title: Normal pressure subdural hygroma with mass effect as a complication of decompressive craniectomy.
abstract: BACKGROUND
  Subdural posttraumatic collections are called usually Traumatic Subdural Hygroma (TSH). TSH is an accumulation of cerebrospinal fluid (CSF) in the subdural space after head injury. These collections have also been called Traumatic Subdural Effusion (TSE) or External Hydrocephalous (EHP) according to liquid composition, or image features. There is no agreement about the pathogenesis of these entities, how to define them or if they are even different phenomena at all.
  
  
  METHODS
  We present a case of a complex posttraumatic subdural collection, the role of cranioplasty as definite solution and review the literature related to this complication.
  
  
  CONCLUSIONS
  Patients who undergo decompressive craniectomy (DC) have a risk of suffering a subdural collection of 21-50%. Few of these collections will become symptomatic and will need evacuation. When this happens, cranioplasty might be the definitive solution.
authors: Department Neurosurgery, '12 de Octubre', University Hospital, Av de Córdoba s/n, Madrid, 28041, Spain.
authors: Igor
authors: I
authors: Paredes
authors: Marta
authors: M
authors: Cicuendez
authors: Manuel A
authors: MA
authors: Delgado
authors: Rafael
authors: R
authors: Martinez-Pérez
authors: Pablo M
authors: PM
authors: Munarriz
authors: Alfonso
authors: A
authors: Lagares