Nasal Tip Deficiency

Nasal tip deficiency can be congenital or secondary to previous nasal surgeries. Underdeveloped medial crura usually present with underprojected tip and lack of tip definition. Weakness or malposition of lateral crura causes alar rim retraction and lateral nasal wall weakness. Structural grafting of alar cartilages strengthens the tip framework, reinforces the disrupted support mechanisms, and controls the position of the nasal tip. In secondary cases, anatomic reconstruction of the weakened or interrupted alar cartilages and reconstitution of a stable nasal tip tripod must be the goal for a predictable outcome.

Key points

  • Structural grafting of alar cartilages strengthens the tip framework, reinforces the disrupted support mechanisms, and controls the position of the nasal tip.

  • Columellar strut is a very useful tool in stabilizing the nasal base and correcting medial crural deformities. When a significant increase in tip projection is desired, a longer and stronger columellar strut can be used, and medial crura are advanced on the strut with sutures.

  • Lateral crural grafts are indicated in the correction of cephalic malposition of lateral crura, alar rim retraction, strengthening of the weak lateral crura, and elongation of short lateral crura.

  • In secondary cases with overresected nasal tip framework, tip projection is usually lost and can be reestablished using a columellar strut, a caudal septal extension graft, and/or a tip graft. Lateral crural grafts are used to strengthen and replace missing segments of lateral crura.

Videos of strengthening of a deficient nasal tip; correction of cephalic malposition; elongation of short alar cartilages; and bending technique for lateral crura and dome reconstruction using rib cartilage accompany this article at www.plasticsurgery.theclinics.com/

Introduction

The lower third of the nose has a tripodlike support structure that is made up of the conjoined medial crura and lateral crural complex based bilaterally on the piriform aperture. The medial crura together form 1 leg of the tripod, and each lateral crus makes up the other 2 legs. In rhinoplasty, the tripod should be maintained and/or restored to provide tip support and a normal-appearing nasal tip shape ( Fig. 1 ).

Fig. 1
The lower third of the nose has a tripodlike support structure that is made up of the conjoined medial crura and lateral crural complex based bilaterally on the piriform aperture.

One of the vital steps of a rhinoplasty operation is to control the nasal tip projection and position. The length and strength of the medial crura is critical for tip projection and definition. Short and weak medial crura can lead to loss of supratip definition due to decreased differential between dorsal height and domal peak. This becomes an important issue, particularly in cases with thick nasal tip skin.

The shape and the stability of the lateral crura are important factors for aesthetic and functional reasons. Poorly supported lateral nasal walls may collapse with negative airway pressure during inspiration, thereby causing nasal airway obstruction.

Introduction

The lower third of the nose has a tripodlike support structure that is made up of the conjoined medial crura and lateral crural complex based bilaterally on the piriform aperture. The medial crura together form 1 leg of the tripod, and each lateral crus makes up the other 2 legs. In rhinoplasty, the tripod should be maintained and/or restored to provide tip support and a normal-appearing nasal tip shape ( Fig. 1 ).

Fig. 1
The lower third of the nose has a tripodlike support structure that is made up of the conjoined medial crura and lateral crural complex based bilaterally on the piriform aperture.

One of the vital steps of a rhinoplasty operation is to control the nasal tip projection and position. The length and strength of the medial crura is critical for tip projection and definition. Short and weak medial crura can lead to loss of supratip definition due to decreased differential between dorsal height and domal peak. This becomes an important issue, particularly in cases with thick nasal tip skin.

The shape and the stability of the lateral crura are important factors for aesthetic and functional reasons. Poorly supported lateral nasal walls may collapse with negative airway pressure during inspiration, thereby causing nasal airway obstruction.

Treatment goals and planned outcomes

Nasal tip deficiency can be congenital or secondary to previous nasal surgeries. Preservation or reconstitution of a stable, well-defined nasal tip framework is essential for a successful rhinoplasty outcome. Structural grafting of alar cartilages strengthens the tip framework, reinforces the disrupted support mechanisms, and controls the position of the nasal tip to resist the scar forces of the healing phase in the long term.

Autologous cartilage is the best material for structural grafting of the nasal tip. If available, septal cartilage is the graft of choice for autologous cartilage grafting because it is rigid, relatively straight, and in the same operative field. It can be used as a columellar strut to support the nasal tip or replace parts of the lower lateral cartilage complex. However, septal cartilage is often insufficient in secondary operations. Auricular cartilage can be used to replace lateral crural defects. Onlay tip grafts and shield-type tip grafts can be prepared from concha, but flaccidity and convolutions inherent in its structure limit its use in structural grafting. If significant support is required, autologous rib cartilage is the graft of choice. Rib offers unlimited amount of cartilage for structural grafting. Long and straight struts can be prepared from the rib cartilage for reinforcement or reconstruction of the alar complex. Rib cartilage is less calcified and more elastic in young individuals and this allows the preparation of thin grafts for alar cartilage reconstruction.

The open rhinoplasty approach provides better visualization without distortion of cartilages, leading to accurate diagnosis and treatment.

Procedural approach

Increasing Tip Projection and Stabilizing the Columellar Base

Underdeveloped alar cartilages usually present with loss of tip projection and ill-defined nasal tip contours. In these patients, cartilage grafting is usually required to increase tip projection and improve tip contours.

