Chapter 98 – The Lacrimal Drainage System
JEFFREY J. HURWITZ
• The tear disposal system of the eye.
• The orbicularis muscle and eyelids provide a lacrimal pump mechanism.
• Lacrimal sac.
• Nasolacrimal duct.
• Congenital obstruction is usually due to an imperforate membrane at the nasal end of the lacrimal duct.
• Acquired obstruction may result from chronic fibrosis of the duct, trauma, or previous nasal or sinus surgery.
• Stenosis or occlusion results in epiphora.
• Testing procedures are designed to localize the site of obstruction.
• Correction of congenital obstruction is typically achieved with a simple probing procedure.
• For acquired obstructions, a dacryocystorhinostomy is usually required for permanent resolution.
Under normal circumstances, the quantity of tears secreted should equal the quantity eliminated. In this way, neither a dry eye nor symptoms of a watery eye occur. Tearing (a watery eye) may be due to hypersecretion of tears or to decreased elimination ( Table 98-1 ). Hypersecretion may result from an increased production of tears from any stimulation of the neurophysiological pathway, either centrally or locally. Decreased elimination is caused by reduced passage of tears into or through the lacrimal drainage system.
ANATOMY AND PHYSIOLOGY
Tears are secreted by the lacrimal gland, with a 24-hour secretory volume of approximately 10?ml. With blinking, the palpebral aperture closes from lateral to medial, and tears are pumped along the marginal tear strips of the upper and lower lids toward the lacrimal lake at the inner canthus. In the normal resting state, most of the tears are lost by evaporation, and only a small percentage of the volume passes down through the nasolacrimal passageways.
Tears pass from the lacrimal lake into the canaliculi through the puncta mainly by capillarity. It is important that the puncta of each lid contact the opposite lid on closure and thereby become physiologically occluded. When the lids separate, capillarity draws the tears into the empty canaliculi. Tears then flow to
TABLE 98-1 — CAUSES OF TEARING
Epiphora (decreased tear elimination)
Corneal foreign bodies
Corneal irritation with dry spots
Ocular surface inflammation
Nasal irritation and inflammation
Foreign bodies (e.g., stones)
Orbicularis muscle weakness
Punctal or eyelid malpositions
Nasal obstruction with normal lacrimal pathway
the common canaliculus and lacrimal sac due to a combination of factors     :
• A change in the caliber of these passages
• A change in pressure within the canalicular passages
• A pumping function (lacrimal pump) of the orbicularis muscle that surrounds these passages
Tears flow into the inferior meatus of the nose through the effect of the lacrimal pump, gravity, and, to a lesser extent, pressure changes within the nose due to respiration. Valves within the drainage system permit only one-way flow of tears.
EVALUATION OF EPIPHORA
The history of symptoms associated with tearing is important. Pain at the side of the nose suggests dacryocystitis, but pain in the eye itself may be due to foreign bodies, keratitis, recurrent corneal erosion, iritis, or glaucoma. Itchiness is suggestive of an allergic problem rather than a lacrimal obstruction. Grittiness and burning of the eyes associated with tearing suggest a tear film problem, such as occurs in keratitis sicca, or dysthyroid eye disease.
A history of medication such as echothiophate iodide (Phospholine Iodide), epinephrine (adrenaline), or pilocarpine is important, since all these drugs may produce lacrimal obstruction. Chemotherapy and radiotherapy also can cause obstruction in the canaliculi.
Poor orbicularis muscle tone and lacrimal pump dysfunction may be presumed if the lid can be pulled more than 8?mm away from the globe, if there is decreased snap-back, or if there is frank ectropion. The puncta normally should be directed backward into the lacrimal lake. Lesions of the caruncle may interfere with the proper drainage of tears. Blepharitis may cause secondary oversecretion of tears.
Facial asymmetry suggests congenital or traumatic anatomical blockage of the nasolacrimal canal. Any mass at the inner canthus should be palpated to determine whether it is soft (indicating mucus) or firm (suggesting a possible tumor) and whether it is compressible or noncompressible. Orbital signs such as proptosis, displacement of the globe, diplopia, and ptosis could indicate that the lacrimal lesion involves the orbit, or vice versa.
