Distraction osteogenesis /certified fixed orthodontic courses by Indian dental academy

DISTRACTION OSTEOGENESIS

INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

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Distraction osteogenesis = callostasis =
stretching of a bone callus

Gradual distraction of bones is accompanied by
the soft tissues = less probability of relaps
Method utilizing body’s own healing mechanism to
generate new bone.
Useful in reconstructing defects or discontinuity
secondary to trauma, malignancy, etc.
Less invasive, decreased morbidity

callostasis = stretching of a bone callus


callostasis = stretching of a bone callus

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Callotasis is a gradual stretching of the reparative callus

that forms around bone segments interrupted by
osteotomy or fracture. Clinically, callotasis consists of
three sequential periods: 1) latency, 2) distraction, and
3) consolidation. Latency is the period from bone division
to the onset of traction and is the time required for
callus formation. The distraction period is the time when
gradual traction is applied and new bone, or distraction
regenerate, is formed. The consolidation period allows
maturation and corticalization of the regenerate after
traction forces are discontinued (Gantous et al., 1994;
Murray & Fitch, 1996).

HISTORY
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Codivilla 1905; First published description.
• Sudden intense pull on the extremity under narcosis
Abbott 1927; modified by step osteotomy.
• Many complications; "left patients more crippled"
Allen 1948; external device with screw
• Allowed for daily activation, controlled elongation
Iliazarov 1948; presented in US
• Used the ring fixator
Modified with DeBastiani; "Callostasis"
Micheli and Miotti 1977 , first OMF reference
• Used to lengthen mandible in sheep
• Bony gap filled with collagenous fibres turning into
lamellar bone

HISTORY
• Distraction Osteogenesis was first used in orthopedic
medicine in the early 1900's, but the current concepts
evolved from the ideas of Dr. Gavriel Ilizarov, who
practiced medicine in Kurgan, Siberia. Dr. Ilizarov, who
had great understanding of the biophysiolgy of bone,
developed techniques to move bone fragments in
controlled vectors using a system of wires and fixed rings
joined together with threaded rods and hinges. This
technique allowed slow transport of bone segments
without invasive surgery and was especially practical in
the treatment of fractures in children and in lengthening
of bones in the legs where there was a discrepancy
between right and left bone lengths.

HISTORY


DENTAL HISTORY
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The transfer of techniques involving D.O. in medicine to
those used in dentistry was not an easy task. The reason
being that the shape, size, location of bones is much
different. The primary boost in the development of
distraction osteogenesis techniques in the dental field
came from the conceptualization and construction of
miniature devices that could move small bone fragments
in a controlled vector. In 1992, McCarthy, was the first
to publish on the use of distraction osteogenesis to
lengthen a human mandible. Dr. Martin Chin, a
maxillofacial surgeon in San Francisco, was and still is a
primary leader in this process.

DENTAL HISTORY

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Distraction osteogenesis was initially used to treat
defects of the oral and facial region in 1990. Since
then, the surgical and technological advances made in the
field of distraction osteogenesis have provided the oral
and maxillofacial surgeons with a safe and predictable
method to treat selected deformities of the oral and
facial skeleton.


DENTAL HISTORY

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Distraction osteogenesis (DO) is a relatively new method
of treatment for selected deformities and defects of
the oral and facial skeleton. It was first used in 1903.
Then, in the 1950’s the Russian orthopedic surgeon, Dr.
Gabriel Ilizarov slowly perfected the surgical and
postoperative management of distraction osteogenesis
treatment to correct deformities and repair defects of
the arms and legs. His work went mostly unnoticed until
he presented to the Western Medical Society in the
mid-1960’s.


INDICATIONS
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Mandibular Lengthening

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Anterior-posterior deformity

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Trauma reconstruction

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Cancer reconstruction

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Craniofacial syndrome

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Mandibular Widening

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Crowding with A-P deformity

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Brodie Syndrome


INDICATIONS
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Asymmetry

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Craniofacial Syndrome

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Maxillary or mandibular alveolar distraction

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Insufficient alveolar height and/or width

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Previously failed bone graft sites

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Insufficient soft tissue coverage

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Insufficient dona bone available

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Patient is not a candidate for a bone graft

Advantages of Distraction Osteogenesis

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Little relapse
Bigger movements possible
Ability to mold the regenerate
Out-patient surgery
No need to extract teeth
Generation of soft tissue
Less likelihood of nerve injury
Less likelihood of idiopathic condylar

resorption

Disadvantages of distraction osteogenesis
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Technique sensitive surgery

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Equipment sensitive surgery

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Possible need of second surgery to remove

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distraction devices

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Patient compliance

Principles of Osteodistraction

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Osteotomy in the area of deficiency

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Application of external fixator

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Initiation of the expansion forces

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Maintenance of newly formed bone


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Latency period
Common to all techniques
• If not observed the new bone will have ¯ density
• If too long; premature ossification
5-7 days according to Ilizarov, 14 d per DeBastiani

Rate
• Premature ossification if < 0.5 mm/d, fibrous >
2mm/d
• 1 mm/d appears to be the optimal


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Rhythm
# of distraction events per day
Best; continuos distraction, but not practical yet
do 0.5 mm bid
Frame design
Must be compact enough to allow patient comfort
The distracted bone must be maintained and
protected from shearing forces
if not fibrocartilage will form instead of new bone

Biology of Osteodistraction

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Bone formation via mesenchymal induction
Unlike fracture healing
•Karp et. al.(‘92) described the sequence of
events
•Initial fibrin clot at osteotomy site
•Day 10 Collagen fibres (parallel to vector) in
the gap.
•Fine bony trabeculae seen at the periphery
•Day 14 trabecular remodeling after distraction
•Advance to middle to form osseous union
•Day 28 bony continuity noted

Biology of Osteodistraction
7-fold increase in the blood supply to regenerate

Hyper-trophy, -plasia of overlying muscle/skin
Mild transient Wallerian degeneration of IAN
Initial flattening of TMJ, remodeled
Beneficial effects found in congenital deformities.

Devices
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Can be performed for the mandible, maxilla,
calvarium, orbit, midpalatal suture and maxillary
or mandibular alveolus
Distraction devices can be internal or external
Internal devices can also be resorbable
Distraction Osteogenesis for the Mandible
Distraction Osteogenesis for the Maxilla


Devices
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Mandibular
- Pediatric
- Linear
Blue Device
External Mandibular
Vertical Distraction
Midface

•Haas Palatal expander
•Mandibular ramus distractor
•Mandibular body distractor
•RED craniofacial distractor
•Mandibular bone transport ( U-Distractor)
•Alveolar distractor

Mandibular

- Pediatric
- Linear


Blue Device

The Lorenz Advantage

The Lorenz Mid-Face Distractor was designed by Doctors
Martin Chin and Bryant Toth. These two surgeons have
experienced several years of clinical success with this type
of distractor. The device also permits use of both Rapid
Distraction and standard distraction techniques.


Blue Device


External Mandibular


Vertical Distraction


Midface


Haas Palatal expander


THANK

YOU


Distraction osteogenesis /certified fixed orthodontic courses by Indian dental academy

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Distraction osteogenesis /certified fixed orthodontic courses by Indian dental academy