Orthognathic surgery involves correcting jaw deformities through combining orthodontics and maxillofacial surgery. It is primarily used in adults once growth has ceased to treat conditions too severe for orthodontics alone, such as malocclusions, airway issues, pain, or poor aesthetics. Planning involves clinical exams, models, virtual surgical planning, and splint fabrication to simulate and guide the surgery, which may include Le Fort osteotomies of the maxilla, sagittal split or vertical ramus osteotomies of the mandible, and genioplasty. Risks include nerve damage, bleeding, infection, and relapse, so patients must be informed and compliant.

2. Dr. Ahmed M. Adawy
Professor Emeritus, Dep. Oral & Maxillofacial Surg.
Former Dean, Faculty of Dental Medicine
Al-Azhar University

3. Orthognathic surgery is the art and science of combining
orthodontics and maxillofacial surgery to correct dento-
facial deformities. The word orthognathic comes from the
Greek word orqos, meaning to straighten, and gnaqos,
meaning jaw. Orthognathic surgery thus, means to correct
or straighten jaw deformities. Such correction may be
isolated to one jaw, to that performed concurrently on both
jaws. Recently, the scope of orthognathic surgery has been
broaden to involves the surgical manipulation of the
elements of the facial skeleton to restore the proper
anatomic and functional relationship in patients with
dentofacial skeletal anomalies. The treatment does not
change only the bony relations of the facial structures, but
soft tissues as well

4. Orthognathic surgery is primarily carried out in adults once
growth has ceased. In childhood and adolescence, some
skeletal malocclusions can be treated merely
orthodontically, but once growth has ceased, this is no
longer possible and additional surgery is needed. In
general, orthognathic surgery to reposition the maxilla,
mandible, or chin is the mainstay treatment for patients
who are too old for growth modification and for
dentofacial conditions that are too severe for either surgical
or orthodontic camouflage. Various benefits of
orthognathic surgery have been reported, including better
masticatory function (1), reduced facial pain (2), more
stable results in severe discrepancies (3) and improved
facial esthetics (4)

5. Dentofacial skeletal anomalies generally occur as a result
of growth discrepancy between the upper facial skeleton
to the lower facial skeleton. Underlying genetic
predisposition and acquired causes can influence the
normal growth of the facial skeleton. Congenital
anomalies, from syndromic conditions to facial clefts,
affect normal growth and development. Traumatic events
in the developing facial skeleton can disturb normal
subsequent growth. Other etiologies that can result in
significant dentofacial anomalies include neoplastic
growth, surgical resection, and iatrogenic radiation.
However, of all the etiologies, developmental anomalies
represent the most common conditions requiring
orthognathic surgery

6. The exact incidence of dentofacial deformities requiring
orthognathic surgery is difficult to estimate because it
includes a broad population of patients with deformities of
congenital, developmental, and traumatic origin.
Generally, however, the prevalence of dentofacial
deformities has been estimated as 20% of the population
world wide of which 2% warrant surgery. The number of
individuals with developmental dentofacial deformities in
the United States who may benefit from orthognathic
surgery is estimated approximately 20% of the US
population (5). In this study, the prevalence of severe
Class II malocclusions (defined as > 6 mm overjet) was
found to be 4.3% in the age groups of 18–50 years, while
that of Class III malocclusions (defined as ≥ – 3 mm
overjet) was 0.3%

7. Correction of maxillofacial deformities requires careful
analysis of the soft tissue with clinical examination and
supporting photographs, skeletal evaluation with
standardized radiographs, dental impressions, face-bow
transfers, bite registrations, and articulator-mounted
models. Clinical assessment should be directed
specifically at evaluating the relative position and size of
each of the facial skeletal elements, the degree of
zygomatic projection, and the maxillary and mandibular
positions in space relative to each other and to the cranial-
orbital region. The nasolabial angle, upper lip length, lip
competency, labial-mental sulcus, and cervicomental angle
should be documented

8. Facial balance typically is assessed by dividing the face in
thirds. The upper third is from the anterior hairline
(trichion) to the glabella, the middle third from the
glabella to the subnasale, and the lower third from the
subnasale to the menton. When each of the thirds is equal,
the face is said to be balanced and of "ideal" proportions.
The lower third may be further divided into an upper third
(subnasale to oral commissure) and a lower two thirds
(oral commissure to menton). Additionally, in profile view
the face should have a slight degree of convexity as
measured from the glabella to the subnasale to the menton.
Excess facial convexity, flatness, or concavity is felt to be
less than ideal. However, facial proportions are only
idealized concepts and have changed over time

9. Facial proportions

10. Profile analysis; angle of convexity

11. Any facial asymmetry should be noted along with the
relationship of the maxillary dental mid line to the
mandibular dental mid line and the dental mid lines to the
facial mid line. The degree of dental display on repose and
smile also should be recorded with the amount of gingival
display. The muscles of mastication and TMJ function
should be assessed. The intraoral examination should
focus on the dental alignment within each arch and
relationship of the dental arches to each other. The
periodontal status of the teeth and the patient's hygiene
should be evaluated

