Iron rod-induced perforating head injury of the posterior cranial fossa: a case report and review of the literature

Abstract

Background

Penetrating injuries to the posterior cranial fossa are extremely rare. Perforating skull injuries are also not frequently recorded, with only ten cases reported in the literature. Combining these two factors, this case report presents a patient with a perforating head injury at the posterior cranial fossa caused by an iron rod and shares the clinical management of this rare case.

Case presentation

An 18-year-old Vietnamese male construction worker was admitted following a 3-m fall from scaffolding due to an occupational accident. Upon admission, the patient was conscious, hemodynamically stable, and no neurological deficits or other associated injuries were detected. A 1-m-long, 0.8-cm-diameter iron rod had penetrated from the left neck to the right occipital region. Owing to the size of the foreign body, only an X-ray was performed. The patient underwent emergency surgery to remove the foreign object and manage the damaged brain tissue. Intraoperatively, a contusion of the right cerebellar hemisphere with a complex dural tear, subarachnoid hemorrhage, and multiple small metallic fragments was found, with no spinal cord or major vessel injuries. Postoperatively, the patient recovered well. After 3 years of follow-up, the patient had excellent results and returned to normal daily activities.

Conclusions

The optimal surgical approach should be carefully planned, especially in cases where preoperative computed tomography imaging is challenging. It is recommended to plan the direction of foreign body extraction and limit the use of artificial materials.

Background

A penetrating traumatic brain injury is defined as a head injury that damages the skull, meninges, and brain parenchyma, caused by a foreign object [1]. Annually, an estimated 32,000–35,000 civilians die from penetrating brain injury, with firearms accounting for the majority of these deaths [2]. Globally, approximately 50–60 million people suffer from traumatic brain injuries each year, and while penetrating brain injuries account for only about 0.4% of these cases, they carry a higher risk of complications and mortality compared with other types of head injuries [3, 4].

In the medical literature, penetrating head injuries are most commonly found in the orbital, temporal, and large foraminal regions, or areas of thin skulls [5]. A 2-year report from a university hospital in Egypt showed that injuries predominantly occurred in the frontal bone, followed by the temporal and parietal bones [6]. However, penetrating injuries to the occipital bone, particularly the posterior cranial fossa, are extremely rare in the literature. Perforating skull injuries—those with a foreign body penetrating both sides of the skull—are also very rare, with only ten cases reported in the literature [7,8,9,10,11,12,13,14,15]. Given the rarity of these two factors, we present the case of an 18-year-old male with a perforating skull injury caused by an iron rod and share the clinical management of this rare case.

Case presentation

History and findings

An 18-year-old Vietnamese male construction worker experienced a 3-m fall from scaffolding during work without a helmet or protective equipment. The patient tipped over to his left and, on landing, an iron pole at the starter bar of the building column pierced through his head. He was released from the embedded starter bar using a metal cutter by his co-workers, before being transported to the hospital by ambulance.

One hour after the incident, the patient was presented to the emergency department in a conscious state. The Glasgow coma scale (GCS) score was 15, the patient had both equally reactive pupils and no motor or sensation deficits. His vital signs were stable (blood pressure 110/80 mmHg, heart rate 110/minute, respiratory rate 22/minute, body temperature 36.5 °C). The patient had no significant past medical history. On closer examination, the foreign object measured approximately 0.7–0.8 cm in diameter, 1 m in length, and punctured through the head and neck region through two holes (Fig. 1A). The entrance hole was on the left lateral neck, whereas the exit hole was in the right occipital region. Blood clots were present at the point of injury, and no signs of hemorrhage or cerebrospinal fluid (CSF) leakage were observed. No additional injury was found. The patient was given analgesics, intravenous fluid, tetanus prophylaxis, meropenem, and metronidazole.

