10.2 Major surgical procedures
Our understanding of the concepts of craniofacial growth is continually
evolving andd the application of this knowledge to clinical practice particularly to
the surgical field is also enormously increasing. The surgeons now a days are
able to correct the various orofacial abnormalities that have resulted from
arrested and perverted development of cranio facial complex.
Major surgical procedures that are undertaken concurrent with orthodontic
1. Orthognathic surgeries which deals with surgical correction of jaws.
2. Facial esthetic/cosmetic surgeries like rhinoplasty, blepharoplasty etc..,
3. facial reconstruction surgeries like cleft palate and lip repair surgeries
The aim of this chapter is to provide a basic view of the principles of
orthognathic surgery. Orthognathic surgery is the surgical correction of
underlying skeletal anomalies or malformations involving the mandible or the
maxilla.. Modification of a severe skeletal discrepancy in adults is not possible by
redirection of growth as growth potential is culminated. They cannot be
effectively masked by camouflage. In such adult patients surgical correction
may be indicated. Orthognathic surgeries are major surgical procedures carried
out along with orthodontic therapy to correct dento-facial deformities or severe
oro-facial disproportions involving the maxilla, the mandible or both in
combination. Surgery is not a substitute for orthodontics in these patients.
Instead, it must be properly coordinated with orthodontics and other dental
treatment to achieve good overall results. This orthognathic surgeries are
combined surgical orthodontic procedures which involve the team work of
orthodontist, an maxillofacial surgeon and some times plastic surgeon.
The team, led by the orthodontist and the oral surgeon, carefully develops a
problem list, which is reviewed with the patient. The desired outcome of the
ideal treatment plan of orthodontic treatment and jaw surgery is to achieve
stability, function, and facial balance.
Malformations of the jaws or skeletal aberration may be present at birth
(congenital), or they may become evident as the patient grows and develops
(acquired). They can cause esthetic disharmony, structural and functional
deficiencies and defects. These include disfigurement of face , masticatory
problems, abnormal speech patterns, breathing problems, early loss of teeth and
dysfunction of the temporomandibular joint. The objective of orthognathic surgery
is to restore the esthetic harmony, functional efficieny and structural balance .
2. Principle of Orthognathic surgery
Orthognathic surgery basically involves planned intentional fracturing or
sectioning of the facial skeletal parts and repositioning them as desired in
acceptable functional position. Orthognathic surgeries can be performed in the
maxilla as well as the mandible or both the jaws to correct jaw discrepancies in
all the three planes of space. They can be done at the level of basal bone itself
or limited to alveolar bone. They should be performed as a team with the oral
surgeon and the orthodontist being important members of the team.
3. Indications of orthognathic surgery
1. Skeletal discrepancy– Significant Class II or III skeletal patterns
2. Facial imbalances or asymmetries– Long lower face, gummy smile etc..,
3. Limitations of tooth movements – Need to keep teeth relatively upright and
in the bone
4. Relapse potential of orthodontic treatment– Excessive dental extrusion
(vertical elastics), expansion or tipping or teeth may not be stable
4 .Steps in orthognathic surgery
The planning and execution of orthognathic surgeries are done in a
methodical manner. The following are the steps involved in Orthognathic
i. Clinical diagnosis and evaluation
ii. interdisciplinary approach and pre orthodontic dental care
iii. Pre-surgical orthodontics
iv. Surgical treatment objective ( STO)
v. Mock surgery
vi. Surgery and stabilization
vii. Post-surgical orthodontics and occlusal detailing.
i. Clinical diagnosis and preoperative evaluation
Pre-operative diagnosis is very important for the success of orthognathic surgery.
The diagnosis is aimed at determining the nature, position, severity and the
possible etiology of the dento-facial deformity. The extent of the malocclusion in
all the three planes is thouroughly evaluated.
a. General medical evaluation : The patient’s general medical history should
be recorded to rule out any systemic condition that may compromise the surgical
b. Dental evaluation :- The patient’s overall dental health should be evaluated.
