Endoscopic DCR has many advantages over external DCR like avoiding scar over the face, avoiding the need of division of medial canthal ligament
and preservation of orbicularis oculi muscle pump action of the lacrimal sac.
Background: Rupture of the medial canthal ligament can be caused by many events.
The medial canthal ligament plays an important role in maintaining shape and function of the eyelids.
(4) demonstrated in a cadaver study that the superficial buccal branches of the facial nerve pass around the inferior nasal margin of the orbicularis oculi muscle and cross over the medial canthal ligament
to innervate the procerus, the corrugator supercilii, and the orbicularis oculi muscles in the nasal periorbit in 94% of the specimens.
An 8 mm incision is made over the medial canthal ligament close to the bridge of the nose and the ligament dissected carefully.
The two slips are passed under the medial canthal ligament with the right angled clamp; the lower slip from below upwards and the upper slip from above downwards to avoid tenting of the skin by the slips.
Through a modified medial canthal ligament
approach, a left radical ethmoidectomy and drainage of the orbital abscess were performed.
After detaching medial canthal ligament
, the periosteum over the lacrimal crest is divided to enter lacrimal fossa.
Endonasal endoscopic DCR has well known advantages over the standard external DCR like it avoids facial scarring, division of the medial canthal ligament
and disruption of the pump action of the lacrimal sac.
The lacrimal fascia was incised 1mm lateral to the anterior lacrimal crest and the bony attachment of the medial canthal ligament
The mucoceles of the frontal sinus may disrupt the medial canthal ligament
and the orbital roof in which surgical interventions should include the reconstruction of these anatomic structures (9, 10).
The lacrimal sac locates behind the medial canthal ligaments
, and within the fossa of lacrimal sac which is composed by the lacrimal bone and process of frontalis maxilla, its upper portion is the caecum, and the lower portion is connected with the nasolacrimal duct, the ideal imaging examination should clearly display the in vivo lacrimal sac and its surrounding tissues, at the same time, it should be economic, convenient, non-invasive and reproducible.