Abstract

Background: Although brain abscesses (BA) are uncommon, they represent a significant clinical challenge due to their potential for high morbidity and mortality. When combined with the presence of foreign bodies (FB), such as those resulting from penetrating craniofacial trauma, the management of BA becomes even more complex. Although craniotomy is the most frequent route described for resolution, endoscopic approaches for BA drainage or FB removal have not been widely documented.

Case Description: A 29-year-old female with the antecedent of an assault two months before her referral to our hospital underwent cranial computed tomography (CT) and magnetic resonance imaging (MRI) revealing a penetrating FB through the left maxillary sinus to the anterior skull base associated with a left frontal abscess. The patient underwent a combined endonasal endoscopic and sublabial transmaxillary approach for FB extraction and navigation-guided abscess drainage using needle aspiration. A multilayer technique was employed for anterior skull base repair. The patient received an antibiotic scheme for six weeks and recovered without any neurological deficit. The control MRI showed complete resolution of BA.

Conclusion: Coexisting BA and penetrating FB represent a challenge for neurosurgical management. When indicated, endoscopic endonasal surgery is a useful tool for FB extraction and allows the resolution of associated complications, such as drainage of a BA.

Keywords: Brain abscess, Endonasal endoscopic, Foreign body, Sublabial transmaxillary

INTRODUCTION

Brain abscess (BAs) remains a challenging clinical problem due to its potential for high morbidity and mortality. The reported annual incidence ranges from 0.4 to 1.3 cases/100,000 population.[ 4 ] The pathogenic mechanisms vary and depend on predisposing conditions.[ 4 , 5 , 18 ] A history of immunocompromised (e.g., infection with the human immunodeficiency virus, treatment with immunosuppressive drugs), or disruption of the natural protective barriers of the brain (e.g., surgery, trauma, sinusitis, or dental infection), or a systemic source of infection (e.g., endocarditis) are factors that result in BA formation.[ 6 ] Approximately 2–14% of all BAs occur due to penetrating trauma or neurosurgical procedures.[ 24 ] However, penetrating trauma brain injury (PTBI) resulting from foreign bodies (FBs) other than ballistic high-velocity objects is rare. Penetrating FBs such as knives, nails, pencils, wood pieces, wire, ice pickles, keys, chopsticks, scissors, and others have been reported in the literature.[ 11 ]

The cornerstone of BA management remains neurosurgical drainage and high-dose antibiotics.[ 4 ] The choice of surgical technique should be tailored to each patient. Burr hole drainage is the recommended method to identify the pathogen and reduce the intracavitary bacterial load to obtain local source control in most cases.[ 4 , 24 ] BAs, as a complication following PTBI, have an incidence of 2–3% and tend to form around retained fragments 2–4 weeks after the initial injury.[ 26 ] The association between PTBI by a pencil or pen and BA is rare, with few cases described in which craniotomy was the resolution route in these cases.[ 7 , 12 , 16 , 22 ] Endoscopic techniques for the management of BAs resulting from trauma or FB extraction are poorly described in the literature.[ 10 , 15 , 19 , 21 ] Herein, we present the case of a young adult woman with a retained FB and associated BA successfully treated through an endoscopic endonasal approach.

CASE PRESENTATION

A 29-year-old woman with no significant medical history was assaulted, sustaining multiple facial bruises and scalp lacerations. Her relatives found her disoriented and reported that a non-metallic FB had been removed from her mouth. She was hospitalized for 7 days, receiving antibiotics and acetazolamide for a suspected cerebrospinal fluid (CSF) leak. Over the following month, she developed a persistent mucopurulent nasal discharge, oppressive headaches, and intermittent fever. After partial treatment with antibiotics, she was referred to our unit. On admission, she referred to persistent headaches and a FB sensation in the sublabial region. Physical examination revealed a Glasgow Coma Scale score of 15, left anosmia, mild edema in the left malar region, and a wound on the upper lip and left canine fossa. There were no signs of meningeal irritation and no evidence of CSF leak. Blood tests showed leukocytosis of 12,530/mm³ with neutrophilia (65%). Cranial computed tomography (CT) revealed a hypodense and circumscribed lesion in the left frontal lobe with perilesional edema [ Figure 1a ]. The bone window showed a hypodense and well-defined image penetrating from the anterior wall of the left maxillary sinus to the anterior cranial fossa [ Figures 1b - d ]. Vascular structure involvement was ruled out by angiotomography. The patient underwent a magnetic resonance imaging (MRI) with gadolinium administration, revealing left maxillary sinusitis and a left frontal lesion with ring enhancement measuring 30 × 23 × 25 mm [ Figure 2 ].

