Chronic subdural hematoma: drainage versus no drainage.

Second, we believe that to compare the two surgical techniques, there must be a certain consistency in the two study groups. The authors only indicate the age and sex distribution of both groups, however it is very important to know several things that make the series are not significantly homogeneous and therefore the results may be biased. It is important to know that the degree of clinical status of the patients using the Glasgow Coma Scale or Markwalder has proven to be a significant prognostic factor in most published series. Clinical status at surgery is one of the most important prognostic factors in CSDH (1,4). It is also important to know the internal architecture of the hematoma. Nagacuchi et al. classify the internal architecture of subdural hematomas in four types: homogeneous, laminar, separated, and trabecular (3). This author has demonstrated that the CSDH with separated structure has a great risk of recurrence (p <0.0001).