Clinical and radiographic evaluation of surgical treatment of zygomatic fractures using 1.5 mm miniplates system

doi:10.4236/ojst.2011.14026

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Open Journal of Stomatology, 2011, 1, 172-178

doi:10.4236/ojst.2011.14026 Published Online December 2011 (http://www.SciRP.org/journal/ojst/ OJST

Published Online December 2011 in SciRes. http://www.scirp.org/journal/OJST

Clinical and radiographic evaluation of surgical treatment of

zygomatic fractures using 1.5 mm miniplates system

Paulo Norberto Hasse, Walter Cristiano Gealh*, Cassiano Costa Silva Pereira,

Luiz Francisco Coradazzi, Osvaldo Magro Filho, Idelmo Rangel Garcia Junior

Maxillofacial Surgery Department, Araçatuba Dentistry School, Universidade Estadual Paulista, São Paulo, Brazil.

Email: *[email protected]

Received 10 July 2011; revised 25 August 2011; accepted 5 September 2011.

ABSTRACT

Fractures of the zygomaticomaxillary complex are am-

ong the most common face traumas. Based upon the

complexity and great variety of reported diagnoses

and treatments, the proposal of this study wa s to eva-

luate, clinically and radiographically, unilateral zy-

gomatic fractures treated through internal rigid fixa-

tion with miniplates and screws of 1.5 mm. Material

and Method: 15 patients with unilateral fractures of

the zygomaticoma xillary complex were analyzed, and

compared with 15 patients without fractures so that a

comparative analysis of the area and the perimeter of

the orbital cavities could be made, as well as the dis-

tance from the nasal point to the zygomatic promi-

nence between both groups. Results: In the radiogra-

phic analysis, the both groups presented similarity in

the perimeter and in the area of the orbital cavities.

Concerning the distance from the nasal point to the

zygomatic prominence, only the operated group show-

ed a significant difference between the sides, even

though clinically the observation of the asymmetry

had been absent or discreet. Conclusions: The treat-

ment of unilateral fractures of the zygomaticomaxil-

lary complex with the use of plates and screws of the

1.5 mm system proved to be effective, showing good

esthetic results and low complication rates.

Keywords: Zygomatic Fractures; Internal Fracture Fixa-

tion; Facial Injuries

1. INTRODUCTION

The treatment of the fractures of the zygomaticomaxil-

lary complex (ZMC) is amply discussed in the literature,

being that three great conflicts still persist in relation to

the applied therapy [1]. The first concerns the best way

for surgical reduction of the fractures. The second is

related to the necessity to fix them or not after the reduc-

tion, and the third concerns the number of fixation points

necessary so that the fractures of the ZMC are stabilized

[2].

Treating with mi nipl at es and screws provi ded faci lity of

use, good stability, bio-compatibility, as well as the pos-

sibility of being used in areas where the bone is not so

thick, with little soft tissue overlap, minimizing the sym-

ptoms of local esthetic discomfort [3].

Technological development together with surgical ne-

cessity stimulated the deve lopment of extremely delicate

systems of plates and screws with guarantees of pro-

moting adequate resistance to bending and three-dimen-

sional mechanical stability assuring predictability in the

treatment of facial fractures [4-6].

Considering the high rate of fractures in the ZMC and

the disagreements about treatment we proposed to carry

out the present study to evaluating the zygomatic fra-

ctures treated with a 1.5 mm fixation system.

2. MATERIAL AND METHODS

Thirty patients were analyzed clinically and radiogra-

phically. Fifteen had been submitted to surgical treat-

ment of a non-comminuted unilateral fracture of the zygo-

maticomaxillary complex, and made up the Treated Group

(TG) and fifteen peoples without fractures of the ZMC

were called the Con trol Group (CG).

On the fifteen patients of the TG access to the fronto-

zygomatic region was carried out through a supraciliary

incision. The second region to be accessed varied ac-

cording to the case, using the infra-orbital region and/or

zygomaticomaxillary pillar. The surgical reduction was

carried out through the use of the Caroll-Girard screw

and the internal fix ation was done in all the patients with

titanium miniplates and screws of the system of 1.5 mm.

Posteroanterior X-rays for the cheeks of the face (Wa-

ter’s X-ray) were carried out in the thirty patients, fifteen

in the TG and fifteen in the CG. After obtaining all radio-

graphs, fifteen being from the operated patients and fif-

teen from the salutary patients without fractures, the scan-

ning of the same were done on a “ScanJet 4c/T” scanner

P. N. Hasse et al. / Open Journal of Stomatology 1 (2011) 172-178 173

(Hewlett-Packard). For all of the radiographs a size of

standard image was established, so that there would not

be differences among them. After obtaining the images,

the analysis was carried out by way of the program Im-

ageLab 2000/2.4—a program of analysis and digital pro-

cessing/computerized image (Figure 1).