Particular attention is paid towards the muscles of mastication and
Temperomandibular joint. Pulpo -periodontal problems should be controlled
prior to the surgical intervention.
b. Socio – psychological evaluation : The patients is to be assessed to
determine whether he /she is aware of the dentofacial deformity and expectation
from treatment outcome. This helps in determining the patient's motivation
c. Cephalometric evaluation: Cephalometric evaluation is an important and
obligatory tool in locating the nature and severity of the skeletal problems and in
selecting the favourable sites for surgical correction. Cephalometric analyses
often have been used as the cornerstone in the differential diagnostic process for
skeletal imbalances. The lateral cephalogram and anteroposterior cephalogram
are evaluated. The commonly used Cephalometric analysis are the Burstone
analyses and the Quadrilateral analysis. Frontal cephalometric analysis helps in
determining facial asymmetry.
Cephalometric analyses using a Jacobson or Broadbent Bolton template method
and the Moorrees mesh are able to graphically qualify (demonstrate which jaw is
not in balance) and quantify (demonstrate the degree to which each jaw, both
dental and skeletal component, contribute to the imbalance). The template
proved to be a simple, quick, and reliable tool to demonstrate the direction and
approximate amount of surgery needed to correct the skeletal disharmony
Indications for surgery include the problems that are too severe for orthodontics
alone. The amount and range of movement possible can be evaluated from
Epker’s envelope of of discrepancies. The envelope of discrepancy outlines the
limits of hard tissue change toward ideal occlusion . The limits vary both by the
tooth movement that would be needed (teeth can be moved further in some
directions than others) and by the patient's age . Growth potential in children
helps to treat conditions by orthodontics alone ( 10mm of overjet) but the same
has to be treated by surgical means in adults.
d. Radiographic examination : A complete radiographic survey of the
maxillofacial region is necessary prior to the surgical intervention .
Intra-oral periapical radiographs : These radiographs help in determining the
condition of the teeth and alveolar bone. Presence of pathology around the tooth
can also be determined using these radiographs. Any pulpal or periodontal
infections should be eradicated before surgery
Panaromic radiographs : Orthopantomogram or OPG offers a wide range view of
the entire dentofacial region. It gives us the periapical and periodontal status of
the dentition. Any impacted/embedded or ectopic teeth, which may come in the
line of the osteotomy should be preferably extracted 6 months prior to surgery.
These radiographs are also useful in evaluation of maxillary sinuses ,
temperomandibular joint. and other bony pathologies in maxillo mandibular
region. Panoramic view points out to the asymmetry of the face also
Submento-vertex view : This view is used to determine the buccolingual
thickness of the mandible as well as degree of deformity of the face. It is also
useful is assessing the condition of condyles.
Hand wrist –X-rays : They are useful for growth assessment and to determine
skeletal age or maturity. Orthogntahic surgeries are indicated after active growth
period or after attaining skeletal maturity.
e. Photographs: Preoperative photographs are necessary in order to have a
record of pretreatment profile. Both the extraoral facial photographs and the
intraoral photographs are taken. Frontal and lateral facial photographs are
usually taken in a natural head position. Morphometric measurements can also
be done on these photographs
g. Evaluation of masticatory system: The temperomandibular joint is evaluated
by inspection, palpation, auscultation and by radiographic examination to
evaluate joint movements and an pathology. Muscles of mastication are
inspected and palpated to evaluate the force of contraction and any underlying
Epker envelope of discrepancy ( fig 1)
The maximum amount of movements possible by three different means of treatment is given by Epker envelope of
discrepancies. It has three envelops. The perimeter of each envelope gives the maximum range of movements possible
by different methods of treatment.
Inner envelope-only orthodontic treatment
Middle envelope- orthodontic and growth modification
Outermost envelope—orthognathic surgery
Table showing the amount of movement possible at incisor region by different methods ( anterioposterior and
vertical direction). Refer figure.- Epker envelope of discrepancies -- ‘A” and “B”
Amount of retraction Amount of Amount of Amount of bite
possible protraction bite opening closing
possible ( intrusion)poss ( extrusion)possi
Maxillary Mandible Max. Mand ible ble
Max Mand Max Mand
Treatment 7 mm 2mm 4mm 4mm 2 mm
3 mm 2 mm 5mm
12 mm 5 mm 5 mm 10mm 5 mm 6 mm 6 mm 5 mm
Orthognathic surgery 15 mm 25 mm 10 mm 12mm 15mm 10mm 10 mm 15 mm
Possibility of each type of treatment is not symmetric with respect to plane of space. For example tooth
movement by orthodontic means alone is more possible anterioposteriorly than vertical direction.
