treatment modalities for angle fractures
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Int . J. Oral Maxi l loJhc. Surg. 1999; 28 :2 43 ~5 2
Printed f lz Denmark. Al l r ights reserved
Copyright 9 M unksg aard 1999
Intemadona]Joumal of
Oral r
M axil l@ cial Surgery
ISS N 090 t-5027
r e a t m e n t m e t h o d s f o r
f r a c t u r e s o f t h e m a n d i b u la r
a n g l e
e a d i n g a r t i c l e
d w a r d l l is
I I I
O ra l a n d Ma x i l l o fa c i a l S u rg ery Th e U n i ve r s i t y
o f T e x a s S o u t h w e s t e r n M e d i c a l C e n te r
Da l l a s Te xa s US A
E . E l l i s I I I . T r e a t m e n t me t h o d s f o r f r a c t u r e s o f t h e ma n d i b u l a r a n g le . I n t . J O r a l
Ma x i l l o f a c . S u r g . 1 9 9 9 , 2 8. " 2 4 3 ~ 5 2 . 9
M u n k s g a a r d , 1 9 9 9
A b s t r a c t . F r a c t u r e s o f th e m a n d i b u l a r a n g l e a r e p l a g u e d w i t h t h e h i g h e s t r a t e o f
c o m p l i c a t i o n o f a l l m a n d i b u l a r f r a c t u re s . O v e r t h e p a s t 1 0 y e a r s , v a r i o u s f o r m s
o f t r e a t m e n t f o r t h e se f r a c tu r e s w e r e p e r f o r m e d o n a n i n d i g e n t i n n e r c i t y
p o p u l a t i o n . T r e a t m e n t i n c l u d ed : 1 ) c l o s e d r e d u c t i o n o r i n t r a o r a l o p e n r e d u c t i o n
a n d n o n - r i g i d f i x a t i o n ; 2 ) e x t r a o r a l o p e n r e d u c t i o n a n d i n t e r n a l f i x a t i o n w i t h a n
A O / A S I F r e c o n s t r u c t i o n b o n e p l a t e ; 3) i n t r a o r a l o p e n r e d u c t i o n a n d i n t e r n a l
f i x a t i o n u s i n g a s o l i t a r y l a g sc r ew ; 4 ) i n t r a o r a l o p e n r e d u c t i o n a n d i n t e r n a l
f i x a t i o n u s i n g t w o 2 .0 m m m i n i - d y n a m i c c o m p r e s s i o n p l a t e s ; 5 ) i n t r a o r a l o p e n
r e d u c t i o n a n d i n t e r n a l f i x a t i o n u s i n g t w o 2 . 4 m m m a n d i b u l a r d y n a m i c
c o m p r e s s i o n p l a t es ; 6 ) i n t r a o r a l o p e n r e d u c t i o n a n d i n t e r n a l f i x a t io n u s i ng t w o
n o n - c o m p r e s s i o n m i n i p l a t e s ; 7 ) i n t r a o r a l o p e n r e d u c t i o n a n d i n t e r n a l f i x a t i o n
u s i n g a s in g l e n o n - c o m p r e s s i o n m i n i p l a t e ; a n d 8 ) i n t r a o r a l o p e n r e d u c t i o n a n d
i n t e r n a l f i x a t i o n u s i n g a s i n g le m a l l e a b l e n o n - c o m p r e s s i o n m i n i p l a t e. T h i s p a p e r
r e v ie w s th e r e s u l t s o f t ho s e m o d e s o f t r e a t m e n t w h e n u s e d f o r t h e s a m e p a t i e n t
p o p u l a t i o n a t o n e h o s p i t a l . R e s u lt s o f tr e a t m e n t s h o w t h a t , i n t h i s p a t i e n t
p o p u l a t i o n , t h e u s e o f e i t h e r a n e x t r a o r a l o p e n r e d u c t i o n a n d i n t e r n a l f i x a t i o n
w i t h t h e A O / A S I F r e c o n s t r u ct i o n p l a te o r i n t r a o r a l o p e n r e d u c t io n a n d i n t e r n a l
f ix a t io n , u s in g a s in g le m in ip la t e , a r e a s s o c ia t e d w i th th e f e w e s t c o m p l i c a t io n s .
K e y wo rd s : ma n d ib u la r fr a c tu re ; b o n e p l a te s ;
f r a c tu re f i xa t i o n
A cce p te d fo r p u b l i ca t i o n 2 4 Ja n u a ry 1 9 9 9
F r a c t u r e s o f th e m a n d i b u l a r a n g l e r ep -
r e s e n t t h e l a r g e s t p e r c e n t a g e o f m a n -
d i b u l a r f r a c t u r e s i n m a n y s t u d i e s . T h e
e t i o l o g y o f th e i n j u r y h a s s o m e t h i n g t o
d o w i t h t h e l o c a t i o n o f t h e m a n d i b l e
t h a t f r a c t u r e s . F r a c t u r e s s u s t a i n e d i n
a l t e r c a t i o n s s h o w a h i g h i n c i d e n c e o f
f r a c t u r e s o f t h e a n g l e o f t h e m a n -
d ib le 33 '4~176 The p rev a i l in g
t h o u g h t i s t h a t a b l o w t o t h e l a t e r a l
p o r t i o n o f t h e m a n d i b l e c a u s e s a f r a c -
t u r e a t t h a t p o i n t , a n d c o m m o n l y a
f r a c t u r e o n t h e o p p o s i t e b o d y / s y m p h y -
s i s r e g io n .
W h y i s th e a n g l e o f t h e m a n d i b l e
c o m m o n l y a s s o c i a t e d w i t h f r a c t u r e s ?
T h e r e a r e s e v e ra l p r o p o s e d r e a s o n s t h a t
in c lu d e : 1 ) t h e p re s e n c e o f t h i rd m o la r s ;
2 ) a t h i n n e r c r o s s - s e c t io n a l a r e a t h a n
t h e t o o t h - b e a r i n g r e g i o n ; a n d 3 ) b i o -
m e c h a n i c a l l y t h e a n g l e c a n b e c o n -
s id e re d a l e v e r a re a . S e v e ra l a u th o r s
h a v e i m p l i c a t e d t h e p r e s e n c e o f t h i r d
m o l a r s , e s p e c i a l l y i m p a c t e d t h i r d m o -
l a r s , a s a r e a s o n f o r m a n d i b u l a r f r a c -
t u r e s o c c u r r i n g i n t h e r e g i o n o f t h e
a n g le . I n f a c t, s o m e h a v e r e c o m m e n d e d
p r o p h y l a c t i c r e m o v a l o f t h i r d m o l a r s t o
e l im in a te th e i r w e a k e n in g e f f e c t i n th e
a n g l e r e g i o n , i n h o p e s o f p r e v e n t in g
fra ctu res fr om oc cu rr ing 1,2,39'61'64'68.
