Congenital Nasolacrimal Duct Obstruction

Sasha Mansukhani
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Congenital Nasolacrimal Duct Obstruction - Treatment
Most obstructions open spontaneously in the first 4-6 weeks of life and around 90% -96% of the babies with nasolacrimal duct obstruction, resolve spontaneously at 1 year of age(1,17).

For this reason conservative management is usually preferred till one year of age, following which surgical intervention can be undertaken if there is no resolution.

Given below is a simplified algorithm for the management of congenital nasolacrimal duct obstruction (CNLDO), based on preferred practices, although there is no clear-cut consensus on the timing of undertaking the various interventions(18,19).




The simple method of hydrostatic sac massage has been found to be effective in the treatment of epiphora(20). The massage is begun by pressure at the medial canthus, which is effective in blocking the common canaliculus thus preventing reflux backwards through the canaliculi. Then pressure is applied downwards, thus increasing the hydrostatic pressure in the sac, and causing rupture of the membrane(21). The technique of massage is important- and has being studied comparing simple or improper techniques (with a success rate of only 21%) with the proper hydrostatic technique (with a success rate of 91%) (22) .


Instruction to be given to the parent
The parent’s nail of the index or little finger that will be used for the massage must be clipped. The hands must be washed well. Vaseline or Baby oil may be applied to the finger as a lubricant(23). The finger is then placed firmly as shown in the figure and pressure is then applied in the downward direction. 5-10 such strokes are to be done, 2-4 times a day (22,24). The technique should be demonstrated to the parent and should be checked on consequent follow-ups.




Optimum age
One school of thought, waits for spontaneous resolution till 1 year of age, thus recommends probing at 1 year of age(18,25). The logic is that the rate of resolution without surgical intervention is around 90% at 1 year. Thus no surgical intervention is taken up till 1 year of age unless there is a specific indication for early probing.


Indications for early probing include:-
• Dacryocystocoele- As there are high chances of acute dacryocystitis. Also it is often associated with an intranasal cyst which can cause breathing difficulties.
• Severe symptoms- Constant mucopurulent discharge and periocular dermatitis due to constant tearing causing infant discomfort.
• Acute dacryocystitis- Under an intravenous antibiotic cover, early probing is done to allow the tears to drain to reduce the risk of local spread with abscess formation and hematogenous spread and septicemia.
• Congenital cataract and glaucoma- Infants to be posted for ocular surgery having chronic dacryocystitis will require early probing followed by intraocular surgery once the infection clears.

The second school of thought recommends early probing in all infants at 4-6 months of age, to avoid unnecessary months of discomfort to the infant(26). Also at 4-6 months, probing can be done as an office procedure under topical anaesthesia, thus avoiding the general anaesthesia, which will be required at 1 year of age. It has been proposed that the pain felt during the office probing procedure with general anaesthesia is akin to the pain of a vaccination.

Studies have found both the 4-6 month office probing as well as the hospital based 1 year probing under general anaesthesia to be equally effective, and thus the decision is upto the discretion of the ophthalmologist (27).


Maximum age
While most studies agree that probing is very efficacious till 1 to 2 years of age, some studies have found that the rate of success is lower in older children (28,29) . This is explained by an increase in the fibrotic changes with increasing age. However others have proposed that decreased success in older children, might be due to a process of natural selection, wherein more and more of the membranous blocks get cured spontaneously, leaving behind a higher percentage of firm or complex blocks(30). Complex or firm blocks are those in which a firm resistance is encountered by the probe. Thus, the older children with a membranous block will respond well to probing. Success rates of 72%-80% have been reported in the 2-5 year age group(28,29).
Thus in conclusion, probing can be attempted in children till 4-5 years, with a backup plan of an alternative procedure if a complex block is encountered intraoperatively.


Technique
The appropriate anaesthesia is given- topical for office-based and general anaesthesia for hospital procedures. The punctum dilator may be used to dilate the punctum. The upper lid is preferred by many, as there is less of an acute turn when the probe enters the sac. The lacrimal probe of the appropriate size as per the age of the baby is taken and while laterally stretching the lid the punctum is entered. The stretch, straightens out the vertical component of the canaliculus thus allowing for easy passage. Once the hard stop is encountered, the probe is rotated 90 degrees and directed downwards, outwards and backwards to enter the nasolacrimal duct so that the probe now lies vertically against the supraorbital margin. The confirmation that the probe is in the nasolacrimal duct is from the finding that the probe stands straight on its own, and there is a spring back movement of the probe on attempt to displace it.

