A crescent or sickle knife or a radio frequency device is used to make the incision over the lateral nasal mucosa down to the periosteum in front of the maxillary line (Fig. 21.2). The first vertical incision is made around 10 mm anterior to the maxillary line with a length of about two-thirds of the vertical height of the middle turbinate starting from the level slightly above the axilla of middle turbinate. A horizontal incision is then made at right angle at the inferior end of the vertical incision until reaching the maxillary line. The upper horizontal incision can be completed with the knife or a pair of Westcott scissors starting from the top of the vertical line over and cut beyond the axilla of the middle turbinate (Fig. 21.3). A Freer periosteal elevator is then used to elevate the mucoperiosteal flap and folded around the middle turbinate to keep it out of the operating field. Alternatively, an anteriorly based nasal mucosal flap can be created in a similar fashion but usually required sutures to retract anteriorly during osteotomy. An anteriorly based flap may allow better mucosal coverage of bare bone at the end of the osteotomy procedure.

A Kerrison Rongeur or forward-biting Hajek-Koeffler punch is used to enlarge and remove the hard bone of the frontal process of the maxilla, starting from the maxillary line (Fig. 21.4). Removal of the maxillary bone should expose the inferior half of the lacrimal sac (Fig. 21.5). Bone removal is continued anteriorly and as far superiorly as possible (Fig. 21.6). The thin lacrimal bone at the posterior half of the lacrimal sac is elevated with Freer elevator and removed using a pair of Takahashi forceps (Figs. 21.7 and 21.8). An osteotomy of at least 15 mm in vertical length is usually required to expose the lacrimal sac from fundus to sac-duct junction. All bones over the lacrimal sac fundus and common canaliculus opening should be removed.

Superoanteriorly, the orbicularis oculi muscle is often exposed (Fig. 21.9). Superoposteriorly, the agger nasi air cells or operculum of the middle turbinate is entered to ensure full fundus exposure (Fig. 21.10). Posteriorly, a limited anterior ethmodiectomy may be required and part of the medial periorbita can get exposed. This allows maximal superior bone removal without using powered instruments and posterior lacrimal sac flap to lie flat. Lacrimal sac fundus is reached when orbicularis muscle is also exposed superiorly. Alternately, one can use special punches like the Malhotra punch, powered drills, or piezoelectric energy to perform a superior osteotomy. Inferior boundary of the osteotomy is the nasolacrimal duct, which is noted after the canal is de-roofed.

The position of the internal punctum can be verified using a Bowman probe, passing through the lacrimal canaliculus into the lacrimal sac and tenting the medial sac wall. With the Bowman probe passed horizontally tenting the medial wall of the lacrimal sac, at least 2 mm space should be left between the tented lacrimal probe tip and the superior edge of the osteotomy.