12. Among the steps in planning for orthognathic surgery,
preoperative cephalometric tracings are noteworthy and
should be performed with accuracy. Tracings are usually
performed on transparent acetate paper. Tracing may aid in
getting the pattern of facial profile changes. Repositioning
these patterns may determine the choice of the type of
osteotomy and provide an estimate of the amount of bone
which must be advanced, recessed or grafted. In addition,
cephalometric records are valuable in assessing the
postoperative changes and accurately measure resultant
relapse. Numerous cephalometric analyses have been
proposed, the simplest one is that of Steiner (6,7)

13. Steiner used the skull cephalometric landmarks (points)
that were proposed by anthropologists and orthodontists.
These points are:
S = Sella turcica center
N = Nasion (the fronto-nasal suture)
ANS = Anterior nasal spine
A = Subspinale (the most deepest point on the midline
contour of the alveolar process of the maxilla)
Pg = Pogonion (the most anterior point of the symphysis)
B = Supramentale (the most deepest point on the midline
contour of the alveolar process of the mandible)

14. Anatomic landmarks

15. Skeletal Analysis

16. To initiate analytical model surgery, maxillary and
mandibular impressions are taken and stone casts poured.
These are subsequently mounted with a face-bow transfer
onto an anatomic articulator. Landmarks, horizontal and
vertical reference marks are made directly on the casts to
quantify the amount, the direction and extent of jaw
movement. Segmental cuts (Mock Surgery) are then
performed on the casts to mimic the cuts that will be made
during surgery. The casts are then remounted according to
the prescribed movements determined in the treatment
plan. Subsequently, surgical guide splint is fabricated,
which is critical for the accurate intraoperative positioning
of the maxilla and/or mandible. Splint fabrication can use
self-cure or light-cure acrylic

17. Dental casts mounted onto an anatomic articulator
Reference lines are marked

18. Surgical guide splint fabrication

19. The final stage of the surgical planning process is
transferring surgical plan to operation room. Surgical
splints are used to place the osteotomized jaw bone
segments into a desired position.
This approach, however, has drawback for accurate
simulation of real bony movement based on 2D
radiographic evaluation and dental models. The limitations
are directed to landmark identification and overlapping of
anatomic structures, especially for patients with facial
asymmetry . Further, it is impossible to simulate different
surgeries with a single model. Once the model is cut, it is
impossible to undo it

20. The advent of virtual surgical planning has recently called
into question the efficacy and accuracy of traditional
analytical model surgery which is time consuming and
imprecise (8). Currently three-dimensional imaging and
computer simulation are used for planning office-based
procedures. The system allows cephalometric analysis, can
be used to perform virtual surgery and establish a
definitive and objective treatment plan for correction of
facial deformity, thus improving the accuracy and
reliability of diagnosis and treatment. Moreover, unlike
conventional model surgery on dental casts, this
technology allows to virtually perform multiple
simulations of different osteotomies and skeletal
movements in order to evaluate multiple surgical plans (9)

21. Three-dimensional imaging

22. 3D cephalometric analysis

23. Computer-aided design and manufacturing (CAD/CAM)
technique, Virtual surgery

24. Surgical splints milled on polymethyl methacrylate

25. More recently, the concept of an occlusal-based
“orthognathic positioning system” has been introduced
(10). The orthognathic positioning system has the
possibility to eliminate the inaccuracies commonly
associated with traditional orthognathic surgery planning
and to simplify the execution by eliminating surgical steps
such as intraoperative measuring, determining the condylar
position, the use of bulky intermediate splints, and the use
of intermaxillary wire fixation. The system attempts
precise translation of the virtual plan to the operating field,
bridging the gap between virtual and actual surgery

26. Maxillary positioning guides firmly attached to splint with
bone footplates placed over previously drilled landmarks

27. Mandibular positioning guide held in place by
temporary screws before skeletal fixation

28. Genioplasty positioning guides in place after osteotomy
and repositioning of skeletal segment

29. Orthognathic surgery is performed to correct a wide range
of minor and major skeletal and dental irregularities,
including the misalignment of jaws and teeth. Aesthetic
improvement has been cited as the main concern of
patients seeking orthognathic surgery (11). Common
indications for orthognathic surgery include the following:
 Difficulty chewing, biting, or swallowing
 Speech problems
 Breathing problems
 Micrognathia / Prognathia
 Chronic jaw pain

30. Numerous risk factors may alter the treatment plan or
preclude surgery, including underlying medical conditions,
bleeding dyscrasias, systemic disease or local factors that
may affect normal wound healing, compromised
vascularity of the surgical region, a patient with unrealistic
expectations, a noncompliant patient, and patients with
poor oral hygiene

31. Historically, the specialty of orthognathic surgery did not
fully develop until Obwegeser (12,13) demonstrated the
possibility of repositioning the maxilla in a stable
consistent manner in 1965 and reported simultaneous
repositioning of the maxilla and mandible in 1970. The
most common surgical techniques currently used for the
correction of dentofacial deformities, with various
modifications, are the Le Fort I osteotomy of the maxilla,
the bilateral sagittal split osteotomy of the mandible, the
oblique ramus osteotomy of the mandible, and genioplasty

