2.1 General information and medical history
The following findings survey contains the anamnesis and clinical examination of the head, neck, and oral cavity including the functional analysis of the temporomandibular joints, the tongue, and the swallowing cycle. The significance of the findings obtained for surgical planning is explained.
2.1.2 General data
The documentation sheet is shown in Fig 2-1.
For interdisciplinary treatment of the patient and for queries, the data of the treating orthodontists and dental practitioners are requested.
Date of diagnosis and admitting physician
The day of admission of the set-up is recorded and the oral and maxillofacial surgeon performing the survey is documented. If the surgical planning is carried out by a person other than the surgeon performing the planning of the operation, queries about the clinical findings can be made in this way.
The documents are checked for completeness and that they are up-to-date.
Current models, photos (see guidelines for photographic documentation; Chapter 1), and a panoramic radiograph, which are either already available or, like the functional MRI (fMRI), are created during setup, are obligatory for surgical planning. A cranial periapical scan or digital volume tomography (DVT)/CT should be available for transverse problems to check the width of the bony base of the arches and the axial inclination of the teeth. The 3D examination also provides information about the positioning of the temporomandibular joints (TMJs). The radiologic images must be up to date in order to be able to detect, for example, dental foci preoperatively and to treat them in time.
If there are previous temporomandibular joint disorders (TMDs), an MRI of the TMJs in occlusion and at maximum mouth opening should be available or, if there is macroglossia, an MRI to size the tongue. The findings must be included in the surgical planning.
Patient’s reason for treatment
Documentation of the reason for treatment from the patient’s point of view is important, since many different aspects develop in the course of long interdisciplinary treatment, which can cause the original reason to be forgotten. However, this should be recalled, especially before surgical interventions, in order to realistically bring the extent of the operation planned by the practitioner into line with the patient’s original and actual wishes. In this way, subsequent changes in the timing of treatment or new treatment goals can be discussed and the patient’s expectations can be converted into postoperative satisfaction.
When taking a general medical history, special attention is paid to allergies (eg, to antibiotics), the use of blood-thinning medications or those with an effect on bone metabolism (eg, antiresorptives), and known anemia, so that preoperative treatments can be initiated if necessary. A current anemia, eg due to a vegetarian diet or a bleeding tendency, is excluded or diagnosed by means of current laboratory values (hemoglobin value, red blood cell count, coagulation values, platelet function test) and treated accordingly pre-, intra-, and/or postoperatively.
Thrombosis or embolism in the patient’s own and/or family history must be additionally inquired about and then further clarified and included in the treatment planning as well as perioperatively.
Orthodontic/maxillofacial surgical history
If orthodontic palatal expansion or excessive transverse expansion of the maxillary dental arch has been performed so that the palatal molar cusps have been lengthened or periodontal lesions have developed in the buccal molar region, this is an indication of a discrepancy between the dental and skeletal transverse width of the maxilla. This can be seen in the analysis of the posteroanterior cephalometric radiograph and the 3D images.
To avoid a postoperative transverse recurrence due to a too-narrow maxilla, the skeletal discrepancy should be corrected by a multi-part division of the maxilla with widening of the apical base and bony torque of the posterior teeth. However, this is only possible up to a skeletal transverse deficit of approx. 5 mm with low recurrence. Larger discrepancies should already have been treated by means of transverse maxillary distraction before the maxillomandibular realignment osteotomy.
The extraction of third molars in the mandible should have taken place more than 6 months prior to mandibular sagittal split osteotomy in order to avoid complications due to incomplete bony regeneration processes during sagittal splitting (eg, nerve damage, bad split). Transverse maxillary distraction and transverse mandibular distraction should have been performed at least 12 months prior to maxillomandibular realignment osteotomy for the same reasons in order to prevent transverse bony instabilities.
2.2 Clinical examination
The following standardized procedure has proven effective for the clinical examination of the patient.
Examination of the face
Examination of the face includes assessment of:
proportions and symmetries of the face
soft tissue and outer skeletal frame in frontal view (Fig 2-2a)
soft tissue and outer skeletal frame in profile view (Fig 2-2b).
These are divided into:
Examination of the TMJs/functional analysis
The TMJs are examined, with functional analysis.
Examination of the oral cavity
Examination of the oral cavity includes:
soft tissue and pharynx.
2.2.2 Examination of the face: frontal view
The frontal view is used and the preoperative data collected as shown in Fig 2-3.
