Surgery of the Lacrimal Drainage System (One Eye)

Overview

Tears are required to keep the eyes moist and healthy. Tears are formed by the lacrimal glands, which are positioned under the upper eyelid in some cases. Tears flow from the eye into the nose via the nasolacrimal duct, often known as the tear duct. Wet eyes or excessive crying might result from a blockage of this drainage duct. A blocked tear duct can also lead to mucus accumulation in the eye or persistent infections in the lacrimal sac, which accumulates tears. Infections cause swelling in the inner corner of the lower eyelid.

Nasolacrimal duct blockages can occur for no apparent reason. Previous sinus or nasal surgery, as well as facial trauma with shattered facial bones, can often clog the tear duct.

Dacryocystorhinostomy (DCR) is a type of lacrimal drainage surgery that can be done in a variety of methods. An external DCR is one form of procedure in which an incision is created on the side of the nose, where eyeglasses may rest. To provide a fresh connection between the lacrimal sac and the inside of the nose, a little portion of bone is removed. Small plastic tubes are occasionally introduced after surgery to prevent the freshly generated aperture from scarring shut during the healing phase. A few months after surgery, the tube is removed.

Another form of procedure makes use of a specialized device known as an endoscope. The endoscope is a short tube with a fiberoptic light that allows a new hole into the nose to be created. The DCR technique has also been performed using several types of laser.

Structure of Lacrimal System

The lacrimal apparatus is a set of connected anatomical structures located within the orbit that are responsible for the production and drainage of tears.

The lacrimal apparatus includes the following structures:

• Lacrimal gland.
• Lacrimal canaliculi.
• Lacrimal sac.
• Nasolacrimal duct.

• Lacrimal gland.

The orbital (bigger) and palpebral (smaller) sections of the lacrimal gland are continuous posterolaterally at the concave lateral margin of the aponeurosis of the levator palpebrae superioris muscle.

The orbital component of the lacrimal gland is positioned within the orbital edge in a shallow depression on the medial aspect of the zygomatic process of the frontal bone. The superior side of the orbital section is convex and bone-related, while the inferior surface is above the aponeurosis of the levator palpebrae superioris muscle and laterally over the top edge of the lateral rectus muscle. The orbital septa form the front boundary of the orbital portion, whereas the orbital fat forms the posterior border.

The palpebral component of the lacrimal gland is divided into two or three lobules and continues beneath the aponeurosis of the superior palpebral levator muscle into the lateral area of the upper eyelid, where it connects to the superior conjunctival fornix. When the lid is everted, the palpebral section of the lacrimal gland is visible through the conjunctiva.

Approximately 12 lacrimal gland ducts go from the orbital to the palpebral parts of the eye and terminate in the superior conjunctival fornix.

In addition to the primary lacrimal gland, the conjunctival sac contains a number of auxiliary lacrimal glands. In the event that the primary gland fails to function, the accessory glands act as a backup to keep the cornea wet.

• Lacrimal canaliculi.

Each lacrimal canaliculus begins with a punctum lacrimalis, an opening on the lower eyelid's edge at the medial corner of the eye where tear draining begins. Superior and inferior lacrimal canaliculi exist. Both of them drain into the lacrimal sac.

The superior lacrimal canaliculus ascends first, then bends at a sharp angle and descends to the lacrimal sac.

The inferior lacrimal canaliculus is bigger and longer than the superior duct, and it descends first before passing practically horizontally to the lacrimal sac.

The ampulla of the lacrimal canaliculus is a small expansion at the bend of each duct. Lacrimal canaliculi can grow to be up to 1 cm long.

Both lacrimal canaliculi are positioned behind the medial palpebral ligament and are surrounded by the lacrimal part fibers of the orbicularis oculi muscle.

• Lacrimal sac.

The lacrimal sac is placed in the orbit's inferomedial region, entrenched in a deep lacrimal fossa at the start of the nasolacrimal canal produced by the lacrimal bone and the frontal process of the maxilla.

The lacrimal fascia and the lacrimal portion of the orbicularis oculi muscle surround the lacrimal sac.

