Orthognathic surgery is an effective approach to correct vertical maxillary excess (VME), which is a common maxillofacial deformity and exhibits excessive vertical development of maxilla. This review summarizes different clinical features of total, anterior and posterior VME, as well as corresponding surgical managements guided by preoperative computer-assisted surgical planning. The virtual simulation will do favor to the final determination of individual surgical plans to achieve satisfactory outcomes. Finally, a typical clinical case will be presented to demonstrate the surgical management of VME.
Key points
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Vertical maxillary excess (VME) is a common maxillofacial deformity affecting the lower third of face, which can take place in posterior, anterior, and total maxilla.
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Orthognathic surgery is the workhorse to correct VME of adult patients via bone removal and maxilla impaction, which can be carried out in posterior, anterior, or total maxilla.
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Preoperative computer-assisted three-dimensional surgical plans show great importance due to the prediction of orthognathic surgery.
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The lower anterior facial height and relationship of upper lip–incisor (ie, the exposure of upper incisor in repose) is critical for the determination of the maxilla repositioning.
Introduction
Patients with vertical maxillary excess (VME) often show excessive vertical maxillary development, which can take place in the whole, posterior, or anterior maxilla, and thus termed as total VME, posterior VME, and anterior VME, respectively. Sometimes it is also named as long face deformity and the clinical features include long face, gummy smile, and occasionally open bite. Approximately 20%–30% of patients show a vertical increase of the lower third part of the face. , It is challenging to correct the long face deformity of patients with VME. There seem no better choices for the adult patient than the combination of orthodontic and orthognathic surgery, which consists of preoperative orthodontics, orthognathic surgery, and postoperative orthodontics.
After preoperative orthodontic treatment, orthognathic surgery will be carried out to correct deformities, which has been the workhorse for the management of VME for decades. The Le Fort I osteotomy of the maxilla makes it feasible to impact maxillary dentoalveolus via bone removal. Then, the mandible will autorotate anteriorly around the condylar hinge axis, which was first described in the 1970s. , On this basis, plenty of surgical techniques have been developed for the management of different kinds of VME. The direction and extent of planned surgical repositioning depend on the original deformity. When planning maxillary impaction, the most significant factors for determination are the low anterior facial height (LAFH) and resultant upper lip–incisor relationship, which is the mainstay of the treatment planning. Furthermore, the application of a computer-assisted three-dimensional (3D) surgical plan can visualize the bone movement during surgery preoperatively and make the surgical plan more accurate.
This review is focused on surgical approaches for the management of total, anterior, and posterior VME, depending on different clinical features, which will be described in this review. Computer-assisted 3D surgical plan will also be introduced for accurate virtual plan of orthognathic surgery. Based on the ideal upper lip–incisor relationship, the different surgical plan will be put forward for individual patient to impact maxilla and correct deformities. A typical clinical case is presented to demonstrate the surgical management of a patient with VME as a summary.
Clinical features
Mandible Rotation
Patients with VME often show mandibular rotation backward, which will affect the position of sagittal chin prominence and mandibular plane angle ( Fig. 1 ). In general, patients’ mandibles will rotate backward and downward if they have normal or reduced length, which will make the chin less prominent and increase the mandibular plane angle ( Fig. 2 A). However, if patients have long mandibles, the chin is rotated to a more normal sagittal position ( Fig. 2 B).
Nasal Morphology
Patients with VME tend to show narrow noses with narrow alar bases ( Fig. 3 A). Prominent nasal dorsa can be observed in patients with long face deformity.
Lip Incompetence
Patients with VME often show an incomplete lip seal (≥4 mm) ( Fig. 3 B), resulting from LAFH increase, the lack of upper and lower lip heights, and the backward mandibular rotation. The interlabial distance at rest and the extent of lip incompetence will increase when these deformities are more severe.
Palatal Vault Morphology
Patients with VME often show high and narrow palatal vaults ( Fig. 3 C), which might be caused by the tongue position, as well as compensatory overeruption of the maxillary dentition resulting from the increased LAFH. As a result, patients with VME may also show posterior dental crossbite.
Anterior Open Bite
The primary etiologic factor of anterior open bite is the excessive face height caused by VME and the resultant clockwise rotation of the mandible, which often happens in patients with posterior and total VME ( Fig. 3 D). The degree of anterior open bite is determined by the LAFH, the compensatory overeruption of incisors and the tongue resting position. However, if patients show the clockwise rotation of maxillary occlusal plane, the anterior open bite may not occur generally.
