**2. Anatomy**

## **2.1 Lacrimal gland and excretory system**

#### **2.1.1 Lacrimal gland**

The main lacrimal gland is located in a shallow depression along the superior lateral orbit. There is fibroadipose tissue between the gland and the orbit. The gland is divided into 2 parts by a lateral expansion of the levator apeunorosis. An isthmus of glandular tissue occasionally exists between the palpebral lobe and the main orbital gland1.

Many accessory lacrimal glands can be found along the inner surface of the eyelids. A variable number of thin-walled excretory ducts, blood vessels, lymphatics, and nerves pass from the main orbital gland into these accessory lacrimal glands. The ducts continue downward, and about 12 of them empty into the conjunctival fornix approximately 5 mm above the superior margin of the upper tarsus. Because the lacrimal excretory ducts pass through the palpebral portion of the gland, biopsy of the lacrimal gland is usually performed on the main part to avoid sacrificing the ducts1.

The lacrimal glands are exocrine glands, and they produce a serous secretion. The body of each gland contains 2 cell types:

acinar cells, which line the lumen of the gland

Endoscopic Dacryocystorhinostomy 51

Fig. 2. Position of lacrimal sac as seen during endonasal visualization

Occasionally, probing may be necessary to achieve patency.

resembles adenoid tissue and has a rich venous plexus and elastic fibers.

**3. Etiologies and predisposing factors of lacrimal obstruction** 

lid. In 90% of people, the two canaliculi join to make a common canaliculus before entering the lacrimal sac. The lacrimal sac is placed in an oval-shaped fossa measuring 15 mm in height and 10 mm in width. This fossa is bounded by anterior and posterior lacrimal crests which fuse at a suture line that crosses the lacrimal fossa in a vertical manner. The lacrimal sac opens into nasolacrimal canal which is formed by the maxillary, lacrimal, and inferior turbinate bones. The nasolacrimal duct passes through this osseous canal for approximately 12 mm. Then it turns into a membranous duct for 5 mm before entering the inferior meatus2. The duct orifice is often covered by Hasner's valve to prevent reflux of secretions. In about 30% of full-term neonates, the outlet of the nasolacrimal duct is closed for up to 6 months.

The lacrimal puncta and the canaliculi are lined with stratified squamous nonkeratinized epithelium that merges with the epithelium of the eyelid margins. Near the lacrimal sac, the epithelium changes into 2 layers: a superficial columnar layer and a deep, flattened cell layer. Goblet cells and occasional cilia are present. In the canaliculi, the substantia propria consists of collagenous connective tissue and elastic fibers. The wall of the lacrimal sac

Patients with obstruction of lacrimal system usually complain of excessive tearing or epiphora. When dacryocystitis occurs, purulent drainage or inflammation can be noticed in

 myoepithelial cells, which surround the parenchyma and are covered by a basement membrane

The lacrimal artery, a branch of the ophthalmic artery, supplies the gland. The lacrimal gland receives secretomotor cholinergic, vasoactive intestinal polypeptide (VIP)-ergic,and sympathetic nerve fibers in addition to a sensory innervation via the lacrimal nerve (CN V1). Cyclic adenosine monophosphate is the second messenger for VIP and β-adrenergic stimulation of the gland; cholinergic stimulation acts through an inositol 1,4,5-triphosphateactivated protein kinase C. The gland also contains α1-adrenergic receptors. Extremely complex, the gland's neuroanatomy governs both reflex and psychogenic stimulation1.

#### **2.1.2 Accessory glands**

The accessory lacrimal glands of Krause and Wolfring are located at the proximal lid borders or in the fornices and are cytologically identical to the main lacrimal gland, receiving a similar innervation. They account for about 10% of the total lacrimal secretory mass1.

