Posture-dependent aphasia: Focal cortical dysfunction in the sinking scalp flap syndrome.

ABSTRACT: Decompressive craniotomies are being increasingly used in the treatment of raised intracranial pressure due to a variety of reasons like large infarcts, hypertensive hemorrhages and contusions. Though effective in decreasing raised intracranial pressure, they have certain complications like the sinking scalp flap syndrome that is caused by cortical dysfunction of the area below the craniotomy which is exposed to the effects of atmospheric pressure. We describe a 60-year-old patient who underwent decompressive craniotomy for acute subdural hematoma and after an initial uneventful postoperative period developed incontinence, irrelevant verbalization and ataxia. He was found to have hydrocephalus and underwent a ventriculo-peritoneal shunt with resolution of his symptoms. Three weeks later his flap had sunk in deeply and the skin was non-pinchable and he was noted to have headaches, vomiting and retching when he sat up. In addition he became aphasic when seated and the symptoms subsided on lying down. A diagnosis of focal cortical dysfunction due to sinking scalp flap syndrome was made. We highlight the incidence and pathophysiology of this unusual complication of decompressive craniotomy and stress the need to be aware of this entity particularly in patients who do not show an initial improvement after decompressive craniotomy as the cause of their poor neurological status may not be explained by any other mechanism.