Page 166 - Manual of Equine Field Surgery
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CHAPTER 27
Nasolacrimal Flush
Laurence E. Galle
or akinesia of the eyelids and nares may facilitate
INDICATIONS
insertion of the catheter.
Catheterization and flushing of the nasolacrimal
duct is indicated to confirm or rule out naso- ANATOMY
lacrimal obstruction as a cause for epiphora,
mucoid, or mucopurulent discharge. Flushing of The structures of the nasolacrimal system are
the nasolacrimal duct may also be a therapeutic divided into secretory and drainage components.
procedure i11 that it can dislodge small foreign The tearfilm is a trilaminar fluid secreted by the
bodies or purulent debris that obstruct the flow lacrimal gland, third eyelid gland, conjunctiva]
of tears through the duct.1 If an obstruction is goblet cells, and meibomian glands. The tearfilm
diagnosed within the nasolacrimal system, dacry- is drained from the eye through the dorsal and
ocystorhinography can be performed to deter-
mine the anatomic location of the obstruction ventral puncta into the dorsal and ventral canali-
culi (Figure 27-1). The canaliculi merge ventro-
by the injection of radiopaque contrast media medial to the medial canthus and form the
through the catheter. 2
lacrimal sac, a dilation of the proximal naso-
lacrimal duct that lies within the Iacrimal fossa of
EQUIPMENT the lacrimal bone. The nasolacrimal duct passes
medially through the maxillary bone and contin-
A 5-Fr male urinary catheter or polyethylene ues rostrally through the soft tissues of the nares
tubing is needed for nasolacrimal catheterization. to the opening or orifice of the duct. This opening
A 3-mL syringe, 5/8-inch 25-gauge needle, and is located on the floor of the nasal cavity approx-
local anesthetic are needed if local anesthesia or imately 5 to 7 cm from the opening of the nares
akinesia is to be used to facilitate placement of the 11ear the mucocutaneous junction (Figure 27-2).
catheter. If the catheter is to be sutured into place, The nasolacrimal duct is approximately 4 to 5 mm
a No. 10 Bard-Parker blade, needle drivers, general in diameter and is narrowed proximally as it
operating scissors, and No. 2-0 or No. 3-0 mono- passes through the maxillary bone.1•3•5
filament nonabsorbable suture are also needed.
PROCEDURE AND PREPARATION.
POSITIONING AND PREPARATION
The opening of the nasolacrimal duct is located
Nasolacrimal catheterization is typically per- on the floor of the vestibulum of the nasal cavity,
formed with standing sedation. Local anesthesia and a 5-Fr male urinary catheter is placed into
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