Treatment Modalities for Angle Fractures

8/9/2019 Treatment Modalities for Angle Fractures

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Int . J. Oral Maxi l loJhc. Surg. 1999; 28 :2 43 ~5 2

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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

4 5

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


4/10

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.


5/10

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 .


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.


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.


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


6/10

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 .


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


7/10

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


8/10

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]

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Treatment Modalities for Angle Fractures