W h i l e t h i s s e e m s a n e x t r e m e s t a n c e o n
th e i s su e , t h e re i s s c i e n t if i c e v id e n c e in -
d i c a t i n g t h a t t h i r d m o l a r s d o w e a k e n
t h e a n g l e o f t h e j a w a n d a r e a s s o c i a t e d
w i t h f r a c t u r e s m o r e c o m m o n l y t h a n
w h e n n o t o o t h i s p r e s e n t. F o r i n s t an c e ,
a s tu d y b y R E IT Z lK e t a l . s3 fo u n d m o n -
k e y m a n d i b l e s w i t h u n e r u p t e d t h i r d
m o l a r s f r a c t u r e d a t 6 0 % o f t h e f o r c e re -
q u i r e d w h e n n o t o o t h w a s p r e s e n t, C l i n -
i c a l i n v e st i g a t i o n s h a v e s h o w n t h a t p a -
t i e n t s w i t h t h i r d m o l a r s p r e s e n t a r e
m o r e l i k e ly to s u s t a i n f r a c t u re s o f t h e
a n g l e t h a n w h e n n o t o o t h i s p r e s -
e n t s6 ,7 ~ F u r th e r , t h e a m o u n t o f s p a c e
o c c u p i e d b y t h e t h i r d m o l a r w a s f o u n d
to d i r e c t ly r e l a t e to w e a k n e s s in th a t r e -
g io n o f t h e m a n d ib le 56,
O n e w o u l d l o g i c a l l y e x p e c t f r a c tu r e s
t o o c c u r a t p o i n t s o f g r e a t e s t w e a k n e s s
i n a s t r u c t u r e . O n e w o u l d a l s o l o g i c a l l y
e x p e c t t h a t t h i n n e r c r o s s - s e c t i o n a l a r e a s
o f a s t r u c t u r e w o u l d b e w e a k e r t h a n
t h o s e a r e a s w i t h g r e a t e r c r o s s - s e ct i o n a l
a reas . A s tud y by SHVBERT e t a l . 63 has
s h o w n t h a t t h e r e g i o n o f th e m a n d i b u -
l a r a n g l e i s t h i n n e r t h a n b o t h t h e b o n e
o f t h e b o d y r e g i o n l o c a t e d m o r e a n t e r i -
o r ly , a n d t h e b o n e o f t h e r a m u s l o c a t e d
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l l i s
more posteriorly. Thus, a given force
applied to the lateral aspect of the man-
dible might be expected to fracture at
the region with the smallest cross-sec-
tional area the angle of the mandible.
Combine this with the fact that the
angle of the mandible is where there is
an abrupt change in shape from hori-
zontal to vertical rami, which would im-
ply that this region might be subjected
to more complex forces tha n a more lin-
ear geometric shape, and one can begin
to understand why fractures occur in
this location.
Fractures of the mandibular angle
represent an important clinical chal-
lenge because their treat ment is plagued
with the highest postsurgical compli-
cation rate of all mandibular frac-
tures 16,34,36,s9,72. Even traditional treat-
ment methods have a high complication
rate in some patient populations49.
With the introduction and popularity
of plate an d screw fixation over the past
30 years, a number of fixation methods
have been advocated for the treatment
of fractures occurring throug h the angle
of the mandible. Many of these tech-
niques are seemingly disparate. For in-
stance, the AO/ ASIF or iginally felt that
plate and screw fixation should provide
sufficient rigidity to the fragments to
prevent interfragmentary mobility dur-
ing active use of the mandible66,67.
LUItR42 similarly recommended large
bone plates, usually with compression,
fastened with bicortical bone screws to
provide such rigidity. Primary bone
union, which necessitates absolute im-
mobility of fragments, is the goal of
treatment of mandibular fractures by
these surgeons.
In 1973, MICHELET et al. 45 repor ted
on the treatment of mandibular frac-
tures using small, easily bendable non-
compression bone plates, placed trans-
orally, attached with monocortical
screws. The application of this tech-
nique was a seeming dichotomy to the
more widely accepted dictum of
r ig id
fixation, and sparked a revolu tion in the
trea tment of fac ial fractures. CHAMPY et
al.8 12 performed several investigations
with a minipla te system to validate
the technique, in their experiments,
they determin ed the ideal lines of os-
teosynthesis in the mandible, or the
locations where bone plate fixation
should provide the most stable means
of fixation. For fractures of the man-
dibular angle, the most effective plate
location was found to be along the su-
perior border of the mandible. Because
the bone plates were small and the
screws inserted monocortically, fixation
could be applied in this most mechanic-
ally advantageous area without damag-
ing teeth. Unlike the AO/ASIF sur-
geons and LUHR, absolute immo-
bilization of bone fragments and
primary bone union was deemed un-
necessary. Clinical studies since have
proven the usefulness of this tech-
nique7,24,26,27,29,31,47,51,73
Questions about the degree of sta-
bility provided by these mini-plate s
have become a point of contention
among surgeons. RAVEH et al. 52,
LUHR44 and AO/A SIF advocates 4 do
not feel that the plates offer adequate
stabilization of the fracture to e liminate
the need for i ntermax illary fixation.
Other surgeons who routinely used the
more rigid AO/AS IF plates began to re-
lent and use miniplates26'27.
Unfortunately, whether or not one
metho d is superior to anoth er is diffi-
cult to determine. Studies in the litera-
ture vary widely in the rates of compli-
cation reported when treating fractures
of the angle. Fo r instance , LUHR &
HAUSMANN 3 report a 0.9% rate of com-
plications in 352 patients treated by
compression plates for fractures of the
angle, whereas ELLIS & SINN 2 report a
32% rate of comp licatio n in 65 patients
treated with compression plates for
angle fractures. IIZUKA & L1NDQVIST 5
reported a 6.6% rate of infection and a
14% rate of malocclusion for 121 frac-
tures of the angle. Analysis in that study
showed that complication s were most re-
lated to the use of compression and two
points of fixation.
How can rates of complication be so
varied? There are several problems when
one attempts to compare treatment
methods for fractures of the mandibu lar
angle. The first difficulty is that there are
few studies that restrict their focus to
fractures of the mandibular angle. Most
studies evaluati ng results for mand ibu lar
fractures include fractures in all regions
of the mandi ble, maki ng it difficult to de-
termine the actual rate of complication
for angle fractures. Another problem is
that treatment in one country may be
very different from treatmen t in another.
For instance, patients treated for man-
dibular fractures in some of the Euro-
pean countries may spend 7 21 days in
hospital after surgery. In the United
States, they are usually discharged the
same or the next day. It is therefore
doubtful that the quality and quantity of
postsurgical care is similar. Studies also
vary in the etiology of the injury. Studies
from the United States generally have
samples drawn from large inner-city hos-
pitals where most of the injuries result
from interpersonal violence, in many
European, Middle Eastern and Asian
studies, motor vehicle-related injuries
are more common. Hand in hand with
the cause of the inj ury is the socioecon-
Omic status of the patients. Those in-
jured by interpersonal violence and
treated in major inn er-city hospitals in
the United States tend to be poor, with
poor oral hygiene and a poor state of
dentition. Those patients whose frac-
tures are sus tained in moto r vehicle acci-
dents, sports or in bicycle accidents tend
to be a higher socioeconomic group and
are more concerned with oral and gen-
eral health. There are also great differ-
ences in the literature in what constitutes
a complication . In countries where rout-
ing removal of fixation devices is com-
mon , soft tissue dehiscence with plate ex-
posure may not be counted as a compli-
cation because the plate will be removed
anyway. In the United States, where
plate removal is not routine, any un-
planned intervention should be con-
sidered a complication. Another major
variable is in the num ber of surgeons in-
volved in the operative interven tion. Be-
cause of these factors and a host of
others, it becomes difficult to accurately
assess treatment results with different
fixation techniques.
The following presents the experience
of one faculty surgeon treating fractures
of the mandibular angle at one insti-
tution, with a consistent patient popu-
lation, using eight different techniques.
While a number of residents were in-
volved in the surgeries, the same fac ulty
member (E.E.) was present for over
95% of the actual open p art of the oper-
ations.
Me t h o d s
Over the past 10 years, various methods of
treatment for fractures of the angle of the
mandible have been studied at Parkland
Memorial Hospital in Dallas, Texas. The con-
tinuing quest for a simple but effective tech-
nique drove us to use different modes of treat-
ment and to examine their efficacy. The fol-
lowing study rela tes our experience with
several accepted methods for treating frac-
tures of the mandibular angle19 2 5 4 9 5 1 . The
first two methods, closed reduction with or
without non-rigid fixation, and the use of the
AO/ASIF reconstruction plate, were retro-
spective studies. All others were prospective n
their data collection.With the exception of the
extraoral approach used in those patients
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T r e a t m e n t o f m a n d i b u l a r a n g l e f r a c t u re s
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t r e a te d w i th the AO/ASIF re c ons t ruc t ion
pla te , a l l techniques were intraora l , with the
e xc e pt ion of t r a ns fa c ia l t roc a r ins t rum e n-
ta t ion .
