Background: Chronic subdural (CSDH), or intracystic haematomas may occur as a complication in patients with arachnoid cyst, even in children and young adults. The aim of the study was to investigate how often an arachnoid cyst is complicated by such haematomas, as this information may be of importance when considering decompressive cyst surgery.
Material and Methods: The study includes a total of 241 consecutive, adult and paediatric patients (157 males and 84 females), that were referred to our department for an arachnoid cyst during the period January 1987-September 2004. Our department is the only neurosurgical department in a well-defined geographic region with a population of 930.000.
Results: A chronic haematoma was found in a total of 11 patients (4.6 %), all harbouring a temporal cyst. For the temporal cysts, the haematoma frequency was 6.5%. Haematomas occurred proportionally frequent between small, middle-sized, and large temporal cysts, age groups, and genders.
Conclusion: As also reflected in a literature review, intracranial chronic haematomas occur most frequently as a complication to middle fossa cyst. Possible mechanisms behind the formation of haematomas, and the strong associations with temporal fossa cysts are discussed, with emphasis on the arachnoid cyst membrane’s loose attachment to the dura in the middle fossa, and its possible role as an “extra wall” covering easy-bleeding vascular structures in the dura.
- arachnoid cysts
- chronic subdural haematoma,
- intracystic haematoma