Distraction osteogenesis (6)

Distraction Osteogenesis
www.indiandentalacademy.com

INTRODUCTION
Distraction Osteogenesis is a biological
process of new bone formation between
surfaces of bone segments gradually
separated by incremental traction.

Distraction Osteogenesis is a method commonly
used to activate bone regeneration in ;
• Non-unions of fractures
• Osseous defects
• Lengthening procedures of tubular bones
The Technique involves ;
• Sectioning of a bone & the subsequent deliberate
controlled movement of the opposing sectioned
edges to lengthen ,widen or reposition a bone or all
three.

Events in Distraction Osteogenesis
• Initiation with incremental traction to the
reparative callus.
• Tension within the callus stimulates new
bone formation parallel to the vector of
distraction.
• Tension is created in the surrounding soft
tissues leading to Distraction
Histogenesis(active histogenesis in skin,
fascia,blood vessels,nerves,muscle,
ligament,cartilage & periosteum.)

Events(Contd…)
• The adaptive soft tissue changes allow
larger skeletal movements hence
minimizing potential relapse.

Overview
• Historical Perspective
• Devices
• Procedures
• Results
• Future
• Conclusion

HISTORICAL PERSPECTIVE
The origin & evolution of Craniofacial
Distraction Osteogenesis was the
development of Dentofacial
traction,Craniofacial osteotomies &
Skeletal fixation techniques after
experiments with Distraction Osteogenesis
on long bones.

Dentofacial traction was practised as early
as 1728 when Pierre Fouchard described
the ‘Bandalette’, the first expansion arch
used to provide dental expansion.
In 1859, Wescott used mechanical forces on
the maxilla. He used two double clasps
separated by a telescopic bar.

Angle, in 1860 , used a differentially
threaded jackscrew connected to the
premolars for palatal expansion.
Goddard, in 1893, standardized palatal
expansion protocol by a stabilization period
after activation to allow deposition of
osseous material in the created gap.

.
According to Wassmund, in 1927 Rosenthal
performed the first mandibular osteodistraction
procedure by using an intraoral tooth-borne
appliance that was gradually activated over a
period of 1 month.

In 1937, Kazanjian also performed
mandibular osteodistraction by
using gradual incremental traction
instead of acute advancement
.After performing modified L-
shaped osteotomies in the corpus,
he attached a wire hook to the
symphysis, thereby providing direct
skeletal fixation to the bone
segment to be distracted.

Crawford, in 1948, applied gradual incremental traction to
the fracture callus of a mandible after a mandibular
symphyseal fracture in which a lower central incisor was
lost. The mandibular halves had collapsed medially,
obliterating the incisor space and creating an apparent
crossbite. By using a jackscrew appliance, the fracture
callus was stretched over a 3 day period to reestablish the
original jaw position, which remained fixed by a sectional
occlusal splint.

Ilizarov in 1989 revolutionized the concept of
distraction osteogenesis with his technique for limb
lenthening. The procedure was called Percutaneous
Subperiosteal Corticotomy which was followed by a
latency period before initiation of incremental
traction.

The first report demonstrating the application of
Ilizarov’s principles to the mandible appeared in 1973 .In
order to simulate a mandibular deformity, Snyder and
co-workers resected a unilateral 15 mm bone segment
from a canine mandible, thereby creating a crossbite. Ten
weeks later, the shortened mandible was osteotomized
and an external distraction appliance was placed. After a
7 day latency period, the device was activated at a rate of
1 mm per day for 14 days, at which time the occlusion
was restored. Reestablishment of the mandibular cortex
and medullary canal across the distraction gap was noted
following 6 weeks of fixation.

Using a similar distraction protocol a few years later,
Michieli and Miotti demonstrated the feasibility of intraoral
mandibular lengthening .Implementing a device cemented to
the teeth, they lengthened the mandibles of two dogs – one 5
mm, the other 15 mm – following a bilateral reverse-step
osteotomy. Histologic examination revealed new bone
formation originating from the parallel-ordered collagenous
fibers, which subsequently remodeled into lamellar bone.