The nasal examination is an essential part of every lacrimal evaluation. Nasal and sinus conditions, which range from infections and inflammations to tumors, may result in epiphora. Symptoms include anosmia (loss of smell), epistaxis, anesthesia around the roof of the nose, and nasal obstruction.
Clinical Diagnostic Tests
The amount of wetting on a strip of filter paper over 5 minutes helps assess tear production. In the normal nonanesthetized eye, 15?mm of wetting is expected in a patient younger than 40 years of age, and at least 10?mm of wetting is expected in a patient older than 40 years. If anesthetic is placed onto the eye, the basal secretion is expected to be 10?mm of wetting in a normal patient younger than 40 years and at least 5?mm in a patient older than 40 years.
In syringing, a lacrimal irrigation cannula is passed into the punctum and advanced through the canaliculus to the medial wall of the lacrimal sac fossa (see Chapter 83 ). If the cannula hits bone (hard stop), the canaliculus is open, so the obstruction is probably in the sac or the duct. If it does not hit bone (soft stop), the obstruction is probably in the common canaliculus, especially if the medial angle of the palpebral aperture shifts medially as the cannula is advanced toward lacrimal bone.
Clear water or saline is then gently irrigated through a cannula. If fluid passes into the nose without reflux out of the opposite canaliculus, the system is totally patent. If fluid passes into the nose with resistance and reflux occurs through the opposite canaliculus, the system is anatomically patent but physiologically stenotic (partially occluded). If no fluid passes into the nose but it all comes back through either punctum, complete nasolacrimal duct obstruction is present.
Jones Fluorescein Dye Test.
The Jones dye test is used to determine whether the lacrimal drainage system is fully patent or, if partially obstructed, whether the problem is in the upper system (lids, puncta, canaliculi, common canaliculus) or in the lower system (sac, duct, nose).
A drop of fluorescein is placed into the conjunctival cul-de-sac. The nose is examined after 5 minutes to determine whether the dye has passed through the lacrimal system spontaneously, which indicates that it is functionally patent. This test may be facilitated by looking into the nose with a flashlight or an endoscope, or by having the patient blow the nose.
In the second part of the test, the cannula is placed in the sac, and the system is irrigated. Any fluid that passes into the nose during irrigation must be recovered and examined. If no fluorescein is present in the recovered fluid, this suggests that it did not pass into the sac during the initial fluorescein test, so the problem is likely in the upper (canalicular) system. If fluorescein is present in the fluid, this indicates that it reached the sac during the initial test and that the upper system is probably normal, meaning that the problem is in the lower (sac, duct) system. Although many surgeons find these tests useful, other tests and radiological investigation may be necessary for diagnosis or surgical planning.
Dacryocystography (DCG), an anatomical test, is extremely useful to determine the exact site of obstruction
Figure 98-1 Dacryocystogram. Complete obstruction of the lacrimal drainage pathways at the medial common canalicular level on the right side.
Figure 98-2 Dacryocystogram. Stenosis at the sac-duct junction is greater on the left side than on the right.
Figure 98-3 Dacryocystogram. Medial deflection of contrast material within the right sac indicates sac stones.
or stenosis within the system ( Figs. 98-1 and 98-2 ) and to visualize any deflection of the passages by diseases of the surrounding structures ( Fig. 98-3 ; Box 98-1 ). Injection of either a viscous oil (conventional macrodacryocystography)  or a water-soluble contrast material (digital subtraction dacryocystography) through a catheter demonstrates the lacrimal drainage pathways and outlines any anatomical abnormalities. This test does not evaluate physiological function.
Figure 98-4 Tearing secondary to neoplasm. A, Patient with right-sided tearing and a mass at the inner canthus. The system was fully patent to syringing. B, CT scan in this patient demonstrates an ethmoidal orbital plasmocytoma with compression of the lacrimal sac.
Figure 98-5 Endoscopy. Endoscopic view of the nose demonstrates the nasal septum (S), lateral wall, and turbinates (T).
Figure 98-6 Lacrimal scan. Complete obstruction on the left side and stenosis on the right side.
