Shiny Foreign Body in the Frontal Sinus Causing Epidural Abscess

A 34-year-old man with headache and fever for the past 7 days was referred to our department. He was diagnosed as having a comminuted fracture of the frontal sinus, where he had had a cranioplasty 15 years earlier. He had no relevant medical history. Nasal endoscopy revealed an edematous right inferior turbinate and nasal septum deviated to the left side. Blood analysis gave a white blood cell count of 33 630/mm³ (neutrophil 29 550), erythrocyte sedimentation rate of 22 mm/h, and C-reactive protein was elevated at 210 mg/dL. Cerebrospinal fluid (CSF) analysis showed that the protein level in CSF was 369.7 mg/dL and glucose in CSF was 17 mg/dL, which was highly suggestive of bacterial meningitis. Computed tomography demonstrated a soft tissue density in the right frontal sinus and a soft tissue density with air bubbles in the left frontal sinus, which extended to the dura mater of the frontal lobe (Figure 1A). Magnetic resonance imaging indicated a high signal from the right frontal sinus on T1- and T2-weighted images, which suggested mucocele. Magnetic resonance imaging also showed a high signal from the left frontal sinus on T1-weighted image and low signal on T2-weighted image, which suggested an abscess in the left frontal sinus (Figure 1B and C). The enhancement in the T1-weighted image indicated peripheral rim enhancement in both frontal sinuses (Figure 1D).

Figure 1.

A, Coronal CT demonstrated a soft tissue density in the right frontal sinus and a soft tissue density with air bubbles (blue arrow) in the left frontal sinus, which extended to the dura mater of the frontal lobe. B, T1-weighted MRI showed a high signal from the right (red arrow) and left frontal sinus (blue arrow). C, T2-weighted MRI showed a high signal (red arrow) from the right frontal sinus and a low signal (blue arrow) from the left frontal sinus. D, Enhancement in the T1-weighted image indicated peripheral rim enhancement in both frontal sinuses (right: red arrow, left: blue arrow). CT indicates computed tomography; MRI, magnetic resonance imaging.

Systemic antibiotics were administrated intravenously (ceftriaxone, 4 g/d). Endoscopic sinus surgery was performed under general anesthesia. After uncinectomy of the right nasal cavity and ethmoidectomy, a yellowish pulsating cyst was noted in the right frontal sinus (Figure 2A). It was removed with frontal suction and it proved to be a mucocele with no bacteria. A yellowish material was seen through a thin interfrontal sinus septum. The same procedure was performed in the left nasal cavity and showed yellowish pus and hard material occupying the left frontal sinus (Figure 2B). A substantial amount of pus filling the left frontal sinus was suctioned out, and Staphylococcus aureus was cultured in the pus. A Draf type IIb procedure was attempted for better visualization to remove the hard foreign material but owing to the limited visual field compared to the extent of foreign material, an external incision had to be made along the previous scar on the forehead to enable a superior and inferior approach to the left frontal sinus (Figure 2C). After drilling, the foreign body was divided into several fragments that were easily removed from the frontal sinus. The dura was exposed intact entirely lacking bone coverage on the posterior side of the frontal sinus. The 7 cm × 4 cm foreign body was confirmed as methyl methacrylate (Figure 2D). The left frontal sinus was left with no reconstruction as the patient would not permit this after surgery. Postoperative 1-year follow-up was uneventful.

Figure 2.

A, A yellowish pulsating cyst (red arrow) was noted in the right frontal sinus. B, Yellowish pus and hard, stern material (blue arrow) occupied the left frontal sinus. C, An external incision was made along the previous scar on the forehead to enable a superior and inferior approach to the left frontal sinus. A shiny foreign body in the left frontal sinus was confirmed as methyl methacrylate (blue arrow). D, After complete removal by a piecemeal technique, the 7 cm × 4 cm foreign body was placed in methyl methacrylate.

Methyl methacrylate had been used for obliteration of the frontal sinus in previous surgery. ¹ Although this material is cheap and easy to use, the use of alloplastic material in the frontal sinus confers a risk of postoperative infection up to 13%. ² It also makes a revision operation difficult if complications occur. An autologous bone graft such as iliac bone can be an option for reconstruction of the frontal sinus structures. ³ If an artificial bone graft is inevitable, all the sinus mucosa in the frontal sinus should be removed and the graft material must be kept separate from the contaminated sinus mucosa.