Habitual head posture
A conspicuous habitual head posture can be an indication of a scoliotic malposition of the cervical spine, shoulder girdle obliquity, muscular asymmetries of the spine, or errors in the overall posture.
In pronounced mandibular retrognathia, the head is partially raised or the mandible and thus the chin are habitually pushed forward in order to unconsciously achieve a more favorable occlusion, which then conceals the underlying malocclusion.
In the case of habitual head malposition, refer to an orthopedist for diagnosis and therapy of concomitant orthopedic diseases, if necessary.
For centric bite registration, the shortened mandible is manually returned to the central position of both condyles. In the case of severe tension, it may even be necessary to relax the masticatory muscles by means of general anesthesia in order to be able to perform centric bite registration in complete muscle relaxation. In this case, preoperative splint therapy should be considered.
Proportions and symmetries
The facial type ethnicity is collected at the beginning of the diagnostic process.
When planning a maxillomandibular rearrangement osteotomy, different normal findings/harmonies must be considered depending on the ethnic face type. In the following explanations, the Caucasian face type is assumed.
To examine the proportions, the facial thirds (upper, mid-, and lower face) are measured vertically:
upper face = hairline to glabella
midface = glabella to anterior nasal spine
lower face = anterior nasal spine to underside of the chin/menton.
In a harmonious face, the three proportions are ⅓ to ⅓ to ⅓. In women, a slightly shorter midface is also considered harmonious.
Short and long face refer to a shortening or lengthening of the entire face from the hairline to the tip of the chin. However, the shortened or lengthened components can affect all three parts of the face – upper face, midface, and lower face. Thus, in the case of a short or long face, it should be indicated which facial component is shortened or lengthened: upper face, midface, or lower face. This differentiated information determines the surgical indication and causal surgical planning (Fig 2-4). Since the upper face is usually not surgically altered, only vertical height changes of the midface or lower face portion can be performed, such as extrusion of the maxilla with bony augmentation by interpositional osteoplasty, intrusion of the maxilla with transmaxillary septorhinoplasty, and/or vertical augmentation or reduction of the mandible by chin osteotomy. In the case of a deep or open bite, the clinically imposing short or long face may be due to occlusion and can be eliminated by surgical adjustment of a normal occlusion.
Facial asymmetries are characterized by a lateral deviation of facial parts from the facial midline. They can occur on both sides and in mild manifestations are only noticeable by a lateral displacement of the chin or mandible. Sometimes, with closed lips, the mouth area is also oblique, and with open lips, an obliquity of the transverse occlusal plane is noticeable. In more severe manifestations of facial asymmetry, a unilateral decreased or increased facial growth component occurs. A unilateral hypoplastic component due to congenital growth retardation exists, for example, in hemifacial microsomia, and a partially hyperplastic side of the face due to a pubertal growth spurt exists, for example, in hemimandibular hyperplasia.
The upper, middle, and lower face should be harmoniously proportioned (see also section 2.3 Clinical correction planning).
The facial midline is determined in frontal view with the mouth slightly open (Fig 2-5). The interpupillary line (connecting the pupil centers) is used as a guide and the median vertical is constructed as the facial midline. Lateral deviations of the tip of the nose, anterior nasal spine, maxilla, mandible, and chin are taken into account in clinical surgical planning.
The anterior nasal spine, maxilla, mandible, and chin midline should be placed in the facial midline during maxillomandibular osteotomy.
Special features arise in the case of a crooked nose with nasal tip deviation, lowering of one eye, or facial asymmetry (see also section 2.3 Clinical correction planning).
Intercanthal distance and alar base (Fig 2-6): In a Caucasian face, the intercanthal distance roughly corresponds to the alar base.
Since the alae nasi are detached from the bony base during Le Fort I osteotomy, they move latero-cranially if appropriate refixation of them is not performed. The patient complains of a “wide nose” postoperatively (Figs 2-7 and 2-8).
Therefore, before suturing the mucosa in the maxilla, the attachment of the levator labii superioris muscles and the levator labii superioris alaeque nasi muscles should be grasped with a suture and sutured bilaterally (“alar cinch suture”) in order to symmetrize the nasal wings, to narrow them to their initial level, and to fix them caudally (Fig 2-9).
