Distraction osteogenesis is a technique that involves cutting bone and gradually separating the bone segments to stimulate new bone growth. It relies on prolonged, controlled distraction to expand soft tissue and bone volume simultaneously without disrupting blood supply. The process was discovered accidentally by Russian orthopedic surgeon Ilizarov in 1988. It has various applications including lengthening of bones like the mandible and advancing structures like the midface. The treatment involves phases like latency, distraction, consolidation and retention to achieve the desired correction.

1. Distraction Osteogenesis-Distraction Osteogenesis-
Principles and MethodsPrinciples and Methods
OLALEKAN T. OmoniyiOLALEKAN T. Omoniyi

2. Definition- 1Definition- 1
 Distraction Osteogenesis is the ability to induceDistraction Osteogenesis is the ability to induce
callus in bone (by an osteotomy or sectioning)callus in bone (by an osteotomy or sectioning)
and then distracting the proximal ends.and then distracting the proximal ends.
 It relies on prolonged, controlled, progressiveIt relies on prolonged, controlled, progressive
and gradual distraction which does not disruptand gradual distraction which does not disrupt
the vascular supply.the vascular supply.
 This results in simultaneous expansion ofThis results in simultaneous expansion of
soft tissue and bone volume.soft tissue and bone volume.

3. Definition-2Definition-2
 It is the ability to reconstruct combinedIt is the ability to reconstruct combined
deficiencies in bone and soft tissue thatdeficiencies in bone and soft tissue that
makes this process unique and invaluablemakes this process unique and invaluable
to all types of reconstructive surgeonsto all types of reconstructive surgeons
 Two main cellular processes are involved:Two main cellular processes are involved:
the formation of a callus and thethe formation of a callus and the
generation of new bone.generation of new bone.

4. HistoryHistory
 In 1988, the Russian orthopaedic surgeon IlizarovIn 1988, the Russian orthopaedic surgeon Ilizarov
described a technique for DO involving only adescribed a technique for DO involving only a
corticotomy-interruption of the cortical bone alone, withcorticotomy-interruption of the cortical bone alone, with
minimum disruption of the periosteum and endosteumminimum disruption of the periosteum and endosteum
hence reducing the incidence of morbidity.hence reducing the incidence of morbidity.
 Interestingly,Ilizarov’s intention was to use externalInterestingly,Ilizarov’s intention was to use external
compression to bone ends in order to treat cases of non-compression to bone ends in order to treat cases of non-
union.A patient who had failed to grasp the instructionunion.A patient who had failed to grasp the instruction
given, turned the screw the wrong way and ended upgiven, turned the screw the wrong way and ended up
distracting rather than compressing their bonedistracting rather than compressing their bone
ends.Ilizarov took radiographs and noticed new boneends.Ilizarov took radiographs and noticed new bone
being formed.being formed.

5. ApplicationsApplications
 Lengthening of the mandible.Lengthening of the mandible.
 Advancing the midfaceAdvancing the midface
 Augmenting the mandibular alveolar ridge.Augmenting the mandibular alveolar ridge.
Has provided options for treatingHas provided options for treating
 Hypoplastic mandiblesHypoplastic mandibles
 Missing boneMissing bone
 Unilateral and bilateral microsomiaUnilateral and bilateral microsomia
 MicrognathiaMicrognathia
 Calvarial expansionCalvarial expansion

6. Treatment Phases of DOTreatment Phases of DO
 Pre-surgical phasePre-surgical phase
 Operative phaseOperative phase
 Latency phaseLatency phase
 Distraction phaseDistraction phase
 Consolidation phase andConsolidation phase and
 Retention phase.Retention phase.

7. Pre-surgical phasePre-surgical phase
 Involves radiographic studies to determine the feasibilityInvolves radiographic studies to determine the feasibility
of placement of the distraction device, the vectorof placement of the distraction device, the vector
(direction, amplitude) of the distraction, and whether an(direction, amplitude) of the distraction, and whether an
internal or external device is more appropriate.internal or external device is more appropriate.
 When possible, 3-D solid models help to visualize theWhen possible, 3-D solid models help to visualize the
placement of the device and simulate the distractionplacement of the device and simulate the distraction
process.process.
 Involvement of the orthodontist is essential asInvolvement of the orthodontist is essential as
presurgical orthodontic preparation typically is needed topresurgical orthodontic preparation typically is needed to
guide the distraction at the occlusal level since theguide the distraction at the occlusal level since the
skeletal component is controlled by the deviceskeletal component is controlled by the device
mechanism.mechanism.