In 1982, Panikarovsky and co-workers performed the first
significant histologic evaluation of mandibular distraction
regenerates in 41 dogs .The study focused on the
histomorphological dynamics of new bone formation. A
fibrous interzone was observed in the central region of the
distraction gap with collagenous fibers and capillaries
oriented parallel to the direction of distraction. Newly
created bone, in the form of longitudinally oriented
trabeculae, originated from the residual mandibular
segments and progressed toward the fibrous interzone. The
results of these studies demonstrated that the mechanism of
new bone formation during gradual mandibular distraction
was similar to that during limb lengthening.

In 1989, McCarthy was the first to clinically apply an
external fixation device for mandibular lengthening).
In 1992, he demonstrated the clinical application of
the distraction osteogenesis technique by using the
Hoffman Mini Lengthener attached to the
osteotomized bone segments with two pairs of 2 mm
half pins.

Karp and co-workers conducted a similar experimental
study with a more comprehensive analysis of distraction
regenerates at different stages of formation .Ten days after
a periosteal-preserving corticotomy, unilateral mandibular
lengthening began at a rate of 1 mm per day for 20 days,
followed by an 8 week consolidation period.
Histomorphologically, the distraction gap can be
represented by four zones: 1) a central zone of fibrous
tissue, 2) a zone of extending bone formation, 3) a zone of
bone remodeling, and 4) a zone of mature bone.

Guerrero,in 1987, used the first Intraoral tooth-
borne device for Osteodistraction & in 1990,
was the first to report Intra-oral mandibular
widening.
McCarthy et al, in 1994, developed an
intraoral bone-borne Uniguide Mandibular
Distraction Device similar to their extraoral
device.
Molina & Ortiz-Monasterio, in 1995, were the
first to use Bidirectional Mandibular
Osteodistraction.www.indiandentalacademy.com

Wangerin, in 1997, designed the Intraoral Titanium
Mandibular Distraction Device.
Diner et al, in 1997, developed two types of
intraoral bone-borne devices for mandibular
lengthening based on the anatomic location of
distraction.
Razdolsky et al in 1998, developed a series of tooth-
borne & hybrid devices(ROD).

Chin and Toth in 1996, were the first to
apply Alveolar Manibular Distraction
Osteogenesis.
A new concept of ‘Distracting the
Periodontal Ligament’ was proposed to
elicit rapid canine retraction in 1998 by
Eric JW Liou and C. Shing Huang.

Overview of Devices
Distraction appliances of the maxillofacial region
can be divided into:
•Extra-oral appliances
•Unidirectional devices
•Bi-directional devices
•Multidirectional devices
•Intra-oral devices
•Tooth-borne devices
•Tissue-borne devices
•Hybrid (tooth and tissue borne) devices

Current Distraction Appliances
(Devices)
In general, two types of mandibular distraction appliances have been
used - extraoral and intraoral. The extraoral appliances are attached to
the mandible by percutaneous pins connected externally to fixation
clamps. The fixation clamps, in turn, are joined together by a linear
distraction bar (distractor) such that when activated, the bar effectively
pushes the clamps and the attached bone segments apart, generating
new bone in its path. Relative to the direction of lengthening, the
extraoral devices can be divided into uni-directional, bi-directional, and
multi-directional devices. The intraoral appliances are entirely
contained within the oral cavity. They are attached to the bone (bone-
borne), to the teeth (tooth-borne), or simultaneously to the teeth and
bone (hybrid). A linear distractor, similar to an orthodontic expansion
device, is used despite the method of intraoral attachment.www.indiandentalacademy.com

Extra-Oral Appliances-
Unidirectional Distractors
McCarthy, in 1989, was the first to clinically apply an
external fixation device for mandibular lengthening .In 1992,
he demonstrated the clinical application of the distraction
osteogenesis technique by presenting case reports of four
children with congenital craniofacial anomalies. He used the
Hoffman Mini Lengthener attached to the osteotomized bone
segments with two pairs of 2 mm half pins.

The Hoffman Mini Lengthener was initially designed
for hand reconstruction. It consists of two double-pin
fixation clamps secured to a telescopic rod that is
activated by a screw mechanism. The device can be
adapted to the anatomic shape and size of the
mandible by rotation of one clamp and sliding the
other clamp along the shaft of the telescopic distractor.

