3. • Orthognathic in Greek
Orthos- straight ; Gnathos- jaw
• Orthognathic surgery refers to surgical procedures designed to
correct jaw deformities
• Orthognathic procedures are divided into three categories:
• Maxillary surgery
• Mandibular surgery
• Bimaxillary procedures
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 3
4. • Indications to orthognathic surgery
• Impaired mastication
• Temporomandibular pain
• Dysfunction
• Sleep apnea
• Susceptibility to caries and periodontal disease
• Unaesthetic appearance
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 4
5. • Once growth has ceased, the combination of orthognathic
surgery with orthodontics, usually becomes the only means
of correcting severe dentofacial deformities
• In severe malocclusion there are three possibilities for
correction:
• Growth modification
• Orthodontic treatment
• Orthognathic surgery in conjunction with orthodontics to establish
proper jaw relationship
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 5
6. • Orthognathic surgery was originally developed in the United States
of America (Steinhäuser ).
• The first mandibular osteotomy is considered to be Hullihen´s
procedure in 1849 to correct anterior open bite & mandibular dento
alveolar protrusion with an intraoral osteotomy.
• Osteotomy of the mandibular body for the correction of mandibular
horizontal excess was performed by Vilray Blair.
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 6
HISTORY
7. • Berger (1897) described a condylar osteotomy for the correction of
prognathism.
• Limberg in 1925 first reported the subcondylar osteotomy as an
extraoral technique, later it was modified to the intraoral vertical
subcondylar osteotomy.
• A variation of the vertical subcondylar osteotomy was suggested
by wassmund in 1927,which is similar to the inverted –L-
osteotomy.
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 7
8. 9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 8
• Hofer in 1936 demonstrated an anterior mandibular alveolar
osteotomy to advance anterior teeth in correction of a mandibular
dentoalveolar retrusion.
• In 1954, Caldwell and Letterman developed a vertical ramus
osteotomy technique, which had the advantage of minimizing
trauma to the inferior alveolar neurovascular bundle.
9. The greatest development in osteotomies of the vertical ramus is the
sagittal split osteotomy credited to obwegeser in 1955. The major
modifications in the osteotomies design were first made by Dalpont in
1961.This was further discussed by Hunsuck in 1968 in order to
decrease the trauma to overlying soft tissues.
Kent & Hinds in 1971 initially presented the use of single tooth
osteotomies of the mandible.
Macintosh closely followed with his description of the total
mandibular alveolar osteotomy in 1974.
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 9
11. • Patient’s perception of the deformity and expectations
• Surgeon’s recognition of the deformity
• Complete physical examination, model surgery, cephalometric analysis
• Optimal treatment plan
• Counseling of the patient
• Informed consent
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 11
PRINCIPLES IN TREATING MANDIBULAR DEFORMITIES
14. Bell and Levy’s work {1970} demonstrated that blood flow through
the mandibular periosteum could easily maintain a sufficient blood
supply to the teeth of a mobile segment, even when the labial
periosteum was degloved.
subapical osteotomies need to be carefully planned to ensure as large
a vascular pedicle as possible.
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 14
VASCULAR STRUCTURES
15. The proximal segment of the vertical sub sigmoid osteotomy maintains
its blood supply through the temporomandibular joint capsule and
the attachment of the lateral pterygoid muscle.
But the inferior tip of this fragment has undergone vascular necrosis
in some studies.
This led to the suggestion that fewer problems may occur if the cut
was made above the angle of the mandible.
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 15
16. We should minimize the periosteal and muscle attachment stripping on
the medial surface of the proximal fragment with either the C or L
osteotomy or any of their variations.
The greater distance from the apices of the teeth not only minimizes
direct pulpal injury but increases the vascular pedicle to the mobile
segment as well.
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 16
17. NERVES
• In most cases in orthognathic surgery avoiding injury to marginal
mandibular branch of facial nerve is achieved because soft tissue
anatomy in patients undergoing the surgery has not been disturbed
by disease or trauma.
• The course of the inferior alveolar nerve into the vertical ramus
and then through the body of the mandible makes it extremely
susceptible to damage from almost every mandibular surgical
procedure.
• Main goal – “To minimize the trauma because its
avoidance is impossible”
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 17
18. MUSCLES
Orthognathic surgery affects muscles in primarily two ways:
• It changes the length of a muscle or it changes the direction of
muscle function.
• The muscles commonly discussed in orthognathic surgery of the
mandible have been the muscles of mastication and the suprahyoid
group of muscles .
