Intracranial nail impalement injuries: a call for structured, multidisciplinary management

Dear Editor,

We are drawing to the attention of readers a type of penetrating brain injury which, although it is described in the medical literature as a series of individual case reports rather than as a consistent and organized body of evidence, still contains lessons that are valuable to neurosurgery, psychiatry, and forensic medicine. Injury to the brain caused by the use of nails holds a rather unusual position within the field of neurosurgery: it is rare so that the majority of medical units will see only a small number of such cases during a physician's career, yet it is so dramatic that each case tends to be remembered. This kind of injury occurs when one or more nails are driven forcibly into the cranial cavity without there being an exit wound, whether the result of self-hammering, an act of assault, or, more and more often, a misfired pneumatic nail gun. The cases that have been published mostly involve middle-aged men, and a significant number have a pre-existing psychiatric history, with depression, psychosis, or unresolved suicidal thoughts appearing repeatedly in the literature (Zima et al., 2022; Cucu et al., 2024; James et al., 2006). Because nail guns have become more widely used in both construction and in domestic settings, the means by which the injury occurs has expanded beyond self-harm caused by hammering, introducing an occupational factor that neurosurgeons in areas with limited resources, where hammering is still the main method, do not always expect (Arıcı et al., 2012; Kang et al., 2024; Yuh and Alaqeel, 2015; Qian et al., 2023; Winder et al., 2008).

The clinical features appear to be highly variable. In some cases patients turn up hours after the injury still fully conscious, able to walk about, and able to give a clear account of what happened, even though their Glasgow Coma Score has not changed from its original value even though the X-rays show a severe damage. In other instances the patients are presented in a critical condition, having scores as low as 6, with hemiparesis or obvious signs of increased intracranial pressure. This discrepancy between the findings on imaging and the clinical condition is one of the more surprising aspects of the disorder: the presence of a skull full of nails does not reliably indicate a severely damaged brain, and conversely, since a single nail placed deep near a major blood vessel can be fatal. It is this variability which has caused a number of writers to classify these injuries according to the depth and the structures affected rather than simply by the number of nails, identifying types such as penetration of the bone only, penetration into the skull cavity without affecting the blood vessels, and injuries with confirmed damage to the blood vessels (Makoshi et al., 2016). Each of these categories has its own rationale for surgical treatment, and assessing a case on its own without determining which category it falls into may result in either under- or over-treating the next case.

The investigation should adhere to a set sequence rather than one that has been made up on the spot. Plain radiographs of the skull are still useful for counting the nails, assessing their position and depth, and are often the quickest test that can be carried out in a busy emergency department. Non-contrast computed tomography then shows the trajectory within the skull, any associated hematoma, pneumocephaly, and bone fragmentation. If a nail is situated close to the middle cerebral artery, a venous sinus, or the carotid canal, CT angiography or digital subtraction angiography must be carried out before any attempt at removing the nail, since damage to blood vessels would alter the whole surgical approach and could not be reliably ruled out on the basis of a CT scan alone (Qian et al., 2023). In cases where presentation is delayed, serial angiography should be done because granulation tissue may have attached the nail to an adjacent artery (Qian et al., 2023). Magnetic resonance imaging plays no significant role in this situation since the metallic foreign body makes the procedure both unsafe and of no value; furthermore, metal artefact on a CT scan can also mask fine details. In hospitals where immediate access to CT angiography is not available, safe surgical planning can still be achieved by combining skull radiography, a thorough neurological examination, and conventional angiography where appropriate, on the condition that the threshold for suspecting involvement of blood vessels remains low whenever a nail is located within a centimetre or two of a named artery or sinus.

The surgical approach is in fact more uniform in the available literature than the dramatic way in which the injury is presented. The standard procedure is to carry out early extraction via a limited craniotomy or craniectomy, following the known path of the nail in order to prevent causing a new laceration. The nail head can be grasped using a vice-grip or forceps so that controlled pulling can be achieved; when the path of the nail is deep or when more than one nail has to be removed in sequence, with the patient repositioned between each extraction, neuronavigation helps to ensure accuracy (Makoshi et al., 2016; Kim et al., 2014). In the case where the nail has become attached to a blood vessel, proximal control whether by microsurgical or endovascular means must be carried out before the nail is removed, not after. The surgical procedure also includes evacuation of the hematoma, debridement, irrigation with saline, and a watertight closure of the dura, and it is important to take a few minutes slowly to examine the entry site afterwards because cortical vessels damaged during entry do not always bleed when the needle exits. Medical management follows a similar pattern: treatment with broad-spectrum antibiotics for one to two weeks, administration of tetanus prophylaxis, and a short course of antiepileptic medication, since the risk of seizures following cortical injury can be as high as 30 to 50 percent (Makoshi et al., 2016).

A number of published cases illustrate how far the technique has progressed. In one instance, a team employed a portable intraoperative CT scanner to verify in real time that an 8-cm nail which had passed through the basal ganglia and into both lateral ventricles had not caused any new bleeding during removal; this represented the first time that intraoperative imaging had been used for this purpose and marked a real advancement in the treatment of injuries involving deep and poorly visible trajectories (Carnevale et al., 2016). In another case, a group encountered a nail pressing against the internal carotid artery and the jugular vein and therefore adopted the contrary strategy: they first carried out coil embolisation of the neighbouring venous sinuses, followed by fluoroscopically guided extraction, and in the case of an intraoperative arterial injury they carried out immediate embolisation rather than opting for open surgery (Dow et al., 2018). In a different situation, a patient with 32 self-driven nails led to the establishment of a six-level risk classification, the levels ranging from bone-only penetration to involvement of the blood sinuses, with the removal being carried out in order of increasing risk and enabling the whole group to be removed in one session without any major complications (Zima et al., 2022). A more recent account of seven self-hammered nails being removed via small incisions in the scalp, with the patient discharged without any neurological problems, serves as a reminder that the outcomes in such injuries are often better than the imaging indicates (Ekpene et al., 2025). Taken as a whole, these reports cover almost the entire range of techniques available in a modern neurosurgical unit, extending from the use of bedside traction under local anaesthesia for the most superficial tracks to the combination of endovascular and open repair for the most vascular cases, and the decision between these methods depends less on the number of nails and more on how the nails relate to named blood vessels.