Bitter and Klein introduced their own external fixation device for
mandibular lengthening – the Uni-directional Mandibular Distractor
developed in cooperation with Normed Medizin-Technik GmbH,
Tuttlingen, Germany. The Uni-directional Mandibular Distractor also
has two clamps - a rotating clamp and a sliding clamp, both connected
to the geared distractor. Each clamp contains a pair of fixation pins for
attachment. Similar to the Hoffman Mini Lengthener, rotation and
sliding of the clamps allow apparatus adaptation to the shape and size of
the mandible. Distraction is performed by turning the advancement
screw on the sliding clamp.

BI-DIRECTIONAL DISTRACTOR
When the congenital mandibular deficiency is such that both the
ramus and body of the mandible are affected, a multiplaner
distraction is required.
The Bi-Directional distractor allows, in addition to a divided
elongation in two directions, a variable adjustment in the angle
between the two arms of the appliance. Following a single or double
osteotomy, one can distract both vertically and horizontally. In very
difficult cases of mandibular hypoplasia, a double osteotomy may be
undertaken in order to obtain two callus sites. This allows a more
rapid distraction as well as the development of a mandibular angle.

MULTI-DIRECTIONAL DISTRACTOR
Because the midface adapts to the mandible in the early
growth phases, a disturbance in mandibular development results
in decreased midface development as well. Concepts of treatment,
to date, employ either orthodontic preparation to bridge the time
from diagnosis to the age at which the patient is able to undergo
bimaxillary repositioning osteotomies, or placement of
costochondral grafts at the disturbed mandibular sites in
childhood, after which orthodontic treatment is employed to effect
correct development of the midface. Alternately, the Multi-
Directional Distractor may be used at an earlier age, avoiding
secondary growth disturbances in the maxilla.

ACE-Normed Bilateral Mandibular Distractors
Uni-Directional Distractor Bi-Directional Distractor
Multi-Directional Distractorwww.indiandentalacademy.com

Intra-Oral Appliances
The initial development of intraoral mandibular distraction
progressed in two directions: 1) modification of available
orthodontic expansion appliances, and 2) further miniaturization
of external devices. In 1987, Guerrero applied the first intraoral
tooth-borne appliance for osteodistraction of the mandibular
symphysis. In 1990, he reported the results of intraoral
mandibular widening on eleven patients with transverse
deficiencies ranging from 4 to 7 mm .He used the same principles
that Bell and Epker described for palatal expansion of the maxilla
.After a vertical symphyseal osteotomy, a custom made Hyrax
appliance was placed and initially activated 48 hours after
surgery. Depending upon the resistance of the soft tissues, 2 to 4
activations were applied per day to achieve the desired
expansion. Upon the completion of distraction, acrylic was flowed
around the distraction appliance in order to stabilize andwww.indiandentalacademy.com

In 1994, McCarthy and co-workers developed a miniaturized bone-
borne Uniguide™ Mandibular Distraction Device suitable for
intraoral placement .Similar to his extraoral appliance, the device
consisted of two clamps that were attached to the bone via pairs of
pins connected by a telescopic distraction rod.

At the same time, Wangerin in Germany designed a similar appliance
– the Intraoral Titanium Mandibular Distraction Device. The device
consists of two mini plates for bone fixation connected by a square-
shaped distraction cylinder.

•ROD™ Distraction Appliances - Oral Osteodi
.
•Intraoral Titanium Mandibular Distraction Dev
•LEAD™ (Leibinger Endosseous Alveolar Disc

•MID (Modular Internal Distraction) System - Stryke
•The Intraoral Distractor - Stryker Leibinger
Dynaform™ Intraoral Distraction System - Stryker

Procedures
• Mandibular Distraction
– Extra-oral
– Intra-oral
• Maxillary Distraction
– Extra-oral
– Intra-oral
• Alveolar Distraction
• Distraction Of The Periodontal Ligament

