Ocular oncology Dog eyelid masses Presented by Rosalie Atkins, DACVO

Eyelid Masses- Neoplasia Chalazion Blepharitis How to excise Cryotherapy Laser Chalazion Blepharitis Infectious Bacterial Fungal Parasitic Immune mediated Infectious Blepharitis Bacterial Blepharitis Meibomianitis Blepharomycosis Parasitic Blepharitis

Neoplastic Eyelid Masses Meibomian gland adenoma, adenocarcinomas, epithelioma, melanoma Generally clinically benign 20-30% histologically malignant Treatment Monitor Growth, rubbing, discomfort/ squinting, ulceration Surgical excision ~30 month mean recurrence rate Cryotherapy ~8 month recurrence rate CO2 laser AVMA 1986 Prevalence and treatment of palpebral neoplasia in the dog

Eyelid Surgery Basics Clip/clean 1/3-1/4 of the lid Lid margin Upper and lower puncta 4-0, 5-0 or 6-0 suture E-collar Antibiotics Palpebral fissure length- 33-35, Cat 28 mm with persians being slightly longer Paper from stades in 1992 You can take 25-33% of the lid

Wedge Resection 2 sided wedge: The V or 2 sided wedge involves cutting the meibomian glands obliquely. The eyelid margin is then aligned, closed with a figure eight. The remaining skin incision is closed in simple interrupted with monofilament or silk sutures.

4-Sided Excision 4 sided wedge: Technique: Parallel incisions are made perpendicular to the eyelid margin 2 to 3 mm away from the mass extending just beyond the dorsal (ventral) extent of the tumor. Converging incisions are then made from the end of the parallel incision to a point dorsal (ventral) to and 1 to 2 mm beyond the mass. A two-layer closure is performed.

Pre-op

Identify Upper Punctum

Perpendicular and Converging

Perpendicular and Converging

Finished Excision

Closure- Muscle/ Tarsus

Closure- Finished Closing Tarsus

Closure- Eyelid Margin- Figure 8 Make sure have correct suture 6-0 5-0 Maybe 4-0

Closure- Eyelid Margin- Figure 8

Closure- Eyelid Margin- Figure 8

Closure- Eyelid Margin- Figure 8

Closure- Finished Figure 8

Closure- Skin- Simple Continuous

8 Days Post-op

8 Weeks Post-op Lateral canthotomy to help close Complications Suture Ectopic or misdirected hair ulceration

Complications- Suture Rub

Complications- Suture Rub

Complications

Cryotherapy Tissue destruction Freezing Thawing Ice crystals Rate of freezing and thawing Vascular stasis Thrombosis Antigenic release Antibody production Freezing Slow large extracellular Fast Intracellular Thawing Enhances recrystalization Cryoadhesion -20 to 40 Cryonecrosis -70

Cryotherapy Liquid nitrogen -195 C Nitrous oxide -89C Spray Probe Poured Nitrous oxide -89C Probe only Probe line pressure 600-625 mmHg Tissue temperature -20C Probe temperature -70C

Cryotherapy Temperature PROCEDURE Tissue temperature Probe temperature Clamp Debulk mass 2-3 freeze thaw cycle 1 min per freeze 3 mm beyond edge of mass 80%

CO2 laser- Light Amplification by Stimulated Emission of Radiation Main Biological targets Blood Melanin Water All tissues have water Converts water to vapor and gas Ablation Periphery Coagulation of small vessels Large vessels bleed

CO2 laser- Safety Glasses- glass or plastic Cornea absorbs energy Wet gauze or tongue depressor Smoke evacuator

references Gelatt and Gelatt, Veterinary Ophthalmic Surgery, 2011 Veterinary Ophthalmology (2016) 19, Supplement 1, 44–55 Veterinary Ophthalmology (2010) 13, 6, 391–394 Veterinary Ophthalmology (2008) 11 , 6, 401–405 The Use of cryosurgery in a veterinary ophthalmology practice The role of the CO2 laser and fractional CO2 laser in dermatology