Growth modification is more effective in mandibular deficiency(10mm) than mandibular excess( 5mm)
- ( 1) There is more potential to retract than protract the teeth
- (2) There is more potential for extrusion (correction of open bite) then intrusion (correction of deep bite)
- (3) since growth of the maxilla cannot be modified independently of the mandible, the growth modification
envelope for the two jaws is same.
-- (4) surgery to move the jaws back has more potential than to advance the mandible
Table showing the amount of movement possible at posterior region by different methods ( transverse and
vertical direction). Refer figure.- Epker envelope of discrepancies -- ‘c” and “D”
Amount of expansion Amount of Amount of Amount of
possible on each side contraction intrusion extrusion
possible on each possible possible
Maxillary Mandible side Max Mand Max Mand
Treatment 3 mm 2mm 4mm 3mm 3 mm
2mm 2 mm 1 mm
4 mm 4mm 3 mm 2 mm 3 mm 6 mm 4 mm 5 mm
Orthognathic surgery 7 mm 5mm 4 mm 3 mm 10mm 10mm 10 mm 10 mm
2.pre orthodontic dental care
Any indicated periodontal or general dental care related to maintaining teeth or
improving dental health should be performed prior to orthodontics and surgical
intervention. The objective is to maintain as many teeth as possible and stabilize
the periodontium. Restorative work has to be completed in indicated cases.
3. Pre - surgical orthodontics
The aim of the Presurgical orthodontics is to position the teeth to the most
desirable position over basal bone in preparation for intended surgery. During
this presurgical orthodontic phase occlusal detailing is not done. This pre
surgical orthodontic fixed appliance will remain in place during surgery and
provide fixation during healing. Preferabbly the fixed appliance should be
edgewise or straightwire appliance. After surgical fixation is released, another
shorter period (4 to 6 months) of orthodontics is indicated to detail the occlusion
before retainers are fitted.
The following procedures are undertaken as part of pre surgical orthodontics.
1.Tooth alignment within the arches : Spacing ,rotations and crowding are to be
eliminated during the presurgical orthodontic treatment. Fixed appliances are
preferred as they offer better control and it is possible to align several teeth.
Space may be needed for these maneuvers which can be gained by interdental
stripping or even extractions. Extractions during presurgical orthodontics is
generally undertaken to relieve moderate to severe crowding within the dental
arches and to accommodate segmental bone cuts. If space calculations permit
to align the arch it is better to avoid extractions at this stage.Extractions can be
done at the time of surgery.
2.Inter arch coordination : Any cross bites whether localized or segmental should
be corrected at this phase. Crossbites with narrow maxillary arch require some
form of arch expanision procedures. As a general rule orthodontic expansion or
contraction to co-ordinate the upper and the lower arches should be carried out
prior to the surgery so as to provide correct post- operative occlusal
3.Incisor inclinations and Decompensation : Most of the severe skeletal jaw
discrepancies are partly compensated by change in axial inclination of the
anterior teeth in opposite direction. For example in class II skeletal condtions the
upper anteriors retrocline to compensate for maxillary prognathism and lower
incisors procline to compensate for mandibular retrognathism. This is called as
natural compensation. In mild skeletal cases this compensation is further
enhanced by comouflage by selective extraction of certain teeth which is
described in earlier chapters. In contrast to dental camouflage, in preparation for
orthognathic surgery, it is necessary to remove any dental compensations
present and to place the teeth in a favorable position with their supporting bone.