Two radiographic points were established in order to

evaluate the symmetry of the zygomatic bone from both

sides. The first point was defined by the intersection of the

nose bones (nasal pyramid) and the nasal septum, being

called the nasal point (NP). The second point, called the

zygomatic point (ZP), was established from the most

sideward point and outside the zygomatic arch.

In this way, the operated side (OpS) was compared to

the opposite side (OS) in the Treated Group, and in the

Control Group, th e right side (RS) and the left side (LS)

was compared, in order to obtain fundamental values for

the statistical study.

The clinical evaluation of the TG was carried out with

the intention of determining clinically the possible con-

sequences resulting from the surgical procedures, as well

as the persistent symptomatology originating from the

trauma. Pointing out that in order to do so, only one ob-

server was used, and he considered the following pa-

rameters for evaluation: ocular movement, dystopia, dip-

lopia, paresthesia, limitation of mouth opening, maloc-

clusion, discomfort, ectropion, entropion, apparent sclera,

enophthalmos, exophthalmos, facial symmetry and the

presence of post operative infection. The fifteen patients

from the TG were observed in frontal norm, mento-oc-

cipital, profile, and supero-inferior.

The data obtained was submitted to the test of vari-

ance for analysis of normality by the Kolmogorov-Smir-

nov test and presented normal distribution, which al-

lowed for the carrying out of the parametric t-student

test for matched data (p < 0.05).

3. RESULTS

In the analysis of the Treated Group (TG), the patients’

ages varied from 21 to 64 years (mean = 33 years). Of

these, 87% were men and 13% were women.

In relation to the side of the face that had a higher in-

cidence of fractures of the zygomatic bone, 67% were on

the left side and 33% on the right side. The postoperative

Figure 1. Standard scanning posteroanterior X-rays on the program ImageLab 2000 / 2.4.

P. N. Hasse et al. / Open Journal of Stomatology 1 (2011) 172-178

174

periods were 6 months at the minimum and 16 months at

the maximum. Among the etiological factors, automobile

accidents prevailed (33%), followed by motorcycle acci-

dents (26.6%) and physical aggression (20%). Automo-

bile accidents with pedestrians, falls and work accidents

were responsible for one of each being responsible for

6.6% in each group.

In order to analyze and compare the Treated Group

with the Control Group we selected individuals of the

same sex and age as the patients with the ZMC fracture.

In the analysis of the Control Group the ages varied from

16 to 62 (mean = 37.3 years), also with 80% of the pa-

tients in this group being men and the women being only

20%.

The surgical procedures of fixation with mini-plates

and screws of 1.5 mm system in the patients that made

up the Treated Group included different pillars of sup-

port. The zygomaticomaxillary pillar was the main choi-

ce, used in 14 patients (93.3%), followed by the frontal-

zygomatic region in 13 patients (86.6%) and the infra-

orbital border involved in 5 (33.3%) operated patients.

The internal fixations, depending on the sustaining pil-

lars, presented combinations among themselves. The to-

tal of 11 patients (73.3%) received fixation in two osse-

ous pillars, 3 patients (20%) in three pillars and only 1

patient (6.6%) in one sustaining pillar.

The numbers obtained from the perimeter, area and

distance from the NP to the ZP in the Treated Group and

Control Gro up are c ont ai ned in Table 1.

Through the Image lab 2000 Program, it was possible

to enhance the osseous outlines in order to facilitate the

demarcations of the NP and the ZP (Figures 2 and 3).

4. STATISTICAL ANALYSIS

4.1. Control Group

The analysis of the matched data of the perimeter be-

tween the right side and the left side did not present any

significant difference (p = 0.782), with measurements of

62.32 mm for the right side and 62.43 mm for the left

side.

For the area, the average of the right side was 263.32

mm and 264.38 for the lef t side, there not being any sig-

nificant statistical difference (p = 0.378).

In measuring the distance from the NP to the ZP, the

average values 42.45 mm for the right side and 42.57

mm for the left side, were also not statistically signify-

cant (p > 0.243).

4.2. Treated Gr oup

The analysis of the matched data of the perimeter be-

tween the operated side and the opposite side did not

present any significant difference (p = 0.249), with val-

ues of 62.90 mm for the operated side and 62.15 mm for

the opposite side.

For the area, the average of the operated side was

263.86 mm and 269.19 mm for the opposite side, not

having any statistical difference between them.

From the measuring of the distance from the NP to the

ZP, the average values of 44.50 mm for the right side

and 45.16 mm for the left side presented a statistically

significant difference (p = 0.003).

4.3. Treated Group × the Control Group

Mean and standard deviation from the perimeter, area

and distance from the NP to the ZP between the Control

Group and Treated Group is on Table 2.

