Tension pneumocephalus (TP) can be a life-threatening postoperative complication, but there are limited data owing to its exceedingly low frequency. A 48-year-old man that suffered a head injury survived the acute phase and cranioplasty was performed using a titanium plate. Progressive deterioration of consciousness occurred the day after the cranioplasty. Computed tomography showed the presence of expanded air in the left epidural cavity and a midline shift to the right side. Emergency skin flap reopening was performed. Tension of the scalp decreased when the skin suture was cut and the wound reopened. Lucidity and improved right hemiparesis were obtained within a few hours after drain insertion. Pooled air in the left epidural cavity gradually dissipated postoperatively and the epidural drain was removed 2 days after insertion. The patient was discharged 27 days after cranioplasty, with a modified Rankin scale score of 2. The mechanism that caused TP was considered. Specifically, the skin flap acted as a one-way valve and trapped air. Then the trapped air expanded as the patient's body temperature warmed. TP should be considered a differential diagnosis after craniotomy. Emergency skin flap reopening and drain insertion may be an effective treatment for TP in the epidural space.
Keywords: Tension pneumocephalus; cranioplasty; emergency skin flap reopening.