1) The document discusses principles of osteosynthesis and various fixation techniques used in maxillofacial trauma surgery. It describes key developments in plate design including dynamic compression plates and eccentric dynamic compression plates. 2) Different types of plates are discussed including compression plates, reconstruction plates, and tension bands. The goal of compression plates is to achieve stability through compression across fractures, while reconstruction plates are used to bridge larger defects. 3) Techniques for plate fixation including screw sequencing, compression, and tension band application are outlined. Factors such as plate selection and positioning are considered based on fracture pattern and bone quality.

1. GOOD MORNING…
1

2. PRINCIPLES OF OSTEOSYNTHESIS
PRESENTED BY,
DR. BHAVIK MIYANI,
3RD YEAR PG,
DEPARTMENT OF OMFS.
GUIDED BY,
DEPARTMENT OF OMFS,
NPDCH, VISNAGAR.
2

3. • Key (1932) - Positive pressure to bone segments
• Danis - first true compression plate in 1947.
• Bagby - first self-compressing plate
• The use compression plate in treatment mand. fractures was advocated by
Luhr & later popularized by Spiessl using the AO/ASIF
• Michelet et al & Champy et al advocated the evolution of plate fixation by
developing smaller & functionally adapted plating systems
• Biomechanics of fracture healing - described by Pawels in 1940 & Bohler
in 1941 3
HISTORY

4. • Disuse atrophy of the muscles
• Decrease in muscle fiber diameter
• Decreased Vascularity
MUSCLES
• Disuse Osteoporosis
• Decreased mineral content
• Decreased cortical thickness and trabecular
bone
• Hypercapnic and hypoxic nutrient veins with
low Ph
BONE
• Capsular and pericapsular tissue contraction
• Synovial hyperplasia
• Fatty tissue proliferation into the joint space
• Thinning and necrosis of the articular cartilage
TMJ
EFFECT OF IMF
4

5. BIOMECHANICS
• MANDIBULAR FRACTURES
• Simple beam mechanics
• Class III lever
• LOADED CANTILEVER BEAM
Tensile forces : Upper surface
Compressive forces : Lower surface.
Line of zero stress - Neutral axis.
5

6. In the loaded mandible:
Tension: At the level of the alveolus.
Compression : At the inferior border.
Neutral axis: Approximately at the level of the inferior alveolar canal.
6

7. Reversal of the tension-compression zones
• If the bite force is applied posterior to the fracture
line or muscular axis.
• Bite force is applied just anterior to the fracture if
the activity of the contra lateral muscular sling
predominates
7

8. Mid facial Fractures
• Do not have significant muscle forces acting on them.
• Tensile forces greatest at the fronto-zygomatic suture and it is the
strongest pillar of the zygomatic complex, it is the most important
point of fixation.
• Best site of fixation to oppose the direction and force of the
masseter muscle is the zygomaticomaxillary buttress.
8

9. 9

10. Basic biomechanics
• Strength of repair must be adequate to overcome
any forces that will act on the repaired bone
during function
10

11. BASIC BIOMECHANICS
NO FORCES ACTING
MINIMAL FIXATION
11

12. BASIC BIOMECHANICS
FORCES ACTING
ADEQUATE FIXATION TO
OVERCOME FORCES
12

13. Forces and requirements
13

14. AREAS FORCES REPAIR TECHNIQUE
FRONTAL/CRANIAL MINIMAL WIRES
MICROPLATES
3-D PLATES MICROPLATES
MINIPLATES
ZYGOMATIC TRIPOD MODERATE
(ROTATIONAL)
MINICOMPRESSION PLATES
MINIPLATE
3-D MICROPLATE
ZYGOMATIC ARCH MODERATE
(MASSETERIC PULL)
WIRES
MICROPLATES
INFRAORBITAL RIM MINIMAL WIRES
MICROPLATES
LEFORT I, II BUTTRESSES MODERATE
(COMPRESSIVE)
MINIPLATE
3-D MICROPLATE(8 HOLE)
BONE GRAFT WITH LAG
SCREW
ANTERIOR MAXILLA MINIMAL WIRES
MICROPLATES
MANDIBLE MAXIMAL
(TORSIONAL,DISTRACTING,
COMPRESSIVE)
MINIPLATES
3-D MINIPLATES
RECON PLATES
NOSE
NASOETHMOID
MINIMAL WIRES
MICROPLATES
MINIPLATES
14

