Endoscopic Approach to Postoperative Maxillary Cysts Ensuring Infraorbital Nerve Safety With Direct Approach to the Anterior and Lateral Part of the Maxillary Sinus With an Endoscope (DALMA): A Case Report.

Postoperative maxillary cysts (POMCs) present significant challenges, especially when located laterally or when the infraorbital nerve's course is unclear on imaging. Traditional endoscopic approaches are often limited by a high risk of recurrence and potential nerve injury. Here, we report a case of a 72-year-old woman with a right maxillary cyst, which caused pain and swelling. Imaging revealed a cyst with infraorbital wall defects and uncertain nerve positioning. Using the direct approach to the anterior and lateral maxillary sinus with an endoscope (DALMA), we successfully identified and preserved the infraorbital nerve while opening the cyst wall. A mucosal flap from the nasolacrimal duct was utilized to cover the cyst opening, secured by suturing with the medial cyst wall to prevent recurrence. Postoperative recovery was uneventful, with significant relief of symptoms. Eight-month follow-up imaging confirmed an open cyst without recurrence or nerve damage. This case demonstrates the efficacy of the DALMA technique in managing complex POMCs, offering a safe and effective method for cases with challenging anatomical features. Using a nasolacrimal duct mucosal flap provided the necessary coverage and stability to prevent recurrence. This approach significantly reduces the risk of infraorbital nerve injury and recurrence, making it a valuable advancement in endoscopic sinus surgery.