ORIGINAL ARTICLE

Diagnostic and therapeutic aspects in the treatment of gunshotwounds of the viscerocranium

A. Grobe • J. Klatt • M. Heiland • R. Schmelzle •

P. Pohlenz

Received: 11 September 2009 / Accepted: 26 January 2010 / Published online: 11 May 2010

� Urban & Vogel 2010

Abstract Gunshot wounds of the viscerocranium are a rare

occurrence during times of peace in Europe. The removal of

projectiles is recommended; in some cases, however, this is

controversial. The material properties of projectiles and

destruction of anatomical landmarks make it difficult to

determine their precise location. Therefore, navigation sys-

tems and cone-beam computed tomography (CT) provide the

surgeon with continuous intraoperative orientation in real-

time. The aim of this study was to report our experiences for

image-guided removal of projectiles, the use of cone-beam

computed tomography and the resulting intra- and postoper-

ative complications. We investigated 50 patients with gunshot

wounds of the facial skeleton retrospectively, 32 had image-

guided surgical removal of projectiles in the oral and maxil-

lofacial region, 18 had surgical removal of projectiles without

navigation assistance and in 28 cases we used cone-beam

CT in the case of dislocated projectiles and fractured bones.

There was a significant correlation (p = 0.0136) between the

navigated versus not navigated surgery and complication

rate (8 vs. 32%, p = 0.0132) including major bleeding, soft

tissue infections and nerve damage. Furthermore, we could

reduce operating time while using a navigation system and

cone-beam CT (p = 0.038). A high tendency between oper-

ating time and navigated surgery (p = 0.1103) was found.

In conclusion, there is a significant correlation between

reduced intra- and postoperative complications including

wound infections, nerve damage and major bleeding and the

appropriate use of a navigation system. In all these cases we

were able to present reduced operating time. Cone-beam

CT plays a key role as a useful diagnostic tool in detecting

projectiles or metallic foreign bodies intraoperatively.

Keywords Gunshot wounds � Projectiles �Imaging techniques � Cone-beam computed tomography �Navigated surgery

Introduction

Gunshot wounds of the maxillofacial region are a rare

occurrence during times of peace in Europe. Recently,

however, there has been a general increase in number and

severity of these injuries [19]. They are mainly caused

by suicide attempts, violent conflicts or negligent handling

[1, 3].

A projectile can contain a variety of materials that show

differences in their deformation and fragmentation behav-

ior. Missile characteristics such as flight velocity and

rotational velocity, mass, caliber, composition and angle of

trajectory all influence the extent of gunshot injuries [2, 7].

The face comprises a complex anatomical arrangement of

bone and soft tissues so that the severity and extent of

injury may range from a simple wound of soft tissues to a

severe combined destruction of the viscerocranium,

including the vascular and nervous systems. Even if the

gunshot injury itself does not cause major problems, the

surgical removal of projectiles can cause damaging of vital

anatomical structures. However, conventional radiography,

computed tomography, image-guided surgical removal and

A. Grobe (&) � J. Klatt � R. Schmelzle � P. Pohlenz

Department of Oral and Maxillofacial Surgery,

University Medical Center Hamburg-Eppendorf,

Martinistr. 52, 20246 Hamburg, Germany

e-mail: a.groebe@uke.de

M. Heiland

Department of Oral and Maxillofacial Surgery,

General Hospital of Bremerhaven-Reinkenheide,

Postbrookstr. 103, 27574 Bremerhaven, Germany

e-mail: Max.Heiland@klinikum-bremerhaven.de

Eur J Trauma Emerg Surg (2011) 37:41–47

DOI 10.1007/s00068-010-0023-z

cone-beam CT have been applied to facilitate that proce-

dure [24, 26].

On the other hand, it has been shown that remaining

projectiles may lead to infection [14, 21] or migrate from

the site of the entry [18], and it is well known that metal

embedded in body tissue can be a source of potential

exposure to toxic effects [22, 28]. Moreover, the pellets

may dislocate within the soft tissue or sinuses spontane-

ously. However, it does not seem appropriate to leave a

pellet as has been proposed previously and is still discussed

with controversy [10, 12].

Even if the exact position is known from imaging data,

the accurate reproduction of this position in the physical

space of the patient can be difficult, if the projectile or

foreign body is not adjacent to a definite anatomical

landmark. Therefore, so called navigation systems and

cone-beam CT allow the registration of image space and

physical space of the patient and give the surgeon contin-

uous real-time orientation intraoperatively.

Cone-beam CT is a recently introduced imaging tech-

nique that uses a cone-beam moving around a part of the

body under examination and allows images to be obtained

at lower doses of radiation than conventional CT. The main

advantage of cone-beam CT over conventional CT is that

the images have considerably fewer metal artefacts and is

thus able to localise metallic foreign bodies [18].

