Conclusions Underexposure or lack of true localization of the sac are the most frequently encountered reasons for dacryocystorhinostomy failure. The maxillary line and adhesion point of the middle nasal concha are the 2 most important landmarks in localization of the sac.
A mucosal incision anterior to the maxillary line and dissection up to the point where the middle concha adheres, followed by osteotomy on the lacrimomaxillary suture, nearly always ensure the exposure of the sac.
Dacryocystorhinostomy is an operation that can be performed externally or endonasally. The endonasal procedure was introduced in , was modified in with endonasal osteotomy to the lacrimal bone, and was advanced with the introduction of endoscopy in The numerous advantages of endoscopic dacryocystorhinostomy have resulted in the widespread use of this method. Dacryocystorhinostomy enables improved visualization, does not pose any risk of creating a lesion in the medial palpebral ligament and orbicularis oculi, does not require an external incision and thus presents a cosmetic advantage, prevents angular vein damage, spares the pumping function of the nasolacrimal system, and promotes faster healing.
Endonasal landmarks are set to establish a correct approach. The landmarks placed on the lateral nasal wall of the nasal cavity are the axilla of the middle turbinate the most anterior part of the middle turbinate, where it adheres to the lateral nasal wall , the maxillary line the protrusion that lies as a curved line from the axilla of the middle turbinate to the inferior turbinate , the ethmoidal bulla, and the uncinate process Figure 1.
This study focuses on the reliability of these endonasal landmarks and evaluates the variations of the anatomical localization of the lacrimal sac. An electronic digital caliper was used to measure the sections, and metric rulers that measure to the millimeter were used for the photographs. During the dissection, the maxillary line was determined by the retraction of the middle turbinate superiorly, and, after the retraction, an incision that involved both the mucosa and the periosteum was made through this line.
The mucosa and periosteum were elevated, and the lacrimomaxillary sutura was exposed. In this way, the relation between the lacrimomaxillary sutura and maxillary line was observed. As a next step, the nasolacrimal duct and lacrimal sac were dissected by the removal of the lacrimal bone that lies posterior to the sutura and the frontal maxilla that lies anterior to the sutura. The relation of the lacrimal bone to the lacrimal sac was observed. The maxillary sinus ostium was then revealed by removing the posterior edge of the uncinate process.
The distance and relation of the lacrimal sac to the maxillary sinus ostium, ethmoidal bulla, and axilla of the middle turbinate were assessed Figure 2. The length of the lacrimal sac and the distance from the lacrimal sac to the inferior turbinate, ethmoidal bulla, uncinate process, and anterior nasal spine were measured Figure 3.
A paired t test was applied to determine whether a significant statistical difference existed in the measurements between the parts on the right side and those on the left. The relations among anatomical structures were evaluated. First, the maxillary line, an important marker in lacrimal sac localization, was identified. The anatomical localization of distances among the maxillary line, lacrimomaxillary sutura, and lacrimal sac were evaluated.
Within a total of 16 cases, in 11 the maxillary line lay on the same projection as the lacrimomaxillary sutura, whereas in 5 the maxillary line was located anteriorly. The maxillary line corresponded with the lacrimal sac in 18 of 20 cases Figure 4 A and B. Within those cases the lacrimal sac corresponded to the maxillary line; the maxillary line was situated in the middle of the lacrimal sac in 9 of 20 cases, whereas it was on the posterior half of the lacrimal sac in 5 of 20 and on the anterior half in 4 of The maxillary line lay totally anterior to the sac in 2 of 20 cases Figure 4 C and D and Figure 5.
In 12 of 17 cases the lacrimal bone covered the posterior half of the lacrimal sac, whereas in 3 of 17 more than half the sac and in 2 of 17 less than half the sac was covered by lacrimal bone. Second, the relation between the lacrimal sac and the axilla of the middle turbinate was observed. In 15 of the 20 cases part of the lacrimal sac was situated on the anterior aspect of the axilla of the middle turbinate, whereas the other part was situated on the posterior aspect Figure 6 C and D.
On the contrary, in 3 of 20 cases, the lacrimal sac was situated entirely on the posterior aspect of the axilla of the middle turbinate Figure 6 E and F , whereas it was situated entirely on the anterior aspect of the axilla of the middle turbinate in 2 of 20 cases Figure 6 A and B and Figure 7. In all 20 cases, the fornix of the lacrimal sac was located superiorly on the axilla of the middle turbinate Figure 6.
The dimensions of the lacrimal sac were observed. The mean SD length of the lacrimal sac was measured as The distance from the lacrimal sac to the landmarks and its relationship to the adjacent areas were analyzed Table. The application of a paired t test to detect whether a statistically significant difference exists in the measurements between the right and left parts of the specimens revealed that no such difference was established.
The surgical technique of endonasal dacryocystorhinostomy involves the removal of the frontal process of the maxilla, which is anterior to the middle turbinate, after the elevation of the mucoperiosteum. Three important factors are responsible for the failure of the endonasal dacryocystorhinostomy approach: the dimension of the bony ostium, localization of this part, and the size of the lacrimal sac, which may differ from patient to patient.
Edit article. View revision history Report problem with Article. Citation, DOI and article data. Knipe, H. Lacrimal sac. Reference article, Radiopaedia. URL of Article. Gross anatomy The lacrimal sac lies in the lacrimal fossa on the inferomedial aspect of the bony orbit between the posterior and anterior lacrimal crests. Related pathology dacryocystitis dacryolithiasis dacryocystocele nasolacrimal duct obstruction: most common at the valve of Krause 3 lacrimal sac infections preferentially spread in the preseptal part of the orbit causing orbital cellulitis.
CT of the inferomedial orbit and the lacrimal drainage apparatus: normal and pathologic anatomy. IMAIOS and selected third parties, use cookies or similar technologies, in particular for audience measurement. Cookies allow us to analyze and store information such as the characteristics of your device as well as certain personal data e.
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The nasolacrimal duct extends intranasally until it exits under the inferior turbinate. The lacrimal sac extends caudally to complete the canalicular system. The inside of the canal breaks down and forms a lumen so that the nasolacrimal system is patent.
This process is generally complete by the time of birth. Blood supply to the nasolacrimal area of the face is generally from the angular artery. The angular artery is considered a branch of the facial artery; however, some studies have shown that it can originate from the ophthalmic artery in some individuals.
It terminates in anastomosis with the dorsal nasal branch of the ophthalmic artery. The angular artery and vein appear alongside the nose near the medial orbit. A correlating angular vein drains this region. The medial and lateral portions of the eyelids have different lymphatic drainage systems.
The medial one-third of the upper eyelid and the medial two-thirds of the lower eyelid drain to the submandibular lymph nodes. The lateral two-thirds of the upper eyelid and the lateral one-third of the lower eyelid drain to the pre-auricular lymph nodes. Cranial nerve VII supplies the motor innervation to the muscles of the face. The movement of these muscles aid in proper drainage of the tears through the nasolacrimal system by what is known as the lacrimal pump mechanism.
This action is the primary driver of the lacrimal pump mechanism. Irritation of the ocular surface stimulates the ophthalmic branch of cranial nerve five, which begins the reflex tear arc pathway. The efferent pathway involves cranial nerve VII and parasympathetic fibers. The role of the sympathetic nervous system in tear production is not well understood. The action of the orbicularis muscle and surrounding tissues helps propel the flow of tears from the canaliculi to the nasolacrimal duct via the lacrimal pump mechanism.
Lacrimal duct injuries can occur in patients of all ages.
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