15. Rigid fixation
“Any form of fixation applied directly to the
bones which is strong enough to prevent inter-
fragmentary motion across the fracture when
actively using the skeletal structure”.
15

16. • Healing by primary intention i.e. Haversian
remodeling
• 3 basic requisites
– Anatomic reduction
– Stable fixation
– Vascularity of both the fragments
16

17. 17

18. Non-rigid fixation
“ Any form of bone fixation that is not strong
(rigid) enough to prevent inter-fragmentary
motion across the fracture when actively
using the skeletal structure”.
18

19. Non-rigid fixation
19

20. “Functionally-stable fixation”
Edward Ellis. JOMS 1996;54(7):864-871
20

21. Functionally-stable fixation
“Forms of non-rigid fixation that are
strong enough to allow active use of the
skeleton during the healing phase but not of
sufficient strength to prevent inter-fragmentary
mobility”.
21

22. • Most of the fixation techniques used in max.fac.
surgery are of functionally stable type.
E.g. Single mini-plate across angle fracture
22

23. ARMAMENTARIUM
PLATES & SCREWS
ANCILLARY EQUIPMENT
23

24. Reduction forceps
24

25. Reduction / compression pliers
25

26. Drill bits and drill guides
26

27. Taps
27

28. Screw holders and drivers
Screwdriver equipped with sleeve to allow screw placement
with one hand
Holding sleeve
Self retaining
28

29. Depth gauges
29

30. Plate benders
30

31. Other Ancillary Equipment
• Plate cutter
• Template
31

32. Basic screw design
Size and shape of screw head
Length and diameter of the screw
Pitch and width of the threads
Presence/absence of flutes
32

33. SCREWS
SELF TAPPING
NON TAPPING
TITANIUM
STAINLESS STEEL
LAG SCREWS
MONOCORTICAL
BICORTICAL
33

34. Types of slots
• Hexagonal
• Cruciate
• Single
• Phillips
Phillips slot : Highest axial pressure
Hexagonal slot: Low axial pressure
Cruciate slot: Low axial pressure
Low risk of stripping
34

35. EMERGENCY SCREW
• Used in cases when a initial screw stripped the bony cortex
during insertion.
• Screw with head and shaft that are the same as those of the
previous but has wider thread
• Inner/core diameter is equal to the outer diameter of a regular
screw that was initially inserted.
• Always self-tapping
• If this also strips leave hole empty
35

36. PLATES
METALLIC NON METALLIC
RESORBABLE NON RESORBABLE
COMPRESSION NON COMPRESSION
DCP MINI PLATES
EDCP MICRO PLATES
RECON PLATES MATRIX PLATES
36

37. Basic principles of rigid fixation
• A screw of proper strength and design
• A properly designed and positioned rigid plate when fixed with
screws to bone
• Devices can be fixed to fractured & osteotomized bones so that
bones remain fixed together despite full loading in function
• If fixation device is strong enough with adequate fixation points ,
a bone defect can be bridged so that remaining segments can
support a functional load
37

38. Technique of screw insertion
a. Drilling of the pilot hole with a
drill corresponding to the core
diameter of the screw
b. The length of the hole in the bone
is measured with a depth gauze
either thru the plate hole or after
countersinking
c. Tapping thru a tissue protector
d. Placement of screw thereafter
38

39. Screw Insertion Methods
1. Manual Tap
39

40. 2. Self Tapping Drill
40

41. Osteosynthesis Techniques
 For optimum success, it is essential that these are
meticulously adhered to.
 Essential that particular attention be paid to careful
drilling and screw insertion.
41

