External DCR technique safe, effective with minor scarring

Method that opens the lacrimal sac ‘like a book’ provides 100% cure of volume symptoms.

PARIS — Appropriate surgical maneuvers can transform external dacryocystorhinostomy into an easy, successful procedure, with minimal bleeding, invisible scars and long lasting results, according to one surgeon speaking at the French Society of Ophthalmology meeting.

Geoffrey Rose, MD, co-author of this year’s French Society of Ophthalmology (SFO) “rapport,” a large monothematic publication dedicated this year to the lacrimal system, introduced his speech by reviewing some basic anatomic definitions.

The lacrimal system, he said, is a three-compartment model composed of lacrimal lake, lacrimal sac and nasal space. Two areas of high-resistance flow join these three compartments.

In the majority of cases, nasolacrimal duct obstruction manifests through both volume and flow symptoms. Volume symptoms are due to the tear fluid washing back from the second compartment to the tear lake, while flow symptoms are due to an incorrect balance between the rate of production and the rate of clearance of the tear fluid.

The role of dacryocystorhinostomy (DCR), Dr. Rose said, is to convert the lacrimal system from a three-compartment model into a two-compartment model consisting of the lacrimal lake and nasal space. In this way, the surgeon can achieve a 100% cure of volume symptoms, because “there is no longer a volume that can wash back into the tear lake,” Dr. Rose said.

Flow symptoms, on the other hand, cannot always be cured, because of the limitation of flow through the canaliculi.

One of the most common causes of DCR failure is that “rhinostomy is made far too small, so that you end up with residual fluid in the second compartment. In addition, small rhinostomies undergo fibrosis,” Dr. Rose said.

To obtain good results, the lacrimal sac has to be “opened to the nose, like a book, right from its very fundus, down to the nasal-lacrimal duct,” he said. In this way, a true two-compartment model is obtained: the lacrimal lake and the nasal space.

No blood, no scars

With the appropriate surgical technique, this wide opening can easily be achieved, Dr. Rose said.

“You must perform a very large rhinostomy that comes in front of the anterior lacrimal crest, on to the side of the nose, down to the level of the sac-duct junction, up to the skull base — because the internal opening of the common canaliculus is very close to that area — and then posteriorly,” he said.

A common concern with DCR is the production of scars; however, with the maneuvers suggested by Dr. Rose scars can be avoided.

“The best way of avoiding scars is to put a straight incision at least 1 cm in front of the medial canthal tendon, on the flat side of the nose. Do not cut down through the muscle, because that is guaranteed to produce a lot of blood and encourage a marked scar. You just go through the skin and then you undermine posteriorly with scissors, till you reach the canthal tendon. So far, no blood,” he explained.

To avoid bleeding, also the orbicularis muscle should be spared. Rather than cutting through it, Dr. Rose said to “spread between the fibers, going from the root of the canthal tendon, superiorly and inferiorly.”

The canthal tendon is then removed and the periosteum is spread anteriorly.

“You end up with bare bone with almost no bleeding at all,” he said.

The following maneuvers are directed toward the lacrimal sac, behind the lacrimal crest. The lacrimal sac is mobilized laterally and displayed. The removal of the anterior canthal tendon allows the surgeon to display the lacrimal sac completely, and to reach its fundus with the following incision maneuvers.

“If you don’t, you are likely to have residual volume symptoms,” he said.

Ethmoidectomy crucial

The operation continues by progressively removing bone, starting from the anterior lacrimal crest.

Bone removal should not start inferiorly, where the bone is thickest, Dr. Rose recommended.

“The place to start removing bone to make rhinostomy easier is by going as high as possible, where the anterior lacrimal crest is at its thinnest. So, do not start with the frontal process of the maxilla,” he said.

The incision is made across the crest, anteriorly and then inferiorly, to obtain an L-shaped rhinostomy. Last of all, the frontal process of the maxilla is removed.

“You always get a little bit of bleeding with bone removal. Use the sucker to keep the area clean,” he recommended.

The ethmoidal cells are always a problem in lacrimal surgery, as their presence only allows for a mucosal anastomosis of limited size.

“But of course we want 100% cure of volume symptoms and signs, which we get by ‘opening the lacrimal sac like a book’, and the best way of doing it is by removing the anterior ethmoidal cells and the posterior lacrimal crest. This does not cause a problem, and it allows you to open wide the lacrimal sac and the nasal mucosa,” Dr. Rose said.

After ethmoidectomy has been performed, he starts opening the sac inferiorly, holding the scissors in his right hand, and cutting into the nasolacrimal duct. Then he reverses hands, moving the scissors to the left, and goes up to the fundus or nasolacrimal duct, feeling the direction within the lumen of the system.

“Once the sac is completely opened, you can see the internal opening of the common canaliculus, open the sac-duct junction, place the intubation and cut the nasal mucosal flaps. Since you’ve done an ethmoidectomy, you have a very large area of nasal mucosa available and can create huge anterior and posterior mucosal flaps,” he said.

Sutures and primary intention healing

The posterior nasal and sac flaps are closed using a soluble suture, with a continuous suture from the skull base to the nasolacrimal duct. The anterior flap is then closed, and the same sutures are passed through the orbicularis, through the anterior nasal mucosa, the anterior sac flap and back to the orbicularis, to suspend the anterior mucosal anastomosis.

“If you do so, you get primary intention healing around the area of the internal opening,” Dr. Rose said.

The skin is then closed with a 6-0-nylon suture.

“The most important thing to avoid visible incisions is making them completely flat at the end of surgery,” Dr. Rose said. “Do not evert the edges, because that tends to cause a prominent scar. Keep them flat, get the patients to wear their glasses straight after surgery, and in 10 days you will often not be able to see where the incision has been.”

In summary, a wide open lacrimal sac and nasal mucosa, anterior ethmoidectomy and primary intention healing of both the anterior and posterior flaps guarantee the success of this surgery, with 100% cure of volume symptoms, he said.

For more information:

• Geoffrey Rose, MD, can be reached at Moorfields Eye Hospital, London, UK. E-mail: geoff.rose@moorfields.nhs.uk.

• Michela Cimberle is an OSN Correspondent based in Treviso, Italy, who covers all aspects of ophthalmology. She focuses geographically on Europe.