If a strip of sclera is visible between the iris margin and the lower eyelid edge (Fig 2-10) when looking straight ahead with a normal eyelid fissure width, this may indicate midface hypoplasia. The receding midface lacks optimal bony support of the overlying soft tissue and lower lid edge. This sinks back and exposes part of the sclera.
Other causes of a scleral show include exophthalmos or lower eyelid retraction (Graves disease), which should be evaluated ophthalmologically.
See “infraorbital rim” below.
A flat infraorbital rim (Fig 2-11) may also be indicative of midface hypoplasia with accompanying scleral show.
If the scleral show or the flat infraorbital rim is based on midface hypoplasia, a forward displacement of the maxilla – if necessary combined with a more cranial osteotomy line – is useful in the Le Fort I osteotomy to give the midface additional volume. The patient should be informed about the postoperative changes, since an increase in volume in the midface is often perceived as “swelling” from the patient’s side.
Especially with a concave facial profile, the type change is obvious to the patients and they occasionally have difficulty adjusting postoperatively to the additional volume in the midface (Fig 2-12).
A flat or asymmetrical zygomatic region (Fig 2-13) is sometimes perceived as non-ideal by the patient.
In the case of maxillomandibular rearrangement osteotomy, unilateral or bilateral augmentation of the zygomatic prominences with consecutive zygomatic arch augmentation can be performed simultaneously, since a bone block graft required here for interposition can be harvested distolingually from the tooth-bearing mandibular portion during sagittal splitting.
Paranasal soft tissue contour
A pronounced paranasal contour results, for example, from protrusion of the maxilla, or, in older age, as an involution process combined with deep nasolabial folds due to a descent of the soft tissue mantle (Fig 2-14).
A flattened paranasal contour may be caused by midface hypoplasia combined with low expression of the nasolabial folds (Fig 2-15).
Paranasal overlay plasty from autologous bone resorbs for the most part. By advancing the maxilla during Le Fort I osteotomy, flattening of a deep nasolabial fold is possible. Additional advanced osteotomy techniques with individualized nasolateral wings can also be used for this purpose (Fig 2-16).
The shape of the nose is documented preoperatively to identify postoperative changes.
The width of the nostrils may change during maxillomandibular surgery, eg widen, if no alar cinch suture is applied.
The nasal axis can be moved slightly to the right or left in its caudal portion by a movement of the anterior nasal spine. The bridge of the nose does not change significantly even after maxilla relocation.
The nasal wings are detached from their bony support during the Le Fort I osteotomy (release of the levator labii superioris muscle and levator labii superioris alaequa nasi muscle) and shift cranio-laterally in the absence of refixation.
Fixation of the attachments of the levator labii superioris muscle and levator labii superioris alaequa nasi muscle to each other and/or to the lower surface for symmetrization, narrowing, and caudalization = alar cinch suture (see intercanthal distance and alar base, Figs 2-6 to 2-9).
Nasal septum and nasal breathing
Causes of nasal obstruction may include a deviated septum or septal spur, nasal valve stenosis, turbinate hypertrophy, or a narrow nasal base based on a transversely narrow maxilla.
In the case of a deviated septum, the septum can be partially straightened during Le Fort I osteotomy and shortened if necessary. However, complete correction can only be achieved with subsequent septoplasty after maxillomandibular osteotomy, eg with scarification for straightening. Nasal valve stenosis is also correctable only with rhinoseptoplasty in a subsequent operation.
A septal spur is removed during Le Fort I osteotomy after down fracture, and hypertrophic inferior nasal concha must also be shortened via submucosal concha resection when the maxilla is cranially displaced to preserve unobstructed nasal breathing and avoid the development of an “empty nose.” Sometimes, hypertrophic inferior nasal concha are even a mechanical obstacle to the planned sufficient cranialization of the maxilla and must be shortened intraoperatively.
If the nasal airway obstruction is caused by a low intranasal airway volume emanating from a narrow nasal base due to a transversely narrow maxilla, a transverse maxillary expansion already brings a significant increase in volume and thus nasal airway improvement.
Measurements of the lower face are discussed below.
Mouth gap width
The mouth gap width is defined as the distance from the right to the left corner of the mouth when the lips are relaxed. The corners of the mouth should be in the area between the perpendicular of the medial canthi and the perpendicular on the pupils (Fig 2-17). A very narrow and also a very wide oral fissure is considered inharmonious.
The oral cleft is enlarged by advancing the maxilla and mandible.
Upper lip shape relaxed