Air rifle injury to the head

Sajid Darmadipura MD Umar Kasan MD Abdul Hafid MD Agus Turchan MD

Department of Neurosurgery, Medical School Airlangga University, Dr Soetomo Hospital, Surabaya, Indonesia.

The authors reviewed 16 cases of air rifle injuries to the head, 14 of them were penetrating. While 50% of the victims were adults, almost all of the culprits were children. The entry wounds were mostly in the frontal area and around or exactly on the eye. None was perforating or through and through. The morhidities encountered were considered to be severe in 2 cases (hemiparesis), ocular injuries in 3 cases, and visual field defects in 3 cases. 1 patient died due to recurrent haemorrhage. The initial wound debridement and short course of antibiotic perioperatively seemed to be most important. Retained pellets were removed only if they were accessible.

Considering the risk of morbidity and mortality and the fact that almost all of the culprits were children, air rifles should require adequate precautions and especially be kept out of the reach of children.

Journal of Clinical Neuroscience 1994, l(3) :188-192 0 Longman Group UK Ltd.

Keywords: Brain abscess, Gunshot, Head injury

Introduction Air rifles are easily available in markets or sport shops, and are commonly used for hunting small animals or target shooting. They are considered to be fairly safe and are not protected from the reach of children, despite the danger they may bear.

Severe morbidities and mortalities caused by air riff es have been reported previously.‘.’ However, reports on this issue are relatively rare and only on small numbers of pa~ents~‘3,45,6,7

This article reviewed 16 well observed cases in order to have a better overview on some problems of this kind of injury.

Clinical materials and methods In the period ofJuly 1989 to the end of December 1992, 16 cases of air rifle injuries to the head were treated in our clinic. 10 of them were referred while 6 came directly to us. 14 of them were penetrating, and in 2 cases the pellets lodged extracranially, 1 in the outer table of parietal bone and 1 in the orbit. None of them was perforating or through and through. Air rifle penetrating injuries predominated in a total of 20 cases of penetrating injuries with retained foreign bodies treated in the same period (Table 1).

Our hospital is a referral university hospital which admits some 2000 head injured patients per year. Air rifle craniocerebral injuries were treated as common missile

injuries. Early wound debridement was the most important step of the management, before the removal of the retained pellets. The removal was regarded as semi urgent, in a properly equipped operating theatre, rather than in the emergency unit. Image intensifier was always ready for use but stereotactic apparatus was not available.

Skull radiographs were made for all patients as the first diagnostic method to locate the pellets. CT scanning was mandatory to get information on the location and the trajectory of the pellet and the intracranial pathology that may develop.

Cerebral angiography was the next investigation for patients with suspected or potential vascular injuries.

Several of our particular concerns were: the site and condition of the entry wounds, the location of the metal pellets, the clinical presentation reflecting the cerebral

Table 1 Penetrating injuries to the head with retained foreign bodies

Causes of injuries Number of cases

Air rifle

Knife blade

Shot gun missile

Metal wire

Shell fragment

Air powered nail

14

1

2

1

1

1

Total 20

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Air rifle head injury Clinical studies

Table 2 Sex/age, entry, pellets, morbidity/mortality and pellet removal ^._~___ ~_

Case Sex/Age Location of Entry Location of Morbidity/Mortality Number (Year/Month) Wounds Pellets

___-., ~~~~~ 1 M/30 yr Supraorbital (d) Chiasm VFD, bitemporal

2 Ml4 yr F (5) F (s) -

3 F/2 yr F (d) 0 (d)

4 M/9 yr T (s) 0 (d) VFD, homonymous,

severe hemlparesls

5 Ml52 yr F (d) F (d) -

6 M/3 yr F (d) F (d) -

7 F/4 yr F (d) F (d) -

8 F/l 8 mo Supenor palpepra (s) Sphenold slnus -

9 M/25 yr Eye bulb (s) F (d) Occular Injury, enucleatlon

10 M/l 3 yr F Cd) F (d)

11 Ml24 yr F (s) P (5) -

12 M/l 8 yr Supraorbital (s) P (d) Severe hemlparesls

13 Ml38 yr T (s) P (~1, n.p -

14 M/l 6 mo Eye bulb (d) P (d) Occular injury, vitrectomy,

lrrldectomy

15 F/l 8 yr Superior palpepra (s) Orbit, n.p -

16 Ml65 yr Glabella Supracllnoid Died, suspected recurrent

F = frontal, T = temporal, 0 = occlpltal, P = panetal. d = dextra, s = slwtra n.p = no penetration. VFD = Visual field defect

injuries, e.g. Glasgow Coma Scale (GCS) , neurological

deficits and the presence of convulsions, and signs of

systemic infections such as elevated ESR, leucocytosis,

elevated temperature and the presence of meningeal signs.

The ages of the culprits and victims were also recorded.

Results Table 2 shows the sex and age distribution, the sites of the

entry wounds, the locations where the pellets lodged, the

morbidity and mortality encountered, and the pellet

removals.

