[Intracranial pressure measurement in large skull defects]

We measured the intracranial pressure continuously for a period of four days before and after cranioplasty in 12 patients with skull defects larger than 100 cm2. The results were obtained by epidural monitoring. The device used was the "Hellige" pressure measuring device (modified according to Gobiet). We found an increased cranial pressure in more than half of the patients (7). In addition the same patients showed the most marked neurologic and psychic changes. A significant return to normal of the intracranial pressure was noticed in all these patients after the closure of the skull defect. Progressive improvement in the clinical symptoms was also seen. The pathogenesis of this phenomenon has not been completely explained. Several authors consider that an important factor is the difference between the intracranial and the atmospheric pressure, However, we suggest that another important factor is the cicatricial changes ("scar plate") occurring between the cortex, dura and the skin, which exerts pressure on the skull contents. Previously, the neurological symptoms which appeared after a period of time in patients with large skull defects were attributed to other causes. It is only during the past decades--thanks to progress in neuroradiologic diagnostics--that a pathoanatomical correlate been found for these changes.