The aim of this study was to report our experiences for

image-guided removal of projectiles and cone-beam CT in

the viscerocranium and whether there is a significant cor-

relation with resulting intra- and postoperative complica-

tions caused by the surgical procedure.

Patients and methods

We investigated 50 patients retrospectively. Patient ages

ranged from 17 to 77 years with a higher frequency in

males (39/78%) than in females (11/22%). Thirty-two had

image-guided surgical removal (Brainlab vector vision2) of

projectiles in the facial region, 18 had surgical removal of

projectiles without navigation assistance. In 28 of the cases

we used cone-beam CT (Siemens Arcadis Orbic 3D)

intraoperatively to detect spontaneously dislocated pro-

jectiles or evaluate the result of treated boney fractures. All

patients were being treated at the Department of Oral and

Maxillofacial Surgery of the University Medical Center

Hamburg-Eppendorf, Germany, between 1998 and 2008.

Information and patient data were gained from patient files

and patient radiographs (conventional radiographs, cone-

beam CT and CT scans) retrospectively and were sorted

according to the age, gender, type and classification of

facial injuries, diagnostic methods, treatment received and

complications. Depending on the pattern of injury,

treatment planning often required different or combined

radiographic examinations, not only to assess the extent of

the hard and soft tissue destruction, but also for location of

projectiles and planning the surgical procedure.

Statistical analysis

For statistical analysis SPSS for Windows (Version 11.5.1)

(SPSS Inc., Chicago, IL, USA) was used. Significance

statements refer to p values of two-tailed tests that were

less than 0.05.

Results

In 23 of the cases we had a retained projectile, followed by

a full penetration, a grazing shot or because of shotguns

(Fig. 1). The majority of the injuries were caused by vio-

lent conflicts (n = 19, 38%), negligent handling (n = 11,

22%), suicide attempts (n = 13, 26%) or because of pro-

fessional reasons (n = 7, 14%).

All patients had soft tissue injuries, in 50% of the cases

(n = 25) combined with hard-tissue injuries to the viscer-

ocranium (Fig. 2). Following the classification of Gant

et al. [9] there were frontal bone fractures, facial injuries,

and supraorbital rim fractures in the upper third and soft

tissue injuries to the temple. In the middle third of the

viscerocranium we had lateral mid-facial fractures (zygo-

maticoorbital), followed by dentoalveolar fractures and soft

tissue injuries to the cheek. These injuries constituted the

greatest amount of injuries of the viscerocranium in this

study. Finally, the lower third injuries, including the

mandible and its related structures, ranged from simple

penetrating wounds of the chin to gross destruction with

bony defects (Fig. 2).

The majority of the sample (n = 44, 88%) had no

associated bodily injuries. The most common associated

injuries were neurocranium (n = 4, 8%), neck and limb

injuries (n = 3, 6%) with the thorax and abdomen (n = 3,

6%) at least common.

No special investigations were required in 8% (n = 4)

of the sample, conventional x-ray films alone were

46%

26%

22%

6%retained projectile, n=23

full penetration, n=13

grazing shot, n=11

shotgun, n=3

Fig. 1 Type of shot causing the injury of the maxillofacial region

42 A. Grobe et al.

requested in 18% (n = 9) and in combination with CT

scans and cone-beam CT in 74% (n = 37) of the cases. The

conventional radiographs and CT-investigations were done

in our Department of Radiology. In case of invisibility of

the projectiles on physical examination and inspection, or

if the foreign body was close to vital anatomical structures,

navigation-assisted surgery was used.

In 70.8% of all conventional radiographs and 84.2% of

CT scans we found pathologic results preoperatively

(Fig. 3).

Depending on the material properties of the projectile, a

suitable imaging technique should be selected. Metal pro-

jectiles are radiopaque and can be detected by all radio-

logical examinations. There are differences between the

imaging modalities in the presence of artefacts and final

imaging quality. Since CT and cone-beam CT both produce

three-dimensional reconstruction images, the presence of

high-density metal objects create artefacts that make it

sometimes difficult to obtain accurate information about

adjacent anatomical structures.

In the case of navigation-assisted surgery, for the

registration process image data was transferred to the

navigation system and the foreign bodies were located and

marked within the planning software (Fig. 4).

