In most patients, surgery is performed without incident, but the pathologic behavior of allergic fungal sinusitis (AFS) theoretically increases surgical risk. Nasal polyposis, expansile accumulations of allergic mucin, and poor intraoperative hemostasis may increase spatial disorientation. Additionally, areas of bony dehiscence may confuse or distort anatomic boundaries while offering little protection to the orbit and intracranial cavities. Conversely, a less than complete surgical procedure (in an attempt to decrease iatrogenic injury) is likely to lead to incomplete retrieval of allergic fungal mucin and rapid recurrence of allergic fungal sinusitis (AFS).
On the basis of currently accepted pathophysiology of allergic fungal sinusitis (AFS), little risk of fungal invasion into adjacent tissues should exist in an immunocompetent host. However, rare exceptions may occur. Tsimikas et al report a single case of an Aspergillus frontal lobe abscess that occurred following surgical treatment of allergic fungal sinusitis (AFS) that had expanded into the anterior cranial fossa. [29, 30] This case may represent seeding of the intracranial cavity as a result of inadvertent dural penetration, and it emphasizes the importance of mucosal preservation.
In addition to fungal or bacterial seeding, penetration of the dura or periorbita iatrogenically during surgery may result in injury of structures within the orbit or intracranial cavities. Such transgressions can cause diplopia, blindness, hemorrhage, stroke, intracranial hemorrhage, encephalocele, and/or cerebrospinal fluid (CSF) rhinorrhea (see the Medscape article Pediatric Sinusitis Surgery).
Erosion by allergic fungal sinusitis (AFS) of the osseous boundaries separating the intracranial fossa from the sinonasal cavities may increase the risk of subsequent encephalocele formation. The otologic community commonly accepts that dural exposure in the absence of dural injury along the tegmen mastoideum rarely results in development of an encephalocele. Unfortunately, no analogous information within the rhinologic literature exists. However, it is logical to assume that eventual encephalocele formation may occur as a result of a combination of factors, including dural injury, location of bony dehiscence, and/or size of the bony dehiscence. In rare cases, accumulations of allergic fungal mucin actually may appear to support intracranial structures. Monitoring for development of encephaloceles is important, because their occurrence may require subsequent repair of bony dehiscence.
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Left middle meatus with suctioning of thick allergic mucin from the ethmoid bulla in the center of the picture; the end of the suction is in the inferior portion of the picture.
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The viscosity of a thick allergic mucin being suctioned from the nasal cavity and vestibule in a patient with allergic fungal sinusitis.
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View just inside the nasal vestibule showing diffused polyposis extending into the anterior nasal cavity and vestibule; the septum is on the right, and the right lateral vestibular wall (nasal ala) is on the left. The polyps all are in the center. The polyps almost hang out of the nasal vestibule.
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A 15-year-old boy with allergic fungal sinusitis causing right proptosis, telecanthus, and malar flattening; the position of his eyes is asymmetrical, and his nasal ala on the right is pushed inferiorly compared to the left.
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A 9-year-old girl with allergic fungal sinusitis displaying telecanthus and asymmetrical positioning of her eyes and globes.
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Coronal CT scan showing extensive allergic fungal sinusitis involving the right side with mucocele above the right orbit and expansion of the sinuses on the right.
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Typical view of a middle meatus in a patient with allergic fungal sinusitis with expansion of the ethmoid complex and extension of the middle turbinate more inferiorly. This is a postoperative view.
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Coronal CT scan showing typical unilateral appearance of allergic fungal sinusitis with hyperintense areas and inhomogeneity of the sinus opacification; the hyperintense areas appear whitish in the center of the allergic mucin.
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Coronal MRI showing expansion of the sinuses with allergic mucin and polypoid disease; the hypointense black areas in the nasal cavities are the actual fungal elements and debris. The density above the right eye is the mucocele. The fungal elements and allergic mucin in allergic fungal sinusitis always look hypointense on MRI scanning and can be mistaken for absence of disease.
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Immediate postoperative 30° angled view showing the complete removal of polyps with a widened frontal sinus recess superiorly and widened ethmoid cavity in the mid portion. The middle turbinate is on the right, pushed against the septum. The lateral nasal wall is on the left.
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Fungal ball in the right maxillary sinus.
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Fungal debris being removed from the ethmoid complex. A suction device is seen in the right lower corner of the picture.
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Allergic mucin, fungal debris, and polyps are shown after removal from the patient. The scale is in inches.
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Coronal CT scan showing the postoperative view following removal of disease after significant disease recurred on both the right and left sides of the nasal cavity and sinuses; mild mucosal thickening of all involved sinuses is present, with some moderate thickening of the left maxillary sinus. All disease, even the lateral mucocele, was removed or drained endoscopically.
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Two-week postoperative endoscopic picture showing polypoid thickening already in the ethmoid cavities while the patient was still on tapering steroids; on the left is the lateral nasal wall. The right shows the middle turbinate next to the septum.
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A polypoid recurrence in the center of the ethmoid cavity. The septum is on the left.