32. Le Fort I osteotomy is a surgical technique which is
performed to correct deficiency of the midface region.
Surgery for maxillary advancement is performed with an
osteotomy subapical to the teeth but inferior to the
infrazygomatic crest from the piriform aperture to the
pterygo-maxillary junction. Osteotomy is also performed
on the nasal septa and the tuberosity is separated from the
pterygoid plates. Osteotomy of these strategic structures
enables the displacement of the maxilla to a new desired
position, where it is rigidly fixed to correct the vertical
and/or sagittal discrepancies (14)

33. Le Fort I osteotomy

34. When a narrowing or widening of the dental arch is
needed, or a level of the occlusal plane is desired, a
segmental Le Fort I can be performed. This procedure
differs from a Le Fort I mainly in the way that the maxilla
is split into segments (15)
Le Fort II and Le Fort III osteotomies are similar to the
Le Fort I but the Le Fort II involves osteotomies to the
orbital floor and the Le Fort III osteotomy involves the
lateral orbital rim and zygoma

35. Three pieces maxilla
segmentation
Two pieces
maxilla
segmentation

36. Le Fort II and Le Fort III osteotomies

37. Surgically assisted rapid maxillary expansion is a
distraction osteogenesis procedure expanding the maxilla
transversally, using either a tooth-borne or a bone-borne
distractor after surgery. The surgery is performed by a
corticotomy from the piriform aperture to the pterygo-
maxillary junction followed by a vertical osteotomy at the
anterior nasal spine and the median palatal suture in order
to separate the maxillary halves. The transversal widening
is performed by the distractor (16)

38. Surgically assisted rapid maxillary expansion

39. Bilateral sagittal split osteotomy (BSSO) has a wide range
of indications and can be used in almost every possible
movement, which includes the entire horizontal ramus of
the mandible. The mandible can be advanced, set back,
tilted or augmented with bone grafts. The surgical
procedure starts with a horizontal cut through the lingual
cortex of the vertical ramus above the mandibular
foramen. The sagittal cut through the cortex follows the
oblique line. The final osteotomy before the split is a
vertical osteotomy through the buccal cortex in the
mandibular body (17)

40. Intraoral vertical ramus osteotomy (IVRO) is a procedure
mainly correcting mandibular prognathism making a
vertical cut through the ramus of the mandible proximal to
the mandibular foramen (17). The main advantage with
IVRO compared to BSSO is a lower incidence of damage
of the inferior alveolar nerve. The main disadvantage with
IVRO compared to BSSO is the need of maxilla-
mandibular fixation (MMF) due to the lack of possibility
of rigid fixation between the segments (18)

41. A variant of IVRO is the extraoral vertical ramus
osteotomy (EVRO), making an extraoral incision,
dissecting to get to the inferior border of the mandible
before making the osteotomy. This has been advocated for
large mandibular setbacks (> 10mm), large vertical moves
and difficult facial asymmetries. Except for the risk of
scarring and the risk of damaging the mandibular branch
of the Facial nerve, the same risks have been reported as
for IVRO (17)

42. Bilateral sagittal split osteotomy

43. Vertical ramus osteotomy

44. In cases treating patients with micrognathia, retrognathia,
prognathia, chin asymmetry or mandibular vertical height
discrepancies, sliding genioplasty is a treatment option,
which involves an osteotomy repositioning the chin to the
desired position. This procedure is performed together
with, or without orthognathic surgery to be able to achieve
good aesthetic results, with fairly high predictability in
soft tissue response and low complication risk (19)

45. Osseous genioplasty procedure

46. Another approach to perform a movement of either the
mandible or the maxilla is distraction osteogenesis, where
the movement is performed gradually after surgery, using
a distractor device. The main advantages of
osteodistraction compared to conventional orthognathic
surgery is that; it allows the soft tissue to expand
simultaneously as the bone expands, it does not require
bone grafts, it is possible to repeat surgery at the same site
and the fact that it is a simple technique with minimal
blood loss (20)

47. Most of the common complications of orthognathic surgery
occur frequently enough that they must be discussed with each
patient in detail. Common complications which may occur in
orthognathic surgery include vascular disease, TMJ problems,
nerve damage, infection, bone necrosis, vision impairment,
hearing problems, and neuropsychiatric problems. Rarely
complications could be fatal. Excessive bleeding has been
reported as a common complication of Le Fort osteotomies.
Injury to the infraorbital nerve during a Le Fort I osteotomy or
the inferior alveolar nerve during a sagittal split osteotomy of
the mandible typically represent a neurapraxia. TMDs may be
improved somewhat by correction of a malocclusion with
orthognathic surgery, however, there is a subset of patients
whose symptoms worsen after surgery (21)

48. With any skeletal movement, the surgeon always must be
aware of the potential for relapse even in the most ideal
situation and with the use of rigid internal fixation. Soft-
tissue forces directed against the vector of the surgical
movement are significant. Generally, the most stable
moves are superior and posterior maxillary impactions and
mandibular setback. Advancements of the maxilla,
whether vertically or sagittally, are inherently less stable,
as is mandibular advancement

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