Uses of Dacryocystography
Complete obstruction where the site of block (canalicular vs sac) cannot be determined clinically
Incomplete obstruction where the area of stenosis cannot be localized on clinical testing
In cases of suspected lacrimal sac tumors to visualize a filling defect
In adnexal disease, to image compression or deflection of the sac or duct
High-resolution computed tomography (CT) in the axial and coronal planes is a useful anatomical study to assess those patients who have diseases in the structures adjacent to the nasolacrimal drainage pathways ( Fig. 98-4 ). Injection of the canaliculi with contrast provides simultaneous visualization of the lacrimal drainage system (CT–DCG).
Conventional ultrasonography of the lacrimal drainage pathways may have a role in demonstrating anatomical abnormalities such as an enlarged lacrimal sac (solid lesion or mucocele). It may also be helpful in patients who have common canalicular obstruction and in whom the sac cannot be demonstrated on DCG. New advances such as ultrasound biomicroscopy, with resolution of the subsurface structures up to 4?mm, allow visualization of the canaliculi. This technique may prove to be of value in the assessment of canalicular diseases.
Nasal endoscopy using a rigid telescope is useful to observe the anatomy of the opening of the nasal lacrimal duct in the inferior meatus and to diagnose any disease within the nose itself ( Fig. 98-5 ). If a lacrimal drainage operation is contemplated, the endoscope is the best method to assess the future surgical site. Should tearing persist following lacrimal surgery, it is useful to view the size and location of the previous dacryocystorhinostomy (DCR) opening using an endoscope to determine whether the opening is obstructed by fibrous tissue, polyps, granuloma, or foreign bodies.
Canalicular endoscopy is in its infancy. In the future, it may play a role in imaging along the canaliculus and into the sac and duct.
NUCLEAR LACRIMAL SCAN.
This is an adjunctive physiological test of lacrimal function; it does not demonstrate anatomical structures. A drop of technetium-99?m pertechnetate is placed into the palpebral aperture, and a pinhole collimator of a gamma camera is used to record its transit to the nose. The lacrimal scan can help determine the extent of stenosis from a physiological point of view ( Fig. 98-6 ). It also can help evaluate the flow of tears to determine whether lid or punctal malpositions contribute to drainage dysfunction.
OBSTRUCTIONS OF THE LACRIMAL SAC AND DUCT
Congenital nasolacrimal obstruction is due to an imperforate membrane, which usually opens spontaneously at the time of birth. Sometimes, this may persist into adult life. If spontaneous resolution does not occur by 1 year of age, the patient may be treated by probing through the membrane. If a child has passed the age of 5 or 6 years, the success rate of probing decreases to such an extent that it is preferable to treat the obstruction with a DCR.
Acquired obstructions of the sac and duct may be classified as nonspecific (idiopathic) obstructions and specific obstructions.
NONSPECIFIC ACQUIRED OBSTRUCTION.
The evolution of nonspecific lacrimal sac inflammation from an early inflammatory stage through an intermediate phase to a late fibrotic stage has been proposed by Linberg and McCormick. The early phase is characterized by vascular congestion, lymphocytic infiltration, and edema. These changes tend to occur at the superior aspect of the nasolacrimal canal just beneath the point where the sac passes into the nasolacrimal intraosseous duct. This seems to occur more commonly in older patients. It is more frequent in Caucasians than in those of African descent and is more common in women than in men; it has also been suggested that it is more common in people from lower socioeconomic levels. Inflammatory conditions that affect the inferior meatus of the nose also may involve the respiratory-like mucosa of the inferior aspect of the nasolacrimal canal, thereby leading to obstruction.
SPECIFIC ACQUIRED OBSTRUCTION.
Specific causes of nasolacrimal drainage system obstruction include inflammatory diseases such as sarcoidosis and Wegener’s granulomatosis. The former is often treated with systemic corticosteroids before a DCR becomes necessary, and the latter is treated either with dacryocystectomy and removal of all involved mucosa or with a full DCR.
Infection, trauma, surgical injury, and foreign bodies, such as retained silicone or eyelashes, also may cause obstruction. Primary neoplasms of the lacrimal sac and duct or secondary tumors arising in the adjacent sinuses are rare causes of obstruction ( Box 98-2 ).