Figure 1:

(a) Sagittal view of a plain computed tomography (CT) scan showing a well-defined lesion with edema and a bone defect involving the ethmoid sinus and sparing the sphenoid sinus. (b-d) Sagittal and coronal CT sections using a bone window showing a foreign body penetrating through the anterior wall of the left maxillary sinus to the anterior base of the skull.

Figure 2:

(a and b) Coronal and sagittal sections of magnetic resonance imaging showing a rim-enhancing lesion in the left frontal lobe associated with midline shift. (c and d) The lesion showed restriction on diffusion-weighted imaging and apparent diffusion coefficient sequences and proximity to the frontal horn of the left lateral ventricle.

The patient underwent surgery under general anesthesia and orotracheal intubation. The head was put in a neutral position, slightly extended, and fixed in a Mayfield three-pin head holder. Initially, an endonasal transethmoidal transcribriform approach was performed, identifying a plastic object with its tip penetrating the posterior ethmoidal cells and the cribriform plate. The distal entry point of the retained object was revealed through a sublabial transmaxillary approach. The FB was then extracted under direct visualization, measuring 8 cm in length and 0.5 cm in width. The abscess was drained by needle aspiration under neuronavigation system guidance, obtaining 20 cc of purulent material. Two directions for the aspiration needle were evaluated: transmaxillary and endonasal routes. The latter was a viable option for reaching the planned target at the center of the abscess. The final anterior skull base defect (1.5 cm approximately) was repaired in a multilayer fashion with fascia lata (inlay and onlay technique), nasoseptal flap, and polyethylene glycol hydrogel (Dural Sealant System) [ Figures 3 and 4 ].

Figure 3:

(a) Endoscopic endonasal view showing the retained foreign body (FB) (white arrow). (b) Surgical view of the transmaxillary (white asterisk) sublabial approach showing the entry zone of the FB (white arrow). (c) Endonasal view after removal of the FB, depicting the defect of the cribriform plate (white arrowheads). (d) Entry of the aspiration needle is directed towards the planned target by the neuronavigation system. (e and f) Images showing the anterior skull base reconstruction with fascia lata and a pedicled nasoseptal flap (white arrow in f).

Figure 4:

(a and b) Coronal and sagittal views of surgical planning for brain abscess (BA) drain guided by navigation. The yellow line corresponds to the foreign body trajectory, and the pink (coronal view) and purple (sagittal view) lines correspond to the needle aspiration direction to the core of BA. (c) The foreign body was compatible with a broken pen (white arrow).

The surgery proceeded without complications, and the postoperative course was uneventful. Immediate CT showed a reduction in the volume of the BA and midline recovery. An intravenous antibiotic regimen of meropenem and linezolid was administered for 3 weeks. The surgical cultures were negative. After being discharged on postoperative day 20 without neurological deficit, the patient received an oral antibiotic regimen for 3 weeks based on linezolid and moxifloxacin. A 2-month MRI showed resolution of the abscess, and the patient remained asymptomatic [ Figure 5 ].

Figure 5:

(a) Sagittal magnetic resonance imaging with gadolinium showed the expected residual enhancement of the lesion. (b and c) Diffusion-weighted imaging and apparent diffusion coefficient sequences did not demonstrate abscess recurrence.

