Cartilaginous Pushdown Nasal Hump Treatment

The reduction of the nasal hump can be based on the partial resection of the cartilages and bones or on the preservation of these structures. The nasal dorsum preservation techniques, like the push down and let down, minimize problems like open roof and inverted V and lessens the necessity of grafts, the mainstays of the structured rhinoplasty. The cartilaginous pushdown preserves the middle third of the nose and let the bony portion to be treated independently. This approach expands greatly the indications of preservation techniques as in complex deviated noses, S shaped humps, and for patients with irregularities on the dorsum.

Key points

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Cartilaginous pushdown hump treatments widens the indications for Preservation Rhinoplasty.
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The preservation of the bony cap reduces the complications on the Key Stone Area.
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Cartilaginous pushdown allows the correction of septal and nasal deviation concomitantly.
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The revisions of Preservation Rhinoplasty hump treatments, when necessary, are usually very simple and fast.

Abbreviation

ULC	upper lateral cartilages

Introduction

Classically, nasal hump reduction is based on the partial resection of the cartilages and bones of the nose, as it was described by Joseph more than a century ago. The cartilaginous portion of the hump consists of a single unity formed by the 2 upper lateral cartilages (lateral process) and the septal cartilage (posterior process). These 3 cartilages are fused on their cephalic portion in an M shaped manner unique in the human anatomy. During the hump reduction in classic rhinoplasty, this structure is slashed in 3 pieces, which is the main cause of irregularities, shadows and pinching in long-term results. The angle and relation between the septal and upper lateral cartilages is reduced, which may compromise the functional aspect of the internal nasal valve.

In order to avoid these problems, several authors have been trying to preserve the integrity of the dorsum during nasal hump treatment. Nowadays, the main approaches for preservation rhinoplasty of the dorsum are the foundation and the surface techniques. The foundation techniques are represented by Cottle’s push-down ^, (1946), Drumheller’s let-down (1993) and its variations. The surface techniques are represented by Ishida’s cartilaginous pushdown (1999) and its variations. The foundation techniques lower the hump as a whole (the bony and cartilaginous portions all together), preserving the integrity of the dorsum and the keystone area transition. The main indications for foundation techniques are small humps, little or no nasal deviations, and thin noses. Large, angled (‘S’ shaped), deviated, or broad humps impose some difficulties to Cottle’s push-down and Drumheller’s let-down.

For the surface techniques, the cartilaginous pushdown treatment of the dorsum was described by Jorge Ishida in 1999. The main idea was to preserve the cartilaginous portion of the dorsum and treat the bony portion independently. The maintenance of the cartilaginous dorsum untouched has shown a lot of advantages, including preserving the middle third of the nose width, the dorsal esthetic lines and the internal nasal valve. Also, the possibility of treating the bony hump separately increases the indications of preservation treatments of the nasal hump. With the cartilaginous pushdown, nasal and septal deviations, broad noses and S shaped noses are now easily treated alongside with mild humps and straight noses. As the cartilaginous hump extends itself under the nasal bones up to 0.9 mm, preserving the cartilaginous portion also provided extra support for the bony portion treatment.

The cartilaginous pushdown gave origin to 3 variations. Ferreira (2016) published the Spare roof A technique, which is a cartilaginous pushdown with a high strip cartilaginous resection and bone rasping of the bony hump. The indications of this approach were the same as the foundation techniques, small V shaped humps, with small or no deviations.

The second variation was the cartilaginous pushdown with bony cap preservation, described by Ishida LC (2020). As the bony cap was removed in the cartilaginous pushdown, even with the underlying cartilage, irregularities and fibrous tissue might develop in this small area. To avoid these problems, it was proposed that the preservation of the bony cap on the keystone area when performing the cartilaginous pushdown dorsum reduction. By doing this, the smoothness of the keystone area was kept intact, adding some of the benefits of the foundation techniques to this surface technique.

The third variation is the Ferreira- Ishida technique or Spare roof B (2022). Alongside a high strip septal resection, now a rectangular bony cap is lowered with the cartilaginous hump, a little wider than the triangular bony cap. The cephalic margin of the bony cap stayed attached to the nasal bones but is mobilized in a green stick manner. The main advantages are the maintenance of the dorsal aesthetic lines if the nose had a beautiful dorsum and the possibility of not undermining the skin of the midline of the nose. Again, this is best suited for noses that have mild deviations and a beautiful shaped dorsum.

Anatomy

The nasal hump is a unique structure composed of an osseous and a cartilaginous portion. The main structure is the cartilaginous portion, which is the septal cartilage. ^, The septal cartilage is formed by its lateral portion (upper lateral cartilages [ULC]) and the posterior portion (septal cartilage). These 3 portions are fused in the midline in an M shaped fashion, and this anatomic structure is responsible for the spring action for opening the internal valve. McKinney showed that at 4 months of intrauterine age, the ULC and septal cartilages are already fused.

The cephalic portion of the ULC (lateral process of the septal cartilage) are overlapped by the nasal bones by 4 to 9 mm. The septal cartilage in its junction with the perpendicular plate of the ethmoid prolongs itself cephalically under the nasal bones up to about 50% to 60% of the length of the overlaying nasal bones ( Fig. 1 ). There is a firm adherence between the ULC and the nasal bones which is stronger toward the midline. The lateral borders of the ULC do not reach the piriform aperture and are connected to the malar bones by a fibrous connective tissue. The septal cartilage is the main structural portion of the nasal hump. ( Fig. 2 ).

Surgical technique

The treatment of the nasal hump with the cartilaginous push down is based on preserving its cartilaginous portion and repositioning the septal cartilage as a single unit without disrupting the M shaped junction that exists between the ULC (lateral process) and the septal cartilage (posterior process). In the open or closed approach, the nasal dorsum is undermined in a sub superficial musculoaponeurotic system (SMAS) plane, and the posterior septum is undermined in a subperichondrial plane on both sides. The undermining goes on until the perpendicular plate of the ethmoid (PPE). A strip of septal cartilage is resected in a parallel plane to the dorsum. The resection should take place at the more deviated portion of the septal cartilage. Usually most of the deviations occurs at the base of the septal cartilage by the palatal crest (low strip). When the septal deviation is absent or minimal, the preferred spot for resection is about 3 to 4 mm below the dorsum (high strip) ( Fig. 3 ). The high-strip septal resection is faster than the low-strip but is less effective in correcting nasal and/or septal deviations. The mid-strip is taken from the middle portion of the cartilaginous septum and is useful in those patients with odd shaped humps or in those cases where opening of the internal valve is necessary (see Figs. 3 and 9 ).