Specific Causes of Acquired Nasolacrimal Pathway Obstruction
TRAUMA AND POSTSURGICAL
Nasal and endoscopic sinus surgery
Primary lacrimal sac tumors
Squamous and basal cell carcinoma
Transitional cell carcinoma
Figure 98-7 A patient who has dacryocystitis localized to the lacrimal sac. Mild pericystitis exists.
Dacryocystitis may be classified as acute, subacute, or chronic. It may be localized in the sac, extend to include a pericystitis, or progress to orbital cellulitis. When dacryocystitis is localized to the sac, a palpable painful mass occurs at the inner canthus ( Fig. 98-7 ), and obstruction is present at the junction of the nasolacrimal sac and duct. A preexisting dacryocystocele may or may not be present. When the infection develops, the lateral expansion of the nasolacrimal sac tends to push on the common canaliculus and produce a kink within it, with the result that the sac is no longer reducible. This allows a buildup of material within the sac and a chronic stasis, which leads to an exacerbated infection and more stasis. Approximately 40% of initial attacks do not recur, but in the other 60% of patients, repeated attacks occur. Chronic dacryocystitis may be the end stage of acute or subacute dacryocystitis, but it may present initially as a subclinically infectious cause of nasolacrimal duct obstruction. A common organism involved is Staphylococcus aureus. In some cases, especially in young women, stones may develop that lead to intermittent attacks of dacryocystitis; this has been termed acute dacryocystic retention syndrome.
In dacryocystitis with pericystitis, there is percolation of infected debris through the mucosal lining of the wall of the sac, and infection around the sac is present. The infection may spread to the anterior orbit and produce a tremendous amount of eyelid swelling ( Fig. 98-8 ). If the infection proceeds posterior to the orbital septum, as might occur in immunocompromised patients, a true orbital cellulitis may occur, resulting in globe proptosis or displacement, afferent pupillary defect, motility disturbance, optic neuropathy, and even blindness.
TREATMENT OF LACRIMAL SAC AND DUCT OBSTRUCTION
Congenital Nasolacrimal Obstruction
More than 90% of patients with congenital nasolacrimal obstruction undergo spontaneous resolution by 1 year of age. Therefore, except under extreme circumstances, initial probing should be postponed until this age. Congenital amnioceles usually resolve on their own and rarely require probing.
Probings are performed more easily with the patient under general anesthesia. The probe is passed into the lower canaliculus with the lid stretched laterally. The probe is turned past the 90° angulation and advanced inferiorly until it perforates the membrane. Fluorescein-tinted irrigation saline is introduced to see whether it passes into the inferior meatus, and metal-to-metal contact may be obtained by inserting a probe into the nose. The success rate of probing is greater than 90%. If this fails, however, one should wait 3 months before doing another procedure,
Figure 98-8 A patient who has dacryocystitis and orbital cellulitis. Ocular mobility is limited, indicating infection posterior to the orbital septum.
during which time most cases of seemingly failed probing resolve spontaneously.
If the repeat probing does not proceed easily, Silastic tubes should be placed and left for at least 3 months (preferably 6 months). If these tubes fail and the child is still tearing, a DCR is performed at a later date. However, one may perform a primary DCR on a 1-year-old patient when no nasolacrimal system has developed inferior to the lacrimal sac. Complications of silicone include cheese-wiring into the nose, with destruction of the punctum and proximal canaliculus, and dislocation of the tubes laterally over the cornea. In this latter situation, it is better to reposition the tubes than to remove them.
If the probe cannot be passed through to the nose, a DCR should be performed.
Acquired Nasolacrimal Obstruction
After an attack of dacryocystitis or obstruction, a period of observation is useful. Occasionally, if a mucous plug develops in the system, symptoms may resolve spontaneously. Medication such as naphazoline nasal spray shrink the nasal mucosa and may be used for a short period (no more than 5 days, for fear of atrophic rhinitis developing).
Medications such as antihistamines, either topical or local, and botulinum toxin have been reported to decrease lacrimal secretion. Surgical removal of the palpebral lobe of the lacrimal gland has been attempted, but there is a risk of producing a dry eye.