The lacrimal sac is oval in shape and is around 1.5 cm in length and 0.5 cm in width. It measures around 12 mm in length. The fornix of the lacrimal sac is its dome-shaped top border. The bottom section of the lacrimal sac enters the nasolacrimal duct directly.

The lacrimal sac connects the superior and inferior lacrimal canaliculi, which drain tears from the eye surface, with the nasolacrimal duct, which opens into the nasal cavity. The lacrimal sac drains into the nasolacrimal duct via the valve of Krause, which is a fold of mucous membrane at the junction between the lacrimal sac and the nasolacrimal duct.

• Nasolacrimal duct.

The nasolacrimal duct is 1.2 to 2.4 cm in length. It enters the nasal cavity through the nasolacrimal canal, which is formed by the lacrimal bone, maxilla, and inferior nasal concha, and exits through an opening - the nasolacrimal duct aperture. The opening is placed under the inferior nasal concha and is protected by a flap-like mucosal fold called the lacrimal fold, also known as the Hasner valve.

The nasolacrimal duct's membranous wall is made up of connective tissue and stratified columnar epithelium. The mucous membrane lining the flattened lumen of the nasolacrimal duct has two or more layers of columnar epithelium with cilia at certain locations and mucous-secreting goblet cells.

The nasolacrimal duct drains surplus tears from the nasolacrimal sac into the nasal cavity, which explains why people cry and have a runny nose.

Evaluation of the Lacrimal Excretory System

• Dye Disappearance Test (DDT)

Fluorescein is injected into the conjunctival sac (a yellow dye that fluoresces green under blue light). After 5 minutes, a blue light is used to see if the dye has been removed. An issue with lacrimal drainage is uncommon if no dye is detectable. This test is especially important in children since diagnostic syringing is frequently not possible.

• Jones Test

Because of its limited sensitivity and specificity, this test is rarely utilized. The DDT is applied, but the investigator then uses a swab to look for fluorescein in the nose (Jones I). If the test results in a negative result, the lacrimal ducts are flushed with saline (Jones II). When fluorescein is discovered, it indicates a relative nasolacrimal duct blockage (NLDO). If no dye is found, this indicates either an absolute or canalicular stenosis, as there is no fluorescein buildup in the lacrimal

• ROPLAS Test

ROPLAS is an initialism for “regurgitation on pressure over the lacrimal sac”. It describes the expression of mucous or mucopurulent material via the canaliculi upon retrograde compression of the lacrimal sac. If secretions are accumulated in the lacrimal sac due to NLDO or atonic sac, the test is positive. It is helpful for children with lacrimal duct stenosis and when contemplating the indications for a dacryocystorhinostomy (DCR).

• Diagnostic Probing

A Bowman's probe is used to probe the canaliculus while the lid is kept under lateral traction. A "soft stop" is an elastic resistance that implies canalicular stenosis (the block may then be measured and the canaliculus on the opposite side probed) or common canalicular stenosis. A "hard halt" indicates that the canalicular system entering the lacrimal sac is open. The bone of the lacrimal sac fossa stops the probe.

• Diagnostic Syringing

Syringing can be done through the upper or lower lacrimal punctum. The examination concludes when the saline or water used reaches the patient's throat. The patient will prove patency by swallowing or coughing. The pressure necessary for flushing should also be considered by the examiner. This operation requires a 5-mL syringe with a blunt, short lacrimal duct cannula. If 100% of the liquid flushed via the lacrimal ducts, they are patent. Partial (or relative) stenosis causes patency with increased pressure or partial regurgitation.

A canalicular stenosis is indicated by fluid reflux through the same lacrimal punctum. While common canalicular block (CCB) causes fast regurgitation of clear liquid via the opposite punctum, prolonged regurgitation, occasionally coupled with mucoid flakes or pus, is symptomatic of NLDO. In these circumstances, syringing might sometimes reveal sac dilatation.