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 18
19. • A- S to lingula - 14.8 +/- 2.90 mm
• C- S to mandibular foramen –
21.6 +/- 3.31 mm
• B- Horizontal distance from lingual
to anterior border of ramus –
17.7 +/- 2.89 mm
• D- Mandibular foramen to ramus –
18.6 +/- 2.49 mm
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 19
Int. J. Oral Maxillofac. Surg, 2008
20. • At a distance between 7.5 to 13.3
mm above the lingula
Buccal and lingual cortex fusion
occurs at a rate of
• 20% in the anterior ramus
• 39% in the posterior ramus
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 20
21. • The position of the lingula is
posterior-inferior relative to the
position of the antilingula
• Any osteotomies performed at
a measurement of 5 mm
posterior to the antilingula (at
the level of the antilingula)- no
risk of damaging the
neurovascular bundle
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 21
Accuracy of Using the Antilingula as a Sole Determinant of Vertical Ramus
Osteotomy Position . J Oral Maxillofac Surg, 2007
22. Position of IAN at second
molar
• Bone thickness from mandibular
canal to buccal plate- 7.2 +/-
1.47 mm
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 22
Int. J. Oral Maxillofac. Surg, 2008
26. • Blood flow is crucial for revascularisation and healing
• Blood flow will be decreased in the areas where the
mucoperiosteum will be elevated
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 27
27. • Immediate post-operatively
• Intermedullary circulation between the proximal and distal
segments
• Margins of osteotomy- avascular
• One week post-op
• Level of hypervascularity around surgical site
• No soft tissue re-attachment
• Isolated areas of sub- periosteal bone formation
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 28
28. • 2 weeks post-op
• Avascular zone at the proximal osteotomy site
• Necrotic zone at the distal osteotomy site
• No soft tissue attachment at the distal necrotic zone
• 3 weeks post-op
• Soft tissue re-attachment
• Vascular anastamoses between proximal and distal
segments
• Osteoid formation through out marrow formation
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 29
29. • 6 weeks post-op
• Circulation reconstituted across the osteotomy site
• Soft tissue re- attachment established
• 12 weeks post- op
• Circulation between the segments is continuous
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 30
30. CLASSIFICATION
9/19/2016 9:29:31
AMRT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115
31
MANDUBULAR ORTHOGNATHIC PROCEDURES
BODY
OSTEOTOMIES
SUB APICAL
OSTEOTOMIES
RAMUS
OSTEOTOMIES
HORIZONTAL
OSTEOTOMY
OF CHIN
SAGGITAL SPLIT
OSTEOTOMY
VERTICAL RAMUS
OSTEOTOMY
INVERTED “L” &
“C” OSTEOTOMY
ANTERIOR SUB
APICAL OSTEOTOMIES
POSTERIOR SUB
APICAL OSTEOTOMIES
TOTAL SUB APICAL
OSTEOTOMIES
32. • First described in 1942 by Schuchardt in German
literature
• Most widely used surgical procedure for correcting mal-
positioned mandible
• It has been modified in many ways, but for longer than 50
years, benefits and advantages of the procedure have
remained unchanged
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 33
33. • Versatility of the procedure allows wide application
• It increases the range of possible movements
compared with orthodontic treatment alone
• Broad bony overlap of the separated fragments allow
not only advancement or set- backs of the distal
tooth- baring mandible, but also rotations
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 34
34. • A. Trauner & Obwegezer,
1957
• B. Dal pont, 1961
• C. Hunshuck, 1968
• D. Epcker, 1977
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 35
35. • Bell and Schendel established the biological basis for
BSSO
• Minimal detachment of the pterygomassetric sling there is
decreased intra- osseous ischemia, and necrosis of the
proximal segment
• 1976, Spiessel advocated rigid internal fixation of
BSSO to promote primary healing, restore early
function, and attenuate relapse
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 36
36. Indications
• Mandibular deficiency
• Advancements beyond 10- 12 mm, extra oral approach
should be considered
• Mandibular prognathism
• Large setbacks of more than 7 -8 mm, IVRO/ inverted L
osteotomy should be considered
• Mandibular asymmetry
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 37
38. ADVANTAGES
• Broad bony overlap of
osteotomised segments
• Minimal alteration of natural
position of muscles of mastication
• Minimal alteration in position of
TMJ
• Short operating time and low
complication rate
DISADVANTSGES
• Requires additional
maxillary surgery for most
dentofacial deformities
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 39
39. Osteosynthesis
• Post- operative fixation of the osteotomised segments was
once a great challenge
• Initially,
No fixation of the fragments
Healing- intermaxillary splinting of the teeth
• Introduction of wires for fixation
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 40
40. • Major breakthrough- development of “stable
compression osteosynthesis”-
Spiessl in 1974
• The degree of immediate postoperative stability
achieved with this technique completely obviated the
need for intermaxillary fixation
• Wide variety of methods and materials for fixation
are available
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 41
41. • Initially the use of three 2.7 mm “lag” screws on
each side was advocated
• Concern
• Compression may cause increased nerve damage
• Displacement of the condyles, with subsequent
temporomandibular joint dysfunction
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 42
