Overdrainage after ventriculoperitoneal shunting in a patient with a wide depressed skull bone defect: The effect of atmospheric pressure gradient.

•Postoperative hydrocephalus is a frequent complication requiring cerebrospinal fluid (CSF) diversion. It is so complicated in the patient who had a wide decompressive craniectomy.•We herein emphasize the efficacy of VP shunting, supine bed rest and cranioplasty in treating hydrocephalus patients who have undergone craniectomy.•The gravitational effect and the atmospheric pressure gradient effect are two factors associated in the treatment of hydrocephalus for the patient who had decompressive craniectomy. These effects can be eliminated by supine bed rest and cranioplasty.