Transpterygoid trans-sphenoid approach to the lateral extension of the sphenoid sinus to repair a spontaneous CSF leak

Objective and Importance: Cerebrospinal fluid (CSF) fistula from the middle cranial fossa into the sphenoid sinus is a rare condition. In the past, the treatment of choice has been closure via a cramotomy. Only few geriatric cases are known, which were successfully operated by endoscopic surgery. We present a further case of nontraumatic CSF fistula originating from the middle cranial fossa. A new endoscopic technique was applied. We discuss treatment options for this rare defect. Clinical Presentation: A 76-year-old patient presented with a 2-year history of rhinorrhea. High levels of P-trace protein pointed to a diagnosis of CSF fistula. The defect was located at the anterior and inferior aspect of the pterygoid recess of the left sphenoid sinus. Intervention: The patient was operated using an endoscopic trans-sphenoidal approach. After endoscopic opening of the maxillary and sphenoid sinus, a complete posterior ethmoidectomy was performed. The medial part of the pterygoid process was removed, allowing endoscopic exposure and closure of the defect. At 1-year follow-up, the CSF fistula had not recurred and the patient had no sequel from the surgical procedure. Conclusion: In selected cases, this new endoscopic partial transpterygoid approach to the middle cranial fossa is recommended for surgical repair of CSF fistula involving the lateral extension of the sphenoid sinus. To our knowledge, ours is the oldest patient with this condition successfully operated by endoscopic means at the world's most northern university hospital.