42. • The position screw or bicortical screw
This technique permits maintenance of the gaps
between the proximal and distal fragments, with no
compression of the two segments together
• Osteosynthesis with miniplates
• 4- holed plate with 2screws on each side of the osteotomy
cut
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 43
43. • Resorbable screws
• Obvious advantage of resorbable fixation is to obviate the
need for future hardware removal
• 4 screws have to be placed on each side of the mandible
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 44
45. • 1st described by Caldwell and
Letterman in 1954- extra oral
• Introduced by Moose in 1964- intra-
oral technique performed from
lingual aspect
• Wistanley, 1968- performing the
technique from the lateral aspect of
the mandible
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 46
46. Comparison between SSRO and VRO
SSRO VRO
OSTEOTOMY PA Saggital split Latero medial cut
Open procedure Blind procedure
Along IAN Rear to IAN
Frequent exposure of IAN No exposure of IAN
BONE HEALING Contact on marrow to marrow Contact on cortex to cortex
BONE FIXATION Rigid internal fixation No fixation
CONDYLAR HEAD Original position New equilibrated position
POST OP IMF None or shorter period Required
PROGNOSIS Weakely dependent on PT Strongly dependent on PT
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 47
47. Indications
• Horizontal mandibular excess
• Mandibular asymmetry
• Minor occlusal discrepancy after
isolated Le Fort I osteotomy
• Asymmetric lateral open bite
• Failure to achieve passive rotation
of the mandible after the release of
MMF
• Patients with significant TMJ
complaints
Contraindications
• Advancement of the distal
segment
• Aesthetic assessment of the soft
tissues of the neck is the
integral factor in planning
mandibular set back by ramus
surgery
• Recent condylar fractures
• Should be differed for 6-12
months
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 48
48. ADVANTAGES
• Can be performed on OPD basis
• Inherent anatomic architecture of
the mandible poses little
interference to place the cuts
• Less chance of damaging the IAN
bundle
• Found to have curable effects in pts
with pre-op TMD
• Less incidence of condylar sag
DISADVANTSGES
• Need for MMF
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 49
50. • IMF-7-10 days .elastic traction-4-5 weeks
• Rigid fixation-uncommonly used because of
• Technical difficulty
• Increased operation time
• Good results with wire fixation or IMF
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 51
51. Bony interference
• Occurring between the overlapped
proximal and distal segments-
causing a backward rotation of the
of the proximal segment
• If interference is not reduced-
forward skeletal relapse upon IMF
release
• Contact between the condyle and
coronoid
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 52
53. • These are designs in the vertical ramus that include
both the condyle and coronoid in the same segment
• Most commonly done via an extra- oral approach
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 54
54. • Indications
• Large advancements >12mm
• Mandibular setback -10mm or more-bypasses the need for
coronoidectomy
• Secondary correction of proximal segment malrotation following
BSSO
• Simultaneous advancement and lengthening of ramus in case of severe
ramus under development.
• Less risk of condylar sag compared with VRO
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 55
57. • Blair -1907-as an extra oral procedure
• Dingman –combination of extraoral and intra oral
access
• Now contemplated only as an intraoral procedure.
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 58
58. Indications
• Mandibular setback
• Mandibular prognathism with ramus procedure.
• Mandibular prognathism where long body in relation to ramus
• Anterior open bite closure
• Curve of spee reduction
• Progenia correction
• In class III-anterior body osteotomy –wedge of bone
removed and set back
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 59
59. Pitfalls
• Anatomic discrepancies leading to reduction in bone to bone contact
• Segment control
• Torquing of the proximal segments is the classic problem
• Root anatomy is variable
• Difficult to perform osteotomy in the premolar region when trying
to skrit the mental nerve and root of the 1st premolar
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 60
61. ANTERIOR MADIBULAR SUB-
APICAL OSTEOTOMY
• Earliest referenced description of symphyseal osteotomies was by
Trauner in 1952
• Aids in correction of dentofacial deformities.
• When combined with AMO non skeletal open bite or bimaxillary
protrusion can be corrected
• Useful to level the plane of occlusion with out decreasing the
vertical facial height
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 62
63. Complications
• Loss of bone or teeth in osteotomised segment.(lingual
tissues not protected-decrease in blood supply)
• Bone cuts placed close to the teeth-loss of vitality and
periodontal defects
• Mental nerve paresthesia-directly related to the amount of
trauma
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 64
64. Posterior Subapical Osteotomy
• First described by- Peterson
Indications
• Correction of super eruption of posterior mandibular teeth
• Ankylosis of one or more posterior teeth
• Abnormal buccal or lingual position of these teeth especially if
orthodontics is not feasible
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 65
65. Total Mandibular Subapical
Osteotomy
• Oldest procedures used to correct Jaw Deformity.
