External Dacryocystorhinostomy
Meseret E. Kassa, MD, MMed, FEACO
INDICATIONS FOR SURGERY
Epiphora from primary acquired nasolacrimal duct obstruction (NLDO)
Epiphora resulting from secondary acquired NLDO
Midface trauma
Sinus disease or surgery
Neoplasms
Dacryoliths
Topical or systemic medications
Functional NLDO
Recurrent or chronic dacryocystitis
Congenital NLDO not responsive to conservative treatment
Dacryocystorhinostomy is contraindicated in the setting of acute dacryocystitis. The infection should be treated with a course of oral antibiotics. If there is any abscess formation, it should be drained with incision and drainage, and the contents should be sent for culture and sensitivity. Once the infection has cleared, a dacryocystorhinostomy can be performed.
SURGICAL DESCRIPTION
Patient preparation
Place the patient in a slight (15° to 20°) reverse Trendelenburg position.
Pack the middle meatus of the nose with cottonoids soaked in oxymetazoline 0.05% nasal spray.
Mark a 15 mm long incision site 10 mm from the medial canthus starting just superior to the attachment of the medial canthal tendon. The incision should run in a curvilinear fashion inferiorly and laterally within the nasojugal fold (Figure 27.1).
FIGURE 27.1. Skin markings for incision site of external dacryocystorhinostomy. The superior extent of the incision lies at the superior border of the medial canthal tendon and approximately 10 mm from the medial canthus. The incision runs along the nasojugal fold for a length of 15 mm.
Inject local anesthetic using 2% lidocaine with 1:100,000 units of epinephrine mixed 50:50 with 0.5% bupivacaine into the soft tissue at the marked skin incision. Inject additional anesthetic at the periosteum along the anterior lacrimal crest. Lastly, after test aspiration, inject local anesthetic at the supratrochlear and infraorbital foramina.
Soft tissue dissection
Use a #15 surgical blade to make a skin incision on the marked line.
Use Stevens scissors to bluntly dissect the soft tissues and orbicularis beneath the skin down to the periosteum along the anterior lacrimal crest. The angular vein lies 8 to 10 mm from the medial canthus and should be carefully avoided by remaining lateral to it during the dissection.
Place a self-retaining retractor or use 4-0 silk traction sutures on each side of the incision line to provide adequate exposure.
Incise the periosteum along the anterior lacrimal crest using a #15 surgical blade.
Use a Freer periosteal elevator to reflect the lacrimal sac fossa periosteum together with the overlying soft tissues posteriorly from the surface of the maxillary and lacrimal bones. Anteriorly, elevate the periosteum widely off the nasal bone.
For better exposure, reflect the periosteum superiorly and disinsert the anterior limb of the medial canthal tendon together with the underlying periosteum.
Dissect the periosteum inside the orbital rim inferiorly to the lacrimal sac fossa.
Extend the dissection superiorly to the level of the base of the skull and inferiorly to the entry point of the nasolacrimal duct canal to expose the entire lacrimal sac fossa.
FIGURE 27.2. Site of initial perforation for osteotomy. The lacrimal sac fossa is composed of two bones separated by a suture — thick maxillary bone anteriorly and thin lacrimal bone posteriorly. The location of the suture within the lacrimal sac fossa is variable and can vary from just posterior to the anterior lacrimal crest to just anterior to the posterior lacrimal crest. By beginning the osteotomy at the posteriormost portion of the lacrimal sac fossa, the surgeon can maximize the chance that the underlying bone is thin and therefore easily perforated.
Osteotomy
Use the blunt end of a Freer periosteal elevator or the tip of a mosquito hemostat to perforate the lacrimal bone just anterior to the posterior lacrimal crest (Figure 27.2).
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