DISCUSSION

PTBI resulting from non-missile injuries occurs rarely and accounts for < 0.4% of all traumatic head injuries.[ 17 ] Most of these result from low-velocity injuries derived from assaults, industrial accidents, accidents during childhood, or self-inflicted injuries.[ 11 ] The direction and velocity of the penetrating FB determine the trajectory and extent of injury.[ 10 ] The entry of FB into the cranium is related to areas of vulnerability such as the orbital roof, temporal squam, and cribriform plate.[ 11 , 12 ] Penetrating transnasal and transorbital injuries with intracranial involvement usually occur at an average age of 30.1 years, and wood FBs are the most frequently involved. Depending on the PTBI trajectory, the paranasal sinuses may be affected. The ethmoid sinus is the most commonly involved (86%), followed by the sphenoid sinus (37%), maxillary sinus (20%), frontal sinus (6%), or multiple sinuses (46%).[ 10 ]

General complications following PTBI are classified into two categories: early (<1 week) and late (>1 week). Hemorrhage and cerebral contusion, vascular injury, infection, and cerebral edema are examples of early complications. Late complications include infections, hydrocephalus, CSF leaks, and FB migration.[ 14 , 17 , 26 ] Intracranial infection incidence following PTBI ranges from 5% to 23% and can appear as early and late complications. These are related to CSF leaks, transventricular and bihemispheric injuries, air sinus wounds, and retained fragments. BA as a complication after PTBI is reported to be 2–3%.[ 26 ] The formation of BA develops in an area of cerebritis, where, as the infection progresses, tissue becomes necrotic and is walled by a collagen capsule.[ 13 ] BAs usually form around retained fragments within a period of 2 to 4 weeks after the initial trauma and rarely develop years later.[ 26 ] CSF leaks are another complication following PTBI in up to 9%. These occur at entry and exit wound sites and are related to the basilar skull or nasoorbitoethmoid fractures. The presence of a CSF leak significantly increases the risk of infections, particularly meningitis.[ 26 , 29 ]

The initial imaging evaluation led a multidisciplinary team in treatment planning. It assesses the type and severity of PTBI, including entry and exit wounds, identifies associated complications, and determines the overall prognosis.[ 26 ] During physical examination, the extracranial component of the FB could not be visible in some cases, and only the entrance site could be detected. All imaging studies are useful, from X-rays that can be helpful for the localization of metallic or plastic FBs, but they do not clearly distinguish wooden objects.[ 23 ] However, cranial CT is the most valuable method of diagnosis as it provides information about the shape, size, and trajectory of FB and the early complications associated. Furthermore, CT angiography can delineate damage to vascular structures if this is suspected, so it is mandatory to perform it preoperatively.[ 11 ] MRI has a limited role in the initial assessment of patients with penetrating FB; however, its usefulness is relevant to documenting non-metallic FB or late complications such as underlying infectious processes.[ 6 , 26 , 28 ]

The basis of treatment is surgery to remove contaminated FBs, repair vascular or dural damage, and drain intracranial lesions.[ 11 ] Therefore, it is essential to tailor the treatment strategy to each case. On one hand, in cases where an FB affects the anterior skull base or orbit, more than 94% of patients receive some surgical management, whether endoscopic or open procedure, which is carried out in the first 24 h in 83% of cases.[ 10 ] A multidisciplinary team is necessary in all cases where the neurosurgeon plays a fundamental role in cases where an intracranial injury has been documented. Some general strategies for removing an FB are as follows: (1) extraction under CT scan guide, (2) removal after performing a craniotomy, or (3) extraction with a transorbital approach without craniotomy. The surgical principle is the elimination of a retained FB under direct vision without changing its angle, especially with relatively long objects, to avoid additional injury.[ 23 ] Depending on the path, for surgical planning, lesions of eloquent brain structures, the internal carotid artery, or the cavernous sinus should be suspected.[ 10 , 23 ] In recent case reports, endoscopic surgery has been employed to manage these patients, allowing a safe and minimally invasive approach for surgical exploration, wound reconstruction, and penetrating FBs.[ 1 , 10 , 15 ]

On the other hand, BA secondary to PTBI requires prompt surgical management. For the general management of BA, the CT-guided stereotactic aspiration is the mainstay method due to the low rate of complications, minimal invasiveness, and lower mortality rate.[ 2 , 4 , 20 ] The craniotomy is reserved for cases with mass effect and increased intracranial pressure, failure of multiple aspirations, presence of a multiloculated abscess, and posttraumatic abscess containing contaminated foreign materials.[ 18 , 24 ] Recent reports indicate that skull base endoscopy may be a potential alternative to the standard aspiration technique. However, its use for BA due to penetration trauma is rarely reported.[ 24 ] The endoscopic endonasal approach has been reported in post-traumatic BA, facilitating direct access to the abscess, obtaining culture samples, and repairing the skull base defect.[ 19 , 21 ]

