Multiple self-inflicted nail gun head injury.

Abstract: Penetrating brain injury resulting from nail-gun use is a well-characterized entity, one that is increasing in frequency as nail guns become more powerful and more readily available to the public. We present a case and offer management strategies for a 50-year-old male with two intracranial penetrating nail gun injuries. Nail gun brain injuries are commonly intentionally self-inflicted. Suicide should be considered when straight nails cause wounds to the chest, head, or abdomen. The primary preoperative concern is formation of a traumatic pseudoaneurism, which prompts both preoperative and follow-up cerebral angiography. Surgery for combined intracranial and extracranial injury may require the collaborative expertise of colleagues from the fields of ophthalmology, otolaryngology, and oral maxillofacial surgery. A rational management strategy should permit these patients to be discharged with no additional injury.

Key Words: brain trauma, penetrating brain injury, self-inflicted injury, nail gun

**********

Penetrating brain injury resulting from nail gun use is a well-characterized entity, one that is increasing in frequency as nail guns become more powerful and more readily available to the public. This mechanism of injury presents unique problems for the patient and the treating clinician. We describe a patient with 2 nails impacted in the cranium and brain parenchyma; he is a rare survivor following removal of multiple foreign objects that purposefully penetrated into the brain. Overall, self-inflicted nail gun injuries are less common than accidental discharges. A review of the literature, however, suggests that for penetrating brain injury, self-infliction is the more common mechanism. For those patients who survive such an injury, clinical decision making must focus on preventing further cortical or vascular damage. A rational management strategy should permit these patients to be discharged with no additional injury.

Case Report

A 50-year-old right-handed man with a history of depression presented to our Level 1 Trauma Center with a Glasgow Coma Scale score of 15 and a complaint of headache after reporting an accidental nail gun discharge to the right side of the head. He walked into the ER and appeared in remarkably good condition, denying loss of consciousness, vertigo, diplopia, or nausea. Physical examination revealed a small right temporal scalp entrance wound with no visible nail; the neurologic examination including cranial nerves was normal. Skull films revealed two 5 cm nails in the right cerebral hemisphere (Fig.). Head CT scan confirmed intracerebral location of the nails with no associated mass effect or hematoma and marked artifact scattering. Before surgical intervention, the patient underwent catheter angiography to rule out the presence of a traumatic pseudoaneurysm or any other vascular injury. The angiograms showed intact anterior and posterior circulations bilaterally, without any extravasation of contrast agent or evidence of a pseudoaneurysm. The patient was taken to the operating room for craniotomy and extraction of the projectiles under general anesthesia. The patient recovered with normal neurologic function and was discharged to psychiatric care after 5 days.

Discussion

Penetrating injury of the skull historically has been used as a punishment for criminals and more recently has been reported as a self-injury in patients with underlying psychiatric disturbances. (1) In 40% of cases, penetrating skull injuries are fatal because of damage to critical structures, vascular disruption, concussion blast injury, or meningitis. (2) The nail gun is a potentially dangerous device that is commonly used in the construction industry to drive various sizes of nails into wood or concrete. They are powered by explosive cartridges or by compressed air supplied by an external compressor. They are powerful enough to drive a steel nail into fully stressed concrete and operate at pressures as high as 8.5 BAR. (3) Just like a handgun, power nailers fire projectiles at high speed--some designs launch nails at speeds reaching 1,400 feet per second (427 m per second). Nail guns are fitted with a hand-pulled trigger that should only fire when the nozzle of the gun is pushed against the structure into which the nail is to be inserted. The common but incorrect method of operation is to keep the trigger continually pulled, and to fire the gun by pressing the nozzle against the structure being nailed. (4) Kenny et al (3) reported the radial aspect of the nondominant hand was exclusively injured in ten patients with hand injuries. This is because the nondominant hand was used to grip the structures being nailed together and was therefore more likely to be in the line of fire of the gun, the radial digits being that part of the hand closest to the gun when it is fired. Nail guns are most commonly used on building sites by construction workers, but these guns can be obtained by members of the general public who often use them without formal training. Construction workers are required to wear protective clothing when using nail guns, and all operators in one series were equipped with protective gloves, goggles, and steel-capped boots and worked in partitioned cubicles. A review of the literature reveals reports of nail gun injuries to various sites of the body, including the head, and damage to various internal structures that were perforated by the nails, some injuries being fatal. (5,6) Some patients claimed that the safety mechanisms on these devices occasionally malfunctioned. It is possible, however, that improper use by continually keeping the trigger depressed and accidentally making contact with their own body instead of the target is a major factor responsible for these injuries. This mechanism could explain our reported case with 2 intracranial nail perforations.