Upper Lip–Incisor Relationship
The upper lip–incisor relation (ie, exposure of maxillary incisors at rest) is determined by the degree of vertical maxillary development of the anterior dentoalveolar. Thus, for patients with total and anterior VME, the exposure of maxillary incisors will increase. However, patients with posterior VME may show impeded anterior dentoalveolar because of the forward resting tongue position, where the maxillary incisor exposure can be normal or even reduced.
Gingival Exposure
“Gummy smile” (ie, gingival exposure when smiling) can be observed both anteriorly and posteriorly, which depends on the extent of VME. Patients with total VME often show increased gingival exposure both anteriorly and posteriorly, whereas patients with anterior and posterior VME only show excessive gingival exposure in the overdeveloped regions ( Fig. 4 ).
Maxillary Occlusal Plane
The rotation of the maxillary occlusal plane depends on the differences of posterior and anterior vertical excess. Its counterclockwise rotation often results from posterior VME and total VME with excessive posterior maxilla growth. Meanwhile, if the anterior maxilla shows greater vertical excess, a clockwise rotation of the maxillary occlusal plane will appear, including anterior and total VME.
Preoperative orthodontics
Generally, the preoperative orthodontic treatments are carried out to prepare for maxillary impaction and subsequent mandibular autorotation. For reduction of the LAFH, the mandibular arch should be leveled as far as possible in the preoperative stage, including incisor intrusion and premolar/molar extrusion. For patients with severe anterior open bite, it is better to align the arch in segments and deviate the roots for the subsequent segmental osteotomy. Furthermore, if a two-piece segmental Le Fort I osteotomy is required to adjust the maxillary dentition transversely, the dental arch should be aligned with the alveolar base.
Preoperative surgical plan
Determining Factors
The orthognathic surgeries for patients with VME generally include maxillary impaction and subsequent counterclockwise mandibular autorotation. When planning the maxillary impaction, the key factors are LAFH and upper lip–incisor relationship, among which the desired exposure of maxillary incisor at rest should be firstly considered. For young adult men, the proper exposure of maxillary incisor at rest is approximately 2 to 3 mm, and about 4 to 5 mm for young adult women. It is also important to plan a slight increase of the maxillary incisor display, considering aging changes of the upper lip. If patients’ maxillary incisor exposure is not excessive and a complete lip seal can be achieved, the increase of face height can be acceptable.
Since the final position of mandible and bony chin depends on the movement of maxilla, it is important to avoid excessive impaction to keep balance of the LAFH, total face height, and the standing height of the patient. Furthermore, excessive impaction may cause unwanted changes of the soft tissue, such as elevation of the nasal tip, broadening of the nasal alar base, and a vertically over-compressed “bunched-up” appearance of the midfacial soft tissues.
To mitigate these disadvantages, Rosen suggested undercorrecting in the vertical dimension and overcorrecting in the sagittal dimension. Venkatesh Anehosur and colleagues also reported a modified Le Fort I osteotomy, where the group carried out the osteotomy below the piriform aperture. After follow-up for 1 year, the width of the alar base showed minimal changes, with the width of 36 mm compared with 34 mm preoperatively. The change of soft tissue could be acceptable even though the maxillary impaction was radical.
Besides, other factors should also be considered before orthognathic surgery, such as sagittal and horizontal position of maxilla, transverse width of the dental arches, and correction of the occlusal curve.
Computer-Assisted Surgical Plan
Two-dimensional (2D) cephalometric analysis and model surgery are conventional methods for preoperative surgical plan. However, 2D images could not provide full information about the 3D structures and unexpected problems might occur during surgery, such as bony collision, rotation discrepancy, midline difference and chin inadequacy.
Computer-assisted virtual planning provides a more accurate and predictable approach for orthognathic surgery, , which integrates surgical plan and intervention via commercial software programs, such as Dolphin Imaging, Maxilim, 3DMDvultus, InVivo-Dental, and SimPlant OMS. 3D diagnostic assessments of facial morphology can make clinical decisions more precisely, and improve surgical outcomes significantly. The steps of computer-assisted orthognathic surgical plan are listed below ( Fig. 5 ):
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Collecting diagnostic data, including clinical examinations, dental models, 3D photographic examinations, MRI, and CT;
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Joint consultation and treatment planning with the orthodontist, surgeon, and the patient;
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Making diagnosis according to a comprehensive analysis of diagnostic data;
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Reconstructing and segmenting anatomic 3D structures in the virtual computer planning;
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Simulating surgical movements and outcomes;
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Designing individualized surgical splints.