When you look at the evidence as a whole, survival is the prevailing outcome: mortality even in cases involving multiple organs is about 20 per cent (Ouda et al., 2023), and the majority of patients who have surgery leave with only minor deficits. Bad outcomes are associated with a clear set of features, namely intraventricular hemorrhage, inward displacement of the bone, suprasellar extension, and confirmed vascular compromise. The complications most likely to be overlooked if follow-up imaging is not arranged between one and three months are delayed hydrocephalus needing shunting and delayed pseudoaneurysm formation (Qian et al., 2023). Injuries caused accidently by nail guns tend to have better results than those that are self-inflicted, partly since the nail head itself often acts as a mechanical brake preventing further penetration (Kim et al., 2014; Sakuta and Arai, 1997). As a result, postoperative care continues well beyond the operating theatre, involving intensive-care monitoring for early neurological changes, carrying out a further CT scan to make sure the lesion has been completely removed, and conducting a neuropsychological evaluation for the mild but persistent deficits, hemiparesis or subtle cognitive changes among others, which can be hidden by a clean postoperative scan.

What the collection of case reports stresses, more than any one technical issue, is the need for a structural framework surrounding the surgery rather than inside it. In neurosurgery there has been a reasonable degree of agreement regarding the operative method; what is still inconsistent, however, is all the other aspects: the psychiatric evaluation carried out before and after surgery, the forensic documentation which must distinguish between self-inflicted injury and an assault or homicide deliberately staged to look like one, and reporting standards that would enable institutions to compare outcomes instead of simply compiling individual case reports. The forensic aspect is not merely a theoretical concern. Establishing intent has an impact on both the legal record and on how the family comes to understand what took place, and it relies on the same CT, angiographic, and operative findings that were used to guide the surgery, with due attention being paid to their second use. The psychiatric element also deserves equal importance: a nail driven into one's own skull is almost never a single, isolated act, and doctors who treat the wound without considering the intent behind it are only dealing with half the problem. Consultation from a range of disciplines neurosurgery, radiology, psychiatry, and forensic medicine is not an optional extra in such cases; it is the standard of care that the body of literature as a whole already suggests (Alex et al., 2025; Shafqat and Okon, 2024; Siddiqui et al., 2024; Udhay et al., 2024; Khan et al., 2025).

We would like to see the adoption of a shared reporting template, something similar to the risk-tier classification mentioned above (Zima et al., 2022), as a standard practice for future case reports. It would be very inexpensive to add to a standard format information on the patients' demographics, the course of their illness, their vascular condition, and the outcome, and this would enable the field to shift from merely documenting a series of remarkable individual cases to building up a real evidence base concerning the way in which these injuries should be managed (Table 1). In the absence of such a framework, the most prudent advice for the individual clinician is still the one that is most frequently repeated in this literature: get images as early as possible, extract the information deliberately, and never discharge the patient until the psychiatrist has seen them in.

Table 1.

Clinical characteristics, management, and outcomes of low-energy nail-penetrating cranial injuries.

Author/year (country)	Nails/site	Age/sex	Intent/mechanism	Key imaging finding	Management	Outcome
James et al., 2006 (UK)	Several, scalp/skull vault	44/male	Suicide	CT and skull X-ray confirmed cranial penetration	Neurosurgical transfer; angiographically guided removal	Survived
Arıcı et al., 2012 (Turkey)	4 nails, temporal/parietal	34/male	Suicide (schizophrenia)	X-ray, CT, angiography; no vascular injury	Direct extraction (temporal); mini-craniotomy (parietal)	Survived, nails removed
Kang et al., 2024 (South Korea)	6 nails over time, frontal bone	30/male	Self-harm/psychiatric	Serial skull X-ray/CT; MRI avoided	Repeated extraction, debridement, antibiotics 14 days	Neurologically intact
Yuh and Alaqeel, 2015 (Saudi Arabia)	10 nails, bilateral temporal/occipitoparietal	33/male	Suicide (depression)	CT/CTA: small SAH, no vascular injury	Bilateral craniectomy/craniotomy; phenytoin, antibiotics	Good recovery
Ouda et al., 2023 (Switzerland)	18 nails, head/neck/thorax/abdomen	59/male	Suicide	Serial CT across all sites	Craniotomy plus cardiothoracic and abdominal repair	Survived, multi-organ repair
Sakuta and Arai, 1997 (Japan)	1 nail, left frontotemporal	24/male	Accidental (nail gun)	CT: hematoma, bone fragments; CAG: extravasation	Emergency craniotomy with vascular management	Recovered uneventfully
Qian et al., 2023 (Finland)	2 nails, right temporal near MCA	70/male	Delayed presentation	CTA/DSA: nails adjacent to MCA, no pseudoaneurysm	Modified pterional craniotomy	Successful removal despite adhesion
Ekpene et al., 2025 (Nigeria)	7 nails, cranial vault	40/male	Suicide (self-hammered)	CT: no major hematoma, minimal edema	Extraction via small scalp incisions	Survived, no deficit

CAG, cerebral angiography; CTA, CT angiography; DSA, digital subtraction angiography; MCA, middle cerebral artery; SAH, subarachnoid hemorrhage.

Declaration of competing interest

Not applicable.