This is called as presurgical decompensation. This usually means that the
planned movement of the teeth before surgery must be in the opposite direction
from the movement with dental camouflage treatment ( fig 2)
For example in Class II skeletal malocclusions associated with mandibular
retrognathism, there is natural dental compensation in the form of proclined lower
anteriors to partially offset or mask the skeletal discrepancy. In such cases
decompensation is typified by maxillary anterior teeth proclination and
mandibular anterior teeth retroclination.
In Class lll patients with prognathic mandible dental compensation is exhibited in
the form of lingually tipped lower incisors and proclined upper central incisors . In
such cases decompensation is typified by retroclination of maxillary anteriors
and proclination of mandibular anteriors.
In other words after presurgical decompensation the condition appears to be still
worse. This should be explained to the patient as the condition is temporary and
gets corrected after surgery.
4.The surgical treatment objective (STO)
The postsurgical profile of the patient can be predicted with some degree of
accuracy by cephalometric means. This is called as “surgical treatment
objective (STO)" or “prediction tracing". It is a two-dimensional visual
projection of the changes in osseous, dental, and soft tissues as a result of
orthodontics and orthognathic surgical correction of the dentofacial and occlusal
deformity. The purpose of the STO is threefold: (1) establish presurgical
orthodontic goals, (2) develop an accurate surgical objective that will achieve the
best functional and esthetic result, and (3) create a facial profile objective which
can be used as a visual aid in consultation with the patient and family members
Essentially, after knowing the location and severity of deformity; the osteotomy
and the extent of movement of the osteotomized segment is determined. On an
acetate tracing of the cephalogram, the osteotomized segment is cut out and
moved as calculated. The soft tissue follow the movement of bone in a ratio
determined by the type of movement and the technique performed. These tissue
changes are marked on the tracing to give the postoperative profile. However,
these soft tissue changes are only meant to be a guide for prediction tracings
and are variable.
5.Mock surgery : Using prediction tracings as a guide a surgical plan is
formulated and then the surgery is simulated on articulated working models The
models are cut and repositioned in the desirable position and the segments
secured in their new position with sticky wax. The mock surgery thus helps in
evaluation of treatment outcome and any possible modifications required in the
surgical treatment plan are noted. The acrylic occlusal splints are constructed in
new occlusal position which are of immense help post surgically.
6.Surgery and stabilization( fig 3)
The next step involves the intentional or surgical fracturing and repositioning of
the bony segments. Immobilization of bone fracture sites is a necessity for
proper healing of the bone. The upper and lower arch are stabilized with the help
of the existing fixed appliance. Intermaxillary fixation usually spans for 6-8 weeks
following which the splint is removed. However with the advent of reigid
immobilization fixation techniques such as screws and plates, the time period of
intermaxillary fixation is greatly reduced. This helps in early mobilization of jaws.
7.Post – surgical orthodontics
During this phase, the final detailing of the occlusion and esthetic root paralleling
is carried out. Most cases of post-surgical orthodontics are completed by 4-6
Surgical methods and techniques .
1. .correction of anterior posterior discrepancies
Maxillary surgeries :- ( fig 4, 5 and 6)The maxilla can be virtually moved in all
the three planes by Lefort I surgery. The maxilla can be advanced by lefort I
down fracture and interposing grafts in retromolar area( fig 40 The maxilla can
be technically retracted backwards but is rarely done. There is anatomical
skeletal restrictions for set back of whole maxilla.( fig 5) This can be overcome by
anterior segmental osteotomies and retraction of the anterior segment after
removal of premolar segment.( fig6)
Mandibular surgeries ( fig 7) :- Bilateral sagittal split osteotomy( BSSO)
introduced by Trauner and Obwegeser's is still the choice for mandibular
surgeries . It is used for both advancement and retraction of the mandibular
ramus but it is commonly used for mandibular set backs as condylar segments
are easily controlled. The BSSO is done by introral method and the two parts are
immobilized by rigid immmobilisation mehods like screws,pins etc. There is early
mobilization of the jaws as the period of Intermaxillary fixation (IMF) is
considerably reduced. The main drawback is injury to inferior alveolar nerve.
