Objective We report the surgical management, long-term follow-up, and unique postoperative
sequelae from a rare case of spontaneous epidural pneumocephalus in a patient with
congenital tegmen defect and hyperpneumatization of the temporal bone.
Clinical Presentation This patient is a 70-year-old man who presented 21 years earlier with spontaneous
epidural pneumocephalus resulting from an unusual tegmen defect and hyperpneumatization
of the cranium. This was repaired via a middle cranial fossa approach and obliteration
using a temporalis muscle flap and pericranial graft. Several years later, he required
tympanoplasty due to outward herniation of the tympanic membrane related to chronic
autoinsufflation. Thereafter, he developed a maximal conductive hearing loss and headaches
in situations of pressure change, most notably during flights. On clinical exam, he
was found to have an obstructing extraluminal pneumatocele of the right external auditory
canal, compressible, and based on the posterior canal skin. CT of the temporal bones
demonstrated mastoid hyperpneumatization with continuity into the posterior superior
bony external auditory canal medial to the bony cartilaginous junction, as well as
extradural free air over the tegmen and extending posteriorly over the temporal lobe
convexity ([Fig. 1A], coronal CT).
Intervention The patient underwent endaural surgical repair of the bony defect in the right external
auditory canal, reconstruction of the ear canal, and reinforcement cartilage tympanoplasty.
Intraoperatively, the widely based pneumatocele was identified in continuity with
the bony defect in the lateral portion of the bony external auditory canal, extending
medially to the tympanic membrane. The margins of the pneumatocele were incised from
the healthy native skin that remained adherent to the ear canal and transected medially
as a free graft. An 8 × 9 mm bony defect was identified laterally ([Fig. 1B], intraoperative image). Irregularities were smoothed with a diamond drill to better
define the extent of the defect. Gelfoam was placed into the largest air cells for
support, and OtoMimix calcium phosphate bone void filler was used to reconstruct the
defect. Revision tympanoplasty was performed using a composite cartilage-perichondrial
graft with concurrent placement of a pressure equalization tube to support satisfactory
healing. The free skin graft was used to resurface the bony canal defect.
Conclusion Hyperpneumatization of the temporal bones is rare and can cause spontaneous intracranial
pneumocephalus. This case demonstrates an obstructive pneumatocele of the external
auditory canal as a rare sequelae related to another bony defect. No recurrence of
symptoms, pneumatocele, or pneumocephalus was noted 2 years following this intervention.
Based on the literature and the success of this case, the optimal management is surgical
obliteration of the involved air cells and repair of communicating defects.
Fig. 1 (A) Coronal CT and (B) intraoperative image.