Fig. 1

Clinical status of the patient and X-ray images. The patient was conscious with an iron rod punctured through the head (A). The iron rod extended from the left cervical region to the right occipital region (B, C)

Owing to the foreign object’s extensive length, we were only able to obtain a cranial X-ray. The film results confirmed that the object had penetrated through the posterior cranial fossa (Fig. 1B, C). No abnormal recordings were found via abdominal ultrasound or chest X-ray. The patient’s laboratory results were within the normal range, with hemoglobin of 147 g/L (normal range: 140–160 g/L) and hematocrit of 0.44 (normal range 0.38–0.50).

Operation

The patient was diagnosed with perforating traumatic brain injury and underwent emergency surgery to remove the foreign object and manage the damaged brain tissue. He was positioned prone and endotracheal anesthesia was performed. For the incision, we chose the occipital incision, which began from the spinous process of C2 to the posterior occipital protuberance (Fig. 2); we later extended the incision to the exit hole (right occipital bone region) to further access the damaged brain tissue.

Fig. 2

Patient position, incision, and view of the iron rod in relation to the patient’s head. The planned surgical incision was the suboccipital incision, with the patient in the prone position. The image shows a foreign object penetrating from the left neck to the right occipital region

After the first incision was made, the posterior arches of C1, C2, and the occipital bone were exposed. In this view, the course of the foreign body was visualized: it ran diagonally and entered the posterior cranial fossa through the foramen magnum, just posterior to the posterior arch of C1 (Fig. 3A). Subsequently, the iron pole pierced through the cerebellum and made an exit through the occipital bone at the position approximately 1 cm posterior to the right sigmoid sinus, just below the right transverse sinus (Fig. 3A–C). A Kerrison rongeur was used to remove the occipital bone along the path of the foreign object, from the foramen magnum to the exit hole, releasing the iron rod from the occipital bone (Fig. 3B, C). On observation, the cerebellum and dura were damaged, subarachnoid hemorrhage was present, and the brain tissue was contaminated with many small iron pieces (Fig. 3B, C). The foreign object was removed (Fig. 4) in a retrograde fashion; the spinal cord, medulla, spinal artery, transverse and sigmoid sinuses remained intact. Subsequently, the occipital bone was further removed until the intact dura was exposed, followed by a durotomy. The foreign body damaged the brain tissue, thus the injured cerebellum was removed, bleeding was controlled, and the remaining brain tissue was irrigated to clean any excess debris. A piece of muscle fascia was taken from the neck region to seal the dura. The surgical site was irrigated multiple times with saline and betadine, after which the skin was closed.

Fig. 3

Intraoperative photograph. The iron rod entered the posterior cranial fossa through the foramen magnum (A). After removing the occipital bone along the path of the rod, it was observed that the rod pierced through the right cerebellar hemisphere, and made its exit at the right occipital region (B, C). There was a complex tear of the dura mater with brain contusion along the path of the rod after the foreign object was removed (D)

Fig. 4

Intraoperative photograph showing the removed iron rod, measuring longer than 90 cm

Postoperative course

Postoperatively, as the patient’s status was stable in the intensive care unit (ICU), he was transferred to the surgical ward on the same day. Meropenem (6 g/day) and metronidazole (1 g/day) were continued until discharge. On examination, the patient was conscious (GCS of 15), and presented with cerebellar syndrome but no other neurological deficits were noted. The postoperative computed tomography (CT) scan result was favorable: no hemorrhage or mass effect was found, mild perioperative edema was present around the right cerebellar hemisphere, and right occipital bone loss during the craniectomy was also present (Fig. 5). The patient was discharged on postoperative day 6. At the 3-year follow-up, Karnofsky’s performance status was 100, with no neurological deficits recorded, and the patient claimed to have resumed normal daily activities. Follow-up CT was also obtained and revealed no hematoma, hemorrhage, or edema (Fig. 6).