Mandibular Distraction Procedure
Make an incision along the external oblique ridge similar to that of a sagittal split
osteotomy. Raise a full-thickness flap, separating the muscle from the overlying
periosteum. Identify the area of bone deficiency. Identify and mark the area of
preplanned mandibular osteotomy. Using a percutaneous approach, drill 1.5mm
bicortical holes 6mm to either side of the planned osteotomy site. Make a second pin
site 4mm to either side of the first pin site. Consequently, you need a minimum of 20mm
of bone stock for pin placement.
Prepare the osteotomy by making full thickness drill holes along the osteotomy site via
an intraoral approach. Then connect the holes with a reciprocating saw. Complete and
verify the osteotomy with an osteotome. Next introduce the 2.0mm pins (35-60mm
length) into the previously made pin hole sites. Apply the distraction device. Then
stabilize on a trial basis. Remove and complete the osteotomy on the lingual cortex and
reapply distraction device. Irrigate the wound and close it with 4-0 cat gut suture.
Beginning on the fifth to seventh post-operative day activate the distraction device
(1mm per day). Expand the mandible until the pogonion is past midline and a posterior
open bite is created. After expansion, leave the distractor in place for six to eight
weeks, until radiographic evidence of mineralization is seen. Then remove the
distractor as an in-office procedure.

To move a Rider:
Loosen the fixation screw ("F") by turning the screw turn counter-clockwise using
the provided screwdriver.
Using the screwdriver, turn the advancement screw ("M") to move the rider in the
desired direction.
The distance the rider is moved is indicated by the scale (marked in 1mm
increments) etched on the geared rod.
Once the desired position of the rider is reached, the rider must be stabilized by
tightening the fixation screw ("F"). This is done by turning the screw clockwise.
Because the distraction process will be carried out primarily by home-caregivers
(relatives or friends of the patient), the fixation and advancement screws are clearly
marked with the letters "F" and "M", respectively.

Maxillary Distraction Procedure
Maxillary Distraction procedures deliver
traction forces through the dentition to the
maxillary bone. To apply traction through the
dentition a rigid intraoral splint is required.
The Intraoral Splint:
Orthodontic bands with 0.050inch headgear
tubes are fitted either on first permanent molars
or second primary molars(below 6yrs). The
splint is made with 0.045/0.050 SS rigid wire.

Transpalatal bars can also be used to enhance
rigidity.The splint is fitted and two markings are
made on the labial wire medial to both
commisures. Two straight pieces of 0.050 SS wire
are soldered perpendicular to the labial wire.
The long ends of these wires are bent under,over
and anterior to the lips in a circle to eliminate
sharp ends as well as have a rigid eyelet to apply
traction. The traction eyelet is at the level of the
nasal floor and its purpose is, to control the
direction of traction forces relative to the
approximate center of resistance of the maxilla
and also to avoid irritation to the lip.www.indiandentalacademy.com

The splint is cemented and during surgery circumdental wires
are used to increase rigidity and stabilty. The splint can also be
made with a orthodontic headgear facebow. In cases where the
arch is to be surgically created the splint is cemented after the
osteotomy .
The Osteotomy:
A complete Le Fort 1 osteotomy including pterygomaxillary and
septal dysjunction is performed. Metallic markers are placed
above and below the osteotomy, and in the anterior aspect of th
maxilla for follow-up. In young children a modified high Le
Fort 1 osteotomy with minimum downfracturing is performed t
avoid disturbing developing tooth buds and prevent an anterior
open bite or elongation of the lower face. Advancements at the
Le Fort 11, 111, monobloc and fronto-orbital levels are a few
recent modifications. www.indiandentalacademy.com

The RED Device :
After completion of the osteotomy, the halo portion of
the RED device is adjusted and rigidly fixed around
the head with scalp screws. A vertical bar was
connected to the halo and a horizontal bar with the
distraction screws. The traction hook and traction
screws were connected with a 25guage surgical
wire. Distraction was done at the rate of 1mm(2
turns) per day. The RED was left in place 2 to
3weeks after distraction to permit bone
consolidation. Traction was continued with one or
two 6 oz elastics on each side through a facemask.
Retention period -6 to 8 weeks.www.indiandentalacademy.com

Alveolar Distraction
Alveolar deformities and defects may result from a variety of
pathological processes including 1) developmental anomalies, such as
cleft palate and congenital tooth absence, 2) maxillofacial trauma,
which often involves damage to the teeth and associated jaw
structures, and 3) periodontal disease leading to bone and tooth loss
from the alveolar process. These deformities may be managed by a
variety of surgical techniques, such as autogenous onlay bone
grafting, alloplastic augmentation, connective tissue grafting, guided
tissue regeneration or non-surgical techniques such as facilitation of
supraeruption in periodontally compromised alveolar ridges.