#### **2.1.3 Lacrimal excretory system**

The lacrimal excretory (drainage) system includes the upper and lower puncta, the lacrimal canaliculi, the lacrimal sac, and the nasolacrimal duct. It is important to note that the first 2 mm of canaliculi are perpendicular to the lid margin but the distal 8 mm are parallel to the

Fig. 1. Anatomy of the left lacrimal apparatus

1.superior punctum 2.superior canaliculus 3.inferior punctum 4.inferior canaliculus 5.medial canthal ligament 6.common canaliculus 7.lacrimal sac 8. Lacrimal duct 9.middle turbinate 10.lacrimal bone 11.inferior turbinate 12.Hasner's valve

myoepithelial cells, which surround the parenchyma and are covered by a basement

The lacrimal artery, a branch of the ophthalmic artery, supplies the gland. The lacrimal gland receives secretomotor cholinergic, vasoactive intestinal polypeptide (VIP)-ergic,and sympathetic nerve fibers in addition to a sensory innervation via the lacrimal nerve (CN V1). Cyclic adenosine monophosphate is the second messenger for VIP and β-adrenergic stimulation of the gland; cholinergic stimulation acts through an inositol 1,4,5-triphosphateactivated protein kinase C. The gland also contains α1-adrenergic receptors. Extremely complex, the gland's neuroanatomy governs both reflex and psychogenic stimulation1.

The accessory lacrimal glands of Krause and Wolfring are located at the proximal lid borders or in the fornices and are cytologically identical to the main lacrimal gland, receiving a similar innervation. They account for about 10% of the total lacrimal secretory

The lacrimal excretory (drainage) system includes the upper and lower puncta, the lacrimal canaliculi, the lacrimal sac, and the nasolacrimal duct. It is important to note that the first 2 mm of canaliculi are perpendicular to the lid margin but the distal 8 mm are parallel to the

1.superior punctum 2.superior canaliculus 3.inferior punctum 4.inferior canaliculus 5.medial canthal ligament 6.common canaliculus 7.lacrimal sac 8. Lacrimal duct 9.middle

turbinate 10.lacrimal bone 11.inferior turbinate 12.Hasner's valve

membrane

**2.1.2 Accessory glands** 

**2.1.3 Lacrimal excretory system** 

Fig. 1. Anatomy of the left lacrimal apparatus

mass1.

Fig. 2. Position of lacrimal sac as seen during endonasal visualization

lid. In 90% of people, the two canaliculi join to make a common canaliculus before entering the lacrimal sac. The lacrimal sac is placed in an oval-shaped fossa measuring 15 mm in height and 10 mm in width. This fossa is bounded by anterior and posterior lacrimal crests which fuse at a suture line that crosses the lacrimal fossa in a vertical manner. The lacrimal sac opens into nasolacrimal canal which is formed by the maxillary, lacrimal, and inferior turbinate bones. The nasolacrimal duct passes through this osseous canal for approximately 12 mm. Then it turns into a membranous duct for 5 mm before entering the inferior meatus2. The duct orifice is often covered by Hasner's valve to prevent reflux of secretions. In about 30% of full-term neonates, the outlet of the nasolacrimal duct is closed for up to 6 months. Occasionally, probing may be necessary to achieve patency.

The lacrimal puncta and the canaliculi are lined with stratified squamous nonkeratinized epithelium that merges with the epithelium of the eyelid margins. Near the lacrimal sac, the epithelium changes into 2 layers: a superficial columnar layer and a deep, flattened cell layer. Goblet cells and occasional cilia are present. In the canaliculi, the substantia propria consists of collagenous connective tissue and elastic fibers. The wall of the lacrimal sac resembles adenoid tissue and has a rich venous plexus and elastic fibers.

#### **3. Etiologies and predisposing factors of lacrimal obstruction**

Patients with obstruction of lacrimal system usually complain of excessive tearing or epiphora. When dacryocystitis occurs, purulent drainage or inflammation can be noticed in