In the presence of frank dacryocystitis, the cardinal rule is to first treat the infection. The antibiotic of choice is an antistaphylococcal one, such as oral cloxacillin. If postseptal orbital cellulitis is present, a CT scan is obtained to rule out an abscess, and intravenous antibiotics are used. If the infection does not resolve and perforation is impending, a dacryocystotomy should be performed. After injecting lidocaine (lignocaine), an incision is made directly over the lacrimal sac, and the debris within the sac is curetted. Transcutaneous aspiration of sac contents for culture may be done with a No. 22 needle.
If epiphora persists after resolution of the infection, probing and syringing may be attempted before bypass surgery. Also, insertion of silicone tubes to hold the passage open may be attempted, but neither technique is very successful. More recently, attempts to dilate the sac and duct have been undertaken with a balloon catheter passed through the normal system or via an opening made through the lacrimal fossa into the nose. Two successive dilatations using a 5?mm-diameter balloon for 60 seconds and then 30 seconds have been reported to permanently dilate the system. Success rates for long-term patency are problematical.
DCR is an operation whereby the lacrimal sac is drained into the nose. The classic transcutaneous procedure of Toti has undergone many minor modifications, but the basic operation has withstood the test of time and has a high success rate of 93–95%. It may be performed with the patient under general or local anesthesia. In either case, the nose is premedicated with naphazoline nasal spray at 2 hours, 1 hour, and 30 minutes before surgery.
The surgical goal is to make an epithelium-lined tract between the sac and the nasal mucosa. It is important that the epithelium of the sac and the epithelium of the nasal mucosa become continuous, with minimal trauma produced in the epithelium of each structure. It seems logical that this goal is most likely to be achieved by directly suturing both posterior flaps and anterior flaps. A Silastic tube is inserted to hold the passage open if adequate separation of the anterior flaps from the posterior flaps cannot be achieved. Any foreign body or stent within the system can produce complications, so intubation should be avoided if at all possible without compromising the ultimate success of the operation.
The procedure is well described elsewhere. An incision as small as 8?mm is made on the side of the nose below the medial canthal tendon, and the dissection is carried down to bone. The periosteum is reflected from the anterior lacrimal crest to reveal the lacrimal sac fossa. The anterior limb of the medial canthal tendon may be cut without compromising the medial canthus because of the tight attachments of the posterior limb of the tendon. The sac is then reflected laterally.
The nose is entered by pushing a blunt instrument through the suture line between the lacrimal bone and the frontal process of the maxilla. Kerrison punches are used to remove bone between the sac fossa and the nose, to create an opening large enough to anastomose the sac and nasal mucosa. Flaps are created in the medial sac wall and in the adjacent nasal mucosa. The posterior flaps and then the anterior flaps of the sac and nasal mucosa are sutured together to form a mucosa-lined tunnel across the ostium ( Fig. 98-9 ). Silicone tubes are usually not necessary, but if desired, they can be placed at this time and left in for 6–12 weeks. Nasal packing is not necessary unless profuse
Figure 98-9 External dacryocystorhinostomy. A, Posterior flaps of the sac (small arrow) and nasal mucosa (large arrow) being sutured. B, Anterior flaps of the sac (small arrow) and nasal mucosa (large arrow) being anastomosed. (Adapted with permission from Hurwitz JJ. Diseases of the sac and duct. In: Hurwitz JJ, ed. The lacrimal system. Philadelphia: Lippincott-Raven; 1996. Artwork courtesy of Terry Tarrant, London.)
bleeding occurs at the end of the operation. Postoperative antibiotics should be considered, even if the patient did not have dacryocystitis preoperatively.
Complications of hemorrhage within the first 24 hours should be controlled by lowering the blood pressure to normal values and by nasal packing. Delayed hemorrhage 4–7 days after surgery is due to clot retraction, comparable to an eight-ball hemorrhage following an initial hyphema. Vaseline gauze packs soaked with thrombin are useful and should be left in place for 48 hours. If all else fails, embolization may be helpful. Orbital hemorrhage may occur, but this is extremely rare.
A hypertrophic cutaneous scar is unusual, but if present, it usually settles quite well with massage. Triamcinolone also may be injected into the scar.
