Page 167 - Manual of Equine Field Surgery

Nasolacrimal Flush 163

--- Dorsal lacrimal punctum

Nasolacrimal sac --+

'
0\

'------Ventral lacrimal

punctum

Figure 27-1 Schematic illustrating the anatomy of the dorsal and ventral puncta, nasolacrimal sac, and naso-

lacrimal duct.

the ostium and advanced gently in a retrograde

manner.1 Using the index finger, gentle pressure is

applied over the opening to "seal" it around the

catheter. Patency of the nasolacrimal system can

be tested by injecting 15 to 20 mL of sterile saline

through the catheter. Patency of the dorsal and

ventral puncta at the medial canthus is individu-

ally determined by alternately applying digital

pressure over each canaliculus.

Alternatively, the nasolacrimal system can be

catheterized in an antegrade manner from the

dorsal punctum." The surgeon should first use

appropriate local anesthesia or akinesia of the

eyelids, topical anesthesia of the cornea, and seda-

tion. The catheter is inserted into the dorsal

punctum and is flushed with sterile saline. The

ventral canaliculus should be occluded with

digital pressure to ensure flushing of the naso-

lacrimal duct to its opening (Figure 27-3).

The nasolacrimal catheter can also be tem-

porarily sutured in place to provide patency of the

nasolacrimal system while treating an obstruc-

tion. If the surgeon intends to suture the naso-

lacrimal catheter in place, then local anesthesia of

the dorsal or lateral nasal wall adjacent to the

nares should be injected prior to placing the tube.

A stab incision is then made through the anes-

thetized area using a No. 10 Bard-Parker scalpel.
Figure 27-2 Nasolacrimal punctum in the vesti- The nasolacrimal catheter is inserted retrograde as

bulum.
described above and is advanced to the naso-

lacrimal sac. The free end of the catheter is

inserted from inside the nasal cavity through the