presentation deals with distraction biology and various application in oral and maxillofacial surgery

1. DISTRACTION
OSTEOGENESIS
Joel D’Silva
Resident
Department of OMFS

2. INTRODUCTION
• Acute advancement of osteotomized bone segments.
• One of the major limitations is the inability of the soft
tissues to be acutely stretched.
• Resulting in degenerative changes, relapse, and
compromised function and aesthetics.

3. DEFINITION:
Distraction osteogenesis is a biologic process of
new bone formation between the surfaces of
bone segments that are gradually separated by
incremental traction.

4. • The process initiated when a traction force is applied to bone
segments and continues as long as the callus tissue are stretched.
• Distraction forces applied to bone also create tension in the
surrounding soft tissues, initiating a sequence of adaptive changes
termed distraction histiogenesis

5. HISTORY
•Hippocrates described the placement of
traction forces on broken bones.
•De Chauliac in the fourteenth century,
who used a pulley system that consisted of
a weight attached to the leg by a cord.

6. • Banon, in 1826, is credited with
being the first to perform a
surgical division of bone, or
osteotomy.
• Codivilla combined these
techniques to perform the first
limb lengthening using external
skeletal traction after an oblique
osteotomy of the femur.

7. • A significant contribution was made by the Russian surgeon
Gavril Ilizarov 1951.
• He designed a new apparatus for bone fixation consisting of
two metal rings joined together with three or four threaded
rods.
• He later developed low energy, subperiosteal osteotomy
technique (corticotomy) and a unique protocol for limb
lengthening utilizing a 5 to 7-day latency period, distraction
at a rate of 1mm per day performed in four increments of
0.25 mm

8. EVOLUTION OF CRANIOFACIAL DISTRACTION
OSTEOGENESIS
Dentofacial traction;
• Fauchard 1728 described use of expansion
arch
• Wescott first reported the placement of
mechanical forces on bones of maxilla in 1859
• Angle introduced palatal expansion screw

9. 1866 Kinsley used extra oral
traction for functional appliances

10. Craniofacial osteotomies
• Hullihen - partial osteoplastic resection
of prognathic mandible in 1848
• Blair horizontal ramus osteotomy
• Eiselberg, Pehr, Gadds introduced
various osteotomies

11. DISTRACTION TECHNIQUES:
• 1927 Rosenthal performed first mandibular
osteodistraction
• 1937 Kazanjian performed mandibular osteodistraction
with incremental traction
• Crawford 1948 – gradual incremental traction to
fracture callus of mandible
• Kole 1959 described method of surgically correcting
anterior open bite
• In 1973 Snyder introduced Ilizarov’s principles to
craniofacial skeleton

12. CLASSIFICATION
Depending on the place where tensional stress was induced, these
techniques can be categorized as either

13. • Distraction epiphysiolysis involves a relatively rapid rate of bone
segment separation, usually ranging from 1.0 to 1.5 mm per
day.
• The rapidly increased tension at the growth plate produces a
fracture of the physis.

14. • The subsequent gradual separation of the epiphysis from the
metaphysis leads to the replacement of growth plate cartilage by
trabecular bone.
• Zavialov and Plaskin, in 1967, introduced the term distraction
epiphysiolysis and reported the first clinical application of this
technique.

15. • Chondrodiatasis utilizes a very slow rate of bone segment
separation (less than 0.5 mm per day).
• Slowly stretched physis intensifies the biosynthetic activity
of cartilage cells, resulting in accelerated osteogenesis.
• De Bastiani introduced term chondrodiatasis

16. Theoretically, physeal distraction osteogenesis offers
significant advantages:
 Single-stage operative procedure.
 No soft tissue incision or osteotomy
 Simulation of "natural" growth
 Large areas of new bone formation
 No additional bone grafts.

17. • Callotasis a gradual stretching of the reparative callus
forming around bone segments interrupted by
osteotomy or fracture.
• Latin noun callum (scar tissue between bone
segments) and the ancient Greek noun taois (tension
or extension).

18. BIOLOGIC BASIS
OF
NEW BONE
FORMATION

19. ILIZAROV DISCOVERED TWO BIOLOGIC
PRINCIPLES OF KNOWN AS THE "ILIZAROV
EFFECTS".
(1) The tension-stress effect on the
genesis and growth of tissues, and
(2) The influence of blood supply and
loading on the shape of bones and joints.