Endoscopic Dacryocystorhinostomy 53

Dacryoliths (lacrimal stones) or "calculi" of the nasolacrimal ducts were described by Cesoni in as early as 16704, and have been reported to occur in between 6 and 18% of patients with nasolacrimal duct obstruction who undergo dacryocystorhinostomy (DCR). Dacryoliths may occur in any part of the nasolacrimal system, albeit most commonly in the lacrimal sac. Several predisposing factors have been suggested, such as increased occurrence in females, patient age below 50 years, association with cigarette smoking and facial-sinonasal trauma, and increased frequency subsequent to previous occurrence of dacryocystitis. However, other studies have indicated increased frequency in males and patients aged above 50 years. Therefore, it seems that both genders are involved to nearly the same extent. Dacryoliths usually become symptomatic when they obstruct the nasolacrimal system. This can result in epiphora, acute dacryocystitis, protrusion of the lacrimal canthal region, and partial closure of the lacrimal passage (recognized during syringing by the ophthalmologist). Interestingly, dacryoliths occur more often in patients with partial and incomplete closure of the lacrimal passage (i.e., patients with epiphora despite patent lacrimal passages on syringing). Scanning electron microscopy has shown that dacryoliths are composed of lobes and lobules built on an amorphous core material5. Atomic absorption spectrophotometric investigations demonstrate that dacryoliths consist almost entirely of organic proteins and, to a much lesser extent, of inorganic material5. According to Lew et al., lacrimal fluid from patients with dacryoliths contains a reduced amount of lysozyme and a lower calcium concentration than normal lacrimal fluid. It is important to recognize that daryoliths are not calcified or composed of any other "hard" substances. Some stones reveal hyphae-like structures,

A comprehensive ophthalmologic examination is mandatory in the primary evaluation of every patient with lacrimal system obstruction. An examination with the slit lamp can reveal the normal or abnormal tear film over the conjunctiva and if the thickness of the tearfilm is more than usual, it can be a sign of lacrimal drainage system obstruction. In addition, the ocular surface, eyelid structures, visual acuity, extraocular motility, and visual

Gentle pressure over the sac produces reflux of mucopurulent material suggestive of lower

Irrigation test is another useful test in assessing patients. In this test, an appropriate lacrimal syringe is passed through the inferior lacrimal punctum and 2-5 ml of sterile distilled water is injected and pushed though the inferior canaliculus. If the water passes easily into the nose and the patient senses that, the patency of the system is confirmed. Otherwise, it is one of the most reliable signs of lacrimal system obstruction. Some authors recommend that after either external or endoscopic DCR, this test can be performed indicating the patency of the system. Nasal examination, especially nasal endoscopy, should be obligatory for every lacrimal obstruction patient. The examination of the lacrimal area with the nasal speculum and headlight provides only a poor view of this region and is not sufficient; Endoscopy provides a clear diagnostic look for nasal polyps, imporant anatomic variations, tumors, and other

although no fungi were recovered by culturing5.

field should be tested and documented before surgery.

pathological endonasal conditions such as septal deviation.

**4. Assessment of the patient** 

sac obstruction (regurgitation test).

**4.1 Physical examination** 

the medial canthal region. It is important to ask patients about any nasal airway obstruction, drainage or epistaxis, which may suggest intranasal causes of lacrimal obstruction, such as polyps or neoplasms. Sometimes, the nasolacrimal duct is injured secondary to prior sinus surgery, particularly a large maxillary antrostomy.

Lacrimal excretory system foreign bodies are rare but they can impair draining function and might be presented as epiphora, recurrent attacks of acute dacryocystitis and in some patients, chronic dacryocystitis3. Exogenous foreign bodies in most patients lodge in lacrimal sac or nasolacrimal duct after external manipulation3. Foreign bodies in some patients have endogenous origin and in the form of dacryoliths may lead to lacrimal flow obstruction3. In both forms, surgical removal of foreign bodies is necessary3. Classic surgical approach is external dacryocystorhinostomy (DCR) but in recent years with rapid improvement of endoscopic techniques intranasal approaches introduce themselves as an effective substitute for external DCR3. These approaches are helpful for preoperative diagnosis and effective for surgical removal of lacrimal foreign bodies.

We had an experience with foreign bodies which was published in Iranian journal of ophthalmology. In our case, the lacrimal sac foreign body was a piece of silicon tube that was used as a stent in previous external DCR. On retrospective enquiry we found that at the time of silicon tube removal, it was pulled forcefully out through the lacrimal canaliculi and when it was impacted at the given site it was cut and the remaining part could not be found through the nose. The presenting signs and symptoms of this case were completely similar to the failed DCR procedure, so she was referred to our department for more evaluation. Anterior rhinoscopy is normal in many of such cases, so we should emphasize on the role of the nasal endoscopy as a safe and rapid diagnostic method. In the nasal endoscopy, the condition of rhinostomy site can be evaluated and any foreign body, granulation tissue, scar formation or synechia between middle turbinate and lateral nasal wall can be found and appropriate treatment plan can be established3.