• Described by HULLIHEN in 1849.
• Popularised by Hofer and Koele.
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 66
66. • Primary indication
Malocclusion caused by
Mandibular Dentoalveolar
deformity with normally
positioned Maxilla and Mandibular
skeletal bases
• Bell concluded that horizantal
osteotomy be completed 0.5cm or
more from the apices of teeth in
order to preserve pulpal
circulation. 9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 67
68. • Facial features often form a basis for stereotyping of
personality charecteristics
• Chin is most prominent facial feature
• Chin deformities can manifest in 3 dimensions but
majority are in the horizontal direction
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 69
69. • Horizontal sliding osteotomy-first described by
Hofer in 1942-through extra oral approach.
• Trauner and Obwegeser-1957- horizontal osteotomy
through an intra oral incision.
• Reichenbach-1965-wedge osteotomy and vertical
shortening of the chin.
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 70
73. Double Sliding Horizontal
Osteotomy
• Indication- severe chin deficiency
• Surgical technique involved-
creation of a stepped
intermediate wafer between the
inferior fragment and mandible.
• Inferior fragment also advanced
to provide bony contact between
upper and lower fragments.
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 75
75. Saggital Splilt Genioplasty
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 77
Sagittal Split Genioplasty: A New Technique . J Oral Maxillofac Surg, 2010
76. Transverse Reduction Genioplasty
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 78
Transverse Reduction Genioplasty to Reduce Width of the Chin
J Oral Maxillofac Surg, 2010
77. Chin Sheild Genioplasty
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 79
Chin shield osteotomy – a new genioplasty technique avoiding a deep mento-labial
fold in order to increase the labial competence . Int. J. Oral Maxillofac. Surg, 2009
78. M- Shaped Genioplasty
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 80
M- shaped genioplasty: new surgical technique for vertical and saggital
chin augmentation: 3 case reports
J Oral Maxillofac Surg, 2012
80. • The major goal of orthognathic surgery is the
establishment of a balanced and stable
dentoskeletofacial complex
• Most important aspect- achieving aesthetically
pleasing facial soft tissue envelope
• Ability to predict soft and hard tissue changes before
an orthognathic surgical procedure is critical to
treatment planning
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 82
81. • Change in soft tissue morphology after orthodontics
+ surgery depends upon
• Method of wound closure
• New spatial arrangement of skeletal and dental elements
• Adaptive qualities of soft tissues
• Vector of tooth movement
• Lip thickness, tonicity, lip area, competence, strength,
postop oedema, etc.
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 83
82. Anterior Repositioning
• Little change in upper lip &
none above ANS
• Variable advancement in
lower lip, it often lengthens
• Lower labial sulcus & chin
adhere to bone, so advance
more than lower lip-opening
of labiomental fold
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 84
83. Posterior Repositioning
• No effect on subnasale or the tissues superior to
subnasale
• Slight posterior displacement of upper lip, with
lengthening can occur
• Slight increase in nasolabial angle
• Soft tissues follow the mandible posteriorly, with
chin following most closely, followed by inferior
labial sulcus
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 85
84. Autorotation
• During autorotation of mandible, the soft tissues
follow the osseous landmarks on approximately 1:1
basis
• But lower lip falls slightly lingual to arc of rotation
• Slight increase in labiomental angle
• Slight thickening of lower lip
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 86
85. Soft Tissue Changes After
Genioplasty
• The soft tissue changes depend on magnitude & direction of
positional change of the genial segment, design of mucosal &
osseous incisions, amount of soft tissue stripping, & other
concomitant jaw movements
• Advantage of genial surgery is preservation of normal tissue contour
• Vertical reduction allows larger soft tissue advancement
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 87
86. Anterior repositioning
• Majority of change is in soft tissue of chin; less effect is in labial sulcus &
lower lip
• Soft tissue follow hard tissue without chin droop
• Small but negligible effect on labiomental sulcus
• Increase in submental length
• Improved lower lip to tooth relationship
• Less soft tissue thinning
• Improved neck chin angle
9/19/2016 9:29:31 AM
RT/8/MANDIBULAR ORTHOGNATHIC
PROCEDURE/115
88
87. Posterior repositioning
• Little improvement in profile
• Soft tissue changes are little correlated with hard
tissue movements (than with advancement)
• Contraindicated in patient with minimal or no
labiomental fold
• Undesirable changes in neck chin proportion
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 89
89. • Surgical relapse to varying degree can occur after
mandibular surgery
• Complications in orthognathic surgery
• Pre-operative phase
• Intra-operative phase
• Post-operative phase
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 91
90. PRE-OPERATIVE PHASE
• Limitations on surgical movement- failure to eliminate
dental compensations
• Molar root fenestrations, transverse surgical relapse-
