Dacryocystorhinostomy (DCR) For Nasolacrimal Duct Obstruction Download PDF, 3.3MB, PDF Dacryocystorhinostomy (DCR) surgery is aimed at creating osteotomy (a small opening in the bone that surrounds the lacrimal sac) to allow tears to drain and bypass the area of obstruction. This allows tears to drain along the new bypass route into the nose and then into the throat. Nasolacrimal duct obstruction (NLDO) is the most common indication for DCR surgery. [Please download the PDF file if you are unable to view the image below.]