42. Drilling
Successful osteosynthesis depends on the quality of the holes drilled
into the bone to take the screws. Careful and accurate drilling is
therefore a top priority. Though the hole need not be exactly
perpendicular to the plate surface, it must be stricly monoaxial.
After drilling 3 – 4mm deep into healthy bone, a decrease in resistance
will be felt, indicating that the cancellous bone layer has been
reached. Stop drilling. 42

43. Drilling
Any change in the drilling angle during the drilling procedure will invariably result
in a conical hole and thus reduce the number of threads finding adequate
purchase in the bone.
During the entire drilling procedure, provide continuous irrigation to avoid
thermal necrosis.
43

44. Screw Tightening
When tightening the screw in the bone, care must be
taken to not use too much force to avoid destruction of
the bone threads.
Each plate must be anchored by at least 2 screws on
either side of the fracture site. 44

45. Screw Anchorage
Should the screw anchorage in the outer
cortex be suspect, the drilling should be
continued though the inner cortex and a
longer screw inserted for bicortical fixation.
45

46. AO/ASIF FOUNDATION
(Arbeitsgemeinschaft fur Osteosynthesefragen)
46

47. AO/ASIF (1950s)
GOALS: RIF with primary bone healing even
under functional loading
4 basic principles for management of #s
1. Accurate anatomic reduction
2. Atraumatic operative technique preserving the vitality of bone
and soft tissues.
3. Rigid internal fixation that produces a mechanically stable
skeletal unit.
4. Avoidance of soft tissue damage and “fracture disease” by
allowing early, active, pain-free mobilization of the skeletal unit
47

48. AO/ASIF (1994)
Need for rigid internal fixation
Functionally stable fixation
48

49. How much fixation is enough???
MAXILLA
• Adaptation osteosynthesis
MANDILE
• Various tech. used
• Selection of fixation scheme is
based on
– Type of #
– Surgical approach
– Amount of soft t. dissection
necessary for exposure of # and
fixation
49

50. Load bearing v/s Load sharing
• Load-bearing fixation is a device that is of
sufficient strength and rigidity that can bear
the entire load applied to the mandible during
functional activities.
50

51. • Indications:
 Comminuted #’s
 #’s of atrophic mandible with
minimum bone contact
 #’s with associated loss of
bone fragment(defect #)
Also called as “Bridging fixation”
Reconstruction plate
51

52. Load sharing
• Load-sharing fixation is
any form of internal
fixation that is of
insufficient strength to
bear all of the functional
loads applied across the
fracture by the
masticatory system.
Miniplating system
Lag screw techniques are also load sharing 52

53. One point V/S two point fixation
Byung Ho Choi, Kyoung Nam Kim
Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1995;79:692-
695.
Dichard A and Klotch DW, Laryngoscope 1994;104:201-208.
53

54. MORE STABLE
MORE STABLE
54

55. Extremely atrophic mandibles it is not possible to fix
two plates far apart from each other
55

56. VARIOUS FIXATION METHODS
56

57. Compression Osteosynthesis:
 Goal is “Absolute stability”
 Enhances the likelihood of
successful primary bone
healing.
 Helps to stabilize the fracture,
minimizing complication such
as osteomyelitis and non-
union.
 300 kilopascals /cm2
57

58. • primary bone healing in two ways.
1. preload, which is the force generated across the
fracture by the fixation system.
2. friction produced by compression of the fractured bone
segments.
“Spherical gliding principle”
58

59. Ideal site for fixation
• Region of maximal tension caused by
muscular pull, which is the superior border of
mandible.
• The plate only be inserted at the lower or
inferior border is capable of providing
compression to the bone fragments, but fails to
control the tensile forces at the alveolar
process.
59

60. Compression plates
DCP EDCP
60

61. DYNAMIC COMPRESSION PLATES
• 1977, Luhr
• Spiessl was the first to apply the AO/ ASIF
principles to the management of mandibular
fractures
• Design- based on a screw head that, when tightened,
slides down on an inclined plane within the plate
61

