Supradiaphragmatic intrathoracic migration of ventriculoperitoneal shunt with "double bending sign".

Ventriculoperitoneal shunt (VPS) is a common treatment for hydrocephalus. An 80-year-old woman presented with subarachnoid hemorrhage caused by rupture of an aneurysm of the right middle cerebral artery. Emergency clipping was performed. Hydrocephalus occurred shortly after and VPS placement was performed. She improved and was transferred to a rehabilitation hospital. She presented with dyspnea 5 months later. Chest computed tomography (CT) showed extensive pleural effusion and intrathoracic migration of the distal VPS catheter. Chest CT confirmed that the distal catheter had penetrated into the pleural cavity under the second rib, and the catheter tip was located at the bottom of the right thoracic cavity. Review of chest CT right after the shunt surgery found the distal catheter passing only under the second and third ribs and otherwise located in the subcutaneous layer to the abdominal cavity. Chest radiography showed that the distal shunt tube was distorted in a characteristic "double bending sign." This rare case of supradiaphragmatic intrathoracic migration of VPS indicates a possible mechanism of this migration, based on the anatomical physiology, and that "double bending sign" indicates the need for further investigation.