Nasal tip bossae are knoblike protuberances of the lower lateral and domal cartilages that can occur after rhinoplasty (Figure 1). These "knukless" of cartilage are laterally noticeable and can tarnish an otherwise excellent result. They may be unilateral or bilateral, and they may contribute to tip overprojection. Although usually considered a late complication of rhinoplasty, they can also appear early in the postperative period.
Several articles heve focused on the etiology of bossae,1-3 yet there has been no in-depth, analytic description of their correction or prevention, to our knowledge. The purpose of this article is to describe our experiences with tip bossae, suggest a stardard nomenclature, discuss predisposing and causative factors, and describe principles of prevention and correction. Specific, etiology-based treatment techniques will be highlighted by means of case examples.
BACKGROUND
Nomenclature
Currently, there exists no standard nomenclature regarding these knobs of alar cartilage. The term bossae and its variations can be traced back to Latin, meaning "bump" or "lump".4 The most commonly found variation in the literature is the Latinized feminine bossa, with bossae as its plural from.1,5,6 However, multiple other variations can be found, including boss as the singular and bossa,7 bossas,8 and bosses9 as plural forms. We propose standarization of the terminology, with bossa as the singular term and bossae the plural, wich is more true to the Latin origin and proper declension.
Etiology
Nasal tip bossae may be congenital, traumatic, or iatrogenic.7 Postrhinoplasty bossae are generally thought to result from the dynamic forces of scar contracture; however, numerous predisposing factors and surgical techniques may contribute to their formation.
Bossae in the early postoperative period (<3 moths) may reflecct static tip anatomy and arise from preexisting, uncorrected domal irregularities ar asymmetry, such as splayed medial crura.7,10 They may also result from inadvertently created asymetries.More commonly, bossae are a later finding, observed 1 to 2 years after surgery,5 although they have been noted to develop as late as 10 years after rhinoplasty.1 Such late-deveploping bossae are often due to dynamic physical forces at work, such as postoperative fibrosis asn scar contracture that tug on the remaining weakened cartilaginous framework.
The factors that predispose an individual to the development of bossae include intraobular bifidity, thin skin, and strong alar cartilages,,1,2,5,6 particulary if they are preoperatively asymmetric, fractured, or blucked. Failure to sufficiently undermine vestibular skin from strong asymmetric cartilages can also lead to persistence of an irregularity as the skin tends to maintain the irregularity of the overlying cartilage.6 Even with sufficient undermining and the use of sutures to attempt to reshape the domes,some cartilages ar so strong that they will spring back and re-form the irrelarity.
The surgical maneuvers that contribute to a bossa formation are, in general terms, those that fail to secure symetric dome cartilages or promote separation of the domes and those that weaken the cephalic margin of the lower lateral cartilages. Lateral rotation maneuvers such as the lateral crural overlay are an example of the former, as this technique tends to pull the medial crura apart. Additionally, the normally strong fibrous attachments between the dome cartilages themselves and the enveloping soft tissue are disrupted in most rhinoplasties; if these are not reconstituted with sutures, bossae may form even if the cartilages have not been weakened (Figure 2).Failure to reconstitute the domal unit with sutures, particulary with the delivery technique, may allow bossa formation as the healing forces cause the medial crura and domes to migrate.11 Improper suturing of the domes may also cause asymmetry. Attaining tip symmetry with the delivery technique can be challenging, as the cartilages are mobilized asymetrically and must be manipulated back into after suturing. an open technique is also not foolproof, as asymmetry may arise as healing takes place or if the medial crura are sewn together before the dome cartilages, without first ensuring that the domes are even.
Maneuvers that weaken or allow migration of the lower lateral cartilages may also lead to bossa formation. These include cartilages may also lead to bossa formation. These include overresection of the cephalic margins of the lower lateral cartilages (Figure 3). The weak remnant cartilage is subject to buckling and the forces of scar contracture2,3,5,6,9 (Figure 4). Many years ago, aggresive resections of the lower lateral cartilages were commonplace, leaving only 3 to 4 mm.Long-term follow-up of these patients has shown that such excessive narrowing of the lateral crus, even with an intact rim, weakens the crura sufficiently to allow the forces of contracture to buckle the lateral crus itself and pull the anatomic dome laterally and upward, predisposing not only to bossa formation but also to alar rim retraction. Most surgeons are now much more conservative in the cephalic trimming, leaving a minimum of 5 to 8 mm of crus intact, depending on the intrinsic shape, size and thickness of the crus itself. Unpredictable healing and bossae can also result if the tip and/or lower lateral cartilages are left intact but morcellized in an attempt to soften domal irregularities. Finally, any maneuver that disrupts the continuity of the crural cartilages, leaving free end of cartilage, predisposes to bossa formation.3 This includes not only techniques that divide the lateral crura, but also vertical dome division and domal unit.11 Additionally, we have noted complete removal of the lateral-most portion of the lower lateral cartilages, wich allows the medial free ends to contract and migrate in an uncontrolled fashion and form bosssae (Figure 5). Weakening of the lower lateral cartilages of excision can furthermore lead to valve collapse, which requires grafting3 (Figure 6).
The different rhinoplasty approaches each carry risks as well. The delivery approach via intercartilaginous and marginal incisions is the most invasive and disruptive, as it separates the scroll area and its ligamentous supports and the domes. This approach distorts domal anatomy, placing symmetry at risk; the required resulting of the domes is technically difficult and may lead to asymmetry.It does, however, provide good exposure, and Simons and Gallo5 report it to be their endonasal approach ofchoice in high-risk patients. Nondelivery approaches via an intercartilaginous or intracartilaginous incision are the least disruptive but are "blind". Therefore, very careful preoperative and intraoperative assessments of symmetry are necessary before excision of any cartilage. The nondelivery approach is also a problematic in that the domes cannot be sutures; thus bifidity, definition, and a wide cannot be aequately addressed. In our experience, however, most bossae are noted in endonasal approaches in which it is difficult to ensure symmetric lower lateral cartilage cephalic resection (Figure 7). In contrast, the open approach offres better visualization and therefore the best oportunity for symmetric resection, as well as the least distortion of natural and resewn anatomy.