62. • Two types of screws are used :
• Compression screw
• Static or passive screw
 For the plate to be a dynamic compression plate one compression
hole should be located in each fragment of the fracture;
 These holes are usually placed most proximal to the line of fracture.
 Because the screw movements produced from the inclined planes of
these holes oppose each other, the fracture ends will move toward
one another relative to the plate
62

63. 63

64. Dynamic Compression Plates
• Design - Screw Head slides down an inclined
plane in the plate
64

65. • Pretension across the fracture is achieved with the use of a bone
forceps
• Adapt the plate to fit passively over the fracture
• Adapting the plate to the buccal cortex of the mandible, the plate
must be over bent by about 1 mm.
• AO/ ASIF plating system, each compression hole will produce 0.8
mm of bone movement.
• Compression is used on both sides of the fracture - a total of 1.6 mm
of bone movement may be achieved
65

66. • At least two screws are necessary on each side of the fracture to
eliminate rotational movements of the plate
• Positional screws are placed passively in the outer holes after the
compression screws have been activated in the holes adjacent to the
fracture
• the holes for the screws are made with the appropriate-sized drill
• screws not self-tapping , a drill guide used
66

67. 67

68. • the screws must be inserted in a specific sequence.
 If compression across the fracture desired, these two
holes are drilled first
 plate is held in position with an instrument while the
first hole is drilled in the compression, or active,
portion of the hole.
68

69. 69

70. • Activation of a DCP at
the inferior portion of the
mandible - result in
distraction of the superior
border of the mandible
during function
• To neutralize this gap
formation at the alveolus,
the tension band was
introduced.
70

71. Tension Band
• Prevents tensile forces from acting at the alveolus - minimizing
distraction at the superior aspect of the fracture.
• Tension band may take the form of a small mini or micro plate, arch
bar, wire ligature.
71

72. Eccentric Dynamic Compression Plate (EDCP)
• 1973,Schmoker, Niederdellman and Schilli
developed
• Provides simultaneous compression across the #
and at the superior border of the # segment.
72

73. • Goal of the EDCP
• 1st establish longitudinal compression across the fracture at
the inferior border
• 2nd to rotate the fragments around these screws to achieve
additional compression at the level of the alveolus
73

74. • Design of this plate is similar
to the DCP
• Plate also contains two
oblique outer compression
holes (Eccentric compression
holes)
• Aligned at an angle oblique
to the long axis of the plate.
• Activation of these outer holes produces a rotational
movement of the fracture segments compression at the
superior border of the mandible 74

75. • Screws are placed in the holes
closest to the fracture margin
first (inner holes)
• Then placed in the outer aspect
of the screw slot in eccentric
position
• If a six-hole plate is used,
screws are then placed in the
remaining holes in a passive
fashion
TECHNIQUE
75

76. Where Compression plates are
contraindicated….
• Severely oblique fractures,
• Comminuted fractures
• Fractures with bone loss
• Bone pathology
• Young children – unerupted teeth
76

77. Reconstruction Plates REUTHER(1975)
• Larger overall dimensions than
compression plates, resulting in
increased strength
• Reconstruction plate can be
contoured in three dimensions
whereas compression plates can
be bent in only two dimensions
77

78. • Indications:
1. Alloplastic bridging of mandibular defect following tumor
ablation
2. Reduction of highly comminuted mandibular fracture as in
shotgun wounds
3. Rigid fixation of bone grafts
 Plates curved/straight
 2 neutral and 2 compression holes on each sides
78

79. Technical considerations:
• Bicortical fixation
• Plates to be contoured exactly to the defect to be bridged
• At least three screws be placed in each of the fractured segments
• If an osseous gap is being bridged, it is suggested that at least
four screws be placed in each segment
• Major disadvantage is buccal and lingual cortical resorption seen
in almost 50% cases.
79

80. 80

81. Locking plates
• Plates function as “internal fixators”.
• Plates are designed with threaded holes through which screw pass.
• Provides 2 separate points of fixation for the screw.
• Screw lock to the plate independent of bone.
Advantages:
• Precise adaptation of plate to bone is not necessary.
• More viable periosteum to aid in # healing.
• Screws are unlikely to loosen from the bone.
• Decreased incidence of inflammatory complications.
• Greater amount of stability.
81