20. • The first Ilizarov principle postulates that gradual traction
creates stress that can stimulate and maintain regeneration and
active growth of living tissues.
• Clinically, after distraction, newly formed bone rapidly remodels
to conform to the bone's natural structure.

21. • The second Ilizarov principle theorized that the shape and mass of
bones and joints are dependent on an interaction between
mechanical loading and blood supply.
• If blood supply is inadequate to support normal or increased
mechanical loading, then the bone cannot respond favorably,
leading to atrophic or degenerative changes.

22. DISTRACTION OSTEOGENESIS (CALLOTASIS)
CONSISTS OF FIVE SEQUENTIAL PERIODS:
(1) Osteotomy,
(2) Latency,
(3) Distraction,
(4) Consolidation,
(5) Remodeling

23. Osteotomy
Latency
is the period from bone division to the
onset of traction and represents the time
required for reparative callus formation
between the osteotomized bone segments.
is the surgical separation of a bone into two
segments.

24. The distraction period
is that time when a traction
force is applied to bone
segments, and new bone, or
distraction regenerate, is
formed within the
intersegmentary gap.

25. Two major parameters are of critical importance during
this period:
The rate
Rhythm of distraction.
• The rate of distraction represents the total amount of
bone segment movement performed per day
• The rhythm of distraction is the number of increments
per day into which the rate of distraction is divided.

26. The
consolidation
period
The
remodeling
period
begins after achieving the desired amount of
lengthening when traction forces are
discontinued.
This period allows mineralization and corticalization of the
newly formed bone tissue prior to distraction device removal.
is the time after removal of the distraction
device.

27. Distraction osteogenesis begins with the development of a reparative
callus between the edges of two bone segments divided by a low-energy
osteotomy.

28. • Gradual incremental separation of bone segments places
the callus under tension; this aligns the inter-segmentary
gap tissues parallel to the direction of distraction.
• After the desired amount of bone length is achieved,
the distraction force is discontinued. The newly formed
bone (distraction regenerate) then undergoes maturation
and remodeling until it becomes undistinguishable from the
residual host bone.

29. OSTEOTOMY
• An osteotomy divides a bone into two
segments, resulting in a loss of continuity
and mechanical integrity; this is also
referred to as a fracture.
• Discontinuity of a skeletal segment
triggers an evolutionary process of bone
repair known as fracture healing.

30. • This process involves recruitment of osteoprogenitor
cells, followed by cellular modulation or osteoinduction,
and establishment of an environmental template
(osteoconduction).
• As a result, a reparative callus is formed within and
around the ends of the fractured bone segments; under
normal conditions, the callus undergoes gradual
replacement by lamellar bone, which is mechanically
more resistant.

31. FRACTURE
HEALING HAS
BEEN DESCRIBED
AS CONSISTING
OF SIX STAGES
OR PHASES:

32. • The stage of impact takes place at the moment of
stress and lasts until there is complete dissipation of
energy, which is absorbed by the bone until failure
occurs.
• The stage of induction provides modulation of cells
needed for the repair process. Possible inductors
include products of cell death, oxygen gradient, electric
potential, noncollagenous proteins, and others.

33. LATENCY PERIOD.
The latency period is the period from bone division to the onset
of traction. This period represents the time allowed for
reparative callus formation.
• The sequence of events occurring during the latency period is
similar to that seen during fracture healing.

34. Initially, as a result of vascular
disruption, a hematoma forms
between and around the bone
segments. The hematoma is
converted to a clot and bony
necrosis occurs at the ends of
the fracture segments.

35. There is an ingrowth of vasoformative elements and
capillaries for the restoration of blood supply, and
tremendous amount of cellular proliferation.
Lasts from 1 to 3 days, at which time the clot is replaced
with granulation tissue consisting of inflammatory cells,
fibroblasts, collagen and invading capillaries.

36. • Following inflammation is the
soft callus stage, which lasts
approximately 3 weeks. This
period is marked by a
continuous in growth of
capillaries into the fracture
callus.

