The endonasal laser technique is carried out with the assistance of a potassium titanyl phosphate (KTP) laser, after suitable laser protection of the patient and staff. The laser settings recommended are 5.0 W, 0.5 s duration, and 0.5 s interval. The laser is used to resect the mucosa and thin bone. Superiorly and anteriorly where the bone becomes thick, a 15° curved 2.9 mm endonasal DCR coarse diamond burr (Medtronic, Jacksonville, FL, USA) is used for removing the hard bone anteriorly over the maxillary bone and above the axilla (Fig. 12.2).

Once wide bone removal, at least 1.5 cm in diameter, has been achieved, the sac should be easily identified with adequate exposure. The lacrimal puncta is dilated with a lacrimal punctal dilator and the lower canaliculus, dilated with a Bowman canalicular lacrimal probe (Fig. 12.3). The lacrimal sac is thus made to tent medially. A vertical incision is made along the lacrimal sac using the KTP laser at 5 W continuous mode (Fig. 12.4). The lacrimal sac is opened with the formation of anterior and posterior flaps. Horizontal incisions are then placed in the posterior flap using KTP laser superiorly and inferiorly and the midportion of the sac is vaporized thus achieving a wide rhinostomy. O’Donoghue silastic stents are then placed via both upper and lower canaliculi (Fig. 12.5), retrieved endonasally and tightened over a silastic tubing to prevent upward migration of the stent knot (Fig. 12.6). The stent loop is ensured not to be too tight as it may cheese wire through the puncta.