[Digital subtraction dacryocystography following surgical interventions].

In our series of over 60 dacryocystograms using the digital subtraction technique we report on two cases in which this examination was done postoperatively. The fine, detailed presentation of the topography showed that the dacryorhinostomy was functionally open in spite of the suspicion of clinical failure. In the second case, the fine fistulas between the nasolacrimal duct and maxillary sinus could only be demonstrated by the subtraction study. A conventional dacryocystogram failed to show this important detail. The time necessary for both examination techniques is about equal. Digital subtraction dacryocystography has the advantages of immediate availability, the capacity to observe the flow of the contrast medium kinetically and a superior topography display. It is therefore ideal for the evaluation of postoperative topography after lacrimal and sinus surgery.