37. • On the fifth day after osteotomy, a minicellular network of growing
capillary loops is formed in the medullary canal of both proximal
and distal segments in the areas adjacent to the fracture line.
• Less differentiated, free circulating osteogenic cells are located
inside the terminals of the newly formed capillaries.

38. • During the soft callus stage,
granulation tissue is converted
to fibrous tissue by fibroblasts.
Cartilage also replaces the
granulation tissue. This occurs
more toward the periphery of
the intersegmentary gap than in
the central region by a front of
endochondral ossification.

39. • The amount of cartilage in the
intersegmentary gap is variable.
• It seems that if the callus outgrows its
blood supply, cartilage provides a
suitable material that is less
demanding of oxygen, which
temporarily bridges the gap until the
blood supply catches up.

40. • Callus formation is the response of determined
osteoprogenitor cells, originating principally in the
periosteum and endosteum, to a number of activating
factors released from freshly injured bone tissue.
• The mechanical role of callus formation is obvious; it
gradually enlarges the diameter of the segment ends and
thereby the cross-sectional area of the segment sites.

41. • Histologically, callus formation occurs mainly by a mixture of
gap healing and direct appositional bone formation, and its
main sites of occurrence (outer and inner surfaces of the
segment ends) selves a solid base on which new bone tissue is
deposited.

42. DISTRACTION PERIOD
The distraction period is characterized by the
application of traction forces to osteotomized bone
segments.
Bone segments are gradually pulled apart, resulting
in formation of new bony tissues within the
progressively increasing intersegmentary gap.

43. • During normal fracture healing,
the fibrocartilaginous tissue of the
soft callus is replaced by
osteoblasts into fiber bone (hard
callus stage). The cartilage
calcifies as capillaries invade and
osteoblasts lay down new bone
on the calcified cartilage matrix.

44. • The stage of hard callus lasts 3 to 4 months for many fractures and
is followed by the stage of remodeling. When fiber bone is slowly
remodeled to lamellar bone and the medullary canal is
reconstituted.
• The stage of remodeling ends when the bone has completely
returned to normal with restoration of the medullary canal.

45. • During osteodistraction, however,the normal
process of fracture healing is interrupted by the
application of gradual traction to the soft callus.
• A dynamic microenvironment is created.
• The tension stress that develops in the gradually
stretched tissues stimulates changes at the
cellular and subcellular levels.

46. • These changes can be characterized as a
growth-stimulating effect and a shape-
forming effect.
• The growth-stimulating effect of tension
activates the biologic elements of the
intersegmentary connective tissue.

47. THIS INCLUDES
• (1) prolongation of angiogenesis with increased tissue
oxygenation, and
• (2) increased fibroblast proliferation with intensification of
biosynthetic activity.

48. • The shape-forming effect of tension causes an altered phenotypic
expression of the fibroblasts.
• The shape forming effect also polarizes these "distraction"
fibroblasts, orienting them and their secreted collagen parallel to
the vector of distraction.

49. • New tissue formation in a direction parallel to the vector of
traction. As distraction begins, the fibrous tissue of the soft callus
becomes longitudinally oriented along the axis of distraction.
• Fibers are also oriented along the direction of distraction. These
cells form collagen fibrils that are grouped into fibers at the distal
and proximal ends of the intersegmentary tissues.

50. • Between the third and seventh days of distraction, capillaries
grow into the fibrous tissues, thereby extending the vascular
network not only toward the center of the gap but also toward
the medullary canal of both adjacent bone segments.
• The newly formed capillary loops are parallel to each other as
well as to the axis of distraction.

51. • Very often, newly formed vessels in the distraction
regenerate have a spiral pathway and numerous
circular folds suggesting growth rates much higher
than the rate of distraction, and 10 times faster than
vessel growth during normal fracture healing.
• Capillary terminals actively invade the fibrous tissues,
supplying them with less differentiated cells that
differentiate into fibroblasts, chondroblasts, or
osteoblasts.

52. • During the second week of distraction, primary trabeculae
begin to form.
• The osteoblasts, located among the collagen fibers, lay down
osteoid tissue on these collagen fibers and eventually become
enveloped as bone spicules gradually enlarge by circumferential
apposition of collagen and osteoid.