The other method used is Trans oral vertical oblique ramus osteotomy(TOVRO)
which is limited to mandibular setbacks. This procedure requires less time than
BSSO and less likely to produce nerve damage. The disadvantage is that
extended period of jaw immobilization after surgery. Another drawback is
difficulty in controlling the condylar fragments .
Bimaxillary dentoalveolar protrusion is treated by maxillary and mandibular
anterior segmental osteotomies.
2. correction of vertical discrepancies
maxillary surgeries ( fig 9 and 10) The skeletal openbites can be corrected by a
LeFort I downfracture of the maxilla, with superior repositioning of the maxilla in
the posterior region after removal of bone from the lateral walls of the nose,
sinus, and nasal septum. The mandible autorotates and do not require separate
surgeries unless there is gross anterioposterior discrepancy.( fig 9)
The maxilla can be impacted in deep bite cases after performing lefort I surgery.
This improves the gummy smiles in vertical maxillary excess cases ( fig)
Mandibular surgeries: In skeletal openbites with long faces the ramal
surgeries can be done to rotate the mandible anteriorly upwards and posteriorly
downwards. This lengthens the ramus and stretches the muscles associated
with ptyerygomandibular sling . However this is highly unstable due to improper
neuromuscular coordination of muscles .
The deep bite cases are best treated by sagittal split mandibular ramus surgery
to rotate the mandible slightly forward and down and the gonial angle area up.
Anterior subapical surgeries can also be performed to relieve the deep bite ( Fig
3. correction of transverse discrepancies
The maxilla can be expanded laterally or constricted with reasonable stability.
The amount of constriction possible is less than the range of expansion. The
only transverse movement easily achieved in the mandible is constriction,
although limited expansion is possible.
Maxillary surgeries . Maxillary constriction or expansion can be accomplished
easily by segmenting the maxilla in the course of LeFort I downfracture
Expansion is done with parasagittal osteotomies in the lateral
floor of the nose or medial floor of the sinus that are connected by a transverse
cut anteriorly. A midline extension runs forward between the roots of the central
incisors. If constriction is desired, bone is removed at the parasagittal osteotmies.
Mandibular surgeries Movements in the posterior region are limited by the
condyle-glenoid fossa relationship. In the anterior region the expansion across
the canine can be achieved by distraction osteogenesis. The constriction of the
arches can be possible by osteotomies by removal of teeth if spacings doesnot
Problem / Surgical treatment
1. Bilateral Sagittal split osteotomy ( BSSO) with
Mandibular mandibular set back
prognathism 2. Oblique sub condylar (sub sigmoid) osteotomy.
3. Some times reduction genioplasty is required.
Mandibular 1. BSSO with mandibular advancement.
retrognathism 2. Mandibular Total Subapical Advancement when change in
the profile is not anticipated.
3. A forward sliding genioplasty of the chin may be required
Horizontal chin Genioplasty . Some times implants may be used to augment
deficiency the chin appearance.
Maxillary Lefort I osteotomy /Maxillary segmental (anterior) set back
Maxillary retrusion Lefort I osteotomy with maxillary advancement
Bimaxillary Maxillary and mandibular segmental osteotomy for set back of
protrusion anterior maxilla and mandible
Maxillary Lefort I osteotomy of maxilla to advance and impact maxilla
deficiency and BSSO with mandibular set back
Maxillary vertical Lefort I osteotomy with maxillary impaction
Open bites Dento alveolar open bites
Minor dento-alveolar open bites can be treated by maxillary
and mandibular anterior segmental osteotomy.
B. Skeletal open bite (with Angle's Class I or II)
These patients usually have vertical maxillary excess. Le forte
I osteotomy with maxillary impaction is done
C. Skeletal open bite (with Angle's Class III)
. They have increased length of ramus and mandibular body.
Sagittal split osteotomy is done to displace mandibular body
upwards and backwards
If there is an associated maxillary retrognathism a Le forte I
with maxillary advancement is done
In case the patient also exhibits a vertical maxillary excess,
then Ie Forte I with maxillary impaction is done
Deep bite Lower anterior dento-alveolar segmental osteo~omy to bring
the lower incisor segment downwards and forwards
Maxillary Usually these are associated with vertical and sagittal
sion Lefort I with parasagittal osteomies is done for expansion and
Mandibular Anterior body osteotomies
Mandibular Distraction osteogenesis.