• Imaging

Imaging of the lacrimal system by means of dacryocystography (DCG) was first described in 1909 by Ewing. A water-soluble or iodized, oily contrast medium is instilled into the lacrimal ducts via the canaliculus with a lacrimal cannula or a catheter and radiography (digital subtraction DCG), CT (CT-DCG) or MRI (MR-DCG) are carried out. This is helpful especially in posttraumatic stenoses, as with CT-DCG in particular the surrounding bony structures can be visualized.

Surgery of the Lacrimal Drainage System

• Preparing for Lacrimal Surgery:

Your surgeon will discuss with you how best to prepare for your DCR. Prior to surgery, you may have a CT scan or MRI to provide your surgeon with detailed imagery of the nasolacrimal area. Be sure to follow your surgeon’s instructions regarding the taking of medications, and about eating or drinking, in the hours leading up to surgery.

• Indications for DCR surgery:

1. Primary acquired NLDO.
2. Secondary acquired NLDO, such as due to prior midfacial trauma, chronic nasal or sinus inflammation, nasal surgery, neoplasms, dacryoliths.
3. Functional obstruction of outflow, due to lacrimal pump weakness or after facial nerve palsy.
4. Congenital NLDO after failed prior probing or intubation.
5. History of dacryocystitis.

• Primary Options for DCR:

1. Primary external dacryocystorhinostomy-
   The external technique has several advantages, including high success rates of up to 90-95%. With direct visibility of lacrimal sac anomalies such as lacrimal stones, foreign substances, or malignancies, a big osteotomy is formed. The nasolacrimal sac and lateral nasal mucosal flaps are sutured directly to enable for good apposition and main intention healing of the flaps to form the bypass system. When contrast to the internal technique, the disadvantages include a visible scar.
2. 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.

• The Procedure:

Anesthesia: DCR can be done under either supervised sedation or general anesthesia, according on the surgeon's and patient's preference. The patient is usually released home the same day. Local anesthetic is injected into the medial canthus, lower lid incision site, and nasal mucosa using an equivalent combination of 1-2% lidocaine and 0.5% bupivicaine with 1: 100,000 epinephrine. Additional nasal anesthetic and mucosal vasoconstriction to the middle meatus are provided by nasal packing soaked with 4% cocaine, lidocaine, or afrin (oxymetazoline). Hemostasis is critical to the success of DCR surgery.
Technique (External DCR): A curvilinear skin incision is created with a surgical marking pen at the level of the medial canthal tendon and extends for approximately 10-12 mm into the thin skin of the lower lid. The patient's face is prepared and draped in the standard sterile manner. To protect the globe during surgery, a lubricated corneal protective lens is frequently put on the ocular surface. A 15-blade scalpel or a monopolar unit with a Colorado needle tip is used to incise the skin. The muscle fibers of the orbicularis oculi are separated until the periosteum of the anterior lacrimal crest is recognized.

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 Bowman probe is used to tent the lacrimal sac medially, then Westcott scissors are used to open the sac from the duct to the fundus, with relaxing incisions at both ends. If present, any atypical scars covering the common canaliculus opening, lacrimal sac stones, foreign substances, or masses are removed. To construct anterior only or anterior and posterior flaps, a matching incision is performed in the nasal mucosa.

The orbicularis muscle and skin are closed in layers after suturing the flaps together to form the new passage into the nose. If the anterior limb of the medial canthal tendon is released sooner, it is also resuspended. To enable office removal, the silicone tubes are knotted and left long in the nasal vestibule. The tubes can be withdrawn 4 weeks to many months following surgery.

Technique (Endonasal/Endoscopic DCR): The absence of skin scarring is the fundamental advantage of the endonasal, or internal, method. The nasal mucosa and middle turbinate are decongested first to facilitate vasoconstriction and hemostasis. The lateral nasal mucosa close to the lacrimal sac is then incised vertically and raised using a nasal endoscope for visibility. The sac is usually seen along the nasal wall, prior to the anterior portion of the middle turbinate. If necessary, a fiberoptic endoilluminator similar to those used in vitreoretinal surgery may be placed via the canaliculi into the sac to assist transilluminate the lacrimal bone medial to the lacrimal sac.