Time and source of referral

Onl! 3 of 16 cases treated were from within the city; 13

were from areas out of the city, either referred or came

directly to our service. This corresponds largely to the fact that air rifles are not any more commonly used in city

life. The time of presentations at the emergency unit were

ranged from day 1, the earliest was 2 hours after in-jury. to

day 9. There was no correlation between the time dela) and the source of referral or the distance to our service.

Two of 4 patients from within the city presented on day 6

and day 8. whereas 6 of 12 from the distant countryside

presented on da!, 1.

Early wound debridement and signs of infections

Most patients who were referred had their entry wound dehrided before arrival at our hospital. 10 referred patients, either early or late, who were debrided elsewhere, showed no signs of local wound infection, whereas those

Pellet removal Removed (+) Unremoved (-)

(+I

(+)

(+I

(+)

(+)

(+)

(+)

(+)

c+j

(+I

(-1

t--i

(+)

(--I

haemorrhage

(+)

(--I

(planned to be removed)

who were not debrided and presented on day 4 or later did so. A short course of antibiotic. usually cloxacillin.

ampicillin or sulbenicillin 3 to 5 days periopcratively. was

also administered. None of this series showed signs of’

systemic infection (see TAle 3).

The age of the victims and culprits

The age of the victims varied from 16 months to 65 years.

Eight of all 16 cases (50%) were adults (see Table 2). The

culprits were almost all children (7.5 f 2.-l veal-s). Only in

1 case of this series was the culprit an aitult (case 15).

Three cases with interesting considerations are described. Case 14 invokes the youngest victim and the youngest

culprit of this series. A 16-month-old bo\, was shot by his 5-

year-old brother while they were playing ill the backyard.

He cried a while, hut still kept his balance. His brother

was not aware what he had done to him. The mother. who worried about the reddish right eve of‘ her youngcar son

brought him to our service. On examination he was awake

with no neurological deficits. His right eye was hyperaemic

and somewhat proptotic. The skull photographs and the

Table 3 Presentation, debridement, signs of infection

Presentation: Number Early wound Signs of infection days after injury of cases debridement Local Systemic

l-2 5 + ._

4

4 1 +

1 +

6 1 +

1 +

8-9 3 +

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Clinical studies Air rifle head injury

Fig. 1 Case 14. The youngest victim (16 months). The pellet was clearly seen. There was no hemiparesis encountered in this case.

CT scans (Fig. 1) confirmed the presence of a small metal pellet in his occipital lobe. The consultant ophthalmologist suggested vitriectomy and iridectomy be done. The pellet was considered to be inaccessible.

After a 5 day course of ampicillin he was discharged in a good clinical condition, except for the condition of his eye.

He was closely followed up and showed neither focal nor systemic infection, at 3 months after the injury. This was not the youngest victim reported in literature, as Miner et al3 reported a 2-month-old victim and 4-year-old assailant.

Case 15 was the only adult ‘assailant’ in this series. The husband of a newly married couple was cleaning his air rifle while they relaxed, chatting casually. Not being aware that it was loaded, he accidentally shot his wife in her right upper eyelid. Skull radiographs confirmed the pellet was lodged in the orbit just under the orbital roof. Her right eye was also injured. Debridement and vitrectomy were done at the same operation, and the pellet removed 2 days later. No neurological deficits were seen.

Case 16 was the oldest victim and the fatal case (Fig. 2).

A man of 65 years was sleeping, when he was shot by his grandson who was 5-years-old. He suddenly awoke, but did not know exactly what had happened to him. He did

Fig. 2 Case 16. The fatal case. Haematoma along the pellet trajectory, extensive subarachnoid hemorrhage, the pellet lodged close to clinoid process.

not lose consciousness but complained of a headache. On presentation he did not show any neurological signs or meningeal signs, and no elevated temperature. The entry wound was a few millimetres left to his glabella, the pellet lodged in the anterior fossa close to the anterior clinoid. A cerebral haematoma was seen on CT along the pellet trajectory. There was also an extensive subarachnoid haemorrhage on CT. Angiography revealed no traumatic aneurysms or other major vascular injury. The entry wound was debrided several hours after the injury according to the standard manner. Laboratory data were normal except the blood sugar (400 mg%) and this was the reason the pellet removal was delayed. Unfortunately on day 6 after injury he suddenly lost consciousness, and succumbed very shortly afterwards. A recurrent haemorrhage was the most likely diagnosis. There was no autopsy performed.

Locations of entry wounds and pellets

In almost all cases the entry wounds were in the front of the head; 7 in the frontal area, 7 around or exactly on the eye, and only 2 in the temporal area. In no case did the pellet pierce twice or was perforating. In 2 cases the pellets were not penetrating, 1 in the orbit (case 15) and 1 just on the outer table of the parietal bone (case 13).

