The Ponticulus Ethmoidalis: A Newly Appreciated Anatomic Landmark in Endoscopic Sinus Surgery

Introduction: Ethmoid sinus anatomy is so variable it has been referred to as a “labyrinth.” Accordingly, this provides a challenge for surgeons performing ethmoidectomy. Identifying consistent anatomic features or landmarks within the ethmoid sinus can aid surgeons performing sinus surgery. The goal of this investigation was to determine if subtle anatomic features are consistently present within the retrobullar recess and could potentially serve as a reliable landmark for surgeons performing ethmoid surgery. Materials and Methods: Ethmoid sinus anatomy was studied in 60 sinonasal complexes through several methods including gross anatomic dissection, endoscopic dissection and 3-D CT stereoscopic imaging. Results: Review of gross sagittal sinonasal specimens revealed that the retrobullar recess was present in all specimens and a tissue bridge was noted emanating from the basal lamella deep within the retrobullar recess in 23/24 gross sagittal specimens; in 1/24 specimens it was quite small or difficult to appreciate. In the radiographic analysis, the tissue bridge was noted in 17/18, in 1/18 it was not appreciated. In the endoscopic dissections it was noted in 17/18, in 1/18 it was small or not appreciated. Conclusion: The small tissue bridge, or ponticulus within the retrobulbar recess was seen in nearly all ethmoid sinuses studied leading us to venture that could be used in surgery to orient surgical dissection through the basal lamella into the posterior ethmoid region.