Factors involved in the development of subdural hygroma after decompressive craniectomy for traumatic brain injury. A systematic review and meta-analysis

Subdural hygroma (SDG) represents a common complication following decompressive craniectomy (DC). To our knowledge we present the first meta-analysis investigating the role of clinical and technical factors in the development of SDG after DC for traumatic brain injury. We further investigated the impact of SDG on the final prognosis of patients. The systematic review of the literature was done according to the PRISMA guidelines. Two different online medical databases (PubMed/Medline and Scopus) were screened. Four articles were included in this meta-analysis. Data regarding age, sex, trauma dynamic, Glasgow Coma Scale (GCS), pupil reactivity and CT scan findings on admission were collected for meta-analysis in order to evaluate the possible role in the SDG formation. Moreover we studied the possible impact of SDG on the outcome by evaluating the rate of patients dead at final follow-up and the Glasgow Outcome Scale (GOS) at final follow-up. Among the factors available for meta-analysis only the basal cistern involvement on CT scan was associated with the development of a SDG after DC (p < 0.001). Moreover, patients without SDG had a statistically significant better outcome compared with patients who developed SDG after DC in terms of GOS (p < 0.001). The rate of patients dead at follow-up was lower in the group of patients without SDH (8.25%) compared with patients who developed SDG (11.51%). SDG after DC is a serious complication affecting the prognosis of patients. Further studies are needed to define the role of some adjustable technical aspect of DC in preventing such a complication.