In 1996, Chin and Toth reported the first application of vertical
mandibular alveolar distraction osteogenesis in a 17-year-old girl.
The patient presented with compromised width and height of the
residual alveolus due to trauma 3 years previously .A segment of
alveolus was osteotomized and distracted vertically after a 5 day
latency period at a rate of 1 mm per day for 9 days. The site was
reentered after 6 weeks and osseointegrated implants were placed
into the reconstructed alveolus.

Distraction Of The Periodontal
Ligament(Dental Distraction)
To achieve rapid canine retraction in 3 weeks, the
first premolar was extracted and the interseptal
bone distal to the canine was undermined, grooving
vertically inside the socket with a bone bur. Then,
an intraoral distraction device was placed to
distract the canine distally, with an activation of 0.5
to 1.0 mm/day. The anchor units were, second
premolar and first molar. The canines were bodily
distracted 6.5 mm into the extraction space in 3
weeks . Anchor loss was nil in 73% and 0.5 mm in
27% of the cases.www.indiandentalacademy.com

Results
The results were analyzed based on 3 cephalometric
measurements: SNPog, CoPog, NMe.
•S: Sella turcica's center
•N: Nasion (frontonasal suture)
•Pog: Pogonion (most anterior median point on mandibular
simphysis)
•Me: Chin (lowest point in manbibular simphysis)
•Co: Condylion (highest and most posterior point of mandibular
condyle)
The patients were evaluated with pre and postoperative
cephalograms by means of lower face proportions. The results of
these analysis are showed in the following table.

Cases Time SNPog CoPog NMe
n0
1
Preoperative
Postoperative
Postoperative
-
4 months
8 months
63º
70º
70º
83
97
97
119
117
117
n0
2
Preoperative
Postoperative
Postoperative*
-
4 months
10 months
69º
70º
78º
94
99
121
116
121
119
n0
3
Preoperative
Postoperative
Postoperative*
-
2 months
9 months
61º
69º
72º
77
86
88
108
115
108
n0
4
Preoperative
Postoperative
Postoperative*
-
4 months
9 months
80º
81º
83º
105
111
116
105
111
114
n0
5
Preoperative
Postoperative
Postoperative
-
2 months
7 months
74º
76º
76º
100
119
119
138
134
134

Future Of Distraction Osteogenesis
• Development of osteotomy techniques that
allow division of bone without disruption of
periosteum, endosteum,neurovascular
bundle & blood supply.
• Development of an ideal distraction device
with the capability of simultaneous linear &
angular adjustments.
• Motorized distraction units with remote
activation & monitoring for precise
dimensional control and calibration of
distraction forces.www.indiandentalacademy.com

Future (Contd…)
• Amplification of distraction degenerates by
addition of growth factors (rhBMP-2 or
recombinant human Bone Morphogenetic
Protein-2) & Cytokines to the reparative
and formative cells in the distraction gap.
• Use of bioresorbable materials such as
Lactosorb(a copolymer of poly-l-lactic
acid-82% & poly glycolic acid-18% ).These
are comparable in strength to Titanium
plating and completely resorb within a
year. www.indiandentalacademy.com

Implants Screwswww.indiandentalacademy.com

Conclusion
Distraction Osteogenesis has taken many different forms and
has evolved into its own super-speciality of orthognathic
treatment for various congenital and post-traumatic
incidences of mandibular and maxillary fracture and
deformity.
The various devices and techniques presented show promising
advances in the treatment of complex clinical problems like
cleft lip and palate, maxillary and mandibular dysplasias and
fractures of the maxilla and the mandible.

Distraction osteogenesis (6)

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Distraction osteogenesis (6)

Similar to Distraction osteogenesis (6) (20)

More from Indian dental academy

More from Indian dental academy (20)

Recently uploaded

Recently uploaded (20)

Distraction osteogenesis (6)