82. LOCKING PLATES Vs CONVENTIONAL
82

83. Titanium Hollow Screw Osteointegrated
Reconstruction Plate (THORP)
Raveh et.al
Indication : Complex # of mandible
Reducing postablation mandibular defect
Bridge large defects
Stabilize bone grafts
Post-traumatic continuity defects.
83

84. THORP screws
Unique design
2 Basic types
Designed with small thread.
Equipped with lateral perforations, coated with argon
84

85. • The anchor screws in the THORP system actually osteointegrate
and become more stable over time
• THORP system is designed to avoid pressure on the bone.
• The THORP uses friction created between the screw and the hole in
the plate to stabilize the plate and fracture
• Advantages / Disadvantages :
85

86. MONOCORTICAL MINIPLATE
OSTEOSYNTHESIS
• Michelet and et.al (late 1960’s , 1973)
• Goal : To provide stable mandibular fracture reduction
without requiring interfragmentary compression or
Maxillomandibular fixation
• Studies have demonstrated that the miniplates achieves this
goal by neutralizing undesirable tensile forces and
retaining favorable compressive forces during function.
86

87. • Advantages :
• Disadvantages:
• Avoided in highly comminuted # or those in which delayed
healing in expected.
• Available in variety of sizes and configuration.
• This technique is the one which is most widely used
nowadays
87

88. OSTEOSYNTHESIS LINES: Champy’s
88

89. • Screws – almost all are self tapping
self drilling( some)
• Bicortical screws can be used at the inferior border
• A minimum of two screws should be placed in each
osseous segment.
• Angle of mandible – superior aspect of mandible onto
broad surface of external oblique ridge
• Between mental foramina – two plates
• Body –one plate used ,below apices but above canal
89

90. MANDIBULAR ANGLE # MIDFACE #
SYMPHYSIS / PARASYMPHYSIS #
90

91. MICROPLATE FIXATION
Why needed????? 91

92. Microscrews and microplates with penny for size comparison.
92

93. Areas with minimal overlying soft tissue
Smaller incisions - aesthetically sensitive areas of the face
Usually made of Vitallium
Preferred site : midfacial #( except zyg.buttress)
NOE #
# of infraorbital area & frontosinus wall
skull reconstruction
glabellar region
Preferred in infants and small children
93

94. Advantages
Smaller incisions and less soft tissue dissection
Placed intra orally, thereby avoiding an external
scar
less likely to be palpable
decrease the degree of stress shielding
minimal risk of dental injury
Reduced risk of neurovascular injury
94

95. • Disadvantages
Not as rigid as the standard mandibular fracture
plates torsional movements infection or
nonunion, or both.
95

96. Holding power of screw???
96

97. • The holding power of microscrew and miniscrew is
similar due to presence of more threads in a given
surface area of bone in microscrew as compared to
miniscrew due to smaller thread pitch
Mitchell DA IJOMS;1995:24:151
Bahr et al J.Cr.Maxfac.Surg.1992:22:87
97

98. LAG SCREW OSTEOSYNTHESIS
• Developed by the AO/ ASIF group
• Used alone if the fracture is sufficiently oblique to allow the
placement of at least two screws
98

99. True Lag screw, has threads in the distal end ,
smooth shank at the proximal end (i.e.,
adjacent to the screw head)
Conventional screw True lag screw
99

100. To achieve this…….
• oversized hole (gliding hole) is
drilled through the proximal
cortex. The diameter of this hole
must be at least as large as the
thread diameter of the
screw(gliding hole)
• The remainder of the hole (in the
distal segment) must be smaller
than the thread diameter - traction
hole.
• COUNTERSINKING
Can conventional screw be used as lag screw????
GLIDING HOLE
100

101. • When the screw is tightened, the distal fragment is pulled into
compression against the proximal fragment by the screw head.
• This compression creates friction, thus reducing the amount of
interfragmentary movement
101