Columellar strut graft

Columellar strut is a versatile and powerful tool to stabilize the columellar base, strengthening the weak medial and intermediate crura, increasing tip projection, and changing rotation. It is placed in a pocket between medial and intermediate crura, keeping a bed of soft tissue above the nasal spine. When a considerable increase in tip projection is desired, a longer and stronger columellar strut should be used and medial crura are advanced on the strut with sutures. The columellar strut is also useful in changing columella-lobule angle, controlling the length of the medial or middle crural segments and correcting intercrural deformities or asymmetries of the lateral crura.

If a significant increase of the tip projection is needed, advancing the lateral crura medially with a spanning suture (lateral crural steal) and the simultaneous use of a long and strong columellar strut give consistent results ( Fig. 2 ). Strong columellar strut grafts can be prepared from the thicker portions of the septal cartilage or lamination of 2 struts from septal cartilage side-to-side suture ( Fig. 3 ). In primary patients who do not have thick septal cartilage and in secondary rhinoplasty patients without sufficient septum cartilage, columellar strut can be fabricated from rib cartilage. The columellar strut is placed between the medial crura, and medial crura are advanced on the strut with sutures to achieve the desired tip projection. In cases with short medial crura and long lateral crura, lateral crural steal procedure is a very useful technique that elongates the medial crura, shortens the lateral crura, and increase the tip projection. This technique also rotates the nasal tip upward, augments the infratip lobule, and changes infratip lobule angle.

Fig. 2
( A ) The original and new domal points are marked to create new domes using spanning sutures, and a long and strong columellar strut is prepared from the septum cartilage. ( B ) Tip projection is increased with lateral crural steal and advancement of medial crura on a strong columellar strut.

Fig. 3
Two struts harvested from septal cartilage are laminated with side-to-side sutures to create a stronger columellar strut.

Tip graft

After placement of the columellar strut, if additional increase in tip projection and further refinement is needed, a tip graft can be used to increase tip projection and improve the tip contour. Shield-type tip grafts are particularly useful in patients with short infratip lobule and in secondary cases.

Caudal septal extension graft

Caudal septal extension graft is a rectangular cartilage that is extended off of the caudal septum and sutured between the medial crura. It is a useful method to increase projection and rotation of nasal tip. To maximize stability and avoid asymmetries, it should be stabilized to existing dorsal septum with bilateral spreader grafts. Then the medial crura are stabilized to the caudal margin of the graft to achieve the desired tip projection and rotation. In this method, first needles are passed through the medial crura and septal extension graft to judge the position of the tip, then medial crura are fixated to the septal extension graft with tongue-in-groove fashion horizontal mattress sutures.

Strengthening the Lateral Crura

If lateral crura are congenitally weak, a structural grafting should be considered. In the presence of a weak lateral crural strip, any surgical intervention may accentuate an external nasal valve collapse. In mild cases of lateral crural weakness, a lateral crura turn-in flap can be used for support. Alar contour graft is another method to reinforce the alar rim in mild to moderate weakness of the lateral crura. Lateral crural strut graft is the most effective method to support weak lateral crura, adding stability to the nostril rim and external nasal valve.

Case analysis

A 20-year-old patient presented with dorsal hump, underprojected tip, acute nasolabial angle, and retracted alae. Her lateral crura were weak, alar rims were not well supported, and domes were weak and pointed. Intranasal examination revealed a deviated septum obstructing the airway ( Fig. 4 A–D).

Fig. 4
( A D ) A 20-year-old patient presented with dorsal hump, underprojected tip, acute nasolabial angle, and retracted alae. Her lateral crura were weak, alar rims were not well supported, and domes were weak and pointed. ( E H ) The patient is shown 2 years postoperatively. The dorsal hump is removed, resulting in a smooth and straight dorsum. Tip projection is increased, the nasal tip is well supported, and alar rim retraction is corrected.

Using the open rhinoplasty technique, septoplasty and septal cartilage harvest were performed. Bony and cartilaginous humps were reduced and medial oblique and lateral osteotomies were performed. Spreader flaps were used to establish the cartilaginous dorsum. To increase tip projection, the lateral crura were advanced medially with spanning sutures. A long columellar strut was prepared from the harvested septum and the medial crura were advanced on the columellar strut with 3 sutures. A subdomal graft was placed to reinforce and widen the weak domes. A thin onlay tip graft was placed for further increase in tip projection. Alar contour grafts were placed bilaterally to support alar rims ( [CR] ).

The patient is shown 2 years postoperatively. The dorsal hump is removed, and a smooth, straight dorsum is achieved. Tip projection is increased, nasal tip is well supported, and alar rim retraction is corrected ( Fig. 4 E–H).

Cephalic Malposition of Lateral Crura

In patients who have cephalic malposition of the lateral crura, the alar rim is not supported, causing a parenthesis deformity of the nasal tip. The malpositioned lateral crus does not parallel the alar rim, resulting in weakness. The degree of cephalic malposition may differ from mild to severe. In mild and moderate malposition, a lateral crural strut graft or an alar rim graft can be placed parallel to the alar rim without caudal transposition of the lateral crura, so as to support the alar rim and correct the supra alar notching. However, in severe cephalic malposition, lateral crural transposition should be the method of choice. In this technique, the malpositioned lateral crus is separated from accessory cartilages and transposed caudally. If the lateral crura are not long and strong enough, it is wiser to strengthen and elongate the lateral crura with a lateral crural strut graft for the predictability of the reconstruction. The lateral end of the graft is placed in a pocket undermined caudal to the accessory cartilages.

Case analysis

A 32-year-old patient presented with dorsal hump, hanging columella, and severe cephalic malposition of the lateral crura ( Fig. 5 A–D).

Nov 21, 2017 | Posted by in Dental Materials | Comments Off on Nasal Tip Deficiency
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