Fig. 3. Rhinostomy site with foreign body T: Middle turbinate, R: Previous rhinostomy site, F: Foreign body

the medial canthal region. It is important to ask patients about any nasal airway obstruction, drainage or epistaxis, which may suggest intranasal causes of lacrimal obstruction, such as polyps or neoplasms. Sometimes, the nasolacrimal duct is injured secondary to prior sinus

Lacrimal excretory system foreign bodies are rare but they can impair draining function and might be presented as epiphora, recurrent attacks of acute dacryocystitis and in some patients, chronic dacryocystitis3. Exogenous foreign bodies in most patients lodge in lacrimal sac or nasolacrimal duct after external manipulation3. Foreign bodies in some patients have endogenous origin and in the form of dacryoliths may lead to lacrimal flow obstruction3. In both forms, surgical removal of foreign bodies is necessary3. Classic surgical approach is external dacryocystorhinostomy (DCR) but in recent years with rapid improvement of endoscopic techniques intranasal approaches introduce themselves as an effective substitute for external DCR3. These approaches are helpful for preoperative

We had an experience with foreign bodies which was published in Iranian journal of ophthalmology. In our case, the lacrimal sac foreign body was a piece of silicon tube that was used as a stent in previous external DCR. On retrospective enquiry we found that at the time of silicon tube removal, it was pulled forcefully out through the lacrimal canaliculi and when it was impacted at the given site it was cut and the remaining part could not be found through the nose. The presenting signs and symptoms of this case were completely similar to the failed DCR procedure, so she was referred to our department for more evaluation. Anterior rhinoscopy is normal in many of such cases, so we should emphasize on the role of the nasal endoscopy as a safe and rapid diagnostic method. In the nasal endoscopy, the condition of rhinostomy site can be evaluated and any foreign body, granulation tissue, scar formation or synechia between middle turbinate and lateral nasal wall can be found and

Fig. 3. Rhinostomy site with foreign body T: Middle turbinate, R: Previous rhinostomy site,

surgery, particularly a large maxillary antrostomy.

appropriate treatment plan can be established3.

F: Foreign body

diagnosis and effective for surgical removal of lacrimal foreign bodies.

Dacryoliths (lacrimal stones) or "calculi" of the nasolacrimal ducts were described by Cesoni in as early as 16704, and have been reported to occur in between 6 and 18% of patients with nasolacrimal duct obstruction who undergo dacryocystorhinostomy (DCR). Dacryoliths may occur in any part of the nasolacrimal system, albeit most commonly in the lacrimal sac. Several predisposing factors have been suggested, such as increased occurrence in females, patient age below 50 years, association with cigarette smoking and facial-sinonasal trauma, and increased frequency subsequent to previous occurrence of dacryocystitis. However, other studies have indicated increased frequency in males and patients aged above 50 years. Therefore, it seems that both genders are involved to nearly the same extent. Dacryoliths usually become symptomatic when they obstruct the nasolacrimal system. This can result in epiphora, acute dacryocystitis, protrusion of the lacrimal canthal region, and partial closure of the lacrimal passage (recognized during syringing by the ophthalmologist). Interestingly, dacryoliths occur more often in patients with partial and incomplete closure of the lacrimal passage (i.e., patients with epiphora despite patent lacrimal passages on syringing).

Scanning electron microscopy has shown that dacryoliths are composed of lobes and lobules built on an amorphous core material5. Atomic absorption spectrophotometric investigations demonstrate that dacryoliths consist almost entirely of organic proteins and, to a much lesser extent, of inorganic material5. According to Lew et al., lacrimal fluid from patients with dacryoliths contains a reduced amount of lysozyme and a lower calcium concentration than normal lacrimal fluid. It is important to recognize that daryoliths are not calcified or composed of any other "hard" substances. Some stones reveal hyphae-like structures, although no fungi were recovered by culturing5.
