Bilateral Subdural Hygromas After Deep Brain Stimulation Implantation in the Setting of Unrecognized Intracranial Hypotension

Cerebrospinal fluid (CSF)-venous fistulas are a recently recognized cause of spontaneous spinal CSF leak and present most commonly with Valsalva (“cough”)-exacerbated or orthostatic headaches. By inducing CSF hypotension, they cause diffuse pachymeningeal enhancement and brain sag on MRI. This unusual case demonstrates the potential for bilateral subdural hygroma development in a patient with an undiagnosed CSF-venous fistula after ventral intermediate nucleus (VIM) deep brain stimulation (DBS) implantation. A 68-year-old gentleman with medically-refractory essential tremor underwent extensive preoperative evaluation by the Mayo Clinic-Rochester DBS Committee. Initial MRI during preoperative evaluation had no evidence of CSF hypotension, but MRI performed the day before surgery demonstrated diffuse pachymeningeal enhancement. He underwent bilateral VIM DBS implantation and presented in the subacute postoperative period with bilateral subdural hygromas. Further testing identified a prominent hyperdense paraspinal vein arising from the T10/T11 nerve root, consistent with CSF-venous fistula. Even when patients undergo rigorous preoperative evaluations for surgical procedures, insidious pathologies can develop and cause unexpected postoperative complications.