The pop ula t ion in the se s tudie s wa s l a rge ly
inne r -c i ty ind ige nt pa t i e n t s w i th poor de n-
t i t ions a nd poor ora l hygie ne . The m a jor i ty
of the c a se s oc c ur re d in m a le s ( a pproxim a te -
ly 85%) . The r a c ia l / e thnic bre a kdown wa s
a pproxim a te ly 50% Af r ic a n-Am e r ic a ns , 30%
N o n - H i s p a n i c C a u c a s i a n s , a n d 2 0 % H i s p a n -
ic . The a ve ra ge a ge of the pa t i e n t s wa s a p-
proxim a te ly 27 ye a r s , w i th the va s t m a jor i ty
in the th i rd a nd four th de c a de s of l if e. Ap-
proxim a te ly ha l f o f the a ngle f r a c ture s we re
i so la te d m a ndibula r f r a c ture s ; the o the r ha l f
ha ving a c ont ra la te ra l f r a c ture of the m a n-
dibula r c ondyle , a ngle , body or sym phys i s .
A l l pa t i e n t s ha d a rc h-ba r s a t t a c he d to the
d e n t i t io n d u r i n g s u r g e r y b u t n o n e o f t h e p a -
t i e n t s r e por te d be low we re p la c e d in to pos t -
surg ic a l in te rm a xi l l a ry f ixa t ion ( IMF) unle s s
o the rwise note d . Howe ve r , the a rc h-ba r s we re
le f t in p la c e unt i l the pa t i e n t wa s fnnc t iona l ly
re ha bi l i t a t e d w i th a n in te r inc i s a l ope ning of
gre a te r tha n 40 r a m . This usua l ly wa s f rom 4
to 8 weeks post-surgery. All othe r f r a c ture s
of the m a ndib le (w i th the pos s ib le e xc e pt ion
of subc ondy la r ) we re t r e a te d w i th p la te a nd/
or s c re w f ixa t ion , a l lowing im m e dia te m a n-
dibula r func t ion . Eve n those pa t i e n t s who
ha d c lose d t r e a tm e n t of c ondyla r f r a c ture s
we re a l lowe d im m e dia te m obi l i z a t ion of the
m a ndib le , bu t m a y ha ve ha d e la s t i c s a ppl ie d
to the de nt i t ion to guide the m in to prope r
oc c lus ion . The va s t m a jor i ty of f r a c ture s in
th i s pa t i e n t popula t ion we re sus ta ine d in
a l t e rc a t ions /a s sa ul t s ( a pproxim a te ly 85
95%) . The t im e be twe e n in jury a nd pre se n-
ta t ion for t r e a tm e nt r a nge d f rom a f e w hours
to severa l weeks , with an average of approxi-
m a te ly 2 .5 da ys . The a ve ra ge t im e be twe e n
in jury a nd surge ry wa s jus t ove r 3 da ys .
The da ta tha t we re c o l l e c te d in e a c h s tudy
included: 1) age , 2) sex, 3) race , 4) number of
frac tures per pa t ient , 5) e t iology, 6) associa ted
m a xi l lofa c ia l o r o the r sys te m t r a um a , 7) type
of f r a c ture , i .e . c om m i nute d versus l inear , ob-
l ique versus s t r a ight , 8 ) c onc om i ta n t m a n-
dibula r f r a c ture s , 9 ) pre se nc e of a too th in the
l ine of f ra c ture , 10) e x t r a c t ion of too th in l ine
of f r a c ture, 11) c om pl ic a t ions du r ing surge ry ,
12) post s urgica l occ lu sa l re la t ionship, an d 13)
c om pl ic a t ions , whic h we re de f ine d a s a ne e d
for fur the r surg ic a l in te rve nt ion . Only pa -
t i e n t s w i th a m ini m u m fo l low-up of s ix we e ks
we re inc lude d . Approxim a te ly 80% of c a se s
ha d a too th a s soc ia te d w i th the f r a c ture in the
a ngle , a nd the se we re r e m ove d dur in g surge ry
in 60 80% of cases .
Closed reduction or intraoral open
reduction and non rigid internal fixation
W i t h t h e i m p l e m e n t a t i o n o f r i g i d f o r m s o f
in te rna l f ixa t ion , c lose d r e duc t ion or non- r i -
g id in te rna l f ixa t ion m e thods ha ve be c om e
le s s f a sh iona ble . Howe ve r , whe n a s se s s ing
t r e a tm e nt r e su l t s of ne w te c hnique s , i t i s im -
p o r t a n t t o h a v e a g r o u p f o r c o m p a r i s o n . T h e
Fig 1 Im m e dia te pos tope ra t ive r a d iogra ph showing a ngle f r a c ture t r e a te d w i th t r a nsos se ous
wi re f ixa t ion a nd in te rm a xi l l a ry f ixa t ion . Wire wa s inse rte d th roug h the buc c a l c or te x o f the
e xt r a c t ion soc ke t .
go ld s t a nd a rd c lose d r e duc t ion or ope n
re duc t ion us ing non- r ig id f ixa t ion ha s be e n
use d for c e ntur ie s a nd c ons t i tu te s suc h a
group. A re t rospe c t ive s tudy wa s pe r form e d
to ga in a n a ppre c ia t ion for the c om pl ic a t ion
ra te of t r a d i t iona l t r e a tm e nt of a ngle f r a c -
ture s in ou r p a t i e n t popu la t ion 49.
The r e c ords o f pa t i e n t s t r e a te d by non- r i -
g i d m e a n s o f f ix a t i o n f o r m a n d i b u l a r a n g l e
frac tures in a 3-year per iod were evaluated
re t rospe c t ive ly . Tre a tm e nt of the f r a c ture s
wa s by c lose d r e duc t ion a nd/or ope n r e duc -
t i o n w i t h n o n - r i g i d m e a n s o f i n t e r o s s e o u s
f ixa t ion su c h a s t r a n sos se o us w i re s , c i r cum -
m a n dibu la r w i re s or sm a l l pos i t iona l bone
pla te s (F ig . 1 ) . Pos t surg ic a l IMF wa s pre -
scr ibed for s ix weeks in all patients .
Dur ing the 3-ye a r pe r iod , 96 pa t i e n t s w i th
9 9 f r a c t u r e s t h r o u g h t h e m a n d i b u l a r a n g l e
( three were bi la tera l) had charts avai lable
wi th suf f i c ien t in fo rm a t ion for inc lus ion in
this s tudY. Of the 99 frac tures , 59 were
t r e a te d w i th c lose d r e duc t ion (59%), 34 w i th
ope n r e duc t ion a nd p la c e m e nt of a t r a nsos s -
eous wire (34 /0) , f ive with o pen redu ction
a nd a pos i t iona l bone p la te , a nd one f r a c ture
wa s t r e a te d by c lose d r e duc t ion w i th the a d-
d i t ion of a c i r c um m a ndibula r w i re (1%) . A l l
pa t i e n t s we re p la c e d in to pos t surg ic a l IMF
for an average o f 40 da ys (range 20 -80 days) .
Fol low-up r a nge d f rom 21 252 da ys w i th a n
a ve ra ge of 75 da ys .
Com pl ic a t ions de ve lope d in 17 f r a c ture s
(17%), of which there were 13 with infec t ions
a nd fo ur c a se s whe re infe c t ion wa s c om bine d
wi th m a lunion a nd m a loc c lus ion . The re we re
no c a se s of non -unio n . Th e t im e be twe e n ini -
t i al p re se nta t ion a nd surge ry in the se pa t i e n t s
wa s s im i la r to the ove ra l l g roup of pa t i e n t s .