Surgical failure may result from closure of the anastomosis between the sac and the nasal mucosa, or an obstruction may occur at the common canaliculus, either undiagnosed preoperatively or developing postoperatively. Whether the obstruction is within the common canaliculus or at the entrance of the lacrimal sac into the nose can be determined by DCG. Initial treatment is conservative, consisting of decongestants or corticosteroid nasal sprays to shrink the inflammatory membrane or granulation tissue. A probe may be performed to perforate the inflammatory membrane, which often produces a permanent cure. In some situations, probing with placement of bicanalicular Silastic tubes may be useful to prevent granulation tissue from closing over the newly formed DCR opening. An endoscope is useful to explore the DCR opening intranasally. If these conservative measures fail, reoperation with revision of flaps may be performed, and a bicanalicular Silastic stent tube is left in place for a minimum of 3 months. The success rate of this last procedure is greater than 80%.
If the obstruction is at the common canalicular level, a canaliculodacryocystorhinostomy (CDCR) may be useful. The scar tissue at the common canaliculus is excised; then the individual canaliculi or residual common canaliculus can be sutured into the nose.
When the obstruction is in the lower drainage system and the canaliculi are anatomically normal, an endonasal approach may be attempted as an alternative to an external DCR. The advantage of this procedure is that it avoids any cutaneous incisions. However, this procedure has a lower success rate than the external approach.   After decongesting the nasal mucosa, a light pipe is passed through the canaliculus to the lacrimal bone and visualized in the nose. The nasal mucosa is incised, elevated, and removed around the light spot with the use of a scalpel or laser.    The thin bone of the lacrimal bone is punctured and enlarged with Kerrison punches. The ostium should not extend behind the posterior lacrimal crest or above the lacrimal sac. The sac mucosa is opened with Vannas scissors, and a portion of the medial wall is excised. Silicone stents must be placed through the system and left for 3–4 months. This approach also allows the surgeon to deal with nasal adhesions, granulation tissue, and hypertrophic turbinates at the same time.
Perspective on Dacryocystorhinostomy Surgery
The creation of a sutured epithelium-lined anastomosis seems to produce the highest success rate for DCR. This can be achieved only by the external route. Resurrection of the endonasal DCR using a laser-assisted endoscopic technique has not produced comparable success rates. However, the endonasal approach without the laser has better success rates than the endonasal procedure with the laser.
Whatever the surgeon’s preference with respect to the indications for surgery in a particular patient, both external and endonasal approaches should be in his or her armamentarium.
TUMORS OF THE LACRIMAL SAC
Primary lacrimal sac tumors present as masses at the medial canthus. Depending on the age of the patient, there may or may not be symptoms of tearing. These patients often exhibit patency to syringing because the tumor usually arises in the epithelium and only later grows toward the lumen. Bloody tears may be present. Lacrimal sac tumors may be benign or malignant, epithelial or nonepithelial. DCG and CT are useful to demonstrate the location of the mass and its extent, as well as associated involvement of the lacrimal drainage pathways. Bony erosion is often present in these cases.
DISEASES OF THE CANALICULI
Canalicular obstruction may have inflammatory, traumatic, idiopathic, or suppurative (canaliculitis—usually actinomycotic) causes. Whereas some diseases certainly involve both the punctum and the canaliculus, many involve either one or the other and so should be considered separately.
Punctal stenosis can be congenital or acquired. Congenital obstruction may be caused by a membrane overlying the punctal papilla. In such situations, the rest of the punctum and the canaliculus are patent, so merely perforating the membrane with a 25-gauge needle may be sufficient to achieve permanent patency. If the papilla of the punctum is absent, the distal canaliculus often has not developed either, so affected patients usually require the placement of a Jones tube. Marsupialization of the remaining canaliculus into the lacrimal lake does not offer a good solution.
Acquired obstructions may result from antiviral or antiglaucoma medications, cicatrizing diseases of the conjunctiva, various infections, radiation, and chemotherapeutic agents, which may also obstruct the canaliculi. Intrinsic tumors, such as papillomas and skin malignancies (e.g., basal cell and squamous carcinoma), also may obstruct the puncta. Most acquired punctal obstructions, however, are secondary to punctal eversion, which may be related to eyelid laxity or to cicatrizing diseases of the skin.
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