[The radiologic study of the nasolacrimal duct decompression surgery for treatment of chronic].

Objective:To explore the possibility of endoscopic nasolacrimal duct decompression surgery for the treatment of chronic dacryocystitis.Method:①Twenty-two eyes with chronic dacryocystitis were treated with 30% iohexol injection for lacrimal sac lithography. Contrast agents were taken from the lacrimal canal reflux to stop the injection. The CT scan for the lacrimal passage was performed immediately. ②Three-dimensional reconstruction of lacrimal duct and its surrounding structures was performed with Sinuses Trachea Ⅰ software. ③The lacrimal sac and nasolacrimal canal were cut and depressed using this software simulation.Result:①The incidence of lacrimal duct obstruction were 4.5% (1/22, in lacrimal duct), 22.7%(5/22, in lacrimal sac), 13.6%(3/22, transition section), 36.4%(8/22, in nasocrimal duct), and 22.7%(5/22, in Hasner valve) separately. The transitional section, nasolacrimal duct, Hasner valve section 72.7%(16/22) totally. ②The lateral wall of the nasolacrimal duct in 3D visual model is constructed of maxillary lacrimal process. The interior wall of the nasolacrimal duct is made of drop process of lacrimal bone and ascending lacimal process of the inferior turbinate. ③Observed from the inferior meatus, hard nasolacrimal duct is surrounded by inferior turbinate bone, and forms the inside wall of openings of the lacrimal duct. ④The removal of the front parts of the inferior turbinate attached to the lateral nasal can lead to the deperession of the membranous nasolacrimal duct sufficiently, and create the efficient space to eliminate nasolacrimal duct obstruction. Conclusion:Endoscopic nasolacrimal duct decompression surgery is efficacy for the treatment of chronic dacryocystitis. The integrity of the membranous lacrimal duct was reserved, and the complication such as lacrimal sac granulation hyperplasia, lacrimal duct obstruction again caused by scar formation was avoided.