A l l pa t i e n t s unde rwe nt inc i s ion a nd dra ina ge
proc e dure s for the i r in fe c tions . N ine pa t i e n t s
were hospita l ized a t leas t once for the ir infec-
t i o n a n d / o r m a l o c c l u s i o n / m a l u n i o n . D u r i n g
the inc i s ion a nd dra ina ge proc e dure s , four
p a t i e n t s u n d e r w e n t r e m o v a l o f o s t e o s y n t h -
es is ; two had tee th in the l ine of f rac ture ex-
t r a c te d ; th re e pa t i e n t s whose in i t i al t r e a tm e nt
wa s c lose d r e duc t ion ha d t r a nsos se ous w ire s
p la c e d to c ont ro l the proxim a l s e gm e nt ; one
pa t i e n t r e qui re d os t e o tom y to c or re ct m a l -
oc c lus ion . Two pa t i e n t s r e qui re d a s e c ond a d-
m is s ion; one for inc i s ion a nd dra ina ge , the
othe r for a n os te o tom y.
The r e su l t s of th i s s tudy showe d tha t m a n-
dibula r a ngle f r a c ture s in th i s pa t i e n t po pula -
t ion we re a s soc ia te d w i th a h ig h inc ide nc e of
pos t surg ic a l c om pl ic a t ions , e ve n whe n t r a -
d i t iona l m e th ods o f t r e a tm e nt we re e m -
ployed.
Extraoral open reduction and internal
fixation using the AO/ASIF reconstruction
plate
The AO re c ons t ruc t ion bone p la te i s a r e -
inforc e d p la te tha t i s th ic ke r a nd s t ronge r
t h a n t h e s t a n d a r d A O / A S I F c o m p r e s s i o n
bone p la te . I t c om e s in va r ious l e ngths a nd
the p la te i s th re e -d im e ns iona l ly be nda ble ,
a l lowing a c c ura te c ontour ing to the sur fa c e
of the m a ndib le . The use of th re e s c re ws on
e a c h s ide of the f r a c ture w i th th i s bo ne pIa te
i s c la im e d to provide a de qua te ne ut r a l i z a t ion
of func t iona l forc e s in the a bse nc e of c o in-
pre s s ion 6~ i t i s use fu l in a re a s of c om m i-
nut ion , bone los s or ob l iqui ty whe re one c a n-
not use s t a nda rd c om pre s s ion bone p la te s .
The r e c ords of a l l pa t i e n t s w i th uni l a te ra l
f r a c ture s of the m a ndib ula r a ngle t r e a te d
wi th a r e c ons t ruc t ion bone p la te ove r a 3-
ye a r pe r iod we re c o l le c ted . Th e t e c hnique for
a ppl ic a t ion of the p la te ha s be e n publ i she d
e l se whe re a nd c ons i s t e d of a n e x t r a ora l a p-
pro ach in mo st in s tanc es (Fig. 2) 21.
The r e c ords of f i f ty -two pa t i e n t s w i th uni -
l a te ra l a ngle f r a c ture s t r e a te d in the 3-ye a r
pe r iod , who ha d a de qua te fo l low-up infor -
mation in the ir char t , were available for re-
view. The frac tures were ca tegorized as be ing
c om m inute d in 31 c a se s , ob l ique in 12 a nd
simple l inear f rac tures in 9. Following appli-
c a t ion of the bone p la te , ' a l l f r a c ture s a p-
peared to be well reduced and s table . All
de ntu lous pa t i e n t s ha d a r e produc ib le oc -
c lus ion in the ope ra t ing roo m . Fou r pa t i e n t s
ha d pre -e x i s te n t in fe c t ions of the f r a c ture
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2 4 6
El is
and i r r iga t ion dra ins were p l aced dur ing
surgery in these pat i ent s . No other pa t i ent
had dra inage of t he wound. Pos topera t ive
radiographs taken within the f i rs t two days
showed exce l lent reduct ion in aII cases . There
was no r adiograph ic evidence of damage to
the infer ior alveolar neurovascuIar s t ructures
f rom placeme nt of t he f ixa t ion hardware . The
occlusal r e l a t ionships were judged as norm al
in a l l but four o f t he dentulous pat i ent s a t
one week fol lowing surgery. These four pa-
t ients had s l ight occlusal i r regular i t ies that
required two to three weeks of elas tic t ract ion
therapy. Al l f our of t hese pat i ent s had con-
comi tant f r ac tures of t he mandible in the
tooth-bear ing area making i t di f f icul t to de-
termine which f racture(s) were not perfect ly
reduced.
Fol low-up ranged f rom 9 to 104 weeks
with a mean of 18 weeks . Al l dentulous pa-
t i ent s had what was thought t o be the nor -
mal occlusal relat ionship for that individual
at longest fol low-up. Four f ractures (7.5%)
required fur ther surgical intervent ion for
postsurgical infect ions . These pat ients de-
veloped acute infect ions within the f i rs t three
postsurgical weeks that were refractory to
ant imicrobial t reatment . These pat ients re-
quired hospi tal izat ion for extraoral incis ion
and dra inage , i r r i ga t ion through dra ins , and
int r avenous ant ib io t i cs . One pat i ent r e-
quired plate removal to completely clear the
infect ion.
Lag screws for mandibular angle fractures
In 1981, NIEDERDELLMANN et al. 46 de sc rib ed
a meth od o f in t ernal f i xa t ion of mandibular
angle fractures using a single lag screw. We
began to use the lag screw technique in 1988
and foun d i t t o be an ext r emely r apid and
simple method for t reat ing f ractures of the
mandibu lar angle . The t echnique for p l ac ing
the lag screw has been descr ibed in previous
pu bli ca tio ns (Fig. 3) 19,25.
Eighty-eight pat ients that were t reated by
open r educt ion and in t ernal f i xa tion of angle
fractures by the lag screw technique were in-
cluded in this s tudy. Intraoperat ively, reduc-
t ions were judg ed as excel lent in al l pat ients .
However , 17 were noted to be unstable to ag-
gres s ive b imanual manipula t ion of t he man-
dible. Supplemental methods of f ixat ion were
appl ied in these cases . In three pat ients , a 2.0
mm compres s ion bone p l a t e was appl i ed a t
the infer ior border . In the remaining 14 pa-
t i ents , pos topera t ive IMF was used for vary-
ing per iods (3-8 weeks) . Fol low-up ranged
from 6 to 167 weeks , wi th a m ean of 22
weeks .
Immedia t e pos topera t ive r adiographic
evaluat ion showed excel lent reduct ion in
every pat i ent except one whose mandibular
ramus w as s l ight ly f lared lateral ly on the sub-
mentover tex view. No t reatment was necess-
ary, as the facial form was minimal ly al tered.
Seven pat ients were found to ha ve very min or
occlusaI discrepancies in the f i rs t two post-
operat ive weeks . These were t reated sat is fac-
tory with 3M weeks of intermax i l lary elas-
t ics . No other postsurgical malocclus ion re-
sul t ed in any pat i ent . One pat i ent had
radiographic evidence of probable impale-
ment of the mandibular canal by the screw.
Eleven pat i ent s developed min or pos t surgica l
sof t t i ssue infect ions/bone exposures within
the f i rs t several weeks (no cases of os teomy el-
i t is occurred) . Six resolved on oral ant i -
microbia l t r ea tment wi thout any fur ther i n-
tervent ion. Five pat ients (13%) required
fur ther i n t ervent ion , i nc luding r emoval of t he
screws and smal l sequestra. One pat ient also
had ext r ac t ion of a t e rminal mola r t ha t was
thought t o be nonvi t a l . Another pa t i ent de-
veloped non-union and was subsequent ly
bone-graf t ed .
Intraoral open reduction and internal
fixation using two 2.0 mm mini dynamic
compression plates
One AO/AS IF metho d to neut r a l i ze the func-
t ional forces of an ang le f racture is by res tor-
Fig 2 Immedia t e pos topera t ive r adiograph showing infec t ed angle
f r ac ture t r ea t ed wi th AO recons t ruct ion bone p l a t e . P l a t e was p l aced
through an ext r aora l approach. Penrose dra in tha t was inser t ed dur -
ing surgery to help resolve infect ion can be seen. Drains were only
placed i f f ractures were infected.
Fig 4 Immedia t e pos topera t ive r adiograph showing angle f r ac ture
t r ea t ed wi th two 2 .0 mm dynamic c ompres s ion p l at es .
