Inferior meatal antrostomy impairs dynamic stability of the orbital walls

Objectives: The medial wall of the maxillary sinus, or the bony buttress, plays an important role in supporting the orbital floor. Since part of the bony buttress is removed in the inferior meatal antrostomy (IMA), it is expected that the IMA makes the orbital floor likely to develop serious fractures in traumatic situations. We conducted the present study to elucidate the effect of the IMA on the vulnerability of the orbital floor. Methods: After producing CAD (Computer Assisted Design) models simulating twelve skulls, we performed simulation antrostomy for each of the twelve CAD models in both the middle meatus and the inferior meatus. According to the site of the antrostomy, the models were categorized as the MMA (middle meatal antrostomy) or IMA groups. We then applied an impact on the orbital region of each model. Using the finite element method, we calculated the area of the orbital wall fracture induced by the impact. Then we compared the area of the orbital wall fractures between the MMA and IMA groups. Results: The orbital wall fracture areas were significantly greater in the IMA group than in the MMA group. Conclusions: The patients who underwent IMA are likely to develop serious orbital fractures if their orbits receive traumatic impacts. Hence, surgeons should be prudent in their indications for IMA.