Drainage of middle cranial fossa epidural abscess through mastoidectomy: Our experience and review of the literature

Abstract

Background: Otitis media (OM) can uncommonly lead to intracranial complications. Epidural abscesses represent a large proportion of cases; however, literature regarding the optimal surgical management of otogenic epidural abscesses is sparse. Favorably located epidural abscesses may be amenable to drainage through a transmastoid approach because the tegmen mastoideum lies immediately inferior to the middle cranial fossa (MCF).

Case description: We report 3 pediatric patients with OM complicated by epidural abscesses of the MCF. The ages ranged from 3 to 6 years old, with 2 females and 1 male. All 3 patients had acute mastoiditis with an abscess of the MCF ranging from 1.6 cm to 6.3 cm at the largest dimension. All patients underwent canal wall-up mastoidectomy with the evacuation of the MCF abscess through a small window, 0.7 × 0.7 cm or less, created in the tegmen mastoideum. All patients were successfully treated through this approach and had complete resolution of their infection on follow-up imaging. There were no postoperative temporal lobe encephaloceles.

Conclusion: This is one of the few descriptions of the treatment of an otogenic epidural abscess of the MCF through a transmastoid approach. Collaboration with neurosurgery is vital because their familiarity with the intracranial space helped to guide the accurate direction of dissection. This highlights the importance of a multidisciplinary approach in the treatment of epidural intracranial abscess of the MCF through this approach. The risk of postoperative temporal lobe encephalocele was minimized due to the small tegmen defect size.

Keywords: Epidural abscess; Mastoidectomy; Middle cranial fossa; Otogenic abscess.

Figure 1:

Left to right. (a) Axial T1+ magnetic resonance imaging (MRI) brain demonstrating a left middle cranial fossa epidural collection with associated regional dural enhancement. (b) Axial T1+ MRI brain on postoperative day 1 demonstrating resolution of left middle cranial fossa fluid collection with residual dural enhancement.

Figure 2:

Left to right. (a) Axial T1+ magnetic resonance imaging (MRI) brain demonstrating a large left epidural abscess within the middle cranial fossa. (b) Axial T1+ MRI brain on postoperative day 2 showing near-complete resolution of the left middle cranial fossa epidural fluid collection. (c) Axial diffusion-weighted imaging at 6 week postoperatively demonstrating an absence of fluid restriction at the site of the previously seen epidural fluid collection.

Figure 3:

Left to right. (a) Axial T1+ magnetic resonance imaging (MRI) brain demonstrating a right epidural abscess within the middle cranial fossa. (b) Axial T1+ MRI brain on postoperative day 5 showing complete evacuation of the epidural fluid collection with expected persistent regional dural enhancement. (c) Axial T1+ MRI brain obtained 9 weeks postoperatively showed near-complete resolution of the previously seen dural enhancement and no evidence of epidural fluid collection.