Fig 3 Immedia t e pos topera t ive r adiograph showing angle f r ac ture
treated with so l i tary lag screw.
Fig 5
Immedia t e pos topera t ive r adiograph showing angle f r ac ture
t r ea t ed wi th two AO/A SIF 2 .4 mm com pres s ion p l a t es des igned for
use in mandible.
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Treatment o f mandibular angle f rac tures
47
Fig. 6. Immedia t e pos topera t ive r adiograph showing angle f r ac ture
t r ea t ed wi th two non-com pres s ion minipla t es .
Fig. 7. Immedia t e pos topera t ive r adiograph showing angle f r ac ture
t r ea t ed wi th s ingle non-comp res s ion minipl a t e according to the pr in-
ciples of CHAMPY et al ) 2.
i ng the t ens ion and compres s ion t r a j ec tor i es
in the m andible 67. The r ecomm ended m ethod
to res tore these t rajector ies in f ractures o f the
mandibular angle is by the appl i ca t ion o f two
bone p l a t es ; one a t t he super ior and one a t
the infer ior border of the buccal cor tex. Tra-
di t ional ly, the plate at the super ior border
was a smal l compress ion plate secured with
monoc or t i ca l s cr ews , whereas the one a t t he
infer ior border was a l a rge compres s ion
plate, us ing bicor t ical screws. The appl i -
cat ion of these two bone plates is not di f f icul t
t hrough an ext r aora l approach. However ,
p l acement o f t hese p la t es v ia an in t r aora l ap-
proach i s more demanding due to decreased
vis ibi l i ty, making adaptat ion of the bone
plates dif f icul t . Because of the dif f icul t ies en-
countered in ada pt ing and secur ing the l arger
bone p l a tes , t he implementa t ion of two 2 .0
mm mini -dynamic compres s ion p l a t es was
unde r taken in a sam ple of pat ients (Fig. 4) 2~
Thir ty consecut ive pat ients with 31 f rac-
tures of t he mandibular angle tha t were
amenable to compres s ion p l a t e os t eosynth-
es is were t reated by open reduct ion and inter-
nal f i xa t ion us ing two mini -dynamic com-
press ion plates placed through a t ransoral in-
cis ion with t ransbuccal t rocar ins t ru-
menta t ion . Nine f r ac tures (29 ) experi enced
compl i ca t ions r equi r ing s econdary surgica l
intervent ion. Three were ear ly infect ions re-
qui r ing inc i s ion and dra inage , r emoval o f t he
pla t es and pos topera t ive IME One was a
non-union wi th malocclus ion r equi r ing ap-
pl icat ion of a more r igid bone plate. Five
fractures developed late chronic swel l ing and
low-grade infect ion requir ing plate removal .
Osseous union had occur r ed in these cases
and no pos topera t ive IMF was neces sary .
Intraoral open reduction and internal
fixation using two 2.4 mm mandibular
dynamic compression plates
Because of t he h igh r a t e o f pos t surgica l com-
pl icat ions in pat ients t reated with two 2.0
mm mini -dynamic com pres s ion p la t es , i t was
decided to s tudy the s t andard AO/A SIF t ech-
nique for t r ea t ing f r ac tures of t he mandibu-
l ar angle by the appl i ca t ion of two com -
press ion b one plates specif ically des igned for
the mandible . The t ens ion band dynamic
compres s ion p l a t e employed 2 .4 mm screws
that were appl i ed mon ocor t i ca l ly in locat ions
where b i cor t i ca l engagement would damage
normal anatomic s t ructures , such as over
tooth roots . The s tabi l izat ion plate was a
l arger compres s ion bone p l a t e us ing 2 .4 mm
bone screws. Addi t ional ly, postsurgical suc-
t ion drainage was used in al l cases .
Sixty-f ive consecut ive pat ients with 65
f r ac tures of t he mandibular angle were
t r ea t ed by open r educt ion and in t ernal f i x-
a t ion us ing two dynamic compres s ion p l a t es
placed through a t r ansora l i nc i s ion wi th
t r ansbuccal t r ocar i ns t rumenta t ion and 2 .4
mm screws (Fig. 5) 22. Overall, 21 fra cture s
(32 ) exper ience d infect ions requir ing sec-
ondary surgical intervent ion. Of the 21 f rac-
tures which required plate removal , nine f rac-
tures were healed and r equi r ed no fur ther
t r ea tment ; 12 had no f i rm bony union and
requi r ed pos t surgica l IME Only one case r e-
sul ted in a malunion with resul t ing malocclu-
sion.
Intraoral open reduction and internal
fixation using two noncompression
miniplates
The AO/ASIF r ecommendat ion for appl i -
ca t ion of two compres s ion bone p l a t es for
angle f ractures was found to resul t in very
high r a t es of compl i ca t ion in our pat i ent
pop ulat io n 2~ Because large bon y se-
ques t r a were f r equent ly encountered in these
pat i ent s , we thought t ha t a r eason for t he
high rate of postoperat ive infect ion was devi-
tal izat ion of bone resul t ing f rom the use of
compres s ion p l a t es . The hypothes i s was put
forward tha t e l iminat ing the use of com-
press ion might improve t reatment resul ts .
The next ser ies of pat ients with f ractures of
the mandibular angle were, therefore, t reated
wi th two 2 .0 mm non-comp res s ion mini -
plates (Fig. 6) . The super ior bone plate was
appl i ed monocor t i ca l ly , t he inf er ior bone
plate bicor t ical ly. The technique for appl i -
ca t ion of t he two bon e p l a t es has been pub-
l ished elsewhere23.
Sixty-seven consecut ive pat ients with 69
f r ac tures of t he mandibular angle were
treated by open reduct ion and internal f ix-
a t ion us ing two non-compres s ion minipl a t es
placed through a t r ansora l i nc i s ion wi th
t r ansbuccal t r ocar i ns t rumenta t ion and 2 .0
mm self - threading screws. Overal l , 19 f rac-
tures (28 ) exper ienced complicat ions re-
qui r ing s econdary surgica l i n t ervent ion .
Mos t of t he compl i ca t ions were pos topera-
t ive infect ions requir ing surgical drainage
(n= lT) and subsequ ent p l a t e removal rl=
16). Of the 17 infec ted fractures, 11 were
healed at th e t ime of plate removal and re-
quired no fur ther t reatment . Five were s t i l l
mobi l e and r equi r ed a per iod of IMF for
heal ing . One o f t he f r ac tures d id not heal and
required bone graf t ing.
Intraoral open reduction and internal
fixation using one non compression
miniplate
Because of t he h igh r a t es of comp l i ca t ion r e-
sul t ing when two bone plates were placed, i t
was decided to at tempt the use of a s ingle
Table 1. Com par i son of 2 .0 mm and 1 .3 mm m inipla t es*
2.0 mm plate 1.3 mm plate
Thickne ss (mm) 0.9 0.5
In-p lan e stiffnes s (N- m 2) 0.007 0.001
Out-of- plane s t i f fness (N-m 2) 0.158 0.029
In-plan e ben ding s t rength (N-m 2) 0.14 0.04
Out-of- plane ben ding s t rength (N-m 2) 0.93 0.40
* Provided by Synthes USA, Paol i , PA,USA
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2 4 8 El l i s
Fig 8
P h o t o g r a p h o f s t an d a r d 2 . 0 m m m i n i p l a te a n d 1 .3 m m m i n i -
p la te use d in th i s inve s t iga t ion (A) . 1 .3 m m pla te i s e x t r e m e ly th in
a nd m a l le a ble a s shown in th i s photogra ph (B) .
m inip la te a c c ord ing to the pr inc ip le s of
CHAMPu e t a l . 12 (Fig. 7). Eig hty -on e co nsecu -
t i v e d e n t a t e p a t i e n t s w i t h n o n - c o m m i n u t e d
f ra c ture s of the m a ndibula r a ngle we re
t r e a te d by in t r a ora l ope n r e duc t ion a nd
in te rna l f ixa t ion us ing a s ing le four -hole
m inip la te a nd m onoc or t i c a l s c re ws in a two-
ye a r pe r iod23i Fol lowing a ppl ic a t ion of the
bone pla te , a l l f rac tures appeared to be well
r e duc e d a nd s ta b le . Pos tope ra t ive r a d io-
gra phs t a k e n w i th in the f i r st two da ys showe d
e xc e l l e n t r e duc t ion in all cases except four ,
whe re a 2~ 4 m m ga p wa s note d a t the in-
f e r ior borde r. In sp i t e of th i s f ind ing on
ra diogra phs , im m e dia te oc c lusa l r e la t ion-
sh ips were judge d a s norm a l in
all
b u t o n e o f
the se pa t i e n t s , who h a d a n s l igh t pos te r ior
ope n b i t e on the s ide of the f r a c ture , a nd r e -
spond e d to l igh t e las t i c t r a c t ion for 10 days .
