Proper screening tests should confirm the diagnosis of primary acquired NLDO. Only patients with chronic epiphora without infection and discharge (dacryostenosis) can undergo ECLDCR. Patients with a history of acute dacryocystitis and mucocoele formation are not good candidates [32]. These conditions should preferably be treated with the external or endonasal approach. This procedure is also contraindicated in patients with suspected dacryolithiasis, neoplasm, and NLDO secondary to sarcoidosis or Wegener’s granulomatosis [7, 13, 16]. Table 24.1 summarizes the oculo-lacrimal contraindications for ECLDCR.

Proper antibiotic treatment and thorough lacrimal irrigation should be initially done to remove the purulent material before ECLDCR. Nasal endoscopy should be a routine practice for preoperative evaluation before ECLDCR. This will give the surgeon an overview of what to expect before the surgery. The two most important nasal structures to look out for are the septum and the middle turbinate. Severe septal deviation is a relative contraindication; therefore, a septoplasty if one is competent or a referral to an ENT surgeon is warranted before proceeding to ECLDCR. An enlarged middle turbinate can be partially resected to expose the surgical area [24, 34]. Patients who have undergone previous nasal surgery (functional endosocopic sinus surgery–FESS, polypectomy, etc.) are not good candidates for ECLDCR [20, 25]. Patients who also had naso-orbital trauma involving the lacrimal system are undesirable for this type of surgery [20, 25]. Table 24.2 summarizes the nasal contraindications for ECLDCR.

The ideal laser in ECLDCR must produce enough power to allow the surgeon to create an adequate osteotomy without inducing damage to surrounding tissues [17, 30]. Different types of lasers have been applied in ECLDCR. These are the Argon laser, the Holmium (Ho): Yttrium Aluminum Garnet (YAG) laser, Neodymium (Nd): YAG laser, Potassium Titanyl phosphate (KTP): YAG laser, Erbium (Er): YAG laser, and the diode laser [6–30] (Table 24.3). In recent years, the diode laser (Fig. 24.2) has been gaining popularity due to a number of advantages.

Diode lasers are designed for multispecialty application in minimally invasive surgery (ophthalmology, otorhinolaryngology, and urology), open surgery (obstetrics and gynecology), interstitial laser therapy, and vascular applications (dermatology and vascular surgery) [5]. Therefore, from a financial perspective a single diode laser in a hospital setting can be shared by surgical specialties. Operating at a wavelength of 810–980 nm in the near-infrared portion of the spectrum, this laser induces excellent hemostasis due to its high absorption in melanin and hemoglobin. It is compact, portable, and can fit neatly into any doctor’s clinic or operating suite. Due to its portability, it can be easily transported from one clinic to another or between hospitals. Setting up this laser is also simple and easy. All diode lasers run from a standard electrical wall socket and are ready for use within seconds. The menu-driven user interface is simple and it gives immediate access to treatment options with continuous, pulsed or repeat-pulse mode. There is also minimal maintenance and service requirements needed because this surgical laser has a solid-state system and has no moving parts. The laser energy delivery system uses a flexible fiber whose diameters range from 400 to 1,000 um [20, 31] and give easy access to confined areas and is also compatible with endoscopic instrumentation for surgical applications (Fig. 24.3).

General or local anesthesia can be used for ECLDCR. Any laser with a rigid laser fiber optic can be utilized, but in the past decade, the diode laser has been the preferred laser of choice due to the advantages reported earlier. The diode laser setting used is at an average of 10 W with continuous laser delivery using the contact mode. A 600 um semirigid laser fiber optic is used. Nasal packing is done with a ¼ inch gauze soaked with 0.5 % oxymetazoline hydrochloride. This is left in place for 10 min and removed just before the laser treatment. The punctum is dilated using a punctum dilator and a bowman 0 probe slid through the canaliculus to also dilate it before the insertion of the fiber optic. Once a hard stop is felt, the Bowman probe is removed. The 600-um laser fiber optic is inserted in the lower punctum into the canaliculus up to the level of the lacrimal sac in a 45° fashion (Figs. 24.4 and 24.5). The nasal pack is removed and a 0° nasal video endoscope attached to a TV monitor (Fig. 24.6) is inserted through the nostril to visualize the transilluminated laser light from the lacrimal sac. We call this the “laser glow.” If the laser glow cannot be visualized, an assistant can minimize the light source from the nasal endoscope. This will reveal the location of the laser glow corresponding to the thinnest portion of the lacrimal bone. This area is anterior and inferior to the insertion of the middle turbinate [16] (Fig. 24.7). A periosteal elevator can be used to medialize the middle turbinate for good exposure during the laser procedure while protecting it from the heat of the laser probe (Fig. 24.8). Laser osteotomy is done by first puncturing the laser fiber optic through the lacrimal bone and nasal mucosa via contact energy mode with continuous setting. This is called “laser puncture” (Fig. 24.9). Once the laser penetration is done, an area of coagulation and necrosis will be seen on the nasal mucosa surrounding the laser fiber optic. From this position, the fiber optic can be moved sideways, upward, and downward in a circular fashion, thereby enlarging the osteotomy (Fig. 24.10). The direction of the laser fiber optic is emphasized mostly on the inferior area. Enlarging this area using a downward direction of the laser fiber optic may prevent the lacrimal sump syndrome. A 10-mm cotton ball is soaked with 0.1 ml of a 0.2 mg/ml of Mitomycin-C (MMC). This is placed on the osteotomy site for 5 min with no irrigation after the application (Fig. 24.11). Nonirrigation of MMC will increase its maximum pharmacologic effect on the osteotomy site [20]. The silicone stents are guided through the inferior and superior canaliculi and retrieved with hooks or mosquito forceps under endoscopic visualization (Fig. 24.12). They are tied in a square knot and encircled using 6–0 silk sutures.

In recent years, combined nasal surgery and ECLDR have been done to maximize the exposure of the surgical area to ensure the patency of the ostium. This is true for patients with enlarged middle turbinates that need to be partially removed [24, 30, 34]. The laterally retracted middle turbinates can also be medialized or infractured to expose the surgical area [20, 34]. Good exposure will lead to a bigger osteotomy and can prevent turbino-ostial synechial adhesions. One recent study utilized endonasal mucosal flaps with ECLDCR. Their success rate is 89 % but only seven eyes were done [30]. This mucosal flap–ECLDCR technique appears to be promising; however, larger sample size with long follow-up is needed to prove its efficacy.