title: Posterior fossa arachnoid cysts in adults: Surgical strategy: Case series.
abstract: OBJECTIVE
  The management of posterior fossa arachnoid cyst (PFAC) in adults is controversial. To review our cases and literature, propose a practically useful surgical strategy, which gives excellent long-term outcome in management of PFAC.
  
  
  METHODS
  We analyzed our case records of 26 large intracranial arachnoid cysts in adults treated over 12 years. Of them, we had 7 patients with symptomatic PFAC. Reviewed the literature of 174 PFAC cases (1973-2012) and added 7 of our new cases with a follow-up ranging from 3 to 12 years.
  
  
  RESULTS
  In 6 cases the PFAC was located in the midline. In the 7(th) case, it was located laterally in the cerebello-pontine (CP) angle. All patients were treated surgically. Excision of the cyst was performed in 5 of these cases. Among the two intra-fourth ventricular cysts, in both the cases cysto-peritoneal shunt was performed. Postoperative computed tomography/magnetic resonance imaging showed variable decrease in size of the cyst even though clinically all patients improved. We propose a surgical strategy for the management of these cases which would aid the surgeon in decision making.
  
  
  CONCLUSIONS
  We observed that these PFACs can occur either in the midline within the fourth ventricle or retroclival region or extra-fourth ventricular region. It can also develop laterally in the CP angle or behind the cerebellum or as intracerebellar cyst. Importance of this is except for Midline Intra-fourth ventricular cyst/retroclival cyst, the rest all can be safely excised with excellent long term outcome. The treatment strategy for Midline Intra-fourth ventricular cyst/retroclival cyst can be either cysto-peritoneal shunt or endoscopic fenestration of the cyst.
authors.affiliation: Department of Neurosurgery, MIOT Hospitals, Manapakkam, Chennai, Tamil Nadu, India.
authors.forename: Uddanapalli Sreeramulu
authors.initials: US
authors.lastname: Srinivasan
authors.affiliation: Department of Pathology MIOT Hospitals, Manapakkam, Chennai, Tamil Nadu, India.
authors.forename: Radhi
authors.initials: R
authors.lastname: Lawrence
keywords: Cysto-peritoneal shunt; endoscopic excision of cyst; excision of arachnoid cyst; intracranial arachnoid cysts; posterior fossa arachnoid cysts