Case Presentation: A 75yo male presented with a few altered mental status. He had been in a rehabilitation facility working on physical therapy with family when he suddenly closed his eyes and became non-responsive. One month ago, the patient had had a fall from a ladder causing a subdural hemorrhage and uncal herniation that required evacuation via a right hemicraniectomy. His post-operative course at the time was complicated by a subdural empyema that required a washout and he was started on Cefepime before going to a rehabilitation facility five days before the current admission. Per his wife, episodes of unresponsiveness had occurred multiple times since he had been in the facility but usually resolved within a couple hours. In the ED, the patient’s helmet was removed and the family noted that his flap appeared more sunken than usual. He was transferred to the floor and worsened overnight; by morning, he would not react to stimulation. The family noted some shaking of all four extremities. A CT head was done showing a sunken flap with no acute hemorrhage. Two twenty-four hour EEGs were done and were negative for seizure-like activity. The Cefepime was stopped due to concern for neurotoxicity and the patient was switched to meropenem. His physical exam at the time showed a sunken head flap, closed eyes, and cheyne-stokes breathing pattern; the patient had an intact oculocephalic reflex without nystagmus and did not withdraw from painful stimuli. The patient was transferred to the Neurocritical Care Unit (NCCU). As the patient’s exam was clinically concerning for sunken head flap syndrome, the head of the bed was lowered to -10 degrees (Trendelenburg position) per the recommended treatment guidelines. Within 45 minutes of initiating treatment, the patient began to mutter simple responses and male spontaneous movements. He progressed as follows:Day 1 after treatment initiation: would say “ouch” to stimulationDay 2: eyes would open to verbal interaction, would not move extremities to commandDay 3: oriented to person, moving all extremities to command Day 5: alert and oriented to person, place, and time (could identify year when given choices)Throughout his hospitalization, the patient continued to improve and the head of the bed was slowly raised to increasing degrees during the day. After his course of meropenem was completed, the patient was taken to the OR for a right cranioplasty with CTH confirming no post-operative changes. One month after admission, he was discharged to a rehabilitation facility on a regular diet with thick liquids, pain controlled with PO medications, and was voiding fine and mobilizing with assistance.

Discussion: Sinking Skin Flap Syndrome is a very rare complication of a hemicraniectomy that can occur within days to months of the post-operative period. Patients with this syndrome chiefly present with altered mental status and may also have hemodynamic instability. The mechanism by which this phenomenon occurs is unknown but has been attributed to “open box” cranial physiology where the atmospheric pressure becomes greater than the intracranial pressure.(1) Management of this condition can be done with lowering the patient’s head to Trendelenburg position and cranioplasty is the definitive treatment.(2)

Conclusions: Sinking Skin Flap Syndrome can lead to neurologic devastation. This case shows the importance of maintaining high clinical suspicion in patients who have undergone a craniectomy to allow for efficient recognition and treatment of this rare post-operative syndrome.