1) A 35-year-old man sustained blunt trauma to the head. STAT Imaging revealed large left subdural hematoma (SDH). After evacuation, and patient remained stable postoperatively. During rehabilitation period, patient was found to have worsening exam with unreactive pupils. When head of bed (HOB) was made flat, patient's pupil reactivity returned. STAT Imaging revealed impending herniation in setting of sunken craniectomy flap. Diagnosis of SSFS was made, and the patient underwent cranioplasty with clinical and radiographic improvement thereafter. 

2) 68-year-old man arrived in our ED due to stroke-like symptoms after sustaining ground-level-fall. STAT Imaging revealed right ICA occlusion as well as evidence of traumatic brain injury with left frontal contusion. After emergent thrombectomy, the patient was found to have an unreactive, dilated left pupil. Mannitol was administered with return of the pupil reactivity. STAT Imaging confirmed expansion of the left frontal hemorrhagic lesion. After emergent decompression, the patient’s left pupil was again found to be unreactive. Sunken craniectomy flap was appreciated; hyperosmolar therapy was avoided. While in Trendelenburg position, reduction in depression of flap was visualized as well as return of left pupil reactivity. STAT imaging confirmed the depressed craniectomy flap with compression of underlying structures.

Once SSFS is recognized, management is counter-intuitive and requires increasing the ICP to restore the anatomical position of midline structures. Conventional therapy addressing signs of herniation may lead to worsening of herniation since SSFS is due to the abnormal pressure gradient that exists between the higher pressure of the atmosphere relative to intracranial pressure without the protection of bone flap.