Endonasal Resection of the Cartilaginous Eustachian Tube with Nasoseptal Flap Closure for Refractory CSF Fistula Following Previous Mastoid and Middle Ear Obliteration

Background: Lateral skull base approaches or previous temporal bone trauma can lead to persistent encephaloceles or CSF fistula despite appropriate management with mastoid obliteration and attempted occlusion of the bony eustachian tube through the middle ear space. These patient scenarios may present a reconstructive dilemma.

Objective/Case Presentation: We present a challenging case of a young male with a remote history of penetrating injury to the lateral skull base. He had resultant cholesteatoma and encephalocele requiring transmastoid repair and obliteration with closure of the external auditory canal. He had persistent infectious complications and subcutaneous emphysema over the temporal scalp when blowing his nose, indicating a persistently patent eustachian tube. There was also some concern for intermittent CSF rhinorrhea on history and examination.

Technique: A submucous resection and partial turbinectomy was first performed to facilitate appropriate exposure and uninarial two-handed technique. Cuts were designed around the torus, extending into the fossa of Rosenmuller posteriorly. The cartilaginous eustachian tube was then resected and surrounding mucosa meticulously removed. The remaining visible lumen was packed with Surgicel. An ipsilateral nasoseptal flap was then harvested and rotated for inset with excellent coverage. Care was taken to avoid covering any native mucosa as to avoid mucocele formation.

Results: The cavity was carefully packed and the patient observed overnight. He has done well in the immediate postoperative setting with no recurrent subcutaneous emphysema and no evidence to suggest CSF rhinorrhea.

Conclusions: Endonasal closure of the eustachian tube may be an option in cases of recalcitrant CSF fistula and infectious complications. Employing a vascularized septal flap ensures optimal wound healing and ample closure.