Genioplasty Techniques. The chin can be augmented either by using an
osteotomy of the lower border of the mandible to reposition the symphysis or by
adding an implant material. The ostetomies are preferred approaches. A wedge
shaped portion of the symphysis and inferior border are segmented by
osteotomy. This segment can be advanced to augment chin contour. This is
called as advancing genioplasty and is used in cases with deficiency of chin. A
wedge of bone can be removed above When reduction is desired. This is called
as reduction genioplasty and is used in cases with prominent chins. It can be
down grafted to increase lower face height. The distal aspects of the wedge can
be flared or compressed if narrowing of the anterior portion is needed. It can
also be shifted sideways to correct asymmetry,. Thus the chin can be controlled
in all the three planes by this plastic surgery.
Silicone implants can be used to augment the chin. The main drawback is the
problems with bone resorption under the silicone material and migration of the
implant . porous hydroxylapatite in block form can also be used but it is difficult
to adapt at the time of surgery and is not immune to the problems of resorption
Osteodistraction is a technique of bone lengthening that uses the body's natural
healing mechanisms to generate new bone. An osteotomy (corticotomy) is made
in an area of bone deficiency, and an external fixator is used to slowly elongate
the bone to its new dimension while natural ossification produces new bone at
the site of distractions.
Although osteodistraction was pioneered by surgeons in the 1880s, Codivilla of
Bologna, Italy, produced the first published accounts in 1905 . In 1949 Dr. Gavriel
O. Ilizarov began to develop new ways of applying the principle of
Ilizarov's principles. Surgeons who have used or modified the distraction
procedure have relied on Ilizarov's basic principles, which can be expressed as
the law of tension stress.
These principles include the following
Latency period The latency period is the time interval between the surgical
procedure and the initiation of application distraction forces.; Ilizarov
recommended a delay of 5 to 7 days
Rate of distraction Achieving the correct rate of distraction is important for
proper activity of cells and bone formation. The optimal rate currently is
considered to be 1 mm per day
Rhythm of distraction The term rhythm of distraction refers to the number of
distraction events per day.For example,a 1 mm a day rate could be divided into a
rhythm of 0.5mm twice a day or 0.25 mm four times a day. In 1994 Aronsons
found that either of those two rates is clinically acceptable,but a continuous
distraction force is ideal
Frame stabilityThe capacity of the fixator to stabilize the newly formed bone
within the area of distraction isknown as the frame stability. Aronson found that
the fixation must be stable enough to support the newly formed microcolumns of
Application of distraction osteognesis in craniofacial complex.
Current developments and refinements in the design of intraoral distraction
devices have allowed orthodontists to treat patients with a variety of
anteroposterior and transverse problems that previously were difficult to manage
other than through major surgery
Intraoral corticotomies performed in conjunction with skeletal toothborne
distraction appear to offer significant advantages over classical treatment of
micrognathia in Class Il mandibular deficiency patients and thus can be used to
lengthen the mandibles.( fig 12). It is also useful in widening of the mandible
along with the lengthening procedures
Another application is in the increase in the transverse diameter of maxilla ie..,
arch expansion. It can also be used in cases of maxillary deficiencies for
The principles of osteodistraction appear to open the door for the new millennium
to a more conservative form of treatment for some of the skeletal jaw imbalances
prevalent in modern orthodontic practice.
They are surgical procedures carried out to improve the esthetic appearance of
the patient. These surgeries can involve the nose and the chin. Cosmetic
surgery of the nose is called rhinoplasty. They are undertaken to correct
abnormal configuration of the nose. Cosmetic surgery of the chin is referred to
Essay type questions
1. Describe the different orthognathic surgeries for class II skeletal condi
Short answer questions
1) Bilateral sagittal split osteotomy ( BSSO)
3) Osteigenesis distraction
4) Mandibular surgeries
5) Lefort I surgeries.
6) preSurgical orthodontics