Navigation surgery can be performed if either CT or

cone-beam CT data sets are available and reference points

are identified. Navigation systems have an accuracy of

±1 mm [20]. For valid tracking, the relation of the patients

rigid body to the patients anatomy has to be established

within the registration-process. Intraoperatively a rigid

body is affixed to the patients head with bone screws

directly to the skull. Afterwards the registration-process

was done by identifying the corresponding positions of the

titanium markers in the image data as well as on the

patient. Navigation facilitates the surgeon’s orientation to

unexposed anatomical structures. It helps to detect the path

of the projectile and to preserve surrounding tissues.

Cone-beam CT is a modern imaging technique that

has the advantage of being associated with a low level of

metal artefacts [29]. Despite limitations for soft tissue

imaging [8], cone-beam CT is well suited to imaging metal

projectiles or to evaluate facial fractures and presents a

valuable addition to the wide range of diagnostic tools

available.

0%

5%

10%

15%

20%

25%

30%

35%

40%

Front

al bo

ne (n

=3)

Orbit (

n=17

)

Zygom

atico

-orb

ital fr

actu

re (n

=6)

Alveolu

s (n=

2)

Tempo

ral fo

ssa

(n=2

)

Cheek

(n=7

)

Ramus

man

dibula

e (n

=3)

Corpu

s man

dibula

e (n

=3)

Ramus

and

Cor

pus m

andib

ulae

(n=4

)

Chin (n

=2)

Lower

lip (n

=1)

Fig. 2 Patterns of injury

(n = 50)

Fig. 3 CT scan, showing

destruction of the lower jaw

after a suicide attempt

Treatment of gunshot wounds of the viscerocranium 43

All projectiles could be removed via minimally invasive

surgical access to the indicated location; revision of the

gunshot wounds were performed and the defect-fractured

jaw was stabilized with a reconstruction plate (Figs. 5, 6).

All surgical procedures were uneventful, patients were

given antibiotics prophylactically.

The overall complication rate was 34%, there was a

significant correlation (p = 0.0136) between the navigated

surgery versus not navigated surgery and complication rate

including major bleeding (n = 4 vs. n = 1; 8 vs. 2%), soft

tissue infections (n = 7 vs. n = 2; 14 vs. 4%) and nerve

damage (n = 3 vs. n = 0; 6 vs. 0%) (Fig. 7, Table 1).

Furthermore there was a significant correlation

(p = 0.038) between the operation time and postoperative

complications including mainly wound infections and

major bleeding.

Another finding was the high tendency between opera-

tion time and navigated surgery (p = 0.1103). While using

a navigation system we could reduce the operation time.

The average duration of a not-navigated surgical procedure

was 164 ± 73 min versus 120 ± 76 min for a navigated

surgical procedure including reference-process.

In 28 of the cases we used a cone-beam CT (Siemens

Arcadis Orbic 3D) to reproduce the new position of

Fig. 4 Preoperative screenshot

from the navigation system

showing a triplanar view with

the current position of a

projectile inside the left orbit

Fig. 5 Intraoperative imaging

system (Siemens Arcadis Orbic

3D) for the detection of a

fractured lower jaw (a, b)

44 A. Grobe et al.

spontaneously dislocated projectiles (sinus maxillaris

n = 9, temporal region n = 3, orbit n = 3) or evaluate

treated bony fractures (n = 13). The foreign bodies were

found and removed uneventful in all cases.

All patients were hospitalized for at least 6 days, the

mean stay was 14.3 days (±7.9).

Discussion

Gunshot injuries are rare in Western Europe in times of peace.

They are usually the result of suicide, violent conflicts and

negligent handling. Literature on gunshot wounds to the vis-

cerocranium remains scare. For optimal interdisciplinary

management a careful clinical examination, a sound knowl-

edge of gunshot wounds as well as ballistics, and a well

planned preoperative examination plan are necessary.

Projectiles should be removed surgically whenever

possible considering the state of the patient and the location

and kind of the foreign body [3, 4]. Gunshot wounds often

show damaged tissue, altered anatomy, and projectiles

often lie close to vital anatomical structures with difficult

surgical access. To identify the exact position of a foreign

body and assess the damaged surrounding tissue, a variety

Fig. 6 Intraoperative situation

showing the destruction of soft

tissue (a, b), the fractured lower

jaw with boney defect (c, d, e),

stabilized jaw (f), removed

projectile (g) and the situation

6 months after treatment (h)

Treatment of gunshot wounds of the viscerocranium 45

of radiological examinations are possible and described in

the literature. Since it is usually impossible to identify the

exact position of a projectile by visual inspection alone,

conventional radiographs, computed tomography (CT

scans) and cone-beam CT, which were introduced a few

years ago [11, 16, 29], are available.

The circumstances that indicated the need of a naviga-

tion system were:

• failure of previous attempts at removal of a projectile or

foreign body;

• the presence of multiple foreign bodies;

• the presence of structures at risk close to the foreign

body or in the path of the surgical access towards the

foreign body; and,

• the objective to achieve minimally invasive surgical access.

