Endoscopic Transfontanellar Approach of a Cyst Anterior to the Brainstem Crossing the Foramen Magnum-Part II: Success of Multiple Fenestrations: Two-Dimensional Operative Video.

ABSTRACT

Premature infants with severe germinal matrix/intraventricular hemorrhage are at high risk of posthemorrhagic ventricular dilation and hydrocephalus (Video 1). We report a 4-month-old premature infant with grade III intraventricular hemorrhage and compartmentalized hydrocephalus with an unusual craniospinal cyst. The cyst extended anteriorly from the mesencephalon to the posterior wall of C6, causing severe compression of the brainstem and spinal cord. An endoscopic procedure was performed first to achieve a unique cranial fenestration, which is detailed in "Endoscopic Transfontanellar Approach of a Cyst Anterior to the Brainstem Crossing the Foramen Magnum-Part I Failure of Unique Fenestration." One month later the clinical picture recurred. Magnetic resonance imaging revealed hydrocephalus and cyst recurrence. A second procedure with endoscopic fenestration and shunt revision was needed. The same right transfontanellar approach was chosen, using a straight 30° endoscope. The procedure and surgical technique are explained in a step-by-step fashion. Extreme care was taken to align the head and the cervical spine. This allowed access to the extreme caudal cyst membrane posterior to C6 to create multiple transfixing fenestrations of the cyst. At 18-month follow-up, the child demonstrated almost normal neurological and psychomotor development with no cyst recurrence or hydrocephalus. Our report underlines the importance of performing multiple fenestrations of such cysts. We believe that performing a transfixing fenestration through the cyst allows cerebrospinal fluid flow and prevents recurrence, as, for instance, has been shown for suprasellar arachnoid cysts.