8. Operative phase – Guidelines forOperative phase – Guidelines for
Mandibular Distraction -1Mandibular Distraction -1
 Make sure that there is adequate mandibular bone stockMake sure that there is adequate mandibular bone stock
for the osteotomy and placement of the device.for the osteotomy and placement of the device.
 Decide on the type of device. External devices allow forDecide on the type of device. External devices allow for
multidirectional control of the distraction, which cannotmultidirectional control of the distraction, which cannot
be achieved with the currently available internal devices.be achieved with the currently available internal devices.
However, external devices may lead to significant facialHowever, external devices may lead to significant facial
scarring, and the application of sequential differentscarring, and the application of sequential different
distraction vectors with a series of internal devices maydistraction vectors with a series of internal devices may
be preferable to a permanent external scar.be preferable to a permanent external scar.
 Exposure can be obtained through either an intraoral orExposure can be obtained through either an intraoral or
extraoral approach, depending upon the exposureextraoral approach, depending upon the exposure
required for the placement of the device and therequired for the placement of the device and the
allowable maxillary-mandibular opening.allowable maxillary-mandibular opening.

9. Operative phase – Guidelines forOperative phase – Guidelines for
Mandibular Distraction -2Mandibular Distraction -2
 The placement and/or direction of the device, not theThe placement and/or direction of the device, not the
osteotomy of the mandible, dictates the distractionosteotomy of the mandible, dictates the distraction
vector. The osteotomy line does not necessarily need tovector. The osteotomy line does not necessarily need to
be perpendicular to the distraction vector but should bebe perpendicular to the distraction vector but should be
placed to avoid injury to the nerve and the developingplaced to avoid injury to the nerve and the developing
dentition. In addition, avoidance of such injury can bedentition. In addition, avoidance of such injury can be
facilitated by an incomplete osteotomy with subsequentfacilitated by an incomplete osteotomy with subsequent
separation occurring during the distraction phase.separation occurring during the distraction phase.
 Temporarily fix the distractor into position prior to makingTemporarily fix the distractor into position prior to making
the osteotomy. Positioning and placement of the devicethe osteotomy. Positioning and placement of the device
after the osteotomy can be difficult because of theafter the osteotomy can be difficult because of the
mobility of the proximal segment.mobility of the proximal segment.

10. Operative phase – Guidelines forOperative phase – Guidelines for
Mandibular Distraction -3Mandibular Distraction -3
 Make the buccal corticotomy with a reciprocatingMake the buccal corticotomy with a reciprocating
saw, and "green-stick" fracture the lingual with asaw, and "green-stick" fracture the lingual with a
fine osteotome to preserve the inferior alveolarfine osteotome to preserve the inferior alveolar
nerve. Complete mobilization is not alwaysnerve. Complete mobilization is not always
necessary since the distraction devicenecessary since the distraction device
completes the osteotomy. Warn the patient andcompletes the osteotomy. Warn the patient and
family of the discomfort the patient will feel untilfamily of the discomfort the patient will feel until
the fracture is completed.the fracture is completed.
 Prior to closure, test the device and clearly markPrior to closure, test the device and clearly mark
for the family the direction (clockwise orfor the family the direction (clockwise or
counterclockwise) of the driver used to turn thecounterclockwise) of the driver used to turn the
device.device.

11. Operative phase – Guidelines for MidfacialOperative phase – Guidelines for Midfacial
and Frontofacial Distractionand Frontofacial Distraction - 1- 1
 Place a palatal device to guide the distractionPlace a palatal device to guide the distraction
vector as part of presurgical preparation.vector as part of presurgical preparation.
 Make the osteotomies as with conventionalMake the osteotomies as with conventional
approaches and complete the mobilization of theapproaches and complete the mobilization of the
mid face.mid face.
 In children in the stage of primary or mixedIn children in the stage of primary or mixed
dentition, modify the typical LeFort I osteotomydentition, modify the typical LeFort I osteotomy
and place it well above the developing dentitionand place it well above the developing dentition
at the level of the inferior orbital foramen.at the level of the inferior orbital foramen.

