Learning Objectives: To illustrate the anatomy of the middle ear ventilation routes to the attic, to understand the pathophysiology that leads to aditus block syndrome and to show how to functionally restore the blocked pathways of ventilation.

Introduction: This narrated six minutes surgical video illustrates a novel concept to treat aditus ad antrum block syndrome through an exclusive transcanal endoscopic approach. Granulation tissue and mucosal webs obstructing the pathways of ventilation from the tympanic isthmus to the mastoid space are removed endoscopically with sparing of mastoidectomy and preservation of mastoid mucosa.

Methods: A pre-operative CT scan of the temporal bone was obtained for surgical planning. The surgery was performed entirely through a transcanal endoscopic approach with rigid 0 and 30 degree endoscopes, 3 mm in diameter and 14 cm in length, connected to a video camera and high definition monitor. Inflammatory granulation tissue and mucosal webs obstructing the movement of the ossicular chain and the ventilation routes to the mastoid were removed with sharp dissection without mastoidectomy. The routes of ventilation to the mastoid were re-established and irrigated through a transcanal endoscopic limited atticotomy and the small scutal defect was repaired with a cartilage graft.

Results: Inflammatory granulation tissue and mucosal webs obstructing the pathways to mastoid ventilation were removed successfully through a transcanal endoscopic approach with integrity of the mastoid space and preservation of mastoid mucosa.

Conclusion: This endoscopic minimally invasive novel approach to mastoid ad antrum block syndrome focuses on functional restoration of the aeration pathways through the tympanic isthmus instead of removal of disease through mastoidectomy. With this approach the epitympanic and mastoid mucosa is preserved to maintain the important function of mucosal gas exchange, buffer mechanism and homeostasis of middle ear ventilation.