53. • Osteogenesis is initiated at the existing bone walls and
progresses toward the center of the distraction gap.
• By the end of the second week, the osteoid begins to
mineralize.

54. • At that time the distraction regenerate has specific
zonal structure.
• A poorly mineralized, radiolucent fibrous interzone is
located in the middle of the distraction gap, where the
influence of tensional stress is maximal.
• This zone consists of highly organized, longitudinally
oriented, parallel bundles of collagen with spindle-
shaped fibroblast-like cells and undifferentiated
mesenchymal cells

55. • The interzone functions as the center for fibroblast proliferation
and fibrous tissue formation.
• The mixture of fibrous and cartilage tissues within the interzone
suggests that during distraction, both membranous and
endochondral processes play an important role in the process of
bone formation.

56. • At the periphery of this fibrous interzone, there are two zones
with longitudinally oriented cylindrical primary trabeculae,
which are covered by a layer of osteoblasts that grow toward
each other.

57. Bone formation occurs along the vector of tension
and is maintained by the growing apexes of the
primary trabeculae, which remain open during the
distraction period.
These areas therefore function as the "growth
zone" of the distraction regenerate, providing
active osteogenesis throughout the period of
elongation.

58. • This zonal distribution of newly formed tissues in the distraction
regenerate and remains until the end of the distraction period.
• In addition, two new zones of primary trabeculae remodeling may
become evident at the junction of the regenerate and the host
bone segments.

59. Consolidation Period
The consolidation period is that time between cessation of
traction forces and removal of the distraction device.
This period represents the time required for complete
mineralization of the distraction regenerate.

60. After distraction ceases, the fibrous interzone gradually ossify and one
distinct zone of fiber bone completely bridges the gap.
Distraction regenerate forms predominantly via membranous
ossification, isolated islands of cartilage may also be observed.
Suggesting endochondral bone formation.

61. • In addition, focal regions of chondrocytes surrounded by a
mineralized matrix may be observed, suggesting a third type
(transchondroid) of bone formation, in which
• cartilage forms, possibly due to decreased oxygen tension; but is
then directly transformed into bone, rather than by the
traditionally accepted endochondral pathway.

62. • As the regenerate matures, the zone of primary trabeculae
significantly decreases and later is resorbed completely.
REMODELING PERIOD
The remodeling period is the period from the application of full
functional loading to the complete remodeling of the newly
formed bone.

63. • Initially formed bony scaffold is reinforced by parallel-
fibered lamellar bone. Both the cortical bone and marrow
cavity are restored.
• Haversian remodeling. Representing the last stage of
conical reconstruction. Normalizes the bone structure. It
takes a year or more before the structure of newly formed
bony tissue is comparable to that of the preexisting bone.

64. Bio-mechanical
parameters
Extrinsic or
fixator-related
Intrinsic or
tissue-related
Distraction device
orientation
Distraction vector
orientation

65. Biologic
parameter
Low power
osteotomy
Adequate
duration of
latency
Stable, but
not rigid
direction of
distraction
with maximum preservation of
osteogenic tissues and periosteal /
endosteal blood supply
to allow development of the fracture
callus,
fixation of the bone segments,
allowing their dimensional movement
while preserving axial micro motion
Which is precisely calculated

66. Optimal rate and rhythm of distraction
Sufficient time for consolidation and remodeling of the newly
formed bone prior to unrestrained functional loading
Proportional relationship between mechanical loading of the
newly formed bone and its blood supply

67. TREATMENT
PLANNING

68. • Thorough clinical examination to reveal and structural
abnormalities and functional deviations that require correction.
• Accurate orthodontic/surgical records -include lateral and
posteroanterior cephalometric radiographs, computed tomography
with three dimensional reconstruction, photographs, and models

69. This information is coupled with an understanding of the
patient's expectations to finalize the treatment goals and
predistraction, intradistraction, and postdistraction
treatment objectives.

70. • Osteotomy design and location,
• Selection of a distraction device,
• Determination of the distraction vector,
• Duration of the latency period,
• Rate and rhythm of distraction
• And duration of the consolidation period.

71. OSTEOTOMY DESIGN AND
LOCATION

72. DISTRACTION DEVICE SELECTION
• Craniofacial distraction devices have been developed for both
external and internal applications.
• Device selection is based on mechanical capabilities and patient
acceptance.

