35 Management of the Bony Nasal Vault



10.1055/b-0036-135581

35 Management of the Bony Nasal Vault

Sam P. Most, Craig S. Murakami, and Wayne F. Larrabee Jr.

Introduction


An important challenge to the surgeon wishing to master modern rhinoplasty is the consideration of nasal function in addition to traditional aesthetic concerns. The importance of nasal function is evidenced by the proposition that the distinguishing features of the human nose arose in Homo erectus in response to the need for more moisture conservation. 1 Recognition of nasal function is particularly important to the surgeon manipulating the bony skeleton of the nose. While suboptimal aesthetic results may occur with either inadequate or inappropriate mobilization of the nasal bony cartilaginous framework, significant reduction of the nasal airway may also occur. A number of techniques are available to appropriately mobilize and reposition the bony nasal vault. Herein we review our experience with a variety of techniques and consider some special situations.



Anatomy



External Landmarks and Soft Tissue Components


Requisite to the use of the techniques described here is an understanding of the bony anatomy of the nose and its relation to the external nasal contour. The external contour of the upper third of the nose is defined by the two sidewalls, the dorsum, and the nasofrontal angle. 2 , 3 The nasion is the bony junction between the frontal and nasal bones. The nasofrontal angle is the external landmark identifying the deepest or most posterior portion of the nasal dorsum and may lie several millimeters inferior to the nasion. The rhinion is the osseocartilaginous junction of the nasal bones to the superior edge of the upper lateral cartilages.


The external appearance of the nose is affected by both the bony cartilaginous framework and the shape and consistency of components of the overlying soft tissue envelope. This soft tissue varies in thickness over the nasal bones. As shown in Fig. 35.1 , the nasal skin is thicker superiorly and inferiorly and quite thin over the central nasal rhinion. 2 Thus, surgery on the nasal profile must compensate for this to avoid a “saddle nose” appearance. For example, a slight hump must be left at the bony rhinion if a straight soft tissue profile is desired.

Fig. 35.1 Skin thickness of the nasal dorsum. The nasal thickness varies greatly from patient to patient but in general is thicker in the supratip and nasion areas (arrowheads). Reduction of the bony cartilaginous framework in rhinoplasty must allow for variations in the thickness of the skin–soft tissue envelope. To maintain a straight soft tissue profile, the framework must maintain a slight hump at the rhinion (arrow). (Adapted from Larrabee WF Jr, Makielski KH. Surgical Anatomy of the Face. New York: Raven; 1993:164.)


Bony and Cartilaginous Framework

The nasal bones are paired structures that attach superiorly to the frontal bone and laterally to the nasal process of the maxillary bones. These structures together form the bony nasal vault. The keystone area is the junction of the perpendicular plate of the ethmoid with the nasal bones at their inferior edge in the midline. This is an important area as destabilization here in the setting of aggressive septoplasty can lead to a saddle nose deformity. The sidewalls are formed by the nasal bones themselves and the frontal process of the maxilla. The area of bone just lateral and superior to the inferior turbinate supports the nasal wall and thus is preserved in osteotomy, as discussed later in this chapter ( Fig. 35.2 ). The nasal bones are thin inferiorly and become thick superiorly. 2 , 4 This is demonstrated by transillumination of the skull ( Fig. 35.3 ). The variable thickness of the bony structures of the nose has implications for osteotomy placement, as discussed later in the chapter.

Fig. 35.2 Cross-section of the nose. Note the supporting soft tissue structures and attachment to the lateral nasal wall. Preservation of the lower portion of the lateral bony nasal wall is critical to preventing nasal airway narrowing postoperatively.
Fig. 35.3 Transillumination of the skull reveals the thinner aspect of the nasal bones, which are mobilized with osteotomies in rhinoplasty (arrowhead). Osteotomies that are carried into the thicker bone of the maxilla or frontal bone are ineffective or result in inappropriate fracture sites.

The septum supports the nose below the inferior edge of the nasal bones. The septum and upper lateral cartilage complex provide the skeletal component of the lower nasal dorsal profile. Preservation of adequate (> 1 cm) dorsal and caudal struts of septum during septoplasty is paramount in preservation of this profile. In the setting of dorsal hump reduction, the amount of septum to be removed during hump reduction must be taken into account. For this reason, the authors regularly perform hump reduction and medial osteotomies prior to removal of any septal cartilage, if septoplasty is being performed concurrently.



Basic Surgical Techniques



Hump Reduction


The soft tissue envelope is elevated from the bony cartilaginous framework up to the level of the nasofrontal angle (via incisions described elsewhere in this text). Care is taken to undermine conservatively, limiting dissection to the dorsum only, yet widely enough to permit adequate hump reduction and subsequent skin redraping ( Fig. 35.4 ). Although adequate exposure is obtained to perform the desired reduction or refinement of the profile, as much soft tissue support is preserved as possible. This soft tissue support helps reduce the risk of producing a flail nasal bone after osteotomy. Either an osteotome or a rasp can be used to lower the dorsum, depending on the surgeon’s experience and preference. In general, an osteotome may be used for larger humps and a rasp for smaller reductions and refinements. To remove larger humps, a conservative correction is performed with a double-guarded osteotome ( Fig. 35.5 ). Refinements are then made with a tungsten carbide pull rasp. The rasp is angled slightly obliquely off the midline to avoid avulsing the upper lateral cartilages from the undersurface of the nasal bones. Removal of a dorsal hump creates a so-called open roof deformity, necessitating osteotomies for closure ( Fig. 35.6 ).

Fig. 35.4 Elevation of the periosteal flap begins with subperiosteal elevation in the midline and development of a tunnel over the dorsum only. Width should be enough to allow a rasp or osteotome to enter the pocket, but no wider. Preservation of the lateral attachments of periosteum to the nasal bones is important in preventing flail segments of nasal bone when osteotomies are to be performed.
Fig. 35.5 The cartilaginous dorsum to be removed is incised sharply and left attached to the nasal bones. After elevating the periosteum, a double-guarded osteotome is then used to complete the hump removal. Care is used to follow the planned profile superiorly to the nasion and to avoid canting the osteotome to the right or left. The hump removal is done conservatively with fine adjustments made with the rasp.
Fig. 35.6 An open roof deformity is created after removal of a bony and cartilaginous dorsal hump, as demonstrated in this cadaver dissection. The flattened nasal dorsum is the external manifestation of an open roof (arrowheads). Osteotomies are performed to close the open roof (see text).

Only gold members can continue reading. Log In or Register to continue

Stay updated, free articles. Join our Telegram channel

Jun 4, 2020 | Posted by in Reconstructive surgery | Comments Off on 35 Management of the Bony Nasal Vault

Full access? Get Clinical Tree

Get Clinical Tree app for offline access