Failure to manage transverse discrepancy
• Immpossibilility in achieving class I cusp relation,
overjet and over bite- failure to indentify and manage
tooth size discrepancies
• Root damage during osteotomies- failure to properly
level and achieve root divergence in segmental cases
• Psychological preparation of the patient
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 92
91. INTRA-OPERATIVE PHASE
• Attributed to improper surgical technique and/or failure
to appreciate patient’s anatomy
• Unanticipated intra-op complications are not unheard of
• Can be categorised into
• Unfavourable osteotomy splits
• Nerve injury
• Bleeding
• Proximal segment malpositioning
• Miscellenaeous
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 93
92. Sagittal Split Ramus Osteotomy
UNFAVORABLE OSTEOTOMY SPLIT
• Incidence- 18%
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 94
Bad split
Abort the procedure
& perform after healing
Correct the split &
Complete the procedure
93. Proximal segment fracture
• Also called “Buccal plate fracture”
• Most frequent
• Presence of impacted 3rd molar
• Recent removal of 3rd molar
• Age of the patient
• Incomplete transection of the inferior border
• Surgeon’s experience
• # of distal segment occurred more often in young people with
impacted 3rd molars
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 95
94. • Role of impacted 3rd molars in unfavorable # is
debatable
• Advocated removal 6months prior surgery
Fracture of coronoid process
• Occurs when the horizontal cut is placed too high
where the ramus is thin
• Fracture of distal segments
• Inferior border remains attached to distal segment
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 96
95. NERVE INJURY
• Damage can occur at many points
• When nerve was transected- usually in 3rd molar region or
anterior to it
• Higher incidence of neurosensory disturbance with
bicortical screws than monocortical screws
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 97
96. BLEEDING
• Incidence decreased from 38% in 1972 to 1% in
2005
• Most common sources
• Maxillary artery and its branches (massetric and inferior
alveolar artery)
• Retromandibular vein
• Facial artery and vein
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 98
97. PROXIMAL SEGMENT MAL-POSITIONING
• Counterclockwise rotation and condylar distraction
are frequent positional changes in proximal segment
• MINOR DIFFICULTIES
• Herniation of buccal fat pad
• Difficulty in incision closure
• Breaking of bur
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 99
98. Vertical Ramus Osteotomy
UNFAVOURABLE OSTEOTOMY
• Inadvertent subcondylar osteotomy
• More likely in
• Prognathic mandible with high mandibular plane angle and
ill- defined gonial angle
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 100
99. NERVE INJURY
• Incidence ranges from 0%- 14%
• Less incidence when compared to SSO
• Can occur in 2 phases
• If osteotomy is close to mandibular foramen
• Medial displacement of the proximal segment compressing
and tearing the nerve
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 101
100. BLEEDING
• Common source- maxillary artery and its branches
PROXIMAL SEGMENT MALPOSITIONING
• Control of proximal segment- major disadvantage
• May be displaced antero- medially, anteriorly towards
articular eminence or can be displaced medially and
inferiorly
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 102
101. Sub- Apical Osteotomies
• Nerve injury
• Damage to teeth roots
• Non- vitality of teeth
• Mal-positioning of mobilised segments
• Inadequate trimming, inadequate bone removal
• Difficulty in stabilisation
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 103
102. Genioplasty
UNFAVOURABLE OSTEOTOMY
• Inadvertent # of body and ramus
• Damage to teeth roots
NERVE INJURY
• Mental nerve is commonly injured
• incision, reflection and retraction, osteotomies, plating or
closure
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 104
103. • BLEEDING
• Damage to lingual soft tissues
• Injury to genioglossus, geniohyoid muscles
• Laceration of sublingual and submental arteries
• Usually not life threatening
• Managed by local measures
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 105
COMPLICATIONS
105. LATE POST-OP
• Long term neurological dysfunction
• TMJ dysfunction
• Dental and periodontal problems
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 107
106. • CONDYLAR SAG
• Immediate or late caudal movement of condyle in the glenoid fossa
after surgical establishment of the preplanned occlusion and bone
fragments leading to change in the occlusion
• Types –
• Central
• Peripheral
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 108
109. REFERENCES
• Maxillofacial Surgery-Peter Ward Booth
• Principles Of Oral And Maxillofacial Surgery- Peterson
• Oral And Maxillofacial Surgery-Fonseca
• Essentials Of Orthognathic Surgery-Reyneke
• Chin shield osteotomy – a new genioplasty technique avoiding a deep mento-labial
fold in order to increase the labial competence Int. J. Oral Maxillofac. Surg, 2009
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 111
110. • Transverse Reduction Genioplasty to Reduce Width of the Chin J Oral
Maxillofac Surg, 2010
• Sagittal Split Genioplasty: A New Technique J Oral Maxillofac Surg, 2010
• M- shaped genioplasty: new surgical technique for vertical and saggital chin
augmentation: 3 case reports J Oral Maxillofac Surg, 2012
9/19/2016 9:29:31
AM
RT/8/MANDIBULAR ORTHOGNATHIC PROCEDURE/115 112
REFERENCES
The medial horizontal osteotomy.