73. EXTERNAL DISTRACTION DEVICES:
PLACED USING TRANSCUTANEOUS PINS.
The multidirectional devices, offer
excellent control of bone segment
movement,
Available in longer lengths.
Easier to place and maintain, and
are simple to replace during
distraction and at the completion of
lengthening.

74. DISADVANTAGES
• Skin scarring
• Poor acceptance by patient. However,
placing the pins with minimal soft tissue
tension and/or within the submandibular
fold can minimize skin scarring.

75. INTERNAL DISTRACTION DEVICES:
Placed either submucosally (buried) or mucosally (intraoral).
Tooth borne HybridBone –borne

76. • neither produce facial scarring
• nor have the negative psychosocial
impact of the external devices.
It should be noted however, that a small
external incision is sometimes
necessary for activation arm access,
may be positioned aesthetically.

77. DISADVANTAGES
• Difficult to place especially when orientation is required,
such as in the case of a hypoplastic ramus.
• The higher risk of injury to nerves and anatomic
structures
• A second surgical procedure is often necessary to remove
the devices following completion of consolidation.
• Lack of the multidirectional adjustment capability

78. LENGTHENING CAPABILITIES.
• In order to complete the desired amount and
angulation of distraction, the appropriate length of
distraction device must be selected.
• Although the magnitude of lengthening is registered on
distraction device, it does not always correlate to the
clinically observed amount of actual bone distraction,
which is usually less than anticipated and difficult to
predict prior to distraction.

79. • The amount of bone distraction clinically observed during
lengthening is a result of linear device activation altered by the
effect of extrinsic and intrinsic biomechanical factors
• Amount of device activation and the observed amount of bone
distraction varies, but reaches as high as 2:1 in some cases.
• When angular correction is incorporated into linear activation, the
total amount of linear distraction decreases even more, further
increasing the length requirement of the distraction device.

80. DIRECTION OF DISTRACTION.
• For a simple linear advancement, a unidirectional distraction
device is suitable.
• If lengthening of the jaw is planned in two or more directions, a
multidirectional device is required.

81. DISTRACTION VECTOR PLANNING
• The distraction vector defines
the desired direction that the
distal segment must move
during lengthening.

82. • Despite precise planning, the actual distal segment movement
is still difficult to predict and is affected by various forces.
• Treatment planning allows the clinician to compensate for,
avoid, or eliminate undesirable reactive forces.

83. Factors that affect the vector of distraction include
• osteotomy design and location,
• distraction device orientation,
• masticatory muscle influence,
• occlusal interferences,
• distraction device adjustment,
• orthodontically or orthopedically applied forces.

84. DISTRACTION DEVICE ORIENTATION.
• Although osteotomy design and location may affect the
muscle tension exerted on the proximal and distal segments,
distraction device orientation is the primary factor that
influences the vector of distraction.

85. • In order to minimize adverse biomechanical effects, devices
should be placed parallel to the desired vector of
distraction. Based on the orientation of the distraction vector,
the distraction device can be placed vertically, horizontally, or
obliquely.

86. • Orientation of the distraction device parallel to the
Vertical long axis of the ramus often results in an oblique
distraction vector as it relates to the occlusal plane, since
the ramus is not actually oriented perpendicular to the
occlusal plane.

87. • If vertical elongation of the ramus and
posterior occlusal bite opening is desired, it
can more predictably be achieved by placing
the distraction device perpendicular to the
occlusal plane rather than parallel to the long
axis of the mandibular ramus.
• If anteroposterior advancement of the
mandibular corpus is desired, placement of
the distraction device parallel to the occlusal
plane is recommended.

88. • When the distraction device is placed parallel, to the long axis
of the mandibular corpus, a divergence of the occlusion may
occur, often resulting in a skeletal anterior openbite during
lengthening.
• Oblique distraction device orientation produces simultaneous
vertical and horizontal movements of the distal segment.
• When an oblique device orientation is chosen, anteroposterior
positional changes occur along with hyper divergence of the
mandible, resulting in clockwise rotation and anterior bite
opening.

