New Concepts in Dorsal Nasal Augmentation

Dorsal augmentation is commonly indicated in many primary and secondary aesthetic nose surgeries. Throughout the history, various synthetic and autogenous materials have been used for dorsal augmentation. In this article, we give an overview of basic concepts of cartilage grafting, review new concepts of dorsal augmentation, and discuss some emerging engineering modalities.

Key points

  • Autologous cartilages are commonly known as the gold standard in dorsal augmentation.

  • Septal, auricular, costochondral cartilage, and temporalis fascia are common autografts for dorsal augmentation.

  • Septal cartilage is ideal for minimal to moderate augmentation.

  • Warping is the main limitation of costochondral graft and needs to be managed by one of the known effective techniques.

  • Engineered cartilage regeneration is an emerging technique that may resolve many limitations of common grafting techniques.

Introduction

Dorsal augmentation is commonly indicated in many primary and secondary aesthetic nose surgeries. Throughout the history, various synthetic and autogenous materials have been used for dorsal augmentation. The first descriptions of dorsal augmentation dates back to late 1800 when sterile paraffin was used to augment saddle nose deformity , ; surprisingly, this immature idea was widely accepted resulting in many disastrous local and systemic complications. , There are several other sporadic efforts at the same time to use bird bone, pork cartilage, and cow leather in restoring defective dorsum. Jack Josef reported the first relatively successful xenografts for dorsal augmentations. He used handmade ivory implant specific for each patient to augment the nose. His brilliant handcrafts resulted in a 40% success rate. , Von Mangoldt may be considered the pioneering figure in the use of autografts for aesthetic surgery; he used the first autogenous graft to repair saddle nose in 2 cases of syphilis. , Many of the most renowned facial plastic surgeons of the time immediately followed his approach but before long, the major drawback of the application of costal cartilage revealed itself: distortion and warping. ,

Gillies suggested to leave a small part of perichondrium on one side of graft to control warping. Mowlem (1938) stored costochondral grafts in the abdominal wall to control distortion. , Nevertheless, none of these techniques fully prevented warping, and both Gillies and Mowlem suggested the application of bone grafts for dorsal augmentation. Tibia, calvarium, and iliac bone were commonly used for nasal augmentation but were very tough to carve and shape, resulting in very unpredictable and unsatisfactory outcomes. This convinced the rhinoplastic surgeons that autogenous cartilage, with all its shortcomings, would still be the material of choice. Peer , in 1945 showed that septal cartilage has ideal properties for nasal grafting. Later, the use of conchal cartilage proved to be efficient. Surgeons, therefore, came up with novel armamentarium to harvest and prepare these grafts. All efforts have since focused on finding the best techniques to prepare and apply the cartilage graft. In this article, we give an overview of basic concepts of cartilage grafting, review new concepts of dorsal augmentation, and discuss some emerging engineering modalities.

Selection of the graft source for dorsal augmentation

Autogenous graft is generally accounted for as the gold standard in dorsal augmentation. Temporalis fascia, septal, auricular, and costal cartilage are the most commonly used autogenous grafts in rhinoplasty. The choice of donor site is very determinant. A comprehensive review of surgical history will reveal any possible donor site manipulations due to previous procedures. In revision rhinoplasty, septum may have been previously opened and it is recommended not to reenter the septum if there is no remaining septal deviations or spurs. Calcified rib is a common condition that is best to be detected preoperatively. A history of autoplasty would be a red flag in the choice of conchal grafts. ,

The surgeon should meticulously evaluate the recipient site (nasal dorsum) preoperatively. Cartilage blocks may show a shadow of sharp edge under thin skin, while being a good choice under thicker skin. All these details should be discussed preoperatively, and consent should be taken for any possible change of plan during the operation.

Dorsal hump reinsertion, a rescue technique

In 1966, Skoog presented his innovative approach in dorsal hump surgery to create a smooth dorsal contour. In this technique, first a bony-cartilaginous cap is removed from the nasal dorsum, the preplanned amount of nasal dorsum is then trimmed and removed, and finally, the hump cap is reinserted as an autograft. This technique has been used for decades. , Meanwhile, in current conservative concepts of rhinoplasty, there is no tendency for these aggressive approaches, and there remain 2 relatively rare and highly resuscitative indications for this technique.