The probe is advanced till a give way sensation is encountered as the probe presumably pierces the membrane. The confirmation that the probe has entered the nose is by endoscopically viewing the probe in the inferior meatus, or by metal-to-metal sensation of another instrument inserted from the nose. The inferior turbinate may additionally be infractured if closely impacted against the NLD opening on endoscopy.

If one is not able to pass the probe or the probe is encountering too much resistance while passage, one can try with a probe of smaller diameter and then progressively use probes of greater size to adequately dilate the nasolacrimal duct. Sac syringing with fluorescein dye maybe done in the end to ensure patency. The throat pack must be in place before syringing for a child under general anaesthesia to decrease the risk of aspiration.


Success of the probing
Success of the probing is established when there is resolution of signs and symptoms and the fluorescein dye test becomes normal. If symptoms persist, repeat probing can be done at 1-3 weeks after the first probing. Repeat probing can be attempted 2-3 times, however repeat probing have lower rates of success.




Indication
Silicon tubing is flexible, soft and knots well as thus is a good material for lacrimal intubation. Failed probing is an indication for silicon intubation(31). Some use intubation as a primary treatment, instead of probing(32). Primary intubation has shown better results than probing in patients with bilateral block, Down’s syndrome and previous history of acute dacryocystitis. Also when probing reveals a tight obstruction, intubation can be done in the same sitting to increase the chances of success.


Technique
Lacrimal probing is first done with increasing probe diameter. The intubation probe with the silicon tubing attached to it is then inserted through the upper punctum and then retrieved from the nose. The lower punctum is then cannulated with the probe at the other end of the silicon tubing, and similarly retrieved from the nostril. The tubing is then tied with multiple knots, the end are trimmed and fixed to the lateral nasal wall with a nonabsorbable suture.

Monocanalicular intubation is also being done, and is found to be as efficacious as bicanalicular intubation by some studies(33)

Rate of success as found by several different studies is around 66-100% (31,32,34,35), with a higher rate of success than probing, in patients with complex nasolacrimal obstructions.


Removal of the tubing
The tubing is removed anytime between 6 weeks to 6 months after intubation, and there is no real consensus on the ideal time of removal (36,37).

Indication
Failed probing is an indication for balloon dacryoplasty(38). The results of balloon dacryoplasty and intubation after failed probing are comparable(34). It can also be used as a primary modality of treatment, instead of probing(38).


Technique
Initially probing is done which is followed by cannulation of the nasolacrimal duct via the upper canaliculus with the balloon catheter. Once it is confirmed that the catheter is in the right place, so that the balloon is at the level of the valve of Hasner, the balloon is inflated so as to produce a pressure of around 8 atmospheres of pressure. This pressure is maintained for about 90 seconds and then deflated. After a few seconds the balloon is elevated again to 8 atmospheres and maintained for 60 seconds.

This double cycle is then repeated with the balloon placed at the lower part of the nasolacrimal duct. The balloon catheter is then deflated and then removed.

Reported success rates are 53-95% (34,38,39).

Indications
A dacryocystorhinostomy is usually done when other procedures have failed. It is especially useful when the block is firm or in craniofacial anomalies, where other procedures are likely to fail.

Technique
The principle involves making an opening in the bones forming the lacrimal fossa. Then sac and nasal mucosal flaps are made and sutured together. Now the tears and the sac secretions empty into the middle meatus of the nose, bypassing the nasolacrimal duct altogether. The approach can be an external one, where there is an external skin incision or endonasal, which is done using an endoscope through the nose.

The success rate for external and endonasal DCR surgery is high, around 83-97%(40,41,42) and 87-93% respectively(43,44).

When there is accompanying chronic dacryocystitis with mucopurulent discharge, an antibiotic eye drop like Tobramycin 0.3% can be instilled in the eye 3-4 times a day. The parents are advised to clean away the discharge to prevent matting and crusting over the lashes and are taught the hydrostatic massage.

In cases developing the rare complication of acute dacryocystitis, hospital admission is usually required. Intravenous antibiotics are required and the infant is taken up for nasolacrimal duct probing under general anaesthesia.


References
Congenital Nasolacrimal Duct Obstruction Congenital Nasolacrimal Duct Obstruction
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