What condition is primarily treated with ethmoidectomy?

Ethmoidectomy is a surgical procedure aimed at removing bone and tissue from the ethmoid sinuses, which are located between the eyes and nose. This treatment is primarily indicated for chronic sinusitis, particularly when it has not responded to conservative management such as medications or other non-surgical interventions.

Chronic sinusitis often involves severe blockage of the sinuses, leading to persistent symptoms like facial pain, pressure, nasal congestion, and sometimes recurrent infections. By performing an ethmoidectomy, the surgeon can improve drainage and ventilation of the ethmoid sinuses, alleviating these symptoms and significantly enhancing the quality of life for the patient.

While conditions like rhinitis (A) and allergies (C) can contribute to sinus symptoms, they are not directly treated with this surgical intervention. Headaches (D) can be associated with sinus issues but are not themselves an indication for an ethmoidectomy. Thus, the procedure is specifically targeted towards the underlying issues related to sinusitis, making it the correct answer in this context.