Patients who develop late complications from traumatic skull base injury may go unrecognized for years secondary to spontaneous healing of the CSF leak or an incorrect diagnosis of some more benign condition like allergic rhinitis. In cases of spontaneous healing the dura does not regenerate and the intracranial space is separated and protected from the nasal cavity by a thin layer of nasal mucosa and scar tissue. This can be an inadequate barrier to the spread of sinonasal infection and bacterial meningitis may occur years after skull base injuries.6
This potential complication of skull base defects may lead to long-term neurologic sequelae and can result in death. In this case the patient presented with meningitis 13 years after his initial injury. A retrospective review of patients with posttraumatic CSF leaks who were treated conservatively (bed rest with or without lumbar drainage) found that 29% (5/17) developed meningitis. This finding suggests that there is a significant risk of ascending bacterial meningitis with a history of skull base trauma.7
A retrospective analysis by Bernal-Sprekelsen et al attempted to specifically address the impact of surgical repair of skull base defects (in the presence or absence of a CSF leak) on the prevention of meningitis.8
In this series of 39 patients who underwent repair only 1 patient developed a recurrent CSF fistula and meningitis. Of the 15 patients who developed meningitis prior to repair there were no further episodes of meningitis at a mean follow-up of 65 months. The results of a retrospective case series can be difficult to apply prospectively, but this was the first series to suggest that repair of skull base defects may prevent ascending meningitis.
Intracranial foreign bodies pose a significant risk for the development of meningitis and brain abscess. Traumatic injury with objects such as pencils and chopsticks often present with innocuous wounds or minor epistaxis. Nishio et al presented a case report of an intracranial abscess presenting 7 years following a chopstick injury in which the upper eyelid was penetrated and a piece of wood was left in the frontal lobe.9
In reviewing the literature they found 23 cases of transorbital penetration of the dura with wooden objects and in 11 of these 23 cases the patients were asymptomatic at presentation. Bursick et al presented a case report and review of intracranial pencil injuries.10
Two patients in this review had transnasal penetrating trauma through the cribriform plate that presented with meningitis 4 and 5 years after the initial injury. Traumatic injury resulting in intracranial wooden foreign bodies occurred primarily in children who fell while carrying sharp objects such as pencils or chopsticks. Miller et al presented the largest series of cases of intracranial wooden foreign bodies.11
In this series of 42 patients that spanned both the pre- and postantibiotic era, 48% of the patients developed a brain abscess. Among patients in the postantibiotic era, infection complicated 64% of the cases and there was a 25% mortality. There are numerous qualities to wood that make it particularly prone to infection, including its porous quality and predisposition to fragmentation. The most common organisms found in this series were Staphylococcus aureus
, β-hemolytic streptococci, and Streptococcus pneumoniae
. Our patient developed S. pneumoniae
meningitis 13 years following his original injury. The most common organism to cause community-acquired meningitis in the setting of a CSF leak is S. pneumoniae
, while Neisseria meningitidis
and Haemophilus influenza
are other common pathogens.12,13,14
As is evident from the review of Miller et al that spans the pre- and postantibiotic era, the use of antibiotics is essential to treatment and avoidance of further intracranial complications. The typical antibiotic course for a brain abscess is 6 weeks of intravenous antibiotics that have good CSF penetration. Following removal of a foreign body from the brain, intravenous antibiotics that achieve good CSF levels should be given for 3 to 6 weeks if a brain abscess is present surrounding the foreign body. A careful history and high index of suspicion is necessary to establish the diagnosis of a retained intracranial foreign body. In cases where there are no neural or vascular injuries and there is no active CSF leak, the relative absence of significant presenting symptoms can give patients and practitioners a false sense of security.
Wooden materials pose a significant diagnostic challenge because of variable appearance on imaging. The density of wood depends on both the type and on the degree of water absorption. It can change with the duration of the foreign body. When wood is dry it can be difficult to differentiate from fat tissue and air in the sinuses. Specht et al describe a case of a wooden golf tee that passed through the optic canal into the interpeduncular fossa.15
The foreign body was not located on the CT scan, but was appreciated as a low-intensity object on MRI. In general, the use of wide window widths on CT scans is helpful in delineating wooden foreign bodies.16
The wooden foreign body in our case had been present for 13 years and it was not visible on CT or MRI. The utility of imaging in diagnosing an intracranial wooden foreign body depends upon the size of the object and the duration of its presence.
There have been at least three prior reports of transnasal endoscopic removal of foreign bodies in the acute setting.3,4,5
In contrast, our patient presented 13 years following the trauma that resulted in the intracranial foreign body. There was substantial scar tissue and an encephalocele present at the ethmoid roof that demanded careful dissection. There was no radiographic evidence of a foreign body and we cannot be certain that every fragment was removed, but an endoscopic approach was chosen to decrease morbidity hoping that no further fragments were present. The use of CT image guidance facilitated a safe dissection of the scarred and recently infected skull base. Dodson et al similarly reported using CT image guidance to define the skull base defect and find two metallic pen nibs located above the ethmoid roof.3
While CT image guidance is not necessary for uncomplicated sinus surgery it can serve as a useful adjunct in more complicated cases involving the skull base. We found it to be particularly useful in our case given the distorted anatomy from the patient's history of trauma and infection as it allowed careful dissection of both skull base defects. If this patient were to develop any further episodes of meningitis or a brain abscess an open approach would be indicated.
The delayed clinical presentation of intracranial foreign bodies is an uncommon clinical problem requiring a multidisciplinary approach to care. In the appropriate setting an endonasal endoscopic approach is a less invasive and minimally morbid option to foreign body removal and repair of the skull base defect. Consultation with neurosurgery and infectious disease is an essential component to the comprehensive care of such patients. Given the difficulty in identifying small foreign bodies with conventional imaging modalities, the surgeon needs to be prepared for possible complications related to removal. The potential for severe vascular injury when contemplating removal of an unexpected intracranial foreign body should prompt a conservative progression. In this case we elected to abort the initial procedure to obtain further imaging and also allowed for preparation for the potential need of a craniotomy approach. Endoscopic techniques applied in the appropriate setting can safely be used to manage intracranial pathology including foreign body removal.