Epidemiology of mandibular fractures treated at Kaunas University of Medicine Hospital, Lithuania.

Abstract

Fractures of the mandible are one of the most common maxillofacial injuries. Because the pattern and incidence of mandibular fractures vary in different countries, there is a need to evaluate aspects of mandibular trauma in Lithuania's population. In this retrospective study hospital files of Oral and maxillofacial surgery unit of Kaunas University of Medicine Hospital were examined. The data that we collected included age, gender, hospitalization time, trauma mechanism, site of fracture, associated injuries, diagnostic and treatment methods. 87.1% of patients were male and they predominated in all age groups with a male to female ratio of 6.8:1. The highest incidence of mandibular fractures in male patients was in the 16-30 year age group and 31-45 year group for females. Interpersonal violence was the main cause of mandibular fractures, followed by falls and road traffic accidents. The incidence of falls in the <16 year age group was higher than expected. The angle was the most common fracture site (34.8%) and 51.7% patients experienced multiple fractures. The mean hospitalization time was 7.34+/-9.02 days. 55% of patients required Kirschner wire osteosynthesis, open reduction with miniplate osteosynthesis or a combination of both methods.

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Stomatologija, Baltic Dental and Maxillofacial Journal, 2009, Vol. 11, No. 3 73
SCIENTIFIC ARTICLES
Stomatologija, Baltic Dental and Maxillofacial Journal, 11:73-76, 2009
SUMMARY
Fractures of the mandible are one of the most common maxillofacial injuries. Because the
pattern and incidence of mandibular fractures vary in different countries, there is a need to
evaluate aspects of mandibular trauma in Lithuania's population. In this retrospective study
hospital files of Oral and maxillofacial surgery unit of Kaunas University of Medicine Hospital
were examined. The data that we collected included age, gender, hospitalization time, trauma
mechanism, site of fracture, associated injuries, diagnostic and treatment methods. 87.1% of
patients were male and they predominated in all age groups with a male to female ratio of 6.8:1.
The highest incidence of mandibular fractures in male patients was in the 16-30 year age group
and 31-45 year group for females. Interpersonal violence was the main cause of mandibular
fractures, followed by falls and road traffic accidents. The incidence of falls in the <16 year
age group was higher than expected. The angle was the most common fracture site (34.8%)
and 51.7% patients experienced multiple fractures. The mean hospitalization time was 7.34±9.02
days. 55% of patients required Kirschner wire osteosynthesis, open reduction with miniplate
osteosynthesis or a combination of both methods.
Key words: mandibular fractures, condyle, interpersonal violence.
Epidemiology of mandibular fractures treated at Kaunas
University of Medicine Hospital, Lithuania
Ricardas Kubilius,Tadas Keizeris
INTRODUCTION
Mandible is the only mobile bone of the facial
skeleton and its anatomical features make this bone
important in speech, mastication and respiration.
Skeletal and soft tissues of the face region are prone
to injuries as it is the most exposed part of the body
[1]. Many authors report mandibular fractures as
the most common site of maxillofacial fractures, fol-
lowed by the zygomatic complex [1,2] and majority
of patients fall in the 20-29 year age group [1-3,9-
15].The most common causes of mandibular frac-
tures remain interpersonal violence (IPV), road traf-
fic accidents (RTA), sports and falls with a domi-
nance of IPV [3,4], while some authors point out
RTA as the main cause [5,6]. The purpose of this
retrospective study is to evaluate current pattern and
aetiology of mandibular fractures in middle, south-
western and northwestern Lithuania and provide
detailed information about some aspects of mandibu-
lar trauma.
MATERIAL AND METHODS
In this study data of 916 patients who reported
to Kaunas University of Medicine Hospital Oral and
maxillofacial surgery unit during a 3 year period (Janu-
ary of 2005 to January of 2008) with radiographically
and clinically confirmed mandibular fractures were
analyzed. 5 patients (.5%) had partially incomplete
data but were included in data analysis. Patient de-
tails were reviewed retrospectively by examining
hospital files. The following data were collected: age,
gender, hospitalization time, trauma mechanism, site
of fracture, associated injuries, diagnostic and treat-
ment methods.
A database was created in Microsoft Excel.
The statistical analysis was performed and results
were tested for statistical significance using SPSS
15.0 for Windows. Statistical analyses included de-
scriptive statistics, Student’s t-test to compare two
groups, χ2 test for bivariate associations and
ANOVA followed by Bonferonni test for multiple
comparisons. Some results were presented as
*Department of Maxillofacial Surgery, Kaunas University of Medi-
cine, Kaunas, Lithuania
Ricardas Kubilius* – D.D.S., dr.hab.med., professor, Head of
Department of Maxillofacial Surgery
Tadas Keizeris* – postgraduate student in medicine
Address correspondence to: Tadas Keizeris, Sviesos str. 20-3, LT-
50281, Kaunas, Lithuania.
E-mail address: tadaskeizeris@yahoo.com