89. • In patients with a deep bite, this may be
advantageous. In most cases, however, clockwise
mandibular rotation results in an undesirable
anterior openbite.
• The oblique orientation of the distraction device
may be changed to either more vertical or more
horizontal depending on whether the ramus or
mandibular body requires more lengthening,
respectively.

90. INFLUENCE OF MASTICATORY MUSCLES.
• The second factor that affects distal
segment movement during distraction is
the force generated by the masticatory
muscle. Patients undergoing distraction
functional compensations for their
gradually changing occlusions. In order
to aid in masticatory function patients
may posture their mandibles anteriorly.

91. • The surgeon and orthodontist may also alter this untoward
distal movement by making adjustments in sequential amount
of activation of the multidirectional device

92. OCCLUSAL INTERFERENCES-
• Alter the planned distraction vector.
• Planned and executed predistraction orthodontic
preparation,
• occlusal interferences may effectively be recognized
and eliminated in many instances. A developing
openbite can be addressed during distraction with the
utilization of bite plane or bite block appliances.

93. Distraction
Device
Activation.
Depending on the dimensional capability of
the device, its activation can be performed
linearly and/or angularly in the sagittal and/or
transverse planes.

94. In the sagittal plane produces rotation of the distal segment around the
axis located in the center of the hinge. Angular rotation of the distal
segment occurs in harmony with rotation of the entire mandible around
the axis located at the mandibular condyle, thereby creating the ability
to open or close the bite anteriorly.

95. • Angular activation reduces the anteroposterior length of
the mandible and must therefore be accompanied by
additional linear distraction in order to maintain the
mandibular advancement achieved.
• Importantly, at least 10mm of linear advancement must
precede any angular activation to avoid undesirable
approximation of the proximal and distal segments,
potentially resulting in premature consolidation.

96. • In the transverse plane angular activation is affected by
the resistance of the temporomandibular joints
posteriorly and mandibular symphysis anteriorly
• This may affect the temporomandibular joint anatomy as
well as result in chin point deviation.
• Transverse adjustment must be made with caution,
always monitoring segment movement and
temporomandibular joint function.

97. DIRECTION OF DISTRACTION
The direction of distraction and the distraction utilized are
determined based on the identified deformity and main goal
of positional changes,
• mandibular ramus or corpus lengthening,
• gonial, or transverse intergonial distance correction.

98. In cases with simultaneous ramus and corpus lengthening,
the distractor may be placed according to the simple
formula: '
Pin Placement Angle =
180 - Gonial Angle x Ramus Deficiency
Total deficiency
Where Pin Placement Angle = the angle between the
distraction vector and the mandibular plane.

99. Later, this formula was tested and modified with more
accurate mathematical calculations:
Pin Placement Angle =
arctan (Db/Dr) _ Sin a
Cos a
• where a = gonial angle, Db = corpus deficiency, Dr =
ramus deficiency.

100. AMOUNT 0F DISTRACTION
The amount of distraction can be determined by simply
drawing a triangle, two sides of which represent the
amount of mandibular corpus and ramus shortening,
respectively. The angle between these two sides is equal
to the gonial angle, and the third side of the triangle
indicates the amount of distraction.

101. The amount of distraction can also be calculated using a
formula:
Distraction Amount =
Dc + Dr - 2(Dc x Dr) x cos a
where Dc = corpus deficiency, Dr =
ramus deficiency,
and a = gonial angle.

102. • In cases with a simultaneous maxillary deficiency, the amount
of maxillary correction should be identified and therefore
included in the calculation of the amount of mandibular
lengthening.

103. FUTURE GROWTH AND OVERCORRECTION
• Finally, the amount of overcorrection must be added when
mandibular lengthening is performed on the growing child
• This parameter is calculated based on the duration of remaining
mandibular growth and percent of yearly growth deficiency.

