Spontaneous migration of a bullet in the cerebellum--case report.

A 15-year-old boy presented with a gunshot wound in the left cerebellar hemisphere. He was confused and left cerebellar signs were noted. The patient underwent the first surgery for debridement of the entry wound in the left parietal region and second surgery to remove the bullet. However, the bullet could not be located via a left unilateral suboccipital craniectomy in the park bench position, because it had migrated to the opposite side due to the effects of gravity in just a few hours. Skull radiography obtained just before the third surgery showed that the bullet had returned to the left side, and it was removed easily via the previous craniectomy in the sitting position. The clinical course suggests that in removing a bullet, skull radiography or computed tomography should be obtained just before surgery, or even intraoperatively, and that those findings should be the basis for the surgical procedure and operative position.