  • Inadvertent hump resection: sometimes a big hump is inadvertently resected. It is very practical to trim and refine the resected hump and reinsert it instead of thinking about graft harvesting or planning a second surgery. ,

  • In many rhinoplasties, a combination of hump resection and radix augmentation is indicated. In these surgeries, a small cap of hump may be obtained in the routine hump surgery and used for radix augmentation ( Fig. 1 ).

    Fig. 1
    ( A ) Resected hump may be tailored and ( B ) used for radix augmentation.

Septal cartilage for dorsal augmentation

Septal cartilage is an ideal material for minimal to moderate dorsal augmentations. It may be easily harvested during rhinoplasty specially when simultaneous septoplasty is to be performed. , , ,

How much of the septal cartilage may be harvested?

Killian and Moster in 1905 emphasized that harvesting cartilage should only be done from the central part of the septum and an L-strut needs to be preserved. Freer suggested a minimum of 6 to 8 mm of width for the L-strut to ensure the stability of the nose ( Fig. 2 A ). Surgeons have now followed these principles for a long time. Meanwhile, many later studies have shown that preservation of even 10 to 15 mm of cartilage does not guarantee nasal stability and the following parameters as well as the L-strut dimensions need to considered when septal graft harvest is planned :

  • Wide septal cartilage resections may cause small displacements of weakened septum during breathing and lead to sever nasal airway damage. Therefore, nasal airway still may be damaged despite an intact mucosa and a strong L-strut.

  • Ted Mau and colleagues showed that leaving a triangle of cartilage in the junction of the bone and cartilage considerably increases the strength of L-strut. This may be simply done by making a back-cut in bone and cartilage junction ( Fig. 2 B).

  • At least 40% of the caudal wing of the L-strut should seat on maxillary crest. It means that the protruding part of nasal cartilage that extends from anterior nasal spine (ANS) does not increase stability of L-strut. A simple guideline is to draw an imaginary line from the caudal edge of the boney vault to ANS. Harvesting may be done from back of this line ( Fig. 2 A–C).

  • Thickness of dorsal cartilage is much more important than the width of the L. Therefore, if dorsal cartilage is very thin, the surgeon should preserve a wider strut.

  • Sharp angles in L-strut create internal stresses and weak points. Chamfering the right angles will remove these weak points (see Fig. 2 C).

  • Conservative and reconstructive septoplasties are progressively growing. Modern septoplasty usually does not advocate a large harvest of septal cartilage and rhinoplastic surgeon should justify if they want to harvest a wider septal cartilage or they rather consider other secondary donor sites.

  • Cartilage crushing, cartilage dicing, or suturing several pieces together may alleviate the need for harvesting a large piece of septal cartilage.

Fig. 2
( A ) A strong L needs to be saved in septum. ( B ) A back-cut at the junction of the cartilage and bone considerably increases the strength of the nasal septum. ( C ) It is recommended to avoid sharp edges to eliminate tension zones. ( A-C ) An imaginarily line is drawn from caudal edge of the bone to the anterior nasal spine. It is recommended that the vertical wing of the L-strut to seat on the bone anterior to this line (enough width of vertical wing).

Preparing the septal graft for dorsal augmentation

Crushed Cartilage

Crushing the cartilage graft may potentially alleviate major complications of grafting such as visible edges and graft warping. Meanwhile, the popularity of technique has waxed and waned several times in the history of the rhinoplasty. The main challenges in using crushed cartilage have been the extent of crushing and the viabilities of the grafts. , Cakmak and colleagues in 2005 started a series of studies that made a strong scientific backbone for this techniques and served as a guide for surgeons through most of their concerns. They proposed a classification for septal cartilage crushing that may help the surgeons plan their graft preparation for optimal results. Based on this classification, cartilage may be (1) slightly crushed, (2) moderately crushed, (3) significantly crushed, or (4) severely crushed (see Table 1 for specifications of each class). These investigators found that the vitality of cells in the crushed septal cartilage is directly related to the crushing techniques and the severity of crushing. They showed that chondrocytes retain their viability in slightly crushed and moderately crushed septal cartilages, and the percentage of viable cells is only minimally lower than the intact cartilage. Another one of their studies indicated that, in the long-term follow-ups, the slightly crushed cartilages are highly predictable, whereas moderately crushed septal cartilages are more likely to result in subtle resorptions. On the other hand, the significantly crushed and the severely crushed cartilages resorbed significantly and were extremely unpredictable.