104. RATE AND RYTHM OF DISTRACTION
• 1 mm per day in 0.25mm increments
• Children 1.5-2 mm in 0.5 mm increments
• Can be adjusted
• 360 degree turn 0.5 mm movement

105. DURATION OF LATENCY
7 days
Young 5
days

106. CONSOLIDATION
• 4- 6 weeks
• 6-8 weeks
• Depending on radiographic evidence of bone
ossification

107. Journal of cranio maxillofacial surgery 2004
Biomechanical and clinical implications of distraction osteogenesis in craniofacial surgery
Meyer, Kleinheinz, Joos

108. POINTS TO BE NOTED
Local
periosteal
blood supply
and size of
distraction
segment
Influence the treatment plan
Small segment eg alveolus
0.5-0.7 mm / day
mandibular sagittal distraction
2mm / day

109. SOME POINTS ON MOULDING
During active
DO
End of DO
Or at the time of removal of the
device manually position & fix it
rigidly with plates
Traction elastics to guide
segment to final position
Perform
moulding
>= 3mm
Perform
regenerate
moulding to
final position
1-3 days
latency
Remove
distractor
permanently
2-4 days in small bone
segments
After three weeks of
consolidation

110. If
discrepancy
occurs
Perform dancing of DO
segment

111. DISTRACTION SURGERY (ORTHOGNATHIC SX)
• Factors influencing are the amount and trajectory of the planned bone
movement
• Surgical approach and technique is similar to orthoganthic surgical
technique

112. Mark osteotomy
Corticotomy
Screw holes for
device placement
Corticotomy converted to
osteotomy
Device fixation Activation Close 1-2mm
To verify the ability to place distractor in proper
orientation
To check the
impedance free
movement of
segments

113. MANDIBULAR DISTRACTION
• Sagittal split plus osteotomy cut above the lingula along the ramus to
the posterior border of the mandible
• Age dependant correction is a treatment option for the affected side.

114. • Pruzansky Mulliken classification of macrosomia – treatment –
mandibular do
• Children with macrosomia with airway compromise – mandibular DO
avoiding tracheostomy , drastic improvement has been reported

115. WITH TMD DISORDERS
• Patient with history of TMD use a modification of the classic sagittal split
tech.
• As proximal and distal segments overlap distraction rate is increased to
2mm / day ( 0.5 mm QID)
• Further horizontal bone cut above lingula for impedance free rotation
• Class II elastics are placed to unload the TMJ
• Splints should be used extending to second molar with final occlusion
indexed

116. MANDIBULAR WIDENING
• Often combined with maxillary transverse widening (SAME)
• Surgical procedure is similar to genioplasy with minimal periosteal
stripping, use tunnelling technique.
• Distractor of choice is hybrid
• Solely bone borne distractor will create a v shaped regenerate chamber.
• 5-7 days of latency distraction at 1mm / day

117. NOTE…..
• Apply slow incremental distraction forces.
• DO forces created during mandibular widening might
translate to mandibular condyle .
• Pre auricular pain or limitation in mouth opening
reduce the distraction to 0.5 – 0.25 mm.
• Place a pontic on the gap btwn incisors created due to
DO or light springs.
• Stabilization wit lingual arch in order to maintain the
new transverse dimension

118. SIMULTANEOUS MAXILLARY AND
MANDIBULAR DISTRACTION
• Pt who has craniofacial microsomia have concomitant maxillary
hypoplasia and occlusal cant towards the affected side.
• If maxillary molar is in full occlusion or if the patient is in permanent
dentition then concomitant maxillary DO is indicated
Corticotomy
Pterygoid Dys-
junction
Orthodontic elastic traction guiding into proper plane during the
DO process
No downfracture

119. MAXILLARY DISTRACTION
• Surgical approach is similar to conventional Lefort l osteotomy.
• Maxilla is freed but not completely downfractured 2-0 poly diaxone suture at
the maxillary 1st molar and zygomatic buttress to prevent the posterior
tipping.
• Device is pre-bend for the placement
• Ideal trajectory – distraction parallel to each other and to the mid sagittal
plane.
• Ensure that the resultant moment arm of the two distractors will not cancel
each other as the distractors reach the maximal length
• Use anterior elastics to guide maxilla to proper position.

