We report the case of an iatrogenic tension pneumothorax related to the placement of a ventriculoperitoneal shunt, followed by pneumocephalus. The patient was pending cranioplasty and shunt placement after decompressive craniectomy for acute subdural hematoma and posttraumatic hydrocephalus. Facilitating the severe and potential life-threatening complication was a severe obesity of the patient as well as incorrect surgical technique.