Control group received the usual postoperative care for patients with CSH, which consisted of strict neurological monitoring for at least 24 hours in an inpatient ward or a more complex setting depending on the patient's clinical condition. The head of the patient was positioned neutral (0°), as were the lower limbs, according to institutional care guidelines. The drain (a latex-gloved reservoir or Hemovac drain) was positioned inferior to the head to promote drainage of any subdural debris. Negative pressure was not used except in patients with Hemovac and a subgaleal drain. Typically, after 24 hours of clinical monitoring and symptom improvement, the drain was removed, and the patient was sent home with recommendations and warning signs, if the patient's clinical condition permitted. Postoperative follow-up imaging was not routinely performed as there was no evidence of clinical benefit.

In addition to the management described above, the postoperative position was modified in the intervention group (trendelenburg). After admission to the hospital unit (general ward, special care, or intensive care unit), the patient's position was adjusted with a 30° leg elevation and a 10° downward head tilt. Proper positioning was verified with a goniometer. This position was maintained until the drains were removed, and the patient was then positioned according to usual care. If the patient decided to get out of bed, the nurse occluded the drains and reopened them when the patient returned to the position described for each group.

In addition to the management described above, the postoperative position was modified in the intervention group (trendelenburg). After admission to the hospital unit (general ward, special care, or intensive care unit), the patient's position was adjusted with a 30° leg elevation and a 10° downward head tilt. Proper positioning was verified with a goniometer. This position was maintained until the drains were removed, and the patient was then positioned according to usual care. If the patient decided to get out of bed, the nurse occluded the drains and reopened them when the patient returned to the position described for each group.

Proportion of patients who experienced recurrence of chronic subdural hematoma at 3 months of follow-up and required repeat surgery

Secondary outcomes were the proportion of patients with favorable functional outcome at three months, as measured by the modified Rankin Scale (mRS). The validated scale has seven categories: no symptoms (0), no clinically significant disability despite symptoms (1), mild disability (2), moderate disability (3), moderately severe disability (4), severe disability (5), and death (6); in this trial, a score of 0 to 2 was considered a favorable outcome, as it is associated with functional independence.