The red line indicates horizontal osteotomy red dash indicates the split
The IAN bundle is in yellow to show the entrance of the nerve blue dot marks the position of antilingula
Fig. 5. The medial horizontal osteotomy.
S. Lowest point of sigmoid notch.
Vertical distance from S to antilingula.
C. Vertical distance from S to entrance of IAN.
B. Horizontal distance from antilingula to anterior border of ramus.
D. Horizontal distance from entrance of IAN to anterior border of ramus.
They recommend that the medial horizontal cut be at or just above the tip of the lingula because a higher cut may be associated with an increased difficulty in splitting or incidence of unfavorable fracture.
Classification of the position of the mandibular canal within the bone. (a) Separate
type, bone marrow space evident; (b) contact type, outer surface of the canal and inner surface
of buccal cortical bone in contact; and (c) fusion type, outer cortical plate of the canal not
evident.
Type I: MN divided into A, inferior labial (IL), and M branches, with the IL branch dividing into ILm and ILl branches
Type II: MN divided into A, ILm, and M branches, with the ILl branch separating from the A branch.
Type III: MN divided into A, ILl, and M branches, with the ILm branch separating from the M branch.
Type IV: MN divided into A and M branches, with the ILl and ILm branches separating from the A and M branches, respectively.
Type V: MN divided into A and M branches, with the IL branch separating from the A branch and then dividing into the ILm and ILl branches
Schuchardt is generally given credit for the use of an intraoral approach to what some call the “step” osteotomy of the vertical ramus. Specifically he described parallel horizontal cuts through the cortex of the vertical ramus, the medial cut being placed above the lingula and a lateral cut being made about 1 cm below that. Medial cut extended from the anterior border of ramus till the posterior border of ascending ramus
Obwegeser- medial horizontal cut above the lingula, extending till the posterior border of the mandible, but the lateral horizontal cut was lower than Schuchardt’s and extended to a point just above the angle, at least 25 mm below the lingual cortical cut
Dal pont- 1961 medial horizontal cut is same as in obwegeser. The change commonly attributed to DalPont is the vertical cut through the lateral cortex behind the second molar.
Hunshuck- 1968 variation of the lingual cut (original cut ends at the posterior border of the ascending ramus), according to the modification cut ends immediately behind the entrance of the neurovascular bundle, so that the split on the medial aspect occurs in the mylohyoid groove rather than the posterior border of the mandible
Epcker – 1977 1. minimal stripping of masseter muscle
2. limited medial dissection
these modifications decrease the post-operative swelling, haemorrhage, manipulation of the neurovascular bundle
Advancements beyond 10- 12 mm, extra oral approach should be considered- since the overlap between the segments is less
MANDIBULAR DEFICIENCY
Increased A/B difference
Class II canine and molar relationship
Increased overjet
Excessive curve of spee in mandible
Incisor crowding
Deep labiomental fold
MANDIBULAR PROGNATHISM- Hapsburg jaw/ Hapsburg lip/ Austrian lip
Mandible more protruded compared to maxilla
Prominent lower third of face
Obtuse gonial angle
Anterior cross bite
Posterior open bite
Concave or straight profile
Decreased labiomental fold
Landmarks for intra oral incision-anterior border of ramus and external oblique ridge
Incision made through the mucosa starting superiorly ,2/3rds up the anterior border of ramus ,inferiorly lateral to external oblique ridge to the area of second molar
Periosteum elevated exposing external oblique ridge.
Sub periosteal dissection over the buccal and lingual sides of the anterior ramus.
Strip lower fibres of temporalis from anterior border and coronoid
Medial sub peiosteal dissection done and lingula identified
Medial ramus osteotomy-parallel to occlusal plane, midpoint between the sigmoid notch and the neurovascular bundle
the correct location of the of the cut at the anterior border of the ascending ramus is the place where horizontal ramus bends into a vertical line
Osteotomy cut terminated posterior to lingula-through lingual cortex into medullary bone.