Sometimes projectiles tend to migrate within the soft tis-

sue from the site of the entry. In these cases navigation based

on preoperatively acquired imaging data becomes useless for

relocation of a foreign body. To replicate the new position of

a projectile within the soft tissue or inside a sinus, cone-beam

CT and C-arm systems are available intraoperatively,

although there are some limitations for soft tissue imaging [6,

8, 17, 23]. We used cone-beam CT to reproduce the new

position of spontaneously dislocated projectiles inside a sinus

or to evaluate the immediate outcome of treated bony frac-

tures. In all cases projectiles could be identified and in two

cases we reconsidered the position of screws because of the

introperative cone-beam CT scan result to avoid any further

operation. However, cone-beam CT and C-arm systems are

seldom available in oral and maxillofacial operating theaters,

alternative techniques like ultrasound guided removal of

projectiles as well as a mobile dental X-ray device for the

acquisition of conventional radiographs in two planes with

reference markers attached to the surgical site are described

in the literature [15, 25]. Although ultrasound is not invasive

and does not expose the patient to radiation, it requires direct

contact with the surgical field and increases the risk of con-

tamination. Moreover, the detection of projectiles behind

bony structures is not possible. In the case of conventional

skull radiographs, the accurate reproduction of a position in

soft tissues is difficult, because the projectile is not adjacent

to a definite anatomical landmark.

Once the position of the projectile has been located and

the extent of the damaged tissue has been assessed, an

individual treatment plan has to be established. In the lit-

erature the removal of projectiles is recommended [4] in

some cases, however, in exceptional cases some authors

leave a projectile in situ [10, 12]. There are few case

reports and not much data about the outcome of those

cases, further studies are needed.

In more than 50% of the cases we had combined soft

tissue and hard tissue injuries. The number of soft tissue

injuries alone appears high, considering the intricate anat-

omy of the maxillofacial region. These findings were

similar to those reported earlier in the literature [9, 13].

Similar to soft tissue repair, the techniques used in

immediate reconstruction of bony defects caused by

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

not navigated navigated

complications

no complications

Fig. 7 Complication rate; surgical removal of projectiles with and

without appropriate use of a navigation system

Table 1 Intra- and postoperative complications in detail

Patient Complication

Navigated Not navigated

Pre- and intraoperative

D.G. – Major bleeding (A. carotis ext.)

O.M. – Major bleeding (A. carotis comm.)

K.F. – Major bleeding (A. carotis ext.)

K.M. – Major bleeding(A. temporalis)

D.H. Major bleeding

(A. facialis)

S.R. – Lesion lingual nerve

P.M. – Lesion facial nerve

R.O. – Lesion inf. alveolar nerve

Postoperative

H.P. – Soft tissue infection (floor of mouth)

P.J. – Soft tissue infection (cheek)

G.S. – Soft tissue infection (cheek)

H.N. – Soft tissue infection (orbit)

W.M. – Soft tissue infection (orbit)

B.M. – Soft tissue infection (orbit)

N.C. – Soft tissue infection (orbit)

H.T. Soft tissue infection

(cheek)

–

O.S. Soft tissue

infection(chin)

–

46 A. Grobe et al.

gunshot wounds are equally as effective as those employed

in reconstruction of routine procedures [5].

The overall complication rate intra- and postoperatively

was relatively high and was caused by wound infections,

nerve damage and bleeding complications, and have been

described before [13, 27]. A possible explanation maybe

the large wound surface and extended damage of tissue

caused by either the pattern of injury or the operation itself.

Our findings highlight the fact that another reason for these

complications is a prolonged operating time, which can be

reduced by the assistance of a navigation system. Fur-

thermore the collateral damage of tissue can be reduced by

minimally surgical access in case of an appropriate use of a

navigation system and cone-beam CT.

In conclusion there is a significant correlation between

reduced intra- and postoperative complications including

wound infections, nerve damage and major bleeding and

the appropriate use of a navigation system and/or cone-

beam CT. Navigation-assisted surgery facilitates the sur-

geon’s orientation to unexposed anatomical structures and

projectiles so that we could present in all these cases

reduced operation time. Cone-beam CT plays an important

role and is a useful diagnostic tool in detecting projectiles

or metallic foreign bodies intraoperatively and to evaluate

the treatment of fractured bones.

Acknowledgment We acknowledge Dr. Henning Hanken and

Associate Professor Marcus Foth for their help and valuable com-

ments on earlier versions of this manuscript.

Conflict of interest statement None.

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Treatment of gunshot wounds of the viscerocranium 47