Decompressive Craniectomy Increases Brain Lesion Volume and Exacerbates Functional Impairment in Closed Head Injury in Mice

Decompressive craniectomy has been widely used in patients with head trauma. The randomized clinical trial on an early decompression (DECRA) demonstrated that craniectomy did not improve the neurological outcome, in contrast to previous animal experiments. The goal of our study was to analyze the effect of decompressive craniectomy in a murine model of head injury. Male mice were assigned into the following groups: sham, decompressive craniectomy, closed head injury (CHI), and CHI followed by craniectomy. At 24 h post-trauma, animals underwent the Neurological Severity Score test (NSS) and Beam Balance Score test (BBS). At the same time point, magnetic resonance imaging was performed, and volume of edema and contusion was assessed, followed by histopathological analysis. According to NSS, animals undergoing both trauma and craniectomy presented the most severe neurological impairment. Also, balancing time was reduced in this group compared with sham animals. Both edema and contusion volume were increased in the trauma and craniectomy group compared with sham animals. Histopathological analysis showed that all animals that underwent trauma presented substantial neuronal loss. In animals treated with craniectomy after trauma, a massive increase of edema with hemorrhagic transformation of contusion was documented. Decompressive craniectomy applied after closed head injury in mice leads to additional structural and functional impairment. The surgical decompression via craniectomy promotes brain edema formation and contusional blossoming in our model. This additive effect of combined mechanical and surgical trauma may explain the results of the DECRA trial and should be explored further in experiments.