Context: Sinking Skin Flap Syndrome (SSFS) is a clinical syndrome in which a patient with a craniectomy develops objective neurologic abnormalities explained by the concavity of their skin flap and the pressure of the atmosphere on the underlying brain. Patients present with postural headaches and delayed neurologic deficits that localize to the craniectomy site where atmospheric pressure compresses the brain under the skin. These symptoms and signs are reversible when supine and after cranioplasty. SSFS is thought to be a rare complication of craniectomy after traumatic brain injury (TBI); however, evidence suggests SSFS is under-recognized, in part due to its diverse clinical presentation.

We present two patients who developed SSFS during inpatient multidisciplinary rehabilitation. As available, qualitative behavioural observation, manual muscle testing (MMT), Timed Up and Go (TUG), Berg, 6-minute walk test (6MWT), O-Log, SCATBI, MoCA and neuroimaging pre- and post-cranioplasty are presented.

Case 1: 72-year-old woman with a severe TBI requiring left hemicraniectomy. On admission to rehabilitation, TUG was 62sec, Berg 20/56, and SCATBI 4words/min. Postural headache, nausea and vomiting limited her participation. During rehabilitation, she deteriorated; consistently after 20min standing or 2hrs sitting, she developed headache, worsening MMT in the right arm and leg (from MRC 3-5 to MRC 2-3) and telegraphic speech. After sitting up for 6hrs, the patient became stuporous with GCS12. Infectious, metabolic, and epileptic causes were ruled out; she was diagnosed with SSFS and planned for cranioplasty. Neuroimaging showed paradoxical pressure on the brain from the skin over the left hemispheric craniectomy site.  While awaiting surgery, the patient was restricted to head elevation <30degrees using a tilt wheelchair and bedrest; her O-log improved from 22/30 to 26/30. 48hrs post-cranioplasty, her speech was fluent, MMT was MRC 4-5, O-log 30/30, and she remained headache-free after sitting upright for 2.5hrs. Postoperatively, TUG was 31sec, Berg 28/56, and SCATBI 14words/min. 

Case 2: 54-year-old man with a moderate TBI requiring right hemicraniectomy. On admission to rehabilitation, 6MWT was 247m, Berg 27/56, and MoCA 25/30. Postural headache limited participation and required multiple medications. During rehabilitation, the patient was noted to have postural left hemi-body neglect and left arm and leg weakness (MRC 3-4) after periods of 1-2hrs sitting upright. Structural, metabolic, and infectious causes for this presentation were ruled out. Neuroimaging showed paradoxical pressure on the brain from the skin over the right hemispheric craniectomy site. He was diagnosed with SSFS and planned for cranioplasty. Post-cranioplasty, the patient’s headaches completely resolved and medications were discontinued. He no longer experienced postural left neglect or weakness. Postoperatively, 6MWT was 543m, Berg 56/56, MoCA 30/30.  

Clinical relevance: This case series highlights the diverse clinical presentation, diagnosis, and rehabilitation challenges associated with SSFS, and the benefit of cranioplasty in this condition.

Postural Neurologic Deficits after Decompressive Craniectomy for Traumatic Brain Injury: A Case Series of Sinking Skin Flap Syndrome