Be s ide s th i s c a se , two o the r pa t i e n t s ha d
s l igh t m a loc c lus io ns tha t r e spo nde d to the
we a r ing of e la s t i cs for one or two we e ks. A t
the t im e of a rc h-ba r r e m ova l , oc c lusa l r e -
l a t ionships we re judge d a s norm a l in a l l
cases.
Overa l l , 13 angle f rac tures (16%) experi-
e nc e d c om pl ic a t ions r e qui r ing s e c onda ry sur -
g ic a l in te rve nt ion . Mos t of the c om pl ic a t ions
(n= l l ) , howe ve r , we re m inor a nd c ould be
t r e a te d in the outpa t i e n t s e t t ing . Mos t c om -
m only , in t r a ora l inc i s ion a nd dra ina ge a nd
la te r r e m ova l of the bo ne p la te we re r e qui re d .
ll p a t i e n t s w i t h m i n o r c o m p l i c a t i o n s h a d
bony union . Only two c om pl ic a t ions r e -
qui r e d hospi t a l i z a t ion for in t r a ve nous a n t i -
m ic robia l t r e a tm e nt a nd fur the r surge ry . One
of the se pa t i e n t s ha d a f ibrous union , r e qui r -
ing a bone gra f t .
Intraoral open reduction and internal
fixation using one malleable non
compression miniplate
The use of a s ing le m inip la te for f r a c ture s of
the a ngle of the m a ndib le wa s a s im ple , r e -
l i ab le t e c hnique w i th a r e lat ively sm a l l nu m -
be r of m a jor c om pl ic a t ions . Howe ve r , the
que s t ion how m uc h f ixa t ion i s a de qua te ?
was s t i l l no t kn own . LoDD~ 13 has r educed the
volum e of the or ig ina l CHAMPY m inip la te by
h a l f, m a k i n g t h e m m u c h m o r e m a l l ea b l e, a n d
ha s not no te d a ny inc re a se in c om pl ic a t ions
w h e n u s e d f o r m a n d i b u l a r f r a c t u r e s . H o w
m uc h re duc t ion in m a te r ia l i s to le ra b le ? The
purpose of th i s l a s t inve s t iga t ion wa s to pro-
spective ly evaluate the use of a thin, malle-
a b le m inip la te (Sy nthe s Ma xi l lofa c ia l , Pa ol i ,
PA, USA) tha t e m ploys 1 .3 m m sc re ws for
s ta b i l i z a t ion of f r a c ture s of the m a ndibula r
angle . This pla te was
not
de s igne d for use in
the m a ndib le , bu t wa s de s igne d for use in the
n o n - l o a d b e a r i n g r e g i o n s o f t h e m i d f a c e
(Table 1)(Fig. 8) . Pa t ients had a seven-hole
s t r ip of the p la te s e c ure d a c ros s the f r a c ture
Fig 9 Im m e d ia te pos tope ra t ive r a d iogra ph showing a ngle f r a c ture t r e a te d w i th s ingle 1 .3 m m
non-c om pre s s ion p la te .
us ing thre e m onoc or t i c a l s t r e ws on e a c h s ide
of the f r a c ture . Be c a use of the th inne s s a nd
m a l le a bi l i ty of the p la te s , i t wa s unne c e s sa ry
to be nd the bone p la te s , a l lowing the s c re ws
to s im ply c oa pt the p la te s to the bone u pon
t ighte n ing . No t r a n sbuc c a l t roc a r wa s ne c e s s -
a ry for ins t rum e nta t ion . A l l s c re ws we re 5
m m in l e ngth .
For ty- s ix c onse c ut ive pa t i e n t s w i th 51
f ra c ture s of the a ngle of the m a ndib le we re
trea ted by the above method (f ive were bi la t-
era l) in a 1.5-year per iod (Fig. 9) St. Followin g
a ppl ic a t ion of the bone p la te , a l l f r a c ture s
a ppe a re d to be we l l r e duc e d a n d s ta ble . Pos t -
ope ra t ive r a d iogra phs t a ke n w i th in the f i r s t
two da ys showe d e xc e l l e n t r e duc t ion in a l l
c a se s . Im m e dia te oc c lusa l r e la t ionships we re
judge d a s norm a l in a l l bu t one pa t i e n t ,
whose m a ndib le wa s sh i f t e d to the c ont ra -
l a te ra l s ide in a s soc ia t ion w i th m ode ra te
swe l ling of the r igh t subm a ndi bula r a nd l a t-
e ra l pha rynge a l spa c e s due to infe c t ion of
the se spa c e s pre se nt pr ior to surge ry . Thi s r e -
so lve d w i th the r e so lu t ion of in fe c t ion a nd
the use of l ight e las t ics for 14 days . At the
t im e of a rc h-ba r r e m ova l , one pa t i e n t wa s
judge d to ha ve a m a loc c lus ion tha t wa s a t t r i -
bu te d to m a lunion a t a f r a c ture s i t e o the r
tha n the a ngle . A l l o the r oc c lusa l r e la t ion-
sh ips we re judge d norm a l .
Se ve n pa t i e n t s (13 .7%) de ve lope d c om pl i -
c a t ions f rom the i r a ngle f r a c ture pos tope ra -
t ive ly, only four (8.7%) required fur ther sur-
g ic a l in te rve nt ion . A l l c om pl ic a t ions we re
c ons ide re d m ino r a nd c ons i s t e d of p la te f r a c -
ture , loc a l in fe c t ion , or bo th . Thre e of the
se ve n pa t i e n t s (42 .9%) ha d a sym ptom a t ic
f r a c ture of the p la te d ia gnose d on r a d io-
g r a p h s , h o w e v er t h e r e w a s b o n y u n i o n o f t h e
f ra c ture a nd no in te rve nt ion wa s r e qui re d .
Two pa t i e n t s (28 .6%) ha d f r a c ture of the
pla te w i th c l in ic a l m obi l i ty of the f r a c ture
a nd we re p la c e d in to IMF for a pe r iod of
6 we e ks . One of the se pa t i e n t s subse que nt ly
developed a loca l ized infec t ion of a devita l-
i z e d too th in the l ine of f r a c ture a nd wa s
t r e a te d w i th ora l a n t im ic robia l d rugs a nd e x-
t r a c t ion of the of fe nding too th . One pa t i e n t
(14.3%) developed an isola ted infec t ion as-
soc ia te d w i th a nonvi ta l too th tha t wa s
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Treatment of mandibular angle.fi actures
Table 2. Treatment for angle fractures (Parkland Memorial Hospital)
Treatment Study Reference Sample (no. of angles) Major Complication~
4 9
Non-rigid fixation
AO reconstruction plate (2.7
m m )
Solitary lag screw
Two mini-dynamic compression plates (2.0 mm)
Two mandibular dynamic compression plates (2.4 ram)
Two non-compression miniplates (2.0 mm)
One non-compression miniplate (2.0 ram)
One malleable non-compr miniplate (1.3 mm)
PASSE•I et al. , 199349 99 17%
ELLIS, 199321 52 7.5%
ELLIS & GHALI, 199119 88 13%
ELLIS & KARAS, 19922o 30 13%
ELLIS &
SINN , 199322
65 32%
E>LIS & WALrCER, 199423 67 23%
ELLIS & WALKER, 199624 81 2.5%
POTTER & ELLIS, 199951 51 0%
~ Majorcomplication refers to the necessity of hospitalization to treat complication
treated by intraoral incision and drainage,
extraction of the tooth, and oral anti-
biotics without plate removal. One patient
(14.3%) developed an isolated infection as-
sociated with loosening of the. plates several
weeks after completing rehabilitation, and
was treated with oral antibiotics and re-
moval of the plate under local anesthesia. No
patient developed major complications that
required hospitalization or intravenous anti-
microbial therapy.