120. Expanding the soft tissue envelope is the only rate limiting factor
Greater than 8-10mm distraction or with platal scarring requires an
external halo frame distractor
Centre of rotation of the maxilla is at the level of roots of maxillary first
molar.
Periodic checking
mandatory
Anterior open bite
If left unchecked

121. ONCE MAXILLA IS STABLE( 5-6 WEEKS )
Palpable
stable
maxilla
Radiograph
ic evidence
No need of rigid fixation to maxilla

122. MAXILLARY SEGMENTAL DISTRACTION
Use of orthodontic
appliances and
arch wires allows
the distraction
segments to follow
the curvature of
maxillary arch

124. • After distraction use orthodontic spring paralleling to the regenerate
chamber 1-2 weeks after distraction ossification
• Orthodontic alignment , repositioning of teeth in the regenerate
chamber leaving the defect for implant surgery if required small
grafting will be done
• This is a form of transport DO

125. • Use tunnelling technique to perform anterior osteotomy
• Horizontal bone cut parallel to the occlusal plane making the vector in
an horizontal axis
• 5 day latency……………………1mm/day
• Anterior traction elastics for the forward thrust of segments

126. TRANSPORT DO
Transport distraction involves creating
a transport disc in the bone , stump
adjacent to the discontinuity defect of
a resection site

127. Transport disc
advancement
done 1mm / day
Discontinuity
defect is filled
till
Size of transport disc = size of regenerate
chamber
Three points of fixation are necessary for
transport DO
1. Proximal stump
2. Distal side
3. Transport disc
Or use a rigid connector with conventional
distractor
1
2
3

128. • Once the transport disc reaches the docking site the segment is held
in neutral position or fixed until cortical outline is formed.
• At the time of distractor removal surgeon might have to place bone
graft between docking site and transport disc.
• Transport disc becomes rounded and encased with fibro cartilaginous
cap. Removal is necessary for bony union

129. During active DO monitor patient to rule out tissue dehiscence
Woumd care + antibiotic treatment (systemic and local)
Post
RT
Compromised
blood supply
Advised disc dancing until dehiscence
site closes

130. NOTE
• Symphysis region is difficult to reconstruct because regenerate tends
to become a straight line rather than curvilinear shape, so intra oral
surgical guides will help maintain the shape

131. View
from
above
View
from
below
Dento alveolar unit
formed is accurate
5 lines
2 body, 2 para symp,
and 1 symphysis
So plan for 5
linear distraction
vectors for the
mandible

132. ALTERNATIVE TREATMENT PLAN
Creation of
large transport
disc 1.5 – 3 cm
Advance in a linear fashion until the junction of
next linear segment
Disc is
divided
into two
segments
Disc is held in
neutral position
until early
ossification occurs
One half of the original
transport disc held in
place to the recon plate
After latency of 3-5 days the other
half will become the new transport
and reoriented in the proper vector

133. TRANSPORT DISTRACTION
Primary transport DO
Done at the time of
resection
If neck dissection is done
latency period will be 7 days
Secondary transport DO
Done at the later stage
Limited dissection is
advised
There will be excessive
scarring due to the previous
sx so rhythm of DO is 4
times/day rather than 2
times to allow incremental
stretching of soft tissue

134. Post
radiation
With HBO therapy – recommended but
not mandatory
Without HBO therapy, careful
monitoring and distraction rate should
be reduced to 0.5 mm / day
Transport DO is also done in conjunction with composite free
flap

135. TRANSPORT DO TO GENERATE A NEO-
CONDYLE
• During transport DO fibro-cartilagenous cap forms. Use this property
to reconstruct a neo-condyle.
• Create a reverse L osteotomy in the ramus of the mandible from the
sigmoid notch behind the lingula i.e 1-1.5 cm above the inferior border
of the mandible.
• Distractor is placed almost parallel to the posterior border of the
ramus to guide the transport disc to the fossa to create a neo-condyle

137. Patients with bony
ankyloses Gap arthroplasty Distraction sx
3D shaping of
glenoid fossa
5 day latency period

138. ALVEOLAR DO FOR DENTAL IMPLANTS
Vertical height for the implant is needed / overlying soft tissue wont
support osseous augmentation
Alveolar DO
Vestibular
incision
Minimal periosteal
stripping
Bone cut
Distractor
placement
Latency 3-5 days followed by 0.7 – 1mm 0.5 – 0.7 recommended

140. CONCLUSION
• The facial aesthetics are Gods gift to mankind, if the person is
handicapped by any facial deformity that is marring his/ her
happiness, thanks to distraction osteogenesis, we as OMFS can make
every effort to restore the aesthetics, confidence and the quality of life
in the social circle of the affected.