Key words: broad nose, columella, flattened maxillary midline, mimic muscle, nasal wing, nasolabial angle, piriform aperture
Correction of the nasal-upper lip complex is indicated when the maxillary surgical displacement has resulted in changes to the position of the piriform aperture or its covering lip soft tissues, including the columella and nostrils. These corrections are key to the harmony of the nasal entrance, nasolabial angle, upper lip, and normal facial expression in the middle of the face, depending on the initial situation and complexity of the maxillary displacement. The corrections take place primarily after maxillary displacement when the bony nasal entrance is too narrow, asymmetrical, or the nasolabial angle is too large or too small, or when a broad nose threatens to develop or the columella is not centered. It may also be indicated secondary to orthognathic surgery if the primary correction of the complex was not satisfactory. For example, if the bony maxillary center is flattened after maxillary transverse distraction, the prominence of the philtrum is missing, or if asymmetries of the lip soft tissue have resulted from scarring, asymmetrical lip movement occurs during smiling. The nasal fistula, columella, and smile line may appear disharmonious, and upper lip prominence may be insufficient after primary correction. These require individual secondary correction.
26.2 Primary corrections of the nasal-upper lip complex simultaneous to Le Fort I osteotomy
Key words: anterior tooth show 3 to 4 mm, digital surgical planning or model surgery, harmonization of the nasolabial angle, maxillary midline adjustment, normalization of facial profile, parallel dental arch adjustment to the interpupillary line, smile line to tooth crown margin, vertical shortening of the upper lip by 1 mm in case of anterior maxillary advancement of 3 mm
Corrections of the nasal-upper lip complex result primarily from the initial findings and the surgical planning. This is done with a cephalometric analysis and a conventional model surgery or digital planning. The key to surgical planning is the center point between the cutting edges of the maxillary central incisors around which the maxilla is positioned in three dimensions: in the transverse direction with dental arch adjustment parallel to the interpupillary line and to the center of the face, in the sagittal direction to normalize the facial profile with harmonization of the nasolabial angle and the upper lip prominence, and in the vertical direction with adjustment of the anterior incisor show and the smile line. The anterior show should be 3 to 4 mm at the end of the treatment and the smile line should reach the edge of the tooth crown. The anterior view is analyzed in the cephalometric image, and the smile line is analyzed clinically. As a rule of thumb for surgical planning, if the soft tissue thickness is average, the upper lip should be shortened by 1 mm if the maxilla is advanced by 3 mm, and by 2 mm if the advancement is 6 mm.
In the following remarks, four different correction possibilities for the entire complex are described, with various aspects assigned to different maxillary displacement directions.
26.2.1 Correction of bony steps, symmetrization, and, if necessary, widening of the bony nasal entrances
Key words: asymmetrical nasal entrances, bone modeling, bony steps, lateral piriform aperture, widening of the nasal entrance
When surgically adjusting the dental maxillary midline to the facial center, bony steps are created in the region of the lateral piriform aperture during the Le Fort I osteotomy. These are leveled out with the bone reamer. Asymmetrical bony nasal entrances are made symmetrical in every case, and in most cases the entire nasal entrance is laterally widened on both sides to eliminate the frequent narrowing of the nasal entrance and normalize nasal breathing. In cases of extensive maxillary advancement, further bone sculpting and retaining suture techniques may be performed to harmonize the nasolabial angle and upper lip.
26.2.2 Correction of the anterior nasal spine
Key words: anterior nasal spine shortening after maxillary advancement, narrow nose, nasolabial angle 100 to 110 degrees, segmental osteotomy of the nasal spine, shortening of the nasal spine, symmetrization of the nasal spine
The anterior nasal spine plays a prominent role in shaping the nasolabial angle, which is approximately 90 to 110 degrees depending on sex (male ≤ female). If the nasolabial angle is too small preoperatively, the forward maxillary displacement leads to a forward movement of the angle vertex, and the nasolabial angle increases. If the nasolabial angle is too large preoperatively, nasal spine shortening alone can cause the angle to decrease. Sometimes an additional rhinoplasty may be necessary.
If the maxilla is advanced, the nasal spine is also advanced. The nasolabial angle opens, which is desirable for small nasolabial angles (≤ 90 degrees). If the nasolabial angle is normal preoperatively, the advancing nasal spine must be shortened to keep the angle the same size.
In the case of simultaneous CWR of the maxilla or apical anterior segment tilts with maxillary three-way division to correct anterior protrusion, the forward displacement of the nasal spine increases. It should then be shortened more extensively (≥ 10 mm) to regain the preoperative normal nasolabial angle. If necessary, the nasal spine can also be completely separated, the bony aperture trimmed, the septum loosely adapted medially, and the paranasal soft tissue held in shape by caudal median pulling retaining sutures (see Fig 26-2). If this surgical planning additionally encounters a preoperative open enlarged nasolabial angle (≥ 110 degrees), these measures should be performed as extensively as possible.