D i s c u s s i o n
In our pati ent population, treatment of
angle fractures with even traditional
methods closed reduction and/or non-
rigid fixation produced a high rate of
compli cat ion (17%) 49 This migh t sur-
prise those surgeons from countries
where fractures occur in a higher socio-
economic group of patients. However,
the association of poor oral hygiene,
poor dentition, substance abuse and a
variety of other factors may predispose
this particular sample of patients to
postsurgical complications48.
The most useful techniques in this
patient population were the use of
either an extraoral open reduction and
internal fixation with the AO/ASIF re-
construction plate, or intraoral open re-
duction and internal fixation using a
single miniplate (Table 2). The use of
the reconstruction bone plate was
found to result in few complications in
a study of angle fractures by IIZUKA &
L I NDQVI ST35. However, the application
of this plate is much easier through an
extraoral approach that can create its
own set of complications. Obviously, we
currently employ the latter approach
with a 2.0 mm plating system for the
vast majority of cases. Every attempt
we made at using a two-plate technique
via a transoral approach was fraught
with high rates of sequestra formation,
infection and need for subsequent
surgery. We no longer recommend an
intraoral two-plate technique.
At the beg innin g of these investi-
gations, we never would have con-
sidered using a single miniplate to ad-
equately stabilize a fracture of the angle
of the mandible without supplemental
IME Ten years ago, indoctrinated by
the AO/ASIF teaching that absolute ri-
gid fixation was necessary, stable
methods were deemed necessary and
were used in this patient population.
Reconstruction plates, lag screws, and
two-plate systems were implemented
with the thought that they were absol-
utely stable methods. However, other
than the reconstruction plate, the intra-
oral techniqu es of stable fixation proved
either unstable in a certain percentage
of cases (solitary lag screw) or fraught
with high rates of major postsurgical
complications (two plates).
The results of these consecutive
series of clinical inves tigations per-
formed in our hospital on a similar pa-
tient population indicate that, contrary
to popular beliefs, up to a point, the in-
cidence of major complications after
fractures of the mandibular angle are
inversely proportional to the rigidity of
the fixation applied. Whenever two
points of fixation were used for frac-
tures of the angle, the c omplication rate
was much higher than when one point
of fixation was applied. That is not to
say that using a single miniplate does
not result in complications. However,
the vast majority of problems that arose
in patients treate d by a single miniplate,
such as w ound dehiscence, wound infec-
tions, plate exposure etc., were easily
treated in the outpa tient clinic under lo-
cal anesthesia. Even removal of the
bone plate after healing of the fracture,
when necessary, is a simple procedure in
the outpatient setting. However, when a
second plate was applied at the inferior
border, the complications tended to be
more severe, with large areas of nonvital
bone, sequestra formati on and need for
plate removal, which were difficult to
treat in the o utpat ient setting. If one de-
fines a complication as an unplanned
intervention, the two-plate techniques
have a higher complication rate than
single plate techniques . However, when
one defines a major complicat ion as one
that requires hospitalizat ion to treat the
problem, the difference between treat-
ment techniques becomes much more
clear and dramatic in incidence (see
Table 2).
The finding that a single minipiate
outperforms two plates and other more
stable forms of fixation defies logic, be-
cause conve ntiona l wisdom would indi-
cate that more stable fixation should
provide fewer complications. However,
our experience has been the opposite.
The use of a single miniplate was as-
sociated with much fewer complicat ions
than if two plates were used, irrespective
of whether the two plates were com-
pression or n on-com pressi on plates.
This seeming dichotomy highlights the
limitations of relying on the results of
biomecha nical bench testing for clinical
treatment recommendations. All bio-
mechanical tests performed to date in-
dicate that two plates are more stable
th a n o n e 14,15,18,2a 38,57,58,62.
Based upon
these biomechani cal studies and clinical
results, some investigators have advo-
cated the use of two miniplates for frac-
tures of the ma nd ib ul ar angle 14,15,41,71
LEvY et al. 41 compared a small sample
of patients who had fractures of the
angle treated with either one or two
miniplates without postsurgical IME
There were no complications in the 18
patients who had double miniplates,
but two complications in the ten pa-
tients (20%) who had a single miniplate.
Interestingly, another sample of 14 pa-
tients with two miniplates plus postsur-
gical IMF had a greater rate of compli-
cation (7.1%) than when no IMF was
used.
Our clinical experience is exactly the
opposite - a single miniplate worked
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2 5 l l i s
m u c h b e t t e r t h a n d o u b l e p l a t i n g s y s -
t e m s . S H I ER L E e t a l . 58 c o m p a r e d a s i n g l e
m i n i p l a t e t o t h e u s e o f t w o a n d f o u n d
n o s i g n i f i c a n t d i f f e r e n c e i n r e s u l t s . T h e
r e s u lt s o f o u r s t u d i e s a n d t h e o n e b y
S C H IR L E e t a l . 58 i n d i c a t e t h a t b i o -
m e c h a n i c s a r e o n l y o n e f a c t o r t o b e
c o n s i d e r e d w h e n t r e a t i n g f r a c t u r e s .
T h e r e a r e m a n y o t h e r s t h a t m a y b e
m o r e im p o r t a n t . P e r h a p s i m p r o v e d
m a i n t e n a n c e o f th e b l o o d s u p p l y t o t h e
b o n e b e c a u s e o f li m i t e d d i s s e c t i o n i s
o n e s u c h f a c t o r s
7 17 32 . W e
t h e r e f o r e ,
a g r e e w i t h E W E RS &
HARLE 26 27
w h o
q u e s t i o n e d t h e n e e d f o r a b s o l u t e r i g i d -
i t y f o r t r e a t m e n t o f f r a c tu r e s . F r o m t h e
f o r e g o i n g , i t i s o b v i o u s t h a t f r a c t u r e s o f
t h e m a n d i b u l a r a n g l e d o n o t r e q u i r e t h e
a m o u n t o f s ta b i li t y as d e t e r m i n e d i n
b i o m e c h a n i c a l t e s t s . T h i s s h o u l d n o t b e
s u r p r i s i n g i n l ig h t o f b i t e f o r c e s t u d i e s
b y G E R L A C H e t a l . 3 ~ a n d T A T E e t a l . 69
w h i c h s h o w e d t h a t b i t e f o r c e s a r e s u b -
n o r m a l f o r m a n y w e e k s a f t e r f r a c t u r e o f
t h e m a n d i b l e .
W h a t h a s y e t t o b e d e t e r m i n e d i s
e x a c t l y w h a t a r e t h e r e q u i r e m e n t s f o r
f i x a t io n o f a n g l e f r a c tu r e s . B a s e d u p o n
t h e r e s u l ts o f u s i n g a m a l l e a b l e 1 .3 m m
p l a t i n g s y s t e m , t h i s p l a t e s h o u l d n o t b e
r o u t i n e l y
u s e d f o r s u c h f r a c t u r e s b e -
c a u s e s o m e f r a c t u r e d d u r i n g f u n c t i o n .
H o w e v e r , t h e f a ct t h a t m o s t d i d n o t
f r a c t u r e i n d ic a t e s t h a t t h e 2 . 0 m m m i n i -
p l a t e s a re p r o b a b l y o v e r - e n g i n e e r e d f o r
t h i s t a s k . P e r h a p s a t h i n n e d d o w n v e r -
s i o n o f t h e 2 .0 m m m i n i p l a t e s y s t e m
w i l l p r o v e e v e n s i m p l e r t o a p p l y a n d a d -
e q u a t e l y s t a b l e w i t h o u t p l a t e f r a c t u r e .
