Intracranial penetrating injury associated with an intraoperative epidural haematoma caused by a spring-laden pin of a multipoise headrest.

@article{Erbayraktar2001IntracranialPI,
  title={Intracranial penetrating injury associated with an intraoperative epidural haematoma caused by a spring-laden pin of a multipoise headrest.},
  author={Serhat Erbayraktar and Necati G{\"o}kmen and Umit Dursun Acar},
  journal={British journal of neurosurgery},
  year={2001},
  volume={15 5},
  pages={425-8}
}
Lack of an intermediary piece that should have been placed between the pin and spring resulted in skull penetration due to a rapid waste in the spring's compensatory capacity. Checking integrity of internal pieces should be performed regularly. Designing intermediary piece and spring as a single piece might increase safety.