The reasons for reoperations after surgery for acute subdural hematoma and the implications of suspected injury mechanisms.

Study aim: The primary aim is to analyze the relationship between the reasons for reoperation after surgery for acute subdural hematoma and the injury mechanism and secondarily the relationship between the acute subdural hematoma primarily operated on and the area of reoperation.

Methods: Among adult patients operated on for acute subdural hematoma between 2013 and 2017, patients reoperated within 14 days were identified. Injury mechanisms, reasons for reoperation, and reoperated lesion location were studied.

Results: Of 86 patients operated on for acute subdural hematoma, 24 patients were reoperated (27.9%). The main indications for reoperation after uncomplicated falls as injury cause (12 patients) were recurrent/significant residual subdural hematoma (7 patients) and contralateral subdural hematoma (3 cases). In complicated falls (long staircase, 3 patients), the reasons for reoperation were expansive intraparenchymal hematoma or brain contusion. In traffic accidents (4 patients, 3 pedestrians hit by cars), the reason for reoperations was brain contusion (two cases), contralateral intracerebral and subdural hematoma and postoperative epidural hematoma. Injury mechanism was unknown in 5 patients. In 20.8% of reoperations, the reoperated lesion (mainly subdural hematoma) was contralateral to the primary subdural hematoma. Prognosis was worse in reoperated patients.

Conclusions: Recurrent/significant residual subdural hematomas are the most frequent reasons for reoperation after acute subdural hematoma surgery. The reasons for reoperations are related to the mechanism of injury. Simple falls are associated mainly with recurrent/significant residual or contralateral subdural hematomas. In complicated falls or traffic accidents (vigorous injuring force) hemorrhagic injuries of the brain parenchyma prevail.