12. Operative phase – Guidelines for MidfacialOperative phase – Guidelines for Midfacial
and Frontofacial Distractionand Frontofacial Distraction - 2- 2
 Midfacial advancements at the LeFort I level withMidfacial advancements at the LeFort I level with
currently available internal devices are limited becausecurrently available internal devices are limited because
of the difficulty in appropriately orienting the devices inof the difficulty in appropriately orienting the devices in
the limited space. The fixation of the device may injurethe limited space. The fixation of the device may injure
the developing dentition. External multidirectionalthe developing dentition. External multidirectional
devices are preferred as they allow more control over thedevices are preferred as they allow more control over the
distraction process.distraction process.
 Midfacial advancement at the LeFort III level andMidfacial advancement at the LeFort III level and
frontofacial advancements can be approached eitherfrontofacial advancements can be approached either
with internal or external devices depending on thewith internal or external devices depending on the
circumstances. Place the internal devices at the level ofcircumstances. Place the internal devices at the level of
the body and arch of the zygoma. External devicesthe body and arch of the zygoma. External devices
require a palatal appliance and additionally traction wiresrequire a palatal appliance and additionally traction wires
at the zygoma, nasal root, and supraorbital regions.at the zygoma, nasal root, and supraorbital regions.

13. Latency PeriodLatency Period
 This is the initial postoperative phaseThis is the initial postoperative phase
when fracture healing is allowed to occurwhen fracture healing is allowed to occur
before distracting forces are applied. Thisbefore distracting forces are applied. This
period typically lasts 5-7 days. In youngerperiod typically lasts 5-7 days. In younger
patients (typically, younger than 4-5patients (typically, younger than 4-5
years), the latency period may beyears), the latency period may be
significantly shortened or omittedsignificantly shortened or omitted
altogether to prevent early consolidation.altogether to prevent early consolidation.

14. Distraction Phase - 1Distraction Phase - 1
 Bone segments gradually pulled apart using either an internal orBone segments gradually pulled apart using either an internal or
external device. Three variables must be set:external device. Three variables must be set:
 the rate of distractionthe rate of distraction
 the rhythm and/or frequency of distraction andthe rhythm and/or frequency of distraction and
 the total time of distraction.the total time of distraction.
 The rate of distraction is typically 1.0 mm/d. Some advocate up toThe rate of distraction is typically 1.0 mm/d. Some advocate up to
2.0 mm/d in younger children to avoid early consolidation and a2.0 mm/d in younger children to avoid early consolidation and a
slower rate of 0.5 mm/d or 0.25 mm qid in older patients to avoidslower rate of 0.5 mm/d or 0.25 mm qid in older patients to avoid
fibrous unions. This can be accomplished either once a day orfibrous unions. This can be accomplished either once a day or
divided throughout the day, determining the rhythm or frequency ofdivided throughout the day, determining the rhythm or frequency of
distraction. While the distraction rate is 1.0 mm/d, ideally maintaindistraction. While the distraction rate is 1.0 mm/d, ideally maintain
the tissues under constant tension by dividing the total daily rate ofthe tissues under constant tension by dividing the total daily rate of
distraction into smaller increments throughout the day to favordistraction into smaller increments throughout the day to favor
histogenesis.histogenesis.

15. Distraction Phase - 2Distraction Phase - 2
 The total time of the distraction phase depends onThe total time of the distraction phase depends on
achieving the clinical goals; individualize it to eachachieving the clinical goals; individualize it to each
patient and to the severity of the deformity. Rememberpatient and to the severity of the deformity. Remember
that the total length of bone desired does not necessarilythat the total length of bone desired does not necessarily
equal the total time of the distraction phase. Externalequal the total time of the distraction phase. External
devices that use pins to transmit the forces frequentlydevices that use pins to transmit the forces frequently
bend, and the distance at the site of the distractingbend, and the distance at the site of the distracting
mechanism on the device rarely equals the distance ofmechanism on the device rarely equals the distance of
the gap at the osteotomy sites. Use clinical guidelinesthe gap at the osteotomy sites. Use clinical guidelines
(eg, position of the chin point, distance from the lateral(eg, position of the chin point, distance from the lateral
canthus to the commissure and the mandibular cant) tocanthus to the commissure and the mandibular cant) to
determine the end point in children with hemifacialdetermine the end point in children with hemifacial
microsomia.microsomia.