Vertical osteotomy cut-starting superiorly from the medial cut staying in the buccal cortex of ramus and end inferiorly mesial to the second molar.
Buccal osteotomy- started at lower border and joined superiorly with the vertical part of ramus osteotomy. The blade should be angled at 60- 45 degrees to protect the inferior neurovascular bundle
Cortices should be gently seperated looking for neurovasvular bundle.
If the neurovascular bundle is in proximal segment it should be lifted out.
Mandible is moved into the desired position, guided into occlusion using occlusal splints, imf is done and the osteotomised segments are fixed in the desired position
Osteosynthesis- is defined as surgical fastening of two separated bone fragments
Position screw or the bicortical screw is same as the lag screw, except that it has screw threads on proximal and distal aspect of the screw, hence on engaging into the bone it does not cause compression of the buccal and lingual cortical plates
Caldwell and letterman- performed the procedure as an extra-oral procedure
Horizontal mandibular excess- good profile, arch and dental relationship can be obtained by retruding intact mandible
can also be done with BSSO but this method is faster, safer and less incidence of IAN damage
Mandibular asymmetry- VRO is indicated on the side which requires movement in posterior direction, if the distal segment needs to advanced then it should be done with BSSO
Aesthetic assessment of the soft tissues of the neck is the integral factor in planning mandibular set back by ramus surgery-
Mandibular set back creats, a rounding effect on the cervicomental soft tissues and neck may appear to be broader
Alternatively- Isolated maxillary advancement
Combination of max. advancement with mand. Setback
Recent condylar fractures- inferior half of the ramus contains marrow between the cortices and the upper half from the anti-lingula to the sigmoid notch is mainly cortical, and the cortical bone takes several months to progress to structural integrity
Less incidence of condylar sag- since post-op rigid fixation is not done in most of the cases
The surface shown in this picture is of the buccal side
Procedure
Straight line incision over bone–level of mandibular occlusal plane medial to external oblique ridge
Incision carried forward 2-3 mm inferior and parallel to mucobuccal junction
Blunt dissection of soft tissues over ascending ramus –sigmoid notch
Periosteum reflected from lateral ramus
Inferior border stripped anterior to ante gonial notch.
Antilingular eminence marked.
Downward vertical guide line –antilingular eminence to antegonial notch.(parallel to posterior boder)
Bicortical - Initial osteotomy cut
Second osteotomy cut-upper end of lower oseotomy and oblique to sigmoid notch.
Same procedure performed on other side.
Proximal surface seperated from the distal segment.
Setback of 4mm or less-inferior cut carried parallel and about 9-10 mm anterior to posterior border.
>5mm-inferior cut-angled progressively anterior-broden base of proximal segment. (maintain sufficient residual width of attachment of masseter and medial pterygoid muscle and tendon to prevent condylar sag
Combined effect of medial pterygoid muscle and masseter provides adequate support and control of proximal segment.
Elastic tracton to guide occlusion-4-5 weeks
Pic- pg 127, fonseca
Occurring between the overlapped proximal and distal segments- causing a backward rotation of the of the proximal segment
This contact occurs in the distal segment between the mid ramus and the sigmoid notch
Interference reduced by-
Temp and pterygoid remain attached to condylar segment
The basic techniques for C & L are same, with only modification being inferior horizontal cut in the C osteotomy
Forms of C osteotomy
Pg 1149- petersoon
TRAUNER and OBWEGESER in 1957
Blend of VRO and BSSRO
Medial exposure and dissection are done as for SSRO
Nerve identified as it enters mandibular foramen medially.
Bicortical horizontal osteotomy cut –superior to the foramen
Exposure of lateral ramus and completion of inferior vertical osteotomy same as VRO
Rigid fixation is performed with patients in MMF
Suction drains to be placed
MMF -5 to 14 days after surgery
Elastic traction -guide the occlusion and resist soft tissue relapse -4-5 weeks
With preservation of inf dental bundle and bone grafting to assist bony union.
gross
Anatomic discrepencies leading to reduction in bone to bone contact- resection in this region leads to reduction in bone contact as distal segment is set into wider proximal segment
rarely used…. blood supply to this area comes through muscle attachments on the lingual. Roots of the teeth should be at least paralleld if not divergentdin the osteotomy/ostectomy sites…….provided that lower vertical height is increased. if in normal limits-mandibular body osteotomy-level plane of occlusion and not dec vertical facial height
Extraction of premolars to obtain space for posterior movements
Incision-in lower lip approx 15 mm from vestibule- premolar to premolar.
