12.1 Indications
Key words: gingival smile, lip incompetence, maxillary excess, maxillary hyperplasia, maxillary intrusion, maxillary rotation, nasal asymmetry, obstructed nasal breathing
A transmaxillary septorhinoplasty is tied to a clear surgical approach and can only be performed as part of a Le Fort I osteotomy with downfracture. Indication can be obstructed nasal breathing, which can be diagnosed by clinical examination, rhinomanometry, or DVT or CT examination. Findings may include changes in anatomical structures of the internal nose with asymmetrical narrow nasal entrance, hyperplastic turbinates, bony groins, spurs, or septal deviations. Even without obstructed nasal breathing, there may be an indication for transmaxillary septorhinoplasty if surgical intrusion and/or clockwise rotation (CWR) of the maxilla is planned, eg in vertical maxillary excess cases (Fig 12-1), so that elevation of the posterior maxillary portion would result in narrowing of the inferior nasal spaces. This can be recognized clinically because of lip incompetence and gingival smile, and in the course of the cephalometric surgical simulation on the lateral cephalometric radiograph. Function-preserving corrections of the nasal inlet, turbinates, and septum are performed in our patient population starting at an elevation of the maxilla of 3 mm in order to ensure normal nasal breathing despite all surgical measures.
Figs 12-1a and 12-1b Initial clinical situation with vertical excess of the maxilla, lip closure insufficiency, chin hypoplasia, and exceptional bialveolar protrusion of the anterior teeth.
12.2 Methodology
Key words: downfracture, nasal base overview, normal nasal breathing, representation of the inner nose, nasal treatment goals
The downfracture of the maxilla allows clear access to the midface with all nasal structures, which is not available in other specialties for performing a septorhinoplasty (Fig 12-2). Both the bony floor of the nose and both maxillary sinuses with their bony boundaries including the inner nose are visualized and easily accessible.
Fig 12-2 After downfracture, the maxilla is pulled caudally with the large hook, exposing the view of the two preserved nasal mucosa tubes of the inferior nasal floor with anterior cartilaginous septum, left and right view of both maxillary sinuses and of the bloody posterior walls.
The type and extent of transmaxillary septorhinoplasty depends on the nature of the nasal airway obstruction, anatomical features, and the extent and direction of displacement of the maxilla. The treatment goal is to improve impaired nasal functions, including nasal airway patency, to establish normal bony facial structures, or to preserve normal nasal breathing if the planned displacement of the maxilla would impair it.
12.3 Osteotomies
Key words: correction of nasal asymmetries, lowering of the nasal floor, maxillary cranialization, nasal floor reconstruction, nasal spine shortening, nasolabial angle change, nesting of the maxilla, septum correction
On the cranial maxillary side, the nasal entrance and the bony nasal floor are included in the treatment. Asymmetrical nasal entrances, which are often associated with original malpositioning of anterior teeth, are made symmetrical and widened if necessary.
Basically, the base of the nose is first freed from bony or cartilaginous ridges and the nasal crest is shortened or completely removed to allow unrestricted median adjustment of the septum. The midface base is also included in the treatment: inspection of the maxillary sinuses, removal of nasal polyps or cystectomies if necessary, and straightening and shortening of the cartilaginous and bony septum if necessary.
In the course of a maxillary cranialization, the septum (see Fig 12-5) and usually also lateral bony borders of the nose are shortened by the amount of the displacement. If the bony growth of the maxilla is vertically prolonged, especially in the anterior region, as occurs in the vertical excess of the maxilla, a lowering of the nasal floor and entrance and thus a reduction of the vertical maxillary height can be achieved by milling out bone (Fig 12-3). However, the extent of lowering of the nasal floor and entrance should be chosen to maintain bony contact with the midface base in order to stably fix the displaced maxilla in its new position with miniosteosynthesis plates, while avoiding constriction of the lower airway. If this is unavoidable, the airways can be additionally widened by surgery on the turbinates, see below.
Figs 12-3a to 12-3d Vertical excess of the anterior alveolar process, reshaping and lowering of the nasal entrance and both nasal floors, a new nasal spine is created to which the shortened septum is later adapted by single suture.
When correcting facial asymmetries, lateral displacements of the maxilla may also be necessary to align the dental maxillary center with the facial center. Lateral displacement of the maxilla can result in nesting of the bony maxillary sinus walls, which can narrow the inferior nasal passages and obstruct nasal breathing. Leveling the median maxillary sinus walls on the bony maxillary base can help maintain nasal breathing.
However, interlocking of thin bony maxillary walls during maxillary intrusion can also contribute to stabilization of the new maxillary position by spacer screw fixation and subsequent gap-filling bone grafting (see Fig 12-6).
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