Clinical presentation

All patients were alert on presentation, but one of them became unconscious suddenly on the sixth day after injury and succumbed very shortly (case 16). Two patients were severely hemiparetic (Fig. 3), one of them had an homonymous hemianopsia, another had an homonymous hemianopsia only and 1 had a bitemporal hemianopsia. Three patients were injured in their eyes, one of them underwent enucleation (case 9). The 2 severely hemiparetic patients were those in whom the pellets traversed the midline.

Appearance of wounds and pellet removal

The entry wounds were small and irregular, sometimes covered with dried blood. They were red and tender when

Fig. 3 Case 12. A case with severe hemiparesis.

190 J. Clin. Neuroscience Volume 1 Number 3 July 1994

Air rifle head injury

infected and sometimes they were already healed. There

were no bone fragments of significant size encountered

during the exploration or debridement.

Where lacerated, dural perforations were irregular,

Brain entry wounds often showed little or no dead or

devitalized tissue.

Ptbllet removal was successfully carried out in 12 of the

14 caqes without any further damage to the brain as was clinically evident. In 2 cases the ‘inaccessible’ pellets were

left unremoved (cases 12 and 14). They showed no signs

of either f&al or systemic infection at least until 5 and 3

monlhs rcspectivelv.

Discussion

The atnolmt of kinetic energy contained by missile is

defined hv the formula E = l/2 m v, where m is the mass

of missile and V is its velocity..” Air rifles in this article were

of the 4.5 mm calibre or. 177 and of low velocity and loaded

with diahlo pellets. It was stated earlier that the velocity

which air rifles can develop exceeds that required to

penetrate the skull.“~‘~”

Pathology mechanisms are similar among penetrating

missiles: piercing the skin and muscle, penetrating the

skull. driving in hone fragments, damaging the brain

tissue, leaving pellets in it and even tearing major cerebral vt~els. Fatal cases have also been reported several timt.s.i.0.l”

The quantity of the brain injured may he small as

manifested hv the full GCS, the lack of signs of intracranial

hypertension and the absence of convulsions. Certain

neurc Jogical deficits do occur, however, if a pellet traverses

an art*a of concentrated fibres, vital centres, or if

haematoma develops.

Missiles traversing the midline result in a significantly

worst’ outcome.” The early KS is related to outcome.“~“‘-‘“~” A

generally good prognosis would he expected following

these type of injury. The only mortality in this series was

caused by presumed recurrent haemorrhage. Tllca absence of convulsions in this series supports the

contc’lltion of not administering anticonvulsants.‘:’

Contrary to this is that the incidence of epileptic

convulsions is high so that anticonvulsants should be

administt-red to all gunshot craniocerebral in_jurrd

paticllls.”

hlrinei. et al” suggested that skull penetrations from

air riflcx pellets initially occurred only in infants in whom

the skull was not fully developed. However, the more

modc~rn air rifles develop higher muzzle velocity exceeding

those required to penetrate skin and developed skull. Ten

of 1-l penetrations in this series did occur in mature skulls

(9 yt’ars 01‘ age or older)

Management of air rifle injuries

Early entr\‘wound debridement seemed to be an effective measrlre to prevent local infection (see Table 3). We were not cclrtain, however if that was due to the debridement or to the antibiotics administered perioperatively.

Clinical studies

Local wound infection was one of‘ our particular

interests as it might potentially extend intradurally due to

the perforated dura. None of this series, however, showed

signs of intracranial or systemic infection. The second step in the management concerned thcb

retained pellets and we followed the commonly acceptable

guidelines for gunshot wounds.‘.” Retained pellet removal

was carried out in a properly prepared operating theatrta

rather than in the emergency unit. We left the pellet

unremoved if it was considered inaccessible, especially il‘ removal might worsen the already existing neurological

deficits or if more damage to tht> brain may occllr.

Hitchcock and Cowiei proposed a stcreotactic method to

remove a deeply lodged pellet. Brandvold et al’!’ tend to

be more conservative on retained fragments. Miner ct al ’ suggested that as the quantip of the bl-ain c-o~~~uscd wah small. antibiotic therapy only would hr able to pre\‘ent

infection. He put stress on a case with a retained pellet which developed no abscess 4 years after- the injury. Our I!

patients with unremoved pellets did not develop a cercsbral abscess at least until 5 and 3 months respectively after the

injur\. (Zerehral abscess due to rtatainrcl nletal fragment . did develop. however, ‘7 year\ slier the injurv as it was

reported by Taha et al.‘!’

Wc !~ollow the commonly accepted policy regarding

retained hone fragments. ’ Xa IZ’C‘ did not t~ncounter

sizeable bone fragments during exploration. we faced less

problems with air rifle injury than the common missilt-

injuries. Bone fragment of less than 1 cm should not

require removal, unless there is wound dehiscenctk, or

signs of’ infection or CSF fistLIla.“’ CSF leakage, as it was

earlier confirmed by Xdrahi”’ significant]! incrcases thr,

incidence of‘ infection.

Received 18 May 1993

Accepted for publication 20 October 1993

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