Stent offers alternative to probing in nasolacrimal duct obstruction

The technique may be useful in children older than 12 months.

Opinions have diverged for more than 2 centuries as to the appropriate treatment regarding nature, timing and anesthesia for congenital nasolacrimal duct obstruction. Roughly speaking, three attitudes coexist.

Some authors claim that the majority of congenital nasolacrimal duct obstructions disappear spontaneously. Approximately 90% of children with congenital nasolacrimal duct obstruction recover spontaneously by 1 year of age, which justifies waiting at least until this time before intervening surgically. Depending on the severity of symptoms, some surgeons will wait until even 3 to 4 years of age, at which point a dacryocystorhinostomy (DCR) is recommended.

Other authors claim that, on the contrary, congenital nasolacrimal duct stenoses will worsen over time due to chronic inflammation. These authors advise that treatment be chosen based on the child’s age at consultation and recommend office probing up to approximately 6 months of age. After 1 year of age, however, probing under a general anesthetic in the operating room is recommended as a first step, followed by nasolacrimal stenting, or balloon dacryoplasty if this is unsuccessful, and then a DCR if the previous steps fail.

With such a gradual therapeutic approach, results are 98% successful, and DCR accounts for only 1% of surgery.

Still other authors claim that it is not the child’s age that is important but the severity of the nasolacrimal obstruction. They make a distinction between complex obstructions requiring balloon dacryoplasty and/or silicone intubation and simple valve of Hasner mucosal obstructions at the distal end of the nasolacrimal duct. These authors claim that a mucosal obstruction will respond to simple probing even after a probing at age 4 or 5 years and recommend careful probing in the operating room, including complex nasolacrimal stenosis (ie, nasocanalicular intubation under general anesthesia) with laryngeal protection and mucosal nasolacrimal stenosis with probing up to 36 or even 48 months.

The Masterka

The Masterka (FCI Ophthalmics) technique is for the treatment of congenital epiphora due to simple mucosal obstruction in the nasolacrimal duct, most commonly at the valve of Hasner. It is an excellent alternative for stenting simple congenital nasolacrimal obstructions at any age.

The Masterka is a pushed lacrimal intubation stent whose anchoring plug for punctal fixation is similar to the original Monoka (FCI Ophthalmics), but the metallic guide is located inside the silicone tube, which is available in 30, 35 and 40 mm. The Masterka principle is comparable to that of venous catheters.

Routine general anesthesia techniques are sufficient and the operating time is similar. The Masterka avoids the unnecessary and often difficult intranasal maneuvers involved in pulling out the stent and tubing of traditional intubation systems. The cost of the Masterka is offset by a much better success rate, meaning fewer repeat procedures.

Placement of the Masterka requires two careful steps: initial probing in the operating room and the insertion of the Masterka. Nasolacrimal duct intubation using the Masterka is technically comparable to lacrimal stenting done at any age and requires the usual medical and anesthetic precautions. Preliminary lacrimal exploration by probing is essential, allowing the surgeon to identify the location and severity of the obstruction, avoid potential false passages and choose the appropriate Masterka length.

Tactile exploratory probing helps distinguish simple nasolacrimal duct stenosis from more complex obstructions.

A larger lacrimal probe with a blunt tip is advanced very carefully beneath the inferior turbinate searching for metal-to-metal contact to confirm that the Masterka stent is properly placed. If metal-to-metal contact is not achieved in the nasal fossa, then a false passage may have been created. To avoid failure, the procedure should be restarted from the beginning. If the metal-to-metal contact is still not achieved, it is better to change the method of intubation altogether or to postpone the procedure.

On this basis, the surgeon can assess whether the Masterka stent system is appropriate for the specific patient.

The distance between the punctum and the nasal fossa floor is measured, and the stent should not be longer than that distance. If the distance between the punctum and the nasolacrimal floor measures 40 mm, the proper stent would be the 40-mm Masterka. If the length is between 35 mm and 40 mm, the proper stent would be the 35-mm stent. The proper stent should always be longer than the distance between the punctum and the nasolacrimal obstruction.

Remove the stent from the package and hold it between two fingers. Mobilize the guide inside the silicone sleeve by rotating the sleeve gently, much like winding a watch. These alternating rotations allow the guide inside the Masterka to exit easily.

Carefully dilate the upper lacrimal punctum. Push the Masterka through the upper canaliculus all the way to the “hard stop,” or bony contact (Figure 1). Maintain contact with the bone while rotating the Masterka inferiorly to catheterize the lacrimal sac and the nasolacrimal duct (as for a routine probing procedure). During vertical stenting, whenever possible one should try to feel the stent as it penetrates through the mucosal obstruction, while still advancing it until the fixation plug reaches the punctal opening.

Figure 1. Carefully dilate the upper lacrimal punctum. Push the Masterka through the upper canaliculus all the way to the “hard stop,” or bony contact. Images: Fayet B

Figure 2. Secure the anchoring plug against the upper lid tissue while carefully extracting the guide.

Figure 3. Once the metallic guide is completely removed, insert the plug into the vertical canaliculus with a single-use plug introducer as for routine punctal plug insertion.

Remove the guide very carefully. Secure the anchoring plug against the upper lid tissue while carefully extracting the guide (Figure 2). Remove the guide by gently pulling it from the external section of the tube, millimeter by millimeter. Simultaneously, make small rotating movements with the guide, as if winding a watch; this helps it slide out of the Silastic sleeve. Throughout this phase, hold the anchoring plug firmly against the lid tissues.

If the anchoring plug shows signs of extruding, push the Masterka back down until the anchoring plug lies secure in the punctal meatus, then continue to remove the guide.

Once the metallic guide is completely removed, insert the plug into the vertical canaliculus with a single-use plug introducer as for routine punctal plug insertion (Figure 3).

The use of a dilator and punctal plug inserter is essential for proper seating of the fixation plug in the punctum. Once the plug is inserted into the punctal opening, the collarette must sit flush on the lid margin. If the collarette looks flat, the Masterka is securely in place.

Postop care

Postoperative care is limited to topical antibiotic ointment for approximately 1 week. The duration of intubation varies according to the surgical indication and the nature of the obstruction. For congenital nasolacrimal duct obstruction, leaving the Masterka in place for 3 weeks is sufficient in most cases, particularly if clearance of fluorescein dye can be documented. The stent is removed as an office procedure with a forceps instrument by pulling on the collarette. This removal is painless and does not require any anesthesia.

For us, with proper selection, Masterka intubation is successful in approximately 85% of cases. The success rate is similar even when used for late and very late probing in older children.

From a technical perspective, the Masterka pushed nasolacrimal intubation is much simpler than the traditional pulled types of nasolacrimal intubation. The anesthetic procedure required is the same as for a late probing procedure, but the functional results are better. The Masterka offers an alternative to simple late probing in the treatment of mucosal nasolacrimal stenoses in patients aged over 12 months.

• Bruno Fayet, MD, can be reached at Department of Ophthalmology, Hôtel-Dieu de Paris, University of Paris, VI Medical School, Paris, France; email: brunofayet@club-internet.fr.
• Disclosure: Dr. Fayet holds the patent for the Masterka.