Subdural tension pneumocephalos

Abstract

Two patients developed subdural tension pneumocephalus after undergoing posterior fossa surgery performed in the sitting position. The mechanism for entry of air into the intracranial compartment is analogous to the entry of air into an inverted soda-pop bottle. As the fluid pours out, air bubbles to the top of the container. We have thus referred to this as the "inverted pop-bottle syndrome." Computerized tomography provided prompt diagnosis and confirmed brain displacement. Twist-drill aspiration of the air resulted in improvement in both patients, although one patient subsequently died from an intracerebellar hemorrhage. Tension pneumocephalus appears to be another potential complication of posterior fossa surgery in the sitting position. This condition is easily diagnosed and treated, and should be considered whenever a patient fails to recover as expected following posterior fossa surgery.

Tension Pneumocephalus as a Complication of Lumbar Drainage for Cerebral Aneurysm Surgery -Case Report-

“…The most likely mechanism in the present case is the inverted soda-pop bottle phenomenon: when the bottle is inverted, soda pours out, leaving an empty space of negative pressure above the fluid level. 6) The same effect can occur when CSF is siphoned out in specific situations such as the sitting position and the CSF diversion system. Positive pressure air rushes into the intracranial space via the bony/dural defect to fill in the negative pressure space created by the loss of the CSF.…”

“…Several factors in addition to lumbar drainage may be associated with the development of post-surgical tension pneumocephalus: nitrous oxide anesthesia; long duration of surgery; presence of hydrocephalus; and intraoperative administration of mannitol. 2,4,6,[8][9][10][11] In the present case, all four factors were probably present and might have contributed to the development of tension pneumocephalus.…”

“…Retrospectively, lumbar drainage might not have been necessary, because the elevated ICP due to hydrocephalus could have been controlled by draining CSF through ventriculostomy or surgical dissection, such as opening of the lamina terminalis. Lumbar drainage is an established method in cerebral aneurysm surgery to facilitate brain retraction, 6,7) but the procedure is not entirely free from complications and the benefit needs must be weighed against the risks.…”

“…In contrast, tension pneumocephalus is an accumulation of air trapped in the cranial cavity resulting in elevated intracranial pressure (ICP) and neurological deficits. Tension pneumocephalus was first reported after head trauma, 6,9) and a number of cases have been reported as a postoperative complication of cranial, transsphenoidal, and spinal surgery. 2,4,6,[8][9][10][11] Therefore, neurosurgeons must understand the origin and corrective procedure.…”

“…2,4,6,[8][9][10][11] Pneumocephalus was originally described as an autopsy finding in a patient who died of ethmoiditis, 6,9) and is relatively common after cranial surgery. The small amount of residual intracranial air is usually absorbed spontaneously and seldom becomes symptomatic.…”