102. • Cancellous bone lag screws should not be used as they
have tendency to fracture maxillary bone.
• When properly used, lag screw fixation offers the most
rigidity of all rigid fixation techniques.
• It is possible to achieve between 2000 and 4000N of
compression compared to 600 N with prebent
compression plates
102

103. Ideal angle
103

104. LAG SCREW Vs BONE PLATES
• Uses less hardware, thus making it cost effective.
• Quicker and Easier.
• Reduction more accurate.
104

105. 3-D bone plates Farmand (1995).
Offers great stability in both horizontal and vertical dimensions.
In mandible: capable of countering both distractive and torsional forces
(esp. in body region).
Midface , upper cranial vault, orbital floor
Used for RF of heavily comminuted fractures of almost every part of
Craniomaxillofacial skeleton 105

106. • Cranial growth restriction Yaremchuk, 1994
• Intracranial implant migration Fearon et al 995, Goldberg et al 1995, Honig
et al 1995, Yu et al 1996
• Implant palpability, temperature sensitivity & even
visibility in thin skin areas Orringer et al 1998
• Imaging & radiotherapy interference Sullivan et al 1994, Castillo 1988
Problems with Metal plates
106

107. • Too stiff for optimal healing in some surgical
applications - stress shielding may result in bone
atrophy and porosis .
Uhthoff 1983, 1994, Kennady 1989
• Accumulation of metals in tissues Rosenberg et al 1993, Schliephake
et al 1993, Katou et al 1996, Jorgenson et al 1997, Kim et al 1997
• Adverse effects of metals can necessitate removal
operation
107

108. Bioresorbable plates :
108

109. BIORESORBABLE PLATES
• 1st reported by Cutright et.al
• This material resorb gradually enough to allow the
fracture to heal but rapidly to prevent plate-induced
osteoporosis.
• Polydioxanone (PDS), Polyglycolic acid, and Polylactic
acid. (tolerated well but strength less)
109

110. 110

111. • To increase the strength SR-PGA & SR-PLA
i.e. self reinforced Polyglycolic acid and lactic
acid.
111

112. Strength????
• Bouwmen et al, yield strength of SR-PGA( Biofix )
is half of that of bicortical titanium screw but twice
as that of Champy’s monocortical miniplate
fixation.
IJOMS;1994:23:46
• Surronen et al shear strength of SR-PLA screws is
173 MPA which is 20-30 times more than that
of cancellous bone.
112

113. Advantages
• No second surgery required
for implant removal
• No long term implant
palpability or temperature
sensitivity
• Non-metallic
• Predictable degradation to
provide progressive bone
loading & no stress shielding
• Implants supplied sterile
✔ Reduced patient trauma & cost
✔ Patient satisfaction
✔ No imaging interference
✔ Improved chance of bone
healing
✔ Reduced cross infection
potential
113

114. Disadvantages
• Inflammation
• Foreign body reaction
• Peri-implant effusion
• Osteolytic changes
• Non-specific lymphocyte activation
• Sterile fluid accumulation.
114

115. • 82L-lactide- 18- Glycolide ( Lactosorb ) most
commonly used
• Common problem : Resorption time????
• Solution :
• Lower Lactide : Glycolide ratio reduces amount of
time needed for plate resorption.
115

116. Resorption of PLA or PGA ? ? ?
 Surronen et.al found that after 24 weeks in vivo, plates exhibited
more than half their initial strength properties.
JOMS 50:255.1992
 Slayer et.al found resorption rate of the material to be
approx.5.3µm per day. Plast Reconstr Surg 93:705,1994
116

117. PGA URINE
PLA
Glycolic acid
Glycine
Serine lactic acid
pyruvate
cyclic acid cycle
H2O and CO2
Citric acid
cycle
J.bone joint surg;1991:73B;679
Stage 1 – Hydrolysis
Stage 2 – Metabolization
Stage 3 - Excretion
117