16. Consolidation PhaseConsolidation Phase
 Once the desired correction is achieved with theOnce the desired correction is achieved with the
distraction phase, allow mineralization of thedistraction phase, allow mineralization of the
immature bone to occur. Lock the distractingimmature bone to occur. Lock the distracting
appliance into place to maintain stability until theappliance into place to maintain stability until the
newly formed bone has sufficient strength. Thenewly formed bone has sufficient strength. The
length of this phase varies depending on thelength of this phase varies depending on the
circumstances. In general, 6-8 weeks iscircumstances. In general, 6-8 weeks is
considered adequate. A guideline used by someconsidered adequate. A guideline used by some
centers is 2 days of consolidation to every day ofcenters is 2 days of consolidation to every day of
distractiondistraction

17. Retention PhaseRetention Phase
 Remove the device and maintain stability,Remove the device and maintain stability,
typically with the assistance of orthodontictypically with the assistance of orthodontic
appliances. In children with hemifacialappliances. In children with hemifacial
microsomia, this may require occlusalmicrosomia, this may require occlusal
splints to guide the maxilla into positionsplints to guide the maxilla into position
when the leveling of the mandibular cantwhen the leveling of the mandibular cant
creates a posterior open bite. In childrencreates a posterior open bite. In children
with midfacial deformity, retention maywith midfacial deformity, retention may
require a face mask with elastic tractionrequire a face mask with elastic traction
for a period of timefor a period of time

18. DO of the alveolar ridgeDO of the alveolar ridge
 Principal problem in Dental Implantation isPrincipal problem in Dental Implantation is
LACK OF SUFFICIENT BONE HEIGHT ORLACK OF SUFFICIENT BONE HEIGHT OR
WIDTH.WIDTH.
Causes include bone loss like periodontalCauses include bone loss like periodontal
disease,pathological disease, trauma anddisease,pathological disease, trauma and
congenital deformities.congenital deformities.
Insufficient alveolar ridge impedes the use ofInsufficient alveolar ridge impedes the use of
implants of sufficient length giving a inadequateimplants of sufficient length giving a inadequate
crown to implant length ratio.crown to implant length ratio.
Options include onlay and interpositional boneOptions include onlay and interpositional bone
grafts.grafts.

19. DO of the alveolar ridge (Contd)DO of the alveolar ridge (Contd)
 DO based on callostasis, the gradual stretchingDO based on callostasis, the gradual stretching
of the reparative callus that forms around boneof the reparative callus that forms around bone
segments interrupted by osteotomy ofsegments interrupted by osteotomy of
fracture.Stretching is gradual, allowingfracture.Stretching is gradual, allowing
maintenance of blood flow.maintenance of blood flow.
 Bone regeneration involves two processesBone regeneration involves two processes
-Osteogenesis:Callus formation and generation of-Osteogenesis:Callus formation and generation of
new bonenew bone
-Histiogenesis:Lengthening of the soft tissues ie-Histiogenesis:Lengthening of the soft tissues ie
mucoperiosteum, nerves and soft tissues.mucoperiosteum, nerves and soft tissues.

20. ProcedureProcedure
Consists ofConsists of
 Latency period of 5-7 daysLatency period of 5-7 days
 Distraction rate of 0.5 – 1mm/dayDistraction rate of 0.5 – 1mm/day
 Consolidation period of 8- 12 weeks.Consolidation period of 8- 12 weeks.
???Immediate distraction-dehiscence and???Immediate distraction-dehiscence and
exposure to oral environment.exposure to oral environment.
Magnitude of force more important thanMagnitude of force more important than
frequency of application.Minimum and maximumfrequency of application.Minimum and maximum
force inducing activation and continued functionforce inducing activation and continued function
of the cells contributing to osteogenesis is notof the cells contributing to osteogenesis is not
known.known.

21. Pathophysiology -1Pathophysiology -1
Distraction osteogenesis takes place primarily throughDistraction osteogenesis takes place primarily through
intramembranous ossification. Histologic studiesintramembranous ossification. Histologic studies
identified 4 stages that result in the eventual formation ofidentified 4 stages that result in the eventual formation of
mature bone.mature bone.
 Stage I: The intervening gap initially is composed ofStage I: The intervening gap initially is composed of
fibrous tissue (longitudinally oriented collagen withfibrous tissue (longitudinally oriented collagen with
spindle-shaped fibroblasts within a mesenchymal matrixspindle-shaped fibroblasts within a mesenchymal matrix
of undifferentiated cells).of undifferentiated cells).
 Stage II: Slender trabeculae of bone are observedStage II: Slender trabeculae of bone are observed
extending from the bony edges. Early bone formationextending from the bony edges. Early bone formation
advances along collagen fibers with osteoblasts on theadvances along collagen fibers with osteoblasts on the
surface of these early bony spicules laying down bonesurface of these early bony spicules laying down bone
matrix. Histochemically, significantly increased levels ofmatrix. Histochemically, significantly increased levels of
alkaline phosphatase, pyruvic acid, and lactic acid arealkaline phosphatase, pyruvic acid, and lactic acid are
noted.