[FIGURE OMITTED]

It may be difficult to distinguish industrial accidents from suicide attempts or even assaults or homicide. Nail guns are relatively new industrial tools that can produce severe or fatal injuries. The configuration of the nail on patients' x-rays after such injuries can be helpful in determining the cause of injury. Steel nails that are bent are due to a ricochet and thus indicate accidental injury. Straight-nail injuries to the coworkers of nail gun users are most likely due to over-penetration of the substance being nailed or accidental midair firing; however, intentional injury cannot be ruled out. Extremity injuries caused by straight steel nails in nail gun users are the result of carelessness or poor technique, but suicide should be considered when straight nails cause wounds to the chest, head, or abdomen. (7)

It is clear from multiple reports that the primary preoperative concern is formation of a traumatic pseudoaneurysm, which prompts both preoperative and follow-up cerebral angiography. Rupture of a traumatic intracranial aneurysm occurs within 3 weeks after the time of injury and carries a 50% mortality rate. In as many as 14% of patients suffering low-velocity stab wounds, a false aneurysm will develop and not all of these lesions are visible on initial arteriograms. Because of the delayed visualization of traumatic pseudoaneurysms and the high risk of their formation in the setting of a nail gun injury, routine angiography should be performed in all patients between 7 and 14 days post injury. (8,9)

The crux of the management strategy lies in how to remove the nail(s). Most reported cases in which intracranial nails were removed fall into one of two treatment groups: emergency craniotomy or removal of the nail after a local anesthetic agent has been given to the awake patient. In the majority of cases in which a local anesthetic was used, only a single nail was removed. (10) Surgery for combined intracranial and extracranial injury may require the collaborative expertise of colleagues from the fields of ophthalmology, otolaryngology, and oral maxillofacial surgery.

Any physician who is called upon to manage a nail gun injury to the head should keep in mind that, despite its unusually impressive clinical image and radiological findings, it is more likely that these nails are low-velocity missiles and produce a very limited local injury. Preoperative cerebral angiography and CT scan are highly recommended to precisely evaluate the brain tissue and vascular damage. (11,12) A wide surgical exposure along with careful manipulation of the embedded nail is of primary importance to avoid inadvertent injury to the surrounding parenchyma or deeper brain structures. In the follow-up period, repeat brain CT scan and careful neurologic examination of the patient are essential for early detection of the nearly devastating complications (intracerebral hematoma, intraventricular hemorrhage, or intracranial infection) that often occur following initial procedure. Finally, when the possibility of a suicide attempt cannot be excluded, close postoperative neuropsychiatric assessment and treatment may prevent the patient from reattempting suicide over the next months.

Conclusions

This case demonstrates that pneumatic nail guns are potentially dangerous tools in the hands of the inexperienced, especially when a mentally or psychologically disordered personality is involved. The completed preoperative radiologic examination (plain skull films, CT scan, cerebral angiogram), careful surgical removal of the embedded nail(s), and close postoperative neurologic evaluation of the patient may prove to be life-saving, even in cases of multiple penetrating craniocerebral injuries caused by a pneumatic nail gun in a suicide attempt.

References

1. Litvak ZN, Hunt MA, Weinstein JS. Self-inflicted nail-gun injury with 12 cranial penetrations and associated cerebral trauma. J Neurosurg 2006;104:828-834.

2. Beaver AC, Cheatham ML. Life-threatening nail gun injuries. Am Surg 1999;65:1113-1116.

3. Kenny K, O'Donaghue D, Haines J. Nail gun injuries. J Trauma 1993;35:943-945.

4. Harris T. How Nail Guns Work. Available at: http://www.home.howstuffworks.com/nail-gun. Accessed March 30, 2007.

5. Gaul JS Jr. Identifiable costs and tangible benefits resulting from the treatment of acute injuries of the hand. J Hand Surg 1987;12:966-970.

6. McCorkell SJ, Harley JD, Cummings D. Nail-gun injuries: accident, homicide, or suicide? Am J Forensic Med Pathol 1986;7:192-195.

7. Panourias IG, Slatinopoulos VK, Arvanitis DL. Penetrating craniocerebral injury caused by a pneumatic nail gun: an unsuccessful attempt of suicide. Clin Neurol Neurosurg 2006;108:490-492.

8. Amirjamshidi A, Rahmat H, Abbassioun K. Traumatic aneurysms and arteriovenous fistulas of intracranial vessels associated with penetrating head injuries occurring during war: principles and pitfalls in diagnosis and management: a survey of 31 cases and review of the literature. J Neurosurg 1996;84:769-780.

9. Aarabi B. Management of traumatic aneurysms caused by high-velocity missile head wounds. Neurosurg Clin N Am 1995;6:775-797.

10. Sahjpaul R. Awake craniotomy: controversies, indications and techniques in the surgical treatment of temporal lobe epilepsy. Can J Neurol Sci 2000;27(Suppl 1):S55-S63.

11. Wu WQ, Tham CF, Oon CL. Cranio-cerebral injuries from nail-gun used in the construction industry. Surg Neurol 1975;3:83-88.

12. Viswanathan R, MacArthur DC, Whittle IR. Nail gun injury to the brain: an unusual case of suicide. Scott Med J 1994;39:83.

I don't like people who have never fallen or stumbled. Their virtue is
lifeless and it isn't of much value. Life hasn't revealed its beauty to
them.
--Boris Pasternak

George M. Testerman, MD, and Laura M. Dacks, MD

From Wellmont Holston Valley Medical Center Trauma Center, Department of Surgery, East Tennessee State University College of Medicine, Kingsport, TN.

Reprint requests to Dr. George M. Testerman, 134 West Park Drive, Wellmont Holston Valley Medical Center, Kingsport, TN 37660. Email: [e-mail]

The authors have no commercial or proprietary interest in any drug, device, or equipment mentioned in the article.

Accepted December 14, 2006.

RELATED ARTICLE: Key Points

* Nail gun injuries are increasingly reported in construction accidents.

* Nail gun brain injuries are commonly intentionally self-inflicted.

* Careful preoperative and postoperative strategies including liberal use of cerebral angiography to rule out cerebrovascular injuries are recommended.