Table 1. Perimeter, area and distance from the nasal point (NP) to the zygomatic point (ZP) from the orbital cavities on the operated

side (OpS) and the opposite side (OS) in the Treated Group (TG) and Control Group (CG).

Patient Perimeter OpS (mm)

TG/CG Area OpS (mm)

TG/CG Distance OpS (mm)

TG/CG Perim eter OS (mm)

TG/CG Area OS (mm)

TG/CG Distance OS (mm)

TG/CG

1 63.9/56.3 279.0/219.5 40.26/39.66 61.8/60.6 275.2/217.4 39.64/40.05

2 62.4/63.8 267.0/263.4 43.95/40.84 58.2/62.5 269.2/261.1 43.58/40.74

3 66.4/64.2 304.3/287.5 47.18/42.53 65.0/65.3 301.2/285.4 48.88/42.85

4 73.4/62.3 325.2/267.5 47.98/41.21 70.8/62.4 322.9/266.4 48.15/41.52

5 62.2/59.7 295.0/221.9 44.28/46.44 62.3/59.1 290.6/220.9 46.13/46.97

6 58.6/55.8 230.4/227.0 45.46/40.82 60.3/54.5 234.9/224.2 46.12/40.00

7 63.7/66.5 275.6/297.7 41.35/46.15 63.4/66.8 274.5/304.4 42.49/46.27

8 58.3/64.2 221.3/280.4 43.11/41.79 58.9/65.9 228.9/281.3 44.48/41.89

9 61.5/61.7 235.7/252.2 44.03/42.30 62.1/61.5 246.1/251.7 44.86/42.03

10 73.8/69.8 317.2/321.5 46.17/41.57 72.4/68.5 310.5/322.5 46.82/42.07

11 62.3/61.6 254.6/258.1 45.19/38.82 58.1/60.9 250.2/258.7 45.79/38.91

12 56.0/64.8 205.9/288.0 45.58/41.33 61.2/64.5 210.8/288.4 46.66/41.94

13 62.3/58.5 269.7/237.5 44.84/45.49 61.9/57.6 359.9/252.5 44.97/45.08

14 59.8/61.7 244.4/256.5 42.89/43.05 59.8/62.5 239.0/257.9 43.29/43.12

15 58.9/63.9 232.6/271.1 45.20/44.71 56.1/63.8 224.0/272.9 45.51/45.12

Mean TG/CG 62.4/61.7 263.4/262.9 44.07/41.93 61.7/62.0 268.7/263.8 44.60/42.13

P. N. Hasse et al. / Open Journal of Stomatology 1 (2011) 172-178 175

Table 2. Mean and standard deviation from the perimeter, area and distance from the nasal point (NP) to the zygomatic point (ZP)

between the Control Group and Treated Group (significant difference for p < 0.05).

Variable Mean standard deviation t p

Perimeter

Control Group 62.37 3.62 0.142 0.888

Treated Group 62.53 4.71

Area

Control Group 263.85 29.02 0.305 0.762

Treated Group 266.53 38.41

Distance NP t o ZP

Control Group 42.51 2.30 4.024 <0.001

Treated Group 44.83 2.16

Figure 2. Enhancing the osseous outlines in order to facilitate the demarcations of the NP, ZP and to calculate the perimeter and area

of the orbitas.

present any significant difference (p = 0.888), with val-

ues of 62.37 mm fo r the control group and 62.5 3 for the

treated group. The analysis of the matched data for the

area between the control group and the treated group did

not present any significant difference (p = 0.762), with

values of 263.8 5 for the con trol grou p and 266.53 for the

treated group.

In measuring the distance from the NP to the ZP the

mean values of 42.51 mm for the control group and

44.83 mm for the treated group presented a significant

statistical difference (p < 0.001).

In the clinical analysis among the patients of the Treat-

ed Group no cases of ectropion, entropion, enophthalmos,

exophthalmos, diplopia, sclera apparent, malocclusion or

P. N. Hasse et al. / Open Journal of Stomatology 1 (2011) 172-178

176

Figure 3. Line of the distance from the NP to the ZP.

mouth opening limitation were found. There was only

one case of asymmetry that was classified as “discreet”,

with an appearance of distopia, but without any com-

plaints by the patient. Only one patient reported a dis-

creet paresthesia in the region of the alveolar mucosa

innerved by the superior anterior alveolar nerve associ-

ated with a slight discomfort after nine postoperative

months.

5. DISCUSSION

From the analysis of the collected data, we observed that

traffic accidents (with auto mobiles and motorcyc les) were

responsible for 59.9% of the fractures, and in second

place, patients who were victims of physical aggression

made up 20% of the cases. This corroborated the rates

from Covington et al. [7], who pointed out as main etio-

logical factors, accidents caused by motor vehicles, with

78.6% of the cases, being 68.8% automobiles and 9.8%,

motorcycles.