Table 1
The classification of crushed cartilages
Grade I Slightly crushed Moderate-force hit to soften the surface without reducing the elastic strength of the cartilage
Grade II Moderately crushed Moderate-force hits to soften the surface and reduce the elastic strength
Grade III Significantly crushed Moderate-force hits enough to cause the graft to bend with gravity
Grade IV Severely crushed 5 or 6 forceful hits to totally destroy the integrity of the cartilage

Pearls and Pitfalls

  • Nasal septal graft and auricular cartilages may be used for crushing ( Fig. 3 ).

    Fig. 3
    ( A , B ) Crushed cartilage is a feasible graft for minimal dorsal augmentation.
  • Crushing is an extremely sensitive technique and is better to be done gently to save the viability.

  • Crushed cartilage may be fixed by delicate polydioxanone sutures.

  • Precision eliminates the need for overcorrection.

  • Under thin skins, crushed cartilage may create sharp edges or shadows that are visible on the dorsum. Covering the crushed cartilage with a layer of fascia (sandwich technique) may be an effective solution ( Fig. 4 ).

    Fig. 4
    ( A–C ) Graft harvest from posterior approach. ( D , E ) Mastoid fascia harvest. ( F , G ) Preparation of fascia overlying crushed cartilage (sandwich technique).

Temporoparietal Fascia

Autogenous fascia especially temporoparietal fascia is commonly used in many facial cosmetic and reconstructive procedures. , Gerosantos (1984) showed versatile applications of deep temporalis fascia in a large number of rhinoplasties. Daniel presented his approach in augmenting the deep radix with temporalis fascia, and Daniel and Calvert showed how diced cartilage wrapped in fascia may be effective in dorsal nasal augmentation. The main advantages of temporalis graft in dorsal nasal augmentation are essay access to harvest the graft, predictable long-term results and very smooth architecture that does not cause any sharp edges or shadows. In general, the main indications of temporalis fasciae in dorsal augmentation are as follows:

  • Minimal dorsal augmentation. Temporalis fascia may be spread over dorsum to minimally enhance dorsum.

  • It may be rolled to make a bigger volume to augment a deep radix ( Fig. 5 ).

    Fig. 5
    Fascia is an ideal material for radix augmentation.
  • Temporalis fascia may be used to cover irregularities of the dorsum after using other augmentation techniques.

  • Temporalis fascia may be used to wrap diced cartilages (see diced cartilage later in this article).

Surgical technique

Conventional Approach

This approach involves a 3-cm to 4-cm incision in the temporalis region, along the hair-bearing area above the ear. After locating the superficial temporal artery and vein and reaching the glistening surface of the deep temporalis fascia, a wide dissection is made to expose the donor area. Then, the graft is marked and harvested. The main drawback of this technique is the possibility of hair loss in incision lines. However, with precise incisions parallels with hair follicles, meticulous surgical techniques and appropriate wound closure, incision line would be adequately concealed by hair. ,

Neck Hairline Approach

In this approach, a 3-cm to 5-cm curvilinear incision is made at the neck hairline. After finding the surgical plane, access to the deep temporalis fasciae is obtained by dissecting upward and forward. Incision line is concealed, and there is little or no risk of hair follicle damage. Moreover, the incision may be used for simultaneous access to mastoid fascia when more graft material is needed (see Fig. 4 A, B; Fig. 6 ).

Apr 19, 2021 | Posted by in Oral and Maxillofacial Surgery | Comments Off on New Concepts in Dorsal Nasal Augmentation
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