Penetration of the Scalp by the Bent Fragment of a Pre-installed Titanium Mini-Plate Due to a Minor Head Injury: A Case Report.

Titanium mini-plates are commonly used for bone flap fixation in craniotomy and are particularly essential for covering burr holes. Plate exposure through the scalp may occur because of scalp thinning caused by infection or local ischemia, and penetration of the scalp by a titanium mini-plate that had been bent by a minor head injury are rare. A 69-year-old man who had undergone covering of a burr hole in the calvarium by a titanium plate for clipping of a ruptured aneurysm 17 years ago was referred to our clinic to examine metal protruding through the scalp. One year previously, he had hit his head on a wall with no consequence until one week ago, when he noted the protruding metal. Plain skull radiography showed that a portion of the pinwheel-shaped titanium mini-plate had been bent upward and was exposed through the scalp. As the wound was contaminated with sebum, the plate and three screws securing it were removed through a linear skin incision under local anesthesia. The wound healed uneventfully, and the sutures were removed 10 days later. Bone flap fixation requires careful attention. When a five-screw hole pinwheel-shaped titanium mini-plate is used to cover a burr hole, all five holes should be fixed to the skull/bone flap to prevent bending in the future. Alternatively, a wing that is not fixed with a screw should be cut or a rectangular or diamond-shaped plate should be used.