title: Spontaneous chronic epidural pneumocephalus resulting from hyperpneumatization of the cranium causing mass effect: case report.
abstract: OBJECTIVE
  We report a rare case of spontaneous epidural pneumocephalus resulting from an unusual boney defect caused by hyperpneumatization of the cranium. The pneumocephalus was also unusual for its chronicity and significant mass effect.
  
  
  METHODS
  A 49-year-old man presented with a 3-year history of diffuse headaches and sensation of air movement in his sinuses on the right side. An evaluation for suspected sinusitis using computed tomography determined extensive pneumatization of most of the cranium, a large accumulation of epidural air, and a critical degree of brain shift.
  
  
  METHODS
  A right frontoparietal-temporal craniotomy with an osteoplastic bone flap was performed. The floor of the middle cranial fossa and the inner table of the bone flap were extensively debrided of air cells. A large pericranial flap was turned down over the floor of the middle cranial fossa and was held in place by a fat graft. After closing the craniotomy, a tympanostomy tube was placed into the right tympanic membrane.
  
  
  CONCLUSIONS
  The incidence of hyperpneumatization of the cranium seems to be very low. Hyperpneumatization when present, however, can cause spontaneous intracranial pneumocephalus. Based on the literature and the success of this case, the optimal management is surgical obliteration of the involved air cells.
authors.affiliation: University of Michigan Medical School, University of Michigan Medical Center, Ann Arbor 48109-0338, USA.
authors.forename: P
authors.initials: P
authors.lastname: Park
authors.forename: W F
authors.initials: WF
authors.lastname: Chandler
authors.forename: S A
authors.initials: SA
authors.lastname: Telian
authors.forename: S
authors.initials: S
authors.lastname: Doran
mesh_terms: D000388:Air; D001847:Bone Diseases / Q000150:complications / Q000601:surgery; D002908:Chronic Disease; D003388:Cranial Fossa, Posterior; D003399:Craniotomy; D003646:Debridement; D004824:Epidural Space; D006801:Humans; D008297:Male; D008875:Middle Aged; D008876:Middle Ear Ventilation; D011007:Pneumocephalus / Q000209:etiology* / Q000601:surgery; D012886:Skull / Q000000981:diagnostic imaging*; D013524:Surgical Flaps; D014057:Tomography, X-Ray Computed