The bone next to the lacrimal sac must be fully exposed. Freer elevators are used to elevate the nasal mucosa, and endoscopic forceps are used to remove the mucosa. Following that, the lacrimal bone is removed using a high-speed drill, Kerrison rongeurs, or pituitary rongeurs. Lasers have also been employed. To minimize continuous buildup in the inferior sac, the final bony ostium should be approximately 8mm in height and contain appropriate clearance of the common canaliculus internal ostium and the inferior sac (lacrimal sump). The lacrimal sac mucosa is infiltrated with local anesthetic for vasoconstriction, incised, and the medial sac mucosa is removed with forceps after the bone is removed.

The unrestricted flow of saline or fluorescein from the canaliculi through the nasal ostium, or direct observation of the common internal punctum with the endoscope, confirms adequate lacrimal sac mucosal excision. Bicanalicular silicone intubation, similar to the external DCR method, can also be put and withdrawn postoperatively in the office. Mitomycin C, an antimetabolite, can be used judiciously to control fibrosis in the intranasal ostium.

Endonasal DCR is not recommended for individuals who have a suspected lacrimal system tumor, lacrimal sac diverticulae, common canalicular stenosis, or significant midfacial trauma.

Recovery Time

Your surgeon will explain the recovery process, which may change depending on whether an exterior incision was made or endoscopic cameras were used. Although the surgery region may be uncomfortable and bruised, over-the-counter pain medicines should suffice. Your surgeon may also advise you to use antibiotic ointment and prescription eye drops. Eye surgery patients can resume bathing immediately, with less risk of noticeable bruising or swelling. Some individuals who have endoscopic surgery may be able to return to work the next day.

You will most likely have a follow-up visit seven to ten days following surgery, as well as any extra appointments indicated by your surgeon. After a week, any skin sutures that have been inserted are usually removed. Depending on your unique circumstances, certain post-operative treatment can be handled through telemedicine. Patients should avoid blowing their noses for a week following the surgery, as well as any vigorous activities during this period.

The scar where the external incision is created will disappear progressively over time and will be barely detectable. If you have a stent, it will most likely be removed within a few months.

Complications

• Intraoperative:

• Hemorrhage – Minimize by adequate anesthetic vasoconstriction, cautery, and bone wax. Avoid excessive cauterization of the nasal mucosa that could induce scarring.
• Injury to the internal opening of the common canaliculus when opening the sac.
• Cerebrospinal fluid leak due to penetration of the cribriform plate.
• Injury to the canaliculi from improper probing.
• Injury to the orbital contents from rongeurs or drill.
• Shredding of the lateral nasal mucosa due to improper bone removal.
• Failure to completely open the inferior portion of the lacrimal sac, resulting in a lacrimal sump syndrome.
• Failure to adequately drain and remove a lacrimal sac diverticulum.

• Postoperative:

• Hemorrhage.
• Infection.
• Incomplete improvement, persistent tearing.
• Early loss of the silicone tube.
• Fibrosis occlusion of the ostium.
• Synechiae between the middle turbinate, nasal septum, or lateral wall.
• Need for additional surgery.
• Sinusitis.

Conclusion

Tear drainage system disease can cause excessive tear buildup in the eye, resulting in eyes that are constantly watering and irritated. Furthermore, tear duct blockages can result in painful recurring infections that require antibiotic drops and pills to treat. This can have an adverse effect on vision and quality of life.

A blockage of the nasolacrimal duct, through which tears flow from the lacrimal sac into the nasal cavity, is a common cause of excessive tearing. The usual flow of tears from the lacrimal gland above the eye, across the eyes, into the lacrimal sac, and ultimately into the nose is disrupted by such a blockage.

Occasionally, the blockage may be relieved by careful probing of the duct and with a stent placed to hold the newly dilated passage open.

In cases of complete obstruction, a dacryocystorhinostomy (DCR) may be necessary. DCR is a surgical procedure that involves creating a new route for the tears to flow from the lacrimal sac directly into the nasal cavity, bypassing the blocked nasolacrimal duct.