22. Pathophysiology -2Pathophysiology -2
 Stage III: Remodeling begins with advancing zones ofStage III: Remodeling begins with advancing zones of
bone apposition and resorption and an increase in thebone apposition and resorption and an increase in the
number of osteoclasts.number of osteoclasts.
 Stage IV: Early compact cortical bone is formed adjacentStage IV: Early compact cortical bone is formed adjacent
to the mature bone of the sectioned bone ends, withto the mature bone of the sectioned bone ends, with
increasingly less longitudinally oriented bony spicules;increasingly less longitudinally oriented bony spicules;
this resembles the normal architecture.this resembles the normal architecture.
 By 8 months, the intervening bone within the distractionBy 8 months, the intervening bone within the distraction
zone achieves 90% of the normal bony architecture. It iszone achieves 90% of the normal bony architecture. It is
believed that the architecture is maintained and that thebelieved that the architecture is maintained and that the
bone responds to normally applied functional loads.bone responds to normally applied functional loads.

23. Alveolar DO – Fig 1Alveolar DO – Fig 1

24. Alveolar DO – Fig 2Alveolar DO – Fig 2

25. Alveolar DO –Fig 3Alveolar DO –Fig 3

26. Alveolar DO- Fig 4Alveolar DO- Fig 4

27. Alveolar DO- Fig 5Alveolar DO- Fig 5

28. Alveolar DO- Fig 6Alveolar DO- Fig 6

29. Alveolar DO – Fig 7Alveolar DO – Fig 7

30. Alveolar DO – Fig 8Alveolar DO – Fig 8

31. Alveolar DO – Fig 9Alveolar DO – Fig 9

32. Alveolar DO – Fig 10Alveolar DO – Fig 10

33. Alveolar DO – Fig 11Alveolar DO – Fig 11

34. Alveolar DO – Fig 12Alveolar DO – Fig 12

35. Alveolar DO – Fig 13Alveolar DO – Fig 13

36. Alveolar DO – Fig 14Alveolar DO – Fig 14

37. AppliancesAppliances
 External devices. Anchored by transcutaneousExternal devices. Anchored by transcutaneous
pins used to achieve transport and stabilizationpins used to achieve transport and stabilization
of the skeletal fragments. (Unacceptable to mostof the skeletal fragments. (Unacceptable to most
patients).patients).
 Internal devices -acceptable, application to aInternal devices -acceptable, application to a
wide range of anatomical locations,no skinwide range of anatomical locations,no skin
incision,limited risk to the facial nerve.incision,limited risk to the facial nerve.
 Internal-juxtaosseous and intraosseous.Internal-juxtaosseous and intraosseous.
Juxtaosseous-placed on buccal aspectJuxtaosseous-placed on buccal aspect
Intraosseous-run through the transport segmentIntraosseous-run through the transport segment
in the direction of the distraction.in the direction of the distraction.

38. ComplicationsComplications
 Arising during surgery, generally related toArising during surgery, generally related to
osteotomy and distractor placementosteotomy and distractor placement
 Arising during distraction, includingArising during distraction, including
incorrect direction of distraction and softincorrect direction of distraction and soft
tissue complicationstissue complications
 Arising after distraction, due to defectiveArising after distraction, due to defective
bone formation.bone formation.

39. A peep into the futureA peep into the future
 What should be the minimum heightWhat should be the minimum height
requirement for DO?requirement for DO?
 Joint use of bone graft and DO.Joint use of bone graft and DO.
 How long after bone graft should DOHow long after bone graft should DO
commence? 3 months or a year?commence? 3 months or a year?

40. ConclusionConclusion
 Alveolar DO is a technique which involvesAlveolar DO is a technique which involves
freeing a bone segment (the transport segment)freeing a bone segment (the transport segment)
from the basal bone, but retaining attachmentfrom the basal bone, but retaining attachment
via the lingual periosteum. It is preferable tovia the lingual periosteum. It is preferable to
bone grafting for increasing bone height andbone grafting for increasing bone height and
width.The regenerated bone has been found towidth.The regenerated bone has been found to
be highly resistant to resorption and capable ofbe highly resistant to resorption and capable of
supporting heavy loads and enables thesupporting heavy loads and enables the
placement of implants with good esthetics.placement of implants with good esthetics.