Finally, CSF leaks should be considered due to the high risk after craniofacial trauma (15–20%).[ 25 ] Most CSF leaks heal spontaneously within 5–10 days, and surgery is suggested if CSF lasts >1 week or in delayed CSF fistulas.[ 9 ] The surgical plan aims to minimize invasiveness while ensuring optimal exposure of the leak site for effective treatment. The transcranial approach is the preferred technique for repairing dural defects, especially after anterior skull base comminuted fractures. However, endoscopic techniques offer significant advantages over cranial approaches, with reported benefits including greater safety and effectiveness, with lower rates of failure and complications.[ 25 , 27 ] The dural leak defect can be repaired intraoperatively with materials such as autologous grafts (e.g., periosteum, fascia lata, septal flap, fat, and muscle) or heterologous biografts.[ 25 ]

In our case, the surgical approach was chosen based on the anatomical alterations derived from the FB and the associated complications. The proximal and distal entry zones were identified through a combined endonasal endoscopic transethmoidal transcribriform and sublabial transmaxillary approach, allowing the pen extraction under direct visualization. The selection of transcranial or burr hole approaches for BA drainage in a second surgical time was ruled out. Therefore, at the same surgical time, the drainage was successfully performed by navigation-guided needle aspiration through an endonasal route. Although no CSF leak was documented on admission, it was expected after FB removal. We considered a multilayer fashion repair of the anterior skull base defect with an inlay and onlay autograph (fascia lata) supported with fibrin glue, nasoseptal flap, and polyethylene glycol hydrogel (Dural Sealant System). In selected patients, like our case, endoscopic approaches offer advantages over traditional techniques, while remaining a minimally invasive procedure.

Although there is a lack of randomized trials for the use of prophylactic antibiotics for PTBI, undoubtedly, the existence of infectious complications requires prompt treatment.[ 8 ] Contiguous spread of bacteria is the predisposing condition in these cases. Common pathogens associated with penetrating trauma or neurosurgical procedures are Staphylococcus. aureus, Staphylococcus. epidermidis, Clostridium species, Enterobacteriaceae, and Streptococcus species.[ 3 , 4 ] Initial therapy should start with broad-spectrum antibiotics until culture reports are available. If the culture is negative, then the broad-spectrum antibiotic therapy should be continued.[ 18 ] Guidelines recommend meropenem combined with vancomycin or linezolid for empirical treatment, and the optimal duration of antimicrobial therapy is 6–8 weeks for these cases. The radiological evolution of BA varies; a new aspiration should be carried out in cases without any volume reduction by 4 weeks after the first aspiration. On the other hand, residual contrast enhancement can persist for up to 3–6 months, and it is not necessary to prolong therapeutic regimens.[ 4 ]

The mortality rate associated with PTBI can be high, with complications often leading to poor neurological outcomes.[ 26 ] A BA alone is linked to a mortality rate of 17–32%, and depending on the patient’s clinical condition, neurological prognosis can be poor. Additional factors, such as the presence of abscesses near the ventricles – as seen in our patient – further increase the risk of rupture into the intraventricular or subarachnoid spaces. This complication can significantly elevate morbidity and mortality, occurring in 10–35% of patients.[ 4 , 18 ]

CONCLUSION

Complications derived from PTBI are not unusual; however, they entail high morbidity and mortality rates when present. Transcranial surgical procedures are the most frequently described for removing FB and resolving associated complications; however, each case must be carefully evaluated, and in selected patients, endoscopy could be an effective tool. In this way, in a single surgical time, the extraction of the FB, the drainage of the abscess, and the repair of the anterior skull defect of this patient were successfully resolved.

Ethical approval:

The Institutional Review Board approval is not required.

Declaration of patient consent:

The authors certify that they have obtained all appropriate patient consent.

Financial support and sponsorship:

Nil.

Conflicts of interest:

There are no conflicts of interest.

Use of artificial intelligence (AI)-assisted technology for manuscript preparation:

The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.

Disclaimer

The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Journal or its management. The information contained in this article should not be considered to be medical advice; patients should consult their own physicians for advice as to their specific medical needs.

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