One of the most controversial top ics in the literature is

about the number of fixation points that are necessary to

avoid the post-surgical dislocation of the fractured zygo-

matic maxillary complex [8-10]. The great majority of

the authors are divided about the need for two or three

places, with a variation of the complexity of the trauma

and the degree of dislocation of the fractured segment [7,

11].

Whenever the primary stabilization of the ZMC frac-

ture was necessary fixation in the region of the zygoma-

tic maxillary pillar (ZM) was chosen, totaling 14 patients

(93.3% of the cases). The frontozygomatic region (FZ)

was fixed in 13 patients (86% of the cases), and the in-

fraorbital rim (IO) in 5 patients (33.3% of the cases).

The combination of the fixation sites followed the fol-

lowing statistics, 9 patients (60%—FZ and ZM), 3 pa-

tients (20%—FZ, ZM and IO), and 1 patient (6.6%) for

each group left over (FZ and IO; IO and ZM; only ZM).

Although there are reports of stability of fractures fixed

only in one point [7,12,13] chose, whenever possible to

put fixation in the two pillars of the ZMC.

The internal fixations carried ou t in the patients in this

study, according to the integrity of the osseous pillars,

presented combinations among them, being that in 11

patients (73.3%) two points of fixation were used, in 3

P. N. Hasse et al. / Open Journal of Stomatology 1 (2011) 172-178 177

cases (20%), there was the need for osteossynthesis in

three pillars and in only 1 patient (6.6%) one fixation

point was used.

Davidson et al. [14] analyzed, in an in vitro study,

several forms of fixation, combining steel wires, plates

and screws, obtaining a total of 25 different combina-

tions. By means of traction that simulated the action of

the masseter muscles they calculated the rotation and the

dislocation after the application of the forces on the dif-

ferent planes. The means of fixation that received the

best results were: fixation with steel wires in three points

and fixation with plates and screws in three points.

However, the stability reached by fixation with plates

and screws in two points was similar to the previous

fixations, highlighting the zygomatic pillar as the strate-

gic point for the opposition of the forces of th e masseter

muscle.

In relation to the combinations and the choice of os-

seous pillars, the combination between the frontozygo-

matic region and the zygomatic maxillary making up a

total of nine (60%) of the fifteen patients treated.

The zygomatic maxillary pillar should be the region of

choice for unstable fractures of the zygomatic bone, for

it acts as a direct antagonist to the action of traction

provoked by the masseter muscle [15].

Strong and Sykes [16] propose a combination of sys-

tems of mini-plates and micro-plates in the different pil-

lars of support of the ZMC. They recommend the use of

microplates of 1.0 or 1.2 mm in the infra-orbital border,

1.5 or 1.7 mm in the frontozygomatic region and 2.0 mm

in the zygomatic maxillary pillar region.

The data obtained from this study are in agreement

with the results obtained in other studies [17]. The diffe-

rences obtained, for the perimeter as well and for the

area of the operated side and the opposite side of the

Treated Group were not statistically significant.

The good stability obtained from the fixation in two

points gains force when compared with the sides obtain-

ed from the Control Group, in other words, the patients

who did not have fractures of the ZMC. In those we

verified that the differences in the values obtained be-

tween the right side and the left side, in referring to the

perimeter and, as well as the area, were also not statistic-

cally significant.

The distance from the NP to the ZP was also another

variable that was analyzed in this study with the aim to

determine a possible zygomatic asymmetry between the

opposite side and the treated side (Figure 3). The results

showed a significant difference between the sides in the

treated group, although the clinical analysis of this data

has not been made evident.

In the patients from the Treated Group a case of asy-

mmetry classified as “discreet” (6.6%) was found, pre-

senting dystopia, but with no complaints from the pa-

tient. Data that corroborates an incidence from 2% to 9%

of facial asymmetry in patients treated by a system of

internal rigid fixation [18,19]. However, in these, the

system used was of 2.0 mm, that structurally guarantees

the smallest rate of deflection, when compared to the

system of 1.5 mm.

The esthetic-functional items evaluated in this study

showed a significant improvement, principally related to

the “bother from the use of the plate”, related by the use

of the system 2.0 mm. One case was reported with dis-

comfort in the region of the zygomatic pillar, however,

associated with a symptomatology of disestesia in the re-

gion of the mucosa near the region with teeth and not

perceptible to palpation.

6. CONCLUSIONS

In this study the treatment of the unilateral fractures of

the zygomatic maxillary complex with the use of plates

and screws of the 1.5 mm system presented good esthe-

tic results and low rates of complications.

7. CONFLICT OF INTEREST

STATEMENT

The authors haven’t any financial and personal relation-

ships with other people or organizations that could inap-

propriately influence this work.

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