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74Stomatologija, Baltic Dental and Maxillofacial Journal, 2009, Vol. 11, No. 3
R. Kubilius,T. KeizerisSCIENTIFIC ARTICLES
mean ±1.96×standard deviation (95% confidence
interval).
RESULTS
798 patients were male (87.1% of the popula-
tion) and 118 patients were female (12.9%) with a
male to female ratio of 6.8:1. The patients’ age ranged
from 1 to 85 years. Mean age of male patients was
31.21±24.24 years and female 35.15±26.63 years and
this difference was statistically significant (p=.001).
The highest incidence of mandibular fractures was
in the 16-30 year age group (50.2%), followed by the
31-45 year age group (32.8%) (Figure 1). Men out-
numbered women in all the age groups with statisti-
cal significance in 16-30 and 46-60 age groups (p<.05).
The preponderant cause of mandibular fractures
was IPV (71.8%), followed by falls (12.3%) and RTA
(6%). The highest incidence of falls was in the <16
year age group at a higher than expected rate. The
highest percentage of male and female patients was
in IPV (64.6% and 7.2% respectively) and there were
no female patients in sports (Table 1).
A total of 916 patients had 1429 mandibular frac-
tures. The most common fracture site by anatomical
location was the angle (497 cases, 34.8%), followed
by body (382 cases, 26.7%) and condyle (327 cases,
22.9%). 442 patients had isolated fractures (48.3%),
among which the commonest was the angle (219
cases, 49.5%) and condyle (97 cases, 21.9%). The
dominant fracture site in male patients was the angle
(447 cases, 36.1%) and in female patients the man-
dibular body (61 cases, 31.9%) (Figure 2). Angle, body
and parasymphysis fractures statistically significantly
occurred more often in male than female patients
(p<.05). The most common combination of fractures
was body and angle (137 cases, 15%), followed by
body and condyle (86 cases, 9.4%) and
parasymphysis and condyle (43 cases, 4.7%). There
were 396 bilateral fractures (43.2%) and right side
mandibular fractures were significantly more frequent
in male patients (95% CI, p=.0004).
69 patients (7.5%) had 102 concomitant maxillo-
facial fractures, the most common of which was na-
sal bone and zygomaticomaxillary complex (25 cases
each, 24.5% each), followed by maxillary bones (18
cases, 17.6%) and zygomatic complex (9 cases,
8.8%). Preponderant cause of these fractures was
IPV (54.7%), followed by RTA (22.1%) and falls
(15.1%).
Mean hospitalization time was 7.34±9.02 days.
Patients with one fractured mandible site had the
shortest hospitalization time (6.74±4.12 days) and the
longest (10.86±7.87 days) was for patients with 3
fracture sites (Table 2). There was a statistically sig-
nificant association between the number of fracture
sites and increasing hospitalization time, except those
who had 4 fracture sites of the mandible (Table 3).
Fig. 1. Distribution of mandibular fractures by age and gender

