What are nasolacrimal duct interventions?
‘Nasolacrimal duct’ is the medical term for your tear duct. Your tear duct system consists of an upper and a lower lacrimal duct, which are tiny channels in your eyelids that join together in an area under your eye called the lacrimal sac. The nasolacrimal sac carries tears from the lacrimal sac into your nasal cavity.
When the tear duct is obstructed or narrowed, the proper balance between tear production and tear drainage is disrupted. This causes watery eyes (epiphora), with patients producing persistent or excessive amounts of tears, a condition that is both uncomfortable and can impair vision. Abnormalities in this area that cause this condition may be present at birth or develop later. They can be diagnosed and treated with minimally invasive techniques, including techniques called dacryocystography and dacryocystoplasty.
How does the procedure work?
Dacryocystography is used to diagnose the condition causing problems with your tear duct. This is a minimally invasive procedure that is performed on an out-patient basis. You will receive an injection of contrast medium, which will allow the interventional radiologist to clearly visualise the lacrimal sac under X-ray.
Once you have received a diagnosis, you may undergo an interventional treatment for the condition called dacryocystoplasty. During this procedure, the interventional radiologist will use fluoroscopy for guidance, and will insert a catheter (a thin flexible tube) into the affected area, before directing a guidewire past the narrowed or blocked section of the duct to a particular part of the nasal cavity.
If you are undergoing a balloon dacryocystoplasty, the interventional radiologist will attach a tiny balloon to the guidewire and will gently inflate the balloon in the affected area, which expands the narrowed or blocked area. The wire and balloon will then be removed. Another possible approach is using a stent (a metal mesh tube) to keep the area open. Stents are usually removed within two to six months.
Why perform it?
Dacryocystoplasty can treat watery eyes caused by various factors, including obstructions within the nasolacrimal duct system, inflammation, conjunctivitis and cysts in the lacrimal sac. It is also used to treat children who are born with a nasolacrimal duct obstruction or who experience recurring obstructions despite a undergoing a procedure called nasolacrimal duct probing, which involves passing a thin metal probe and squirting water through the duct to open it.
What are the risks?
There is a risk of nosebleeds (which are self-limiting so do not require treatment) and pain during the procedure. The contrast medium may leak, or the doctor carrying out the procedure may accidentally create a false passage, meaning an unnatural passage leading off from a natural canal. However, this usually has no lasting effects.
Post-operative complications are rare, but include headaches and blurred vision. It has been reported that some patients experience an abnormal presence of air in the eye socket’s soft tissue spaces. The risk of radiation exposure is low because radiosensitive organs such as the eyes remain in the field of the primary X-ray beam.
Bibliography
1. Wilhelm KE, Hofer U, Textor HJ, Böker T, Strunk H, Schild HH, “Nonsurgical fluoroscopically guided dacryocystoplasty of common canalicular obstructions,” CardioVascular and Interventional Radiology, January/February 2000, Volume 23, Issue 1 pp 1-8.
2. Lee JM, Song HY, Han YM, Chung GH, Sohn MH, Kim CS, Choi KC, “Balloon dacryocystoplasty: results in the treatment of complete and partial obstructions of the nasolacrimal system,” Radiology, 09/1994; 192(2):503-8.