This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: ENT
During DCR surgery, an osteotomy was done in the anterior and superior region. Which area does it accidentally open into? 
Select and explain. 
A. Anterior Ethmoidal Sinus, B. Maxillary Antrum, C. Superior Meatus, D. Middle Meatus
A: Anterior Ethmoidal Sinus
Answer: A: Anterior Ethmoidal Sinus 
Explanation: COMPLICATIONS OF CONVENTIONAL EXTERNAL DACRYOCYSTORHINOSTOMY: Persistent or recurrent tearing (most common complication) Bleeding following an infratrochlear block due to damage of anterior ethmoidal aery (2nd most common complication) Post-operative subcutaneous or subperiosteal hematoma near the incision site. CSF leak as a rare complication Postoperative infections requiring prophylactic antibiotics Secondary failure of DCR due to rhinostomy closure/insufficient size of osteotomy (mitomycin c improves success rates) Osteotomy opening into anterior ethmoidal air cells (in 46% of DCR surgeries)