Fig. 5

Immediate nonconstrast postoperative CT scan. The scan showed minimal hemorrhage around the tract traversed by the iron rod, a skull defect in the right posterior cranial fossa, with several hematoma-air pockets at the surgical site, along with slight brain edema around the area. There was no active bleeding at the surgical site

Fig. 6

Three-year follow-up CT scan. A skull defect with old brain parenchyma damage in the right posterior cranial fossa was present

Discussion

Characteristics of the injury

Penetrating skull injuries in the occipital bone region are relatively uncommon in the literature. A review of clinical case reports of penetrating head injuries from 2011 to 2015 revealed that most foreign objects penetrated the frontal, parietal, or temporal bone region; the occipital region was reported in only 5 out of 44 cases, and none of those involved the cerebellum or posterior cranial fossa [8]. The rare occurrence of this type of injury may be partially explained by the anatomical features of the skull. Specifically, out of four of the large bones that protect the brain (frontal, parietal, temporal, occipital bone), the occipital bone is the thickest, rendering it less susceptible to fractures [16, 17]. However, fractures in this region may indicate a worse prognosis since thicker bone requires much more significant force to cause damage, which can be fatal to the patient. A study of head injuries in India over 2 years found that among 91 cases, only 3 had posterior cranial fossa injuries, and none of the patients survived due to the significant force of impact that led to occipital bone fractures [17]. In our case, despite the damage to the occipital bone, the patient remained stable because of the diameter of the penetrating object. The small diameter (< 1 cm) of the iron rod focused the force on a localized point, creating a drilling effect rather than causing a fracture that would be fatal [18]. Additionally, the foreign body penetrated through the right cerebellar hemisphere, without damaging any deep cerebellar nuclei, hence explaining the positive recovery of the patient.

Our patient presented with a wound to the left lateral neck region, extending from above the angle of the mandible to below the base of the skull. According to neck zone divisions in trauma, this injury falls within zone III, an area traversed by numerous vital structures including the carotid artery, vertebral artery, pharynx, and cranial nerves VII, IX, X, XI, and XII [19]. Owing to the patient’s specific fall position, the foreign object penetrated between the posterior arch of the C1 vertebra and the posterior border of the foramen magnum, resulting in all vascular and neural structures (spinal cord, brainstem, and cranial nerves) being anterior to the foreign object and thus preserved.

Preoperative imaging

In patients with penetrating head injuries with foreign objects, before hospital arrival, the foreign object should be stabilized and movement should be restricted to prevent further injury [20]. However, transporting long foreign objects is sometimes impractical, or the object’s length may surpass the bore size of the CT scanner’s gantry and require shortening under ideal conditions. There have been reported cases using cold saws, wire cutters, hydraulic clamps of firefighters, and rod cutters [8, 9, 11, 21]. In our case, the iron rod was shortened by the patient’s coworkers using a handheld metal saw before arrival at the hospital. However, it was still too long for a CT scan. We decided against a second cut because the initial cutting attempt had likely caused vibrations that affected the brain tissue in addition to the existing injury from the rod itself, further manipulation risked exacerbating the damage.

Head CT is commonly used to confirm the presence of a penetrating foreign body through the cranial cavity [22]. While X-ray can also be used, it is not recommended because of its low accuracy in cases involving bullets or small fragmented objects, and lack detail on intracranial structure [8, 23,24,25]. Some authors suggest that magnetic resonance imaging (MRI) is superior for wooden foreign bodies, but this method is time consuming, contraindicated for metal foreign objects, and depends on the availability of MRI, especially in developing countries [25,26,27]. For the diagnosis of vascular injuries, digital subtraction angiography (DSA) remains the gold standard, but it is an invasive procedure that requires time and trained doctors [8]. Therefore, CT angiography (CTA) is the preferred method in head trauma. In our case, due to the length of the iron rod, we could only perform a plain skull X-ray to confirm the penetrating wound. DSA was not performed as we did not detect any signs of vascular injury, and the patient’s vital signs and laboratory results were within normal limits.

Management of the trauma

Due to the diverse nature of head injuries, there is no standardized treatment protocol, and each patient requires adapted treatment based on the specific injury and the patient’s condition. However, the general approach to penetrating head injuries involves assessing the damage caused by the foreign object, creating a surgical approach, removing the foreign body, debriding the brain tissue, controlling hematoma, removing necrotic brain tissue, and closing the dura [4].