Anterior mandible degloved upto inferior border
Vertical bone cuts-passing through premolars
Inferior horizontal cut must be made perpendicular to bone connecting vertical cuts at inferior extent.
Segment mobilized by gentle prying at osteotomy sites.
Preformed surgical splint should be used to guide the segment in its predetermined position.
Segment secured by transosseous wires /semirigid fixation
Incision extending from canine to canine.
Incision given to the mucosa- mentalis muscle divided on a bevel inferiorly towards bone and periosteal incision given
Horizontal osteotomy with anterio- posterior reduction- necessary to reduce the proximal tips of the mobilised fragments to ensure smooth transition along the inferior border and avoid palpable wings
Pg 409- fonseca
U shaped mono-cortical osteotomy created centrally on the symphysis, with lateral extensions developed below the mental nerves connecting the tenon corticotomy superiorly
Full-hickness osteotomies are completed only on the lateral extensions and only through the lingual cortex on the superior aspect of the tenon
The resultant full thickness of the tenon facilitates the mortisising of the tenon and lag screw fixation
When the posterior movement is desired the u is inverted and the osteotomy completed
Large cants in chin
First osteotomy-superior osteotomy-parallel to occlusal plane
Second osteotomy-parallel to lower border of chin
Traingular segment rotated 180°while muscle attachment maintained
The osteotomy is begun below and slightly posterior to the mental foramen on either the right or the left side of the mandible. The reciprocating saw
blade is used and is oriented almost vertically and in the sagittal plane
The cut starts approximately 6 mm below the mental foramen and exits at the inferior border. The saw is carried forward in this plane until the area mesial to the cuspid tooth is reached. At this point the saw blade is rotated into a horizontal position as the remainder of the cut is completed in the usual manner as shown. This results in a sagittal split of the lateral one third to two thirds of the inferior chin segment
Horizontal osteotomy was performed 5 mm below the mental foramina to avoid injury to the inferior alveolar nerve
Two vertical osteotomies were performed according to the previously marked lines, and the mobilized central segment was removed
Distal segments were positioned medially and fixed together and were then fixed to the upper bone segment by miniplates and screws
(bunching of tissues, which stretch more when advanced)
soft tissue stripping give more predictable hard & soft tissue response because of less bone resorption of advancedsegment
Decision must be made on a case- by- case analysis
Incomplete transection of the inferior border – thin buccal plate is the area of least resistance and can be # by the force used to split the mandible
Fracture of distal segments- occurs when the 3rd molars are present and in edentulous cases where the bone is weakend in these areas
Damage can occur at many points- it can be stretched, avulsed, transected
Facial artery in the antegonial notch- this is the vicinity vor the vertical cut in SSO
Difficulty in incision closure- if it is placed too high and on attached gingiva
Breaking of bur- common while giving horizontal osteotomies, due to excessive torquing
Bauer retractors- placed in sigmoid notch
lavasseur Merril retractors- along the posterior border of the mandible
Inadvertent subcondylar osteotomy-
Maxillary artery close to the sigmoid notch and deep to the ramus
If displaced
Antero- medially- IAN bundle may be torn when it enters lingula
Posteriorly- difficult to set back properly
Nerve injry-
Inadvertent # of body and ramus- incomplete osteotomy of the symphysis and the use of exccessive force and torque in an attempt to down fracture
These result in
Central condylar sag-. The condyle is positioned inferiorly in the glenoid fossa with no contact with bone, while the teeth are in occlusion and rigid fixation is placed (A). After removal of IMF the condyle moves superiorly leading to immediate relapse (B).
Central condylar sag
Bilateral condylar sag
Dental midlines correct
Overjet increased
Anterior open bite
Class II malocclusion
Unilateral condylar sag
Mandibular dental midline towards offending side
Overjet increased
Class II dental relationship on the offending side
Overjet corrected and the correct occlusion reestablished if mandible is moved until midlines coincide
Peripheral condylar sag-
Type I- condyle positioned inferiorly with some fossa contact with MMF in position and rigid fixation
Provides physical support to occlusion
Post operative resorption or change in condylar shape will lead to late relapse.
Difficult to diagnose intra-operatively
Type II- condyle positioned correctly in the fossa with MMF in position.
with the placement of rigid fixation-torquing force is applied to condyle and ramus of mandible.
Tension on ramus released when MMF removed-condyle will move either laterally or medially and slide inferiorly
Clinical features
Type II-Bilateral peripheral condylar sag
Dental midlines correct
Ant cross bite or edge to edge incisor relationship
Bilateral posterior open bites
Unilateral peripheral condylar sag
Dental midline of mandible towards contraletaral side
Edge to edge incisor relationship with tendency to cross bite on the offending side
Posterior open bite on offending site with teeth in occlusion