INTRODUCTION
The nail gun is a tool to drive a nail into hard materials with ease. Nail guns fall into 2 types: air-powered and explosive-powered types. The air-powered type is powered by compressed air, and the explosive-powered type uses gas pressure acting directly on the nail to drive it6). In spite of the convenience of nail guns, nail gun injuries can occur when a nail gun is used carelessly or misused, such as in a suicide attempt. Head injuries caused by nail guns are extremely rare; most cases have good clinical outcomes, while some are life-threatening10).
In this paper, an unusual case of penetrating intracranial nail gun injury is presented.
CASE REPORT
A 53-year-old man presented to our Emergency Department with a 1-hr history of unconsciousness after nail gun injury. He committed suicide by shooting a nail gun in his forehead. At presentation, his Glasgow Coma Scale (GCS) score was 13 points (eye opening 3 points, verbal response 4 points, and motor response 6 points). The pupil size was 2mm, and the pupil reflex was present on both sides. The muscle strength of extremities was normal. There was an entrance wound in the right forehead, but no nail was found. There was no specific medical or family history. Initial skull X-ray revealed the presence of a nail in the cranial cavity (Fig. 1). A brain computed tomography (CT) scan demonstrated a comminuted and depressed fracture of the frontal bone, right frontal lobe contusion with hematoma, and intraventricular hemorrhage (IVH) (Fig. 2A). The brain CT scan also revealed the nail directing toward the entrance and a hematoma in the path of the projectile (Fig. 2B). Brain CT angiography could not be performed because the patient was irritable. At presentation, white blood cell count was 16,400/μL, erythrocyte sedimentation rate was 33mm/hr, and C-reactive protein was 1.12mg/L. Bilateral frontal craniotomy was performed via the bicoronal approach. Some bony fragments scattered along the path of the nail were removed, and a large amount of hematoma was sucked out. Since there was no injury to vessels, the nail that lodged in the right front horn of the lateral ventricle was taken out carefully. The nail measured 3cm (Fig. 3). The tissue surrounding the nail was cultured for fungi and bacteria. A drain catheter was inserted into the intraventricular cavity. The bone flap was secured with 2 craniofix devices and 1 burr hole-type mesh.
A postoperative brain CT scan exhibited the remnant of IVH but no bony fragment (Fig. 4). The patient was treated in the neurointensive care unit. Anticonvulsants and third-generation cephalosporins were prophylactically administered. He had no fever, and his vital signs were stable. He had alert metal status and no motor weakness. Cranial function test results were all normal. Since the patient still had suicidal ideation, depressed mood, and anxiety, he was referred to the Department of Psychiatry for further evaluation. Cultures of the tissue surrounding the nail, cerebrospinal fluid, and blood were all negative. A brain CT scan taken 14 days after surgery showed the completely absorbed remnant of IVH and no abnormal finding except a low-density lesion along the path of the nail (Fig. 5). A brain magnetic resonance angiogram taken 1 month after surgery revealed intact anterior and posterior circulation on both sides without any vascular abnormalities such as pseudoaneurysm (Fig. 6).
DISCUSSION
Historically, intracranial nail gun injury has been associated with favorable outcomes10). Litvack et al.4) reported a 33-year-old man who had 12 nail gun nails impacted in both temporal areas and only showed slight limitation of mandibular movement, mild paralysis of the right face, dysarthria, and short-term memory impairment. Selvanathan et al.9) reported a case of a 52-year-old patient who only presented with visual impairment due to the presence of 7 nail-gun nails that lodged in both frontal areas. The mild clinical manifestation of these cases may have been attributed to the low velocity of the nail guns.
The force of the projectile is proportional to its velocity. It can damage adjacent structures in the path of the projectile and can introduce bony fragments that are capable of causing brain damage5,10). There have been a few reports of catastrophic outcomes following nail gun injury. Oh et al.7) reported a case of a patient with nail gun injury who remained in a state of stupor even after surgical treatment. Rezai et al.8) reported 1 patient who developed a left posterior cerebral artery pseudoaneurysm with associated intraventricular and subarachnoid hemorrhage. Penetrating trauma to the cerebrovascular system can cause arterial dissection, traumatic aneurysm, arterial or venous rupture/thrombosis, and arteriovenous fistula. Furthermore, this trauma can also cause life-threatening intracranial hemorrhage (ICH)1,3). Life-threatening vascular abnormalities, such as pseudoaneurysm with potential ICH, occur in 25% of patients with penetrating nail-gun injuries10). Delayed pseudoaneurysm occurs within 3 to 4 weeks after trauma and carries a mortality rate of 50%2,4). Therefore, it is mandatory to perform angiography 3 to 4 weeks after trauma in order to confirm vascular pathology.
CONCLUSION
We reported the case of a penetrating brain injury caused by a nail gun. Head injuries caused by nail guns are extremely rare; most cases have good clinical outcomes, while some are life-threatening. Catastrophic outcomes in penetrating nail-gun injuries caused by high-velocity devices are associated with deep brain damage, vascular injury, and delayed vascular disease causing ICH. Therefore, it is mandatory to perform angiography 3 to 4 weeks after trauma in order to confirm vascular pathology. We don’t know how to spin the nail in the brain.