Dacryocystorhinostomy – EyeWiki

• Probing and irrigation: Gold standard of nasolacrimal outflow testing. A drop of topical anesthetic is placed on the ocular surface, and a punctal dilator is used to dilate the punctum. A 0-0 Bowman probe can be used to assess the canaliculus for any diffuse stenosis or focal strictures. If present, the distance of the stricture from the punctum is recorded to determine if a conjunctivodacrycystorhinostomy (CDCR) is indicated. A 21 or 23 gauge lacrimal cannula on a 3cc syringe is advanced through each canaliculus, and saline is injected. Reflux of saline through the same canaliculus indicates obstruction of the canaliculus, whereas reflux from the opposite punctum indicates obstruction in the nasolacrimal sac or duct. Passage of saline into the nose and throat with ease and no reflux signifies an anatomically patent nasolacrimal excretory system.

A partial obstruction can also exist if there is some flow into the nose but with increased resistance to irrigation and/or some degree of reflux.

• DSG: A radioactive agent, technetium-99m pertechnetate or technetium-99m-labeled sulfur colloid, is placed on the ocular surface. [4] [5] The patient is seated and immediately imaged using a gamma camera to take rapid pictures of the lacrimal outflow system as the tracer flows passively through the lacrimal pump system. The canaliculi and sac should be visualized within 10-12 seconds following injection, with passage into the nasal cavity occurring within 10-30 minutes. The disadvantages of DSG include the low resolution and lack of anatomic detail.

Advantages of the external approach include excellent success rates, reported to be up to 90-95%. A large osteotomy is created with direct visualization of lacrimal sac abnormalities, such as lacrimal stones, foreign bodies, or tumors. Direct suturing of the nasolacrimal sac and lateral nasal mucosal flaps allow for optimal apposition and primary intention healing of the flaps to create the bypass system.

• Primary endonasal/endoscopic dacryocystorhinostomy– Advantages of the internal, or endonasal, approach include lack of a skin incision. This can be an option for the pediatric population or in younger patients without skin creases that could camouflage a scar. There is some evidence that endoscopic DCR may be as effective as external DCR, with high success rates. [6]

Anesthesia: DCR may be performed under monitored sedation or general anesthesia based on the surgeon and patient’s preference. The patient may typically be discharged home on the same day. Local anesthesia, using an equal mixture of 1-2% lidocaine and 0.5% bupivicaine, with 1:100,000 epinephrine, is infiltrated into the medial canthus, lower lid incision site, and nasal mucosa. Nasal packing soaked in 4% cocaine, lidocaine, or afrin (oxymetazoline) provides additional nasal anesthesia and mucosal vasoconstriction to the middle meatus. Meticulous hemostasis is crucial to a successful DCR surgery.

Technique (External DCR): A curvilinear skin incision is made with a surgical marking pen at the level of the medial canthal tendon and extending into the thin skin of the lower lid for approximately 10-12 mm. The patient’s face is prepped and draped in the usual sterile fashion. A lubricated corneal protective lens is often placed on the ocular surface to protect the globe during surgery. The skin is incised with a 15-blade scalpel or monopolar unit with a Colorado needle tip. The orbicularis oculi muscle fibers are separated until the periosteum of the anterior lacrimal crest is identified. The dissection should be lateral to the angular vessels to avoid bleeding. The periosteum along the anterior lacrimal crest is next incised from the level of the medial canthal tendon extending inferiorly, and the periosteum widely elevated with Freer elevators anteriorly off the nasal bone. The periorbita and lacrimal sac are similarly elevated posterolaterally off the lacrimal sac fossa. The fossa is next carefully perforated where the bone thins at the suture line between the thicker frontal process of the maxilla and the adjacent thinner lacrimal bone. Kerrison rongeurs or a high-speed drill are used to remove the bone of the lacrimal fossa, inferiorly to the lacrimal duct at the inferior orbital rim, and anteriorly past the anterior lacrimal crest. A bony ostium measuring approximately 15mm is removed, taking care to avoid a cerebrospinal fluid leak or injuring the underlying nasal mucosa.

A 0-0 Bowman probe is passed into the lacrimal sac to tent the sac medially, and Westcott scissors are used to open the lacrimal sac from the duct to the fundus, with relaxing incisions at both ends. Any abnormal scar overlying the opening of the common canaliculus, lacrimal sac stones, foreign bodies, or masses are removed if present. A corresponding incision is made in the nasal mucosa, to create anterior only, or anterior and posterior flaps.

The silicone tubes are placed through the new ostium and the flaps sutured together.After suturing the flaps together to create the new pathway into the nose, the orbicularis muscle and skin are closed in layered fashion. The anterior limb of the medial canthal tendon is also resuspended if released earlier. The silicone tubes are tied and left long in the nasal vestibule to facilitate office removal later. The tubes may be removed anywhere from 4 weeks to several months after surgery.

Technique (Endonasal/Endoscopic DCR): The primary benefit of the endonasal, or internal, approach is the lack of skin scarring. The nasal mucosa and middle turbinate are first decongested for vasoconstriction and hemostasis. Using a nasal endoscope for visualization, the lateral nasal mucosa adjacent to the lacrimal sac is then incised vertically and elevated. The sac location is typically located anterior to the anterior aspect of the middle turbinate along the nasal wall. A fiberoptic endoilluminator, as used in vitreoretinal surgery, may be inserted through the canaliculi into the sac in order to help transilluminate the lacrimal bone medial to the lacrimal sac if needed.

Full exposure of the bone adjacent to the lacrimal sac is needed. Wide elevation of the nasal mucosa is performed with Freer elevators, and the mucosa removed with endoscopic forceps. The lacrimal bone is next removed with a high-speed drill, Kerrison rongeurs, or pituitary rongeurs. Lasers have also been used as well. [7] [8] The final bony ostium should be approximately 8mm in height and include adequate clearance of the common canaliculus internal ostium and the inferior sac to avoid persistent accumulation in the inferior sac (lacrimal sump). After bone removal, the lacrimal sac mucosa is infiltrated with local anesthetic for vasoconstriction, incised, and the medial sac mucosa removed with forceps. Adequate lacrimal sac mucosal removal is confirmed by free flow of saline or fluorescein from the canaliculi through the nasal ostium, or direct visualization of the common internal punctum with the endoscope. Bicanalicular silicone intubation may also be placed as in the external DCR approach, and removed postoperatively in the office. Mitomycin C, an antimetabolite, may judiciously be applied to the intranasal ostium to modulate fibrosis. [9]

Following surgery, the patient is discharged home if stable and instructed to rest for one week, without heavy lifting, exercise, or strenuous activity that may induce bleeding. Hot drinks and food should be avoided for the first 12-24 hours postoperatively in order to decrease the risk of epistaxis caused by heat-induced nasal vasodilation. Ice/cold compresses are placed on the incision site for 48 hours while awake to minimize swelling and bruising. The patient’s head should remain elevated at all times at a 45 degree angle and the patient instructed to avoid nose blowing for one week to decrease the risk of hemorrhage. Skin sutures are removed one week postoperatively if nonabsorbable sutures were used, and the silicone tube is removed typically at 4-8 weeks after surgery.