118. CT : Streaking or Sunburst artifact
 S.S. and Vitallium produces max. artifacts than Titanium
Fiala TGS et.al Plast Reconstr Surg 92:1227,1993
EFFECTS ON IMAGING
VITALLIUM TITANIUM
118

119. MRI : oblong dark gray or black shadow that can obscure
or distort adjacent structure.
 Stainless Steel > Vitallium > Titanium
Fiala TGS et.al Plast Reconstr Surg 93:725,1994
 Plate deflection and Heat generation during MRI
Kanal et al & Laakman et al J.Radiology 1985 & 1990
Resorbable plate is associated with minimum distortion of
image on CT and MRI 119

120. 120

121. 121

122. • METAL SENSITIVITY
 Components of stainless steel:-Allergic response
 Vitallium
Symptoms : Generally localized to implant area
Eczema, erythema and vesicles
Usually occur 3 to 6 months after placement.
• INFECTION ( 3 to 27%)
 Technical errors
 Other factors
122

123. • SCREW FAILURE
 Causes
• Indicator for screw failure : - Fracture mobility
- Infection
• PLATE FRACTURE 0-10%
Causes – Surgeon error - improper size of plate
- Excessive bending of plates
- Metal failure.
• STRESS SHIELDING
• A potential complication of RIF is the possibility that plates will absorb
the functional stress on the bone, resulting in a disuse osteoporosis
termed as stress shielding.
• Protection from stress occurs if the RIF system has higher modulus of
elasticity than the bone. 123

124. • SENSORY NERVE INJURY 0.9%- 46.6%
• Cause: overzealous retraction
• MOTOR NERVE INJURY
• RESTRICTION TO CRANIOFACIAL GROWTH
• HYPERTROPHIC SCAR FORMATION
• INJURY TO ROOTS
• NONUNION, MALUNION AND MALOCCLUSION
• Malunion 3.6 to 14% Nonunion 1-3%
Causes
• Poor plate bending,
• Loosening of screws
• Poor intra op reduction
•Infection sole reason
•Inadequate rigid fixation
•Trauma, compromise blood supply are
other factors.
•Radiographically 124

125. EFFECT OF RIF ON GROWTH
• Metallic plates restrict the growth of CF in infants
• Translocation rate is 10 – 14 %
• Wong et al - coronal suture study in white rabbits.
• Lin et al - study on kittens
• Laurenzo et al – RIF has significant effect on growth ,
soft tissue and bone injury on growth
125

126. Mistakes in application and tech.
• Insufficient reduction of # with incongruency of # surface
and interposition of soft tissue.
• Poor positioning of screw(nerve damage, root damage).
• Choice of inadequate hardware(too small, too weak).
• Compression in comminuted areas.
• Insufficient fixation of plate(too few screws).
• Screw in # gap
• Stripping of screw holes.
• Plate bending error.( gapping, torsion, increased
intercondylar distance)
126

127. Future….
• Minimally invasive techniques are currently
being utilized with endoscopic assistance.
• Absorbable technology
127

128. TAKE-HOME MESSAGE
• Rigid internal fixation, in terms of conceptualization and
application, is not as complicated as it seems. Nevertheless,
it stands to reason that the various forms of RIF that have
evolved in the past have never been completely amenable to
the complex functional demands of the masticatory system.
While some systems have gained wide acceptance, others
have resigned to historical date backs. But again, the ability
to adopt a particular mode of internal fixation- whether
rigid or semi-rigid, as dictated by the clinical situation, lies
in the perception, technical know-how and experience of
the operator.
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129. References
• Oral and maxillofacial trauma , Vol.2 – Fonseca R.J
• Manual of internal fixation in the craniofacial skeleton – J.Prein
• Craniomaxillofacial fractures – Alex M. Greenberg
• Maxillofacial surgery – Vol.1 – Peter ward booth
• Atlas of Craniomaxillofacial fixation – Robert M.Kellman
• Oral and maxillofacial surgery, Vol.1 – Peterson.
• OCNA facial plating - Vol.20, No.3, Aug. 1987
• Stability of orthognathic surgery: a review of rigid fixation BJOMS
1996
•
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