Fluoroscopically guided neocanalization for treatment of nasolacrimal atresia in two horses

Endoscopic-guided diagnosis of and interventional stent placement for nasolacrimal duct obstruction in a horse

OBJECTIVE

To describe the successful use of endoscopy to visualize and place a soft canine ureteral stent to relieve a chronic nasolacrimal duct (NLD) obstruction in a horse.

ANIMAL STUDIED

A 7-year-old, Quarter horse gelding.

PROCEDURE

Under general anesthesia, retrograde nasolacrimal endoscopy was performed using an 8.5 Fr Storz Flex XC ureteroscope through the nasal punctum (NP). An obstructive web of fibrous tissue was visualized approximately 20 cm proximal to the NP. A 0.035″/150 cm hydrophilic guidewire was passed normograde from the ventral lacrimal punctum and used to puncture the stenotic tissue. Then, a 5.0Fr/70 cm open-end ureteral catheter was threaded normograde over the guidewire and NLD patency was re-established. The catheter confirmed a NLD length of 30 cm and was then removed. A 5.0Fr/22-32 cm Universa© Soft Ureteral Stent was threaded normograde over the guidewire until the loops of the stent were exposed at each end. The guidewire was removed and the stent loops were sutured in place.

RESULTS

The stent was withdrawn 1 month after the procedure. Telephone follow-up with the client reported significant improvement in the amount of ocular discharge and decreased sensitivity around the face and ears.

CONCLUSION

Endoscopy is a safe and effective procedure allowing for definitive diagnosis of NLD obstruction and to assist in interventional procedures. Placement of a canine indwelling ureteral stent seems to be an effective alternative treatment option for equine NLD obstruction compared to conventional invasive surgical procedures.

Stenting of a partially obstructed nasolacrimal duct using a steerable angle-tipped hydrophilic guidewire in a cat

OBJECTIVE

This case report describes the successful correction of partial obstruction of the NL duct in a cat by means of a modified retrograde NL duct cannulation using a steerable angle-tipped hydrophilic guidewire (AH guidewire) following a paranasal incision.

ANIMAL STUDIED

A 2-year-old neutered male American domestic shorthair cat was referred to the Purdue University Veterinary Hospital (PUVH) for chronic epiphora suspected secondary to nasolacrimal (NL) system obstruction.

PROCEDURES

At the first visit, the cat had epiphora OD and facial dermatitis but no other abnormalities on physical and ophthalmic examinations. Computed tomography (CT)-dacryocystorhinography revealed partial obstruction of the NL duct secondary to stenosis near the distal root of the right maxillary third premolar (107). A digital three-dimensional (3D) model of the right maxilla and NL duct was created for inspection and virtual cannulation of the NL. The model was 3D printed and cannulation of the NL duct was rehearsed with various stent materials. Retrograde NL stenting with the guidance of a steerable angle-tipped hydrophilic guidewire was conducted following a paranasal incision. A urethral catheter was cannulated over the guidewire and maintained for 44 days.

RESULTS

The epiphora resolved immediately after stenting. At 21 days post-stenting, the cat developed acute bullous keratopathy secondary to self-trauma which was treated with a third eyelid flap. On the final follow-up communication with the owner at 210 days post-stenting, no epiphora or any other concerns were reported.

CONCLUSION

To the authors' knowledge, this is the first report of successful NL stenting and resolution of epiphora in a cat with a partial NL system obstruction.