[Role of computed tomographic dacryocystography in lacrimal path damage]

To explore the diagnostic role of computed tomographic dacryocystography (CTDCG) in lacrimal path damage and provide operative approach guidance for the endoscopic transnasal dacryocystorhinostomy (DCR).

Twenty-eight cases with lacrimal path damage underwent CTDCG. The following reconstruction techniques including volume rendering (VR), multiple planar reconstruction (MPR), maximum intensity projection (MIP) and three-dimensional reconstruction (3-d R) were done on the real-time workstation. The morphology of dacryocyst, displacement fracture of the lacrimal fossa (FS) and the relationship between the uncinate process (UP) and the FS were observed. The thickness of inner walls of anterosuperior and posteroinferior aspects of lacrimal fossa was measured.

The morphology of dacryocyst, the displacement fracture of the lacrimal fossa and the block site of the lacrimal passage could be displayed clearly by CTDCG with the following reconstruction techniques including VR, MPR, MIP and 3-d R, 6 cases of canaliculus obstruction, 14 cases of lacrimal sac obstruction, 8 cases of lacrimonasal duct obstruction were showed. Meanwhile the relationship between the UP and the FS could also be showed clear. The average bony thickness of the anterosuperior part of FS was (2.96 +/- 0.30) mm, while the bony thickness of the posteroinferior half was (0.02 +/- 0.005) mm, and the distance between the top and bottom of dacryocyst to the operculum of the middle turbinated (OMT) are (6.80 +/- 1.50) mm, (4.00 +/- 1.80) mm respectively (P < 0.05).

The morphology of dacryocyst, the displacement fracture of the lacrimal fossa, block site of the lacrimal passage and the relationship between the UP and FS can be clearly displayed by CTDCG, which provide operative approach guidance for the endoscopic transnasal dacryocystorhinostomy.