[30,31] Alar base surgery is performed to address excessive width of the nasal base, alar flaring, large nostril size, and alar base or nostril asymmetries.[3,30] Each issue may require different techniques.[30,31] It should be performed at the conclusion of rhinoplasty since alar flare changes with alterations in tip projection.[30,31] If the tip is deprojected, flaring will increase; if projection is increased, flaring will decrease.[31]

Upper Lip

Ideal upper lip position is considered 1–2 mm of gingival show on maximum smile (slightly less in males).[32] Excessive incisor show is considered a ''gummy smile'' whereas a ''long lip'' may cause an inadequate incisor show.[32] Upper lip length should be accessed as well as the dynamic effects of depressor septi nasi. This paired muscle originates at the orbicularis oris and/or maxilla, and inserts on the medial crura, caudal septum, and dermocartilaginous ligament.[32–34] A hyperactive depressor septi muscle is associated with a deformity during animation (particularly with smiling) characterized by a drooping nasal tip, shortened upper lip, and a transverse crease in the midphiltral area.[33] Resection and release/transposition techniques were proposed to correct this deformity and enhance the tip-lip relationship.[33,34]

Comments

3090D553-9492-4563-8681-AD288FA52ACE

processing....