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Stomatologija, Baltic Dental and Maxillofacial Journal, 2009, Vol. 11, No. 3 75
SCIENTIFIC ARTICLESR. Kubilius,T. Keizeris
The most common mandibular fracture diagnos-
tic method was anteroposterior craniogram combined
with orthopantomogram (65.5%). Only anteroposte-
rior craniogram was taken for 9% of patients and
orthopantomogram for 24.9% of patients.
Conservative treatment (intermaxillary fixation)
as initial therapy was applied to 685 (74.8%) pa-
tients and for 374 of these patients (54.6%) it was
successful. Kirschner wire osteosynthesis, open re-
duction with miniplate osteosynthesis or a combina-
tion of both methods were required by 55% of all
patients, including those whom conservative treat-
ment was not sufficient, and the most common
method (70.6%) was open reduction with miniplate
osteosynthesis. When there was more than one frac-
ture site, active treatment was required in 58.2% of
patients, statistically significantly more than com-
pared to 51.5% of patients having one fracture site
of the mandible (Table 4). 12 patients (1.3%) re-
fused of active treatment.
DISCUSSION
The causes and incidence of maxillofacial frac-
tures varies according to geographical region, culture,
siocioeconomic status, religion and era [6,7]. In this
study men were injured more common and this ten-
dency corresponds to previously published reviews,
although male to female ratio varies in different re-
gions [7-14]. The majority of patients (50.2%) were
in the 16-30 year age group and this also supports
international trends of mandibular trauma [9-15]. K.
H. Lee [3] reported falls as a category which ac-
counted for most mandibular fractures in the >60 year
age patient group. Contrary to these data we found
falls to be responsible for 45.8% (more than expected)
of fractures in the <16 year age group and this dif-
ference was statistically significant compared to all
age groups (95% CI, p≤.001). IPV in this age group
also accounted for 45.8% (less than expected) of
mandibular fractures with a statistically significant
difference among all other age groups (95% CI,
p≤.012) except >60 year age group (95% CI, p=.151).
Such results might show a possibility that teenagers
tend to report violence as falls because of fear or
other reasons. This requires closer investigation.
However, we got a striking similarity with K. H. Lee
regarding sports. He observed 74% of all sport-re-
lated fractures affecting young adults in the 16-30
year age group, compared to 75% of sport injuries
falling in the 16-30 year age group in our review.
Many authors have reported road accidents as
the main cause of mandibular fractures [5,6,10,14],
Fig. 2. Site of mandibular fractures
Table 1. Distribution of mandibular fractures by aetiology
and gender
Aetiology
IPV
Falls
RTA
Daily activities 32 (3.5%)
Sports
Work
Others
Men (%)
592 (64.6%)
88 (9.6%)
41 (4.5%)
Women (%)
66 (7.2%)
25 (2.7%)
14 (1.5%)
4 (.4%)
0
1 (.1%)
8 (.9%)
Total (%)
658 (71.8%)
113 (12.3%)
55 (6%)
36 (3.9%)
16 (1.7%)
3 (.3%)
34 (3.7%)
16 (1.7%)
2 (.2%)
26 (2.8%)
IPV – interpersonal violence; RTA – road traffic accident.
Table 2. Mean hospitalization time according to number of
fracture sites
No of fracture sites
1
2
3
4
Mean hospitalization time (days)
6.74 ± 8.08
7.61 ± 8.96
10.86 ± 15.42
8.00 ± 9.99
Table 3. Mean difference of hospitalization time according to
number of fractures
No of fracture sites
compared
1 – 2
1 – 3
1 – 4
2 – 3
2 – 4
3 – 4
Mean difference
(days)
-.865
-4.123
-.865
-3.257
-.393
2.865
p (95% CI)
.030
.000
1.000
.000
1.000
1.000
CI – confidence interval.
Table 4. Treatment methods used in cases of one and more
than one fracture sites
Treatment
method
IW
IW followed by KW 79 (17.8%)
ORMO
IW followed by
ORMO
IW followed by
KW and ORMO
Total active
treatment
1 fracture
site
197 (44.5%)
>1 fracture
site
177 (37.7%)
46 (9.8%)
107 (22.8%)
107 (22.8%)
p
(95% CI)
.0195
.0002
.0637
.0000
83 (18.7%)
56 (12.6%)
10 (2.3%) 13 (2.8%) .3037
228 (51.5%) 273 (58.2%) .0203
IW – interdental wiring; KW – Kirschner wires; ORMO – open re-
duction with miniplate osteosynthesis; CI – confidence interval.

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76Stomatologija, Baltic Dental and Maxillofacial Journal, 2009, Vol. 11, No. 3
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R. Kubilius,T. KeizerisSCIENTIFIC ARTICLES
while others have reported IPV as the main cause
and confirms our results [3,4,12]. This difference is
usually explained by different geographical region,
culture, siocioeconomic status and religion.
We found a statistical significant tendency of
hospitalization time increase proportionally to the num-
ber of fracture sites of the mandible, except in the
group of 4 fracture sites. This might be explained by
a small patient population (4 patients, one of them
left the hospital without permission after 3 days) in
the aforesaid group.
King R. E. et al [9] reported a statistically sig-
nificant association between motor vehicle accidents
and parasymphyseal fracture and between assault and
angle fracture. In our population the highest incidence
of condylar fracture was in RTA, angle fracture oc-
curred most often in sports and IPV.
According to King R. E. et al [9], mandibular
fractures more often occur in multiple sites. 51.8%
of patients in our study had more than one fracture
site, among which the highest incidence was in RTA
(67.9%), followed by IPV and falls (52.9% and
47.3%, respectively).
Most fractures which required active treatment
were caused by IPV (70.6%), but the highest inci-
dence of active treatment was related to RTA
(75.5%). More than half of conservative treatment
cases appeared to be successful and the rest 45.4%
of patients were treated with Kirschner wires or/and
open reduction with miniplate osteosynthesis.
CONCLUSIONS
The leading cause of mandibular fractures is in-
terpersonal violence and most of the affected patients
are young men. There is a need of further investiga-
tion for possible associations between mandibular in-
juries and other contributing factors.
Received: 24 06 2009
Accepted for publishing: 28 09 2009