A n o t h e r a l t e r n a t i v e m i g h t b e t o t h i c k e n
t h e 1 . 3 m m p l a t e . T h e s e r e s u l t s a l s o i n -
d i c a t e t h a t b i o d e g r a d a b l e f i x a t i o n s ys -
t e m s , w h i c h d o n o t h a v e t h e s a m e
s t r e n g t h a s m e t a l l i c p l a te s o f t h e s a m e
d i m e n s i o n , m a y p r o v i d e a d e q u a t e f ix -
a t i o n i n t h i s r e g i o n .
T h e r e h a v e b e e n s t u d i e s o n t h e t r e a t -
m e n t o f f ra c t u r e s o f t he m a n d i b l e t h a t
h a v e s h o w n t h a t o p e r a t o r e x p e r i e n c e i s
a n i m p o r t a n t f a c t o r i n t r e a t m e n t r e -
s u l t s 3 '3 4'3 7. T h e r e i s n o q u e s t i o n t h a t e x -
p e r i e n c e d s u r g e o n s c a n t r e a t i n j u r i e s
f a s t e r a n d p e r h a p s w i t h l e s s s u r g i c a l
t r a u m a t h a t t h o s e w h o a r e l e ss e x p e r i -
e n c e d . B e c a u s e t h e t e c h n i q u e s t h a t
p r o v e d m o s t b e n e f i c i a l w e r e t h o s e c o m -
p l e t e d l a t e s t i n t h i s 1 0 - y e a r e x p e r i e n c e ,
o n e m i g h t a r g u e t h a t t h e i m p r o v e d r e -
s u l t s a r e n o t d u e t o t r e a t m e n t m e t h o d s
b u t i n s t e a d d u e t o o p e r a t o r e x p e r i e n c e ,
w h i c h o n e w o u l d p r e s u m e t o i n c r e a s e
o v e r t i m e . T h e r e i s o n e f a c t o r t h a t r e -
f u t e s t h i s s u p p o s i t i o n , h o w e v e r . A v a r -
i e t y o f r e s i d e n t s w e r e i n v o l v e d w i t h t h e
o p e r a t i v e p r o c e d u r e s o v e r t h e 1 0 - y e a r
p c r i o d . T h e e x p e r i e n c e l e v e l o f t h e r e si -
d e n t s w a s s i m i l a r b e c a u s e t h e y r o t a t e d
t o t h e t r e a t i n g h o s p i t a l f o r t h e s a m e
d u r a t i o n d u r i n g t h e i r t r a i n i n g p r o -
g r a m s . T h e o n l y i n d i v i d u a l p r e s e n t o v e r
t h e e n t i r e 1 0 y e a r s w a s t h e f a c u l t y s u r -
g e o n , w h o m e r e l y d i r e c t e d a n d a s s is t e d
d u r i n g t h e s u r g e r y . A t l e a s t o n e o t h e r
s t u d y h a s a ls o d e m o n s t r a t e d t h a t s i n g le
p l a t e s p e r f o r m a s w e ll a s w h e n t w o a r e
us ed 58.
A m o r e i m p o r t a n t c o n s i d e r a ti o n
a b o u t o p e r a t o r e x p e r i e n c e , h o w e v e r , i s
t h a t i t ta k e s m u c h less e x p e r i e n c e t o b e -
c o m e a d e p t a t u s i n g a s i ng l e m i n i p l a t e
t h a n t h e o t h e r t e c h n i q u e s . A p p l i c a t i o n
o f a s i n g l e m i n i p l a t e t a k e s o n l y a fe w
m i n u t e s a n d c a n b e t a u g h t v e r y q u i c k l y
t o a t r ai n e e . P l a c e m e n t o f th e s e c o n d
p l a t e a t t h e i n f e r i o r b o r d e r i s a m o r e
d i f fi c u l t t a s k a n d r e q u i r e s m o r e e x p e r i -
e n c e t o b e c o m e f a c i le . P l a c e m e n t o f a
s o l i t a r y l a g s c r e w i s a l s o t e c h n i q u e s e n -
s i t i v e . F o r t u n a t e l y , t h e t e c h n i q u e t h a t
o f f e r s t h e b e s t r e s u l t s i s a l s o t h a t w h i c h
i s t h e s i m p l e s t t o l e a r n .
T h e u s e o f a s i n gl e m i n i p l a t e w a s n o t
i n k e e p i n g w i t h t h e o r i g i n a l A O / A S I F
p r i n c i p l e s . H i s t o r i c a l l y , t h e f o u r A O /
A S I F p r i n c i p l e s f o r t r e a t i n g s k e l e t a l
f r a c t u r e s w e r e : 1) a n a t o m i c r e d u c t i o n ;
2 )
r ig id
f i x a t i o n ; 3) a t r a u m a t i c s u r g i c a l
t e c h n i q u e ; a n d 4 ) i m m e d i a t e a c t i v e
f u n c t i o n , i n 1 9 9 4, th e A O / A S I E f o r t h e
f i r s t t i m e i n i t s h i s t o r y , c h a n g e d t h e s e c -
o n d p r i n c ip l e t o f u n c t i o n a l l y s ta b l e
f i x a t i o n , r a t h e r t h a n
r ig id
f i x a t i o n .
T h i s c h a n g e a r o s e o u t o f o r t h o p e d i c
s u r ge r y , w h e r e i n t r a m e d u l l a r y n a i ls a n d
o t h e r l es s r i g i d f o r m s o f f i x a t i o n w e r e
p r o v e n t o b e f u n c t i o n a l l y s t ab l e. T h e
a b i l it y o f a s i n g l e m i n i p l a t e a p p l i e d a t
t h e s u p e r i o r b o r d e r o f t h e m a n d i b l e t o
n e u t r a l i z e f u n c t i o n a l fo r c e s a n d a l lo w
i m m e d i a t e a c t iv e m o b i l i t y i s f i n a ll y r e c-
o g n i z e d b y t h e A O / A S I F a s a r e l i a b l e
m e a n s o f p r o v i d i n g f u n c t i o n a l s t a b i li t y
o f t h e f r a c t u r e .
T h e a b o v e r e l a t e s t h e e x p e r i e n c e o f
o n e h o s p i t a l , w i t h o n e p a t i e n t p o p u l a -
t i o n , t r e a t e d b y a la r g e g r o u p o f r e s i-
d e n t s w i t h o n e f a c u l t y m e m b e r .
W h e t h e r o r n o t t h e r e s u l t s a r e r e p e a t -
a b l e a t o t h e r i n s t i t u t i o n s i s u n k n o w n .
S c i e n t if i c a ll y , t h e q u e s t i o n a b o u t w h i c h
t e c h n i q u e o f f e r s t h e b e s t r e s u l t w i l l
r e q u i r e a r a n d o m i z e d p r o s p e c t i v e
s t u d y . T h i s t y p e o f a s t u d y w i l l a l lo w
f a c t o r s s u c h a s o p e r a t o r e x p e r i e n c e ,
p a t i e n t p o p u l a t i o n a n d t h e m u l t i t u d e
o f o t h e r u n c o n t r o l l e d f a c t o r s t o b e le s s
l i k e l y t o a f f e c t th e o u t c o m e . S u c h a
s t u d y h a s n o t y e t b e e n p e r f o r m e d b u t
i s c u r r e n t l y u n d e r w a y i n t h e U n i t e d
S t a t e s .
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A d d r e s s :
Edward Ellis 11I, D.D.S., M.S.
Professor, Oral and Maxillofacial Surgery
The University of Texas Southwestern
Medical Center
5323 Harry Hines Blvd. CS3.104
Dallas, Texas 75235 9109
USA
Tel. +1 214 648 8963
Fax: +1 214 648 7620
e-mail: [email protected]