In our case, due to the limited imaging data of the trauma, we opted for a suboccipital craniotomy to allow for the most comprehensive assessment of both neck and brain injuries. The location and trajectory of the iron rod were of particular concern in this case, as any involvement of the spinal cord structures would have necessitated the collaboration of spinal surgeons. Fortunately, the patient did not present with any spinal cord-related injuries.

Following our assessment, we determined that the patient only had brain damage and proceeded with foreign body removal. A craniectomy was performed owing to contamination of the damaged bone, which is a potential source of infection. Furthermore, bone loss in the occipital region in this patient can be compensated by the structural support from the neck muscles, making postoperative cranioplasty unnecessary [28].

Subsequently, the direction of foreign object removal and contamination of the brain parenchyma during the process were critical considerations. As the foreign body entered and left the skull through two orifices, it could be removed in either retrograde or anterograde fashion [10]. The direction of removal should be guided based on the characteristics of the penetrating object [29]. In the literature, we identified ten cases of traumatic brain injury with similar characteristics of a perforating iron rod similar to our case [7,8,9,10,11,12,13,14,15] (Table 1). Two cases involved spearguns, whose tips were attached to sharp blades, where anterograde removal was preferred to avoid contact between the blades and the brain parenchyma [11, 13]. In another case involving a construction iron rod similar to this case, anterograde removal was selected because the iron rod was slightly bent at the exit hole, making it easier and less damaging to extract in this fashion [9]. In our case, the iron rod did not present with any concerning characteristics and could be removed from either direction. However, when comparing the iron rod from either site of penetration, the section of the rod near the exit orifice had already contacted the brain parenchyma during the accident, whereas those at the side of the entrance orifice had never, hence it was considered safer to remove the iron rod retrogradely. During the removal process, the iron rod near the exit orifice would enter the brain tissue before exiting, increasing the risk of bacterial contamination [9]. Therefore, the rod was sterilized and cleaned before extraction to minimize infection risk.

Table 1 Summaries of perforating head injuries from 1848 to 2022

Finally, after the injured brain tissue was removed and cleaned, and bleeding was controlled, dural closure was performed. In our case, autologous fascia from the neck region was used for dural closure because of its safety, cost-effectiveness, and reduced risk of infection compared with other materials [30].

Postoperative risks

Postoperatively, the risk of infection is a significant concern in patients with penetrating head injuries, as it can increase rates of disability [25]. While various antibiotic regimens have been proposed, the optimal choice depends on local antibiotic resistance patterns [25]. In our case, we combined meropenem and metronidazole to cover a broad spectrum of bacteria including commonly resistant strains in Vietnamese hospitals [31]. Prophylactic antibiotics were administered from preoperative to postoperative day 7, consistent with the recommended guidelines of 7–14 days [25]. CSF leakage is another potential complication of penetrating head injuries, with an incidence of 0.5–3% [32, 33]. Caused by dural tears by foreign objects or unsuccessful dural repair, CSF leaks are associated with a high risk of infection [25]. Fortunately, our patient did not experience postoperative CSF leakage.

Limitations

As preoperative planning was based solely on plain radiography in this case, it would be ideal if a preoperative CT scan was feasible. Currently, no guidelines or studies have mentioned how to properly shorten the foreign objects as in this current case, and to what extent the brain parenchyma is damaged during the process. Further study is necessary to address this problem.

Conclusions

We present a case of perforating brain injury caused by an occupational accident involving an iron rod. This case highlights the unique trajectory of the foreign body through the posterior cranial fossa. Despite preoperative planning based solely on plain radiography, we successfully removed the iron rod using an appropriate surgical approach to control the entire injury. We recommend that surgeons consider the characteristics of the perforating foreign body to plan the direction of extraction and limit the use of artificial materials to reduce the risk of infection.