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Eyelid surgical management Nick Cassotis, DVM, Dipl. ACVO

The importance of vision to our patients and their owners / companions is significant. The absence of vision is devastating to quality of life and quality of the human animal bond. The primary function of the is protection of the and therefore vision. Preservation of structure and function in the face of disease is important to prevention of vision loss. The decisions for type of , invasiveness of the procedure, and prognosis for preservation of function should all be considered when assessing a patient for surgical correction.

The goal of eyelid surgical intervention should be elimination of the disease process while preserving eyelid length, position, blink, and the ability to protect the globe.

Entropion

Entropion correction is among the more challenging of in given the varied facial structures between breeds and species. Although general surgical techniques will be discussed, the specifics of surgery vary. Incision location, length and width, orientation, and closure must balance the need to eliminate irritation as well as preserve some breed -related / -imposed cosmetic needs. Surgical planning must account for tissue laxity and position that can challenge post-operative outcomes.

Preoperative planning is essential in entropion cases. A no-touch / hands-off observation of the eyelid position in the awake patient is needed. Observations of not only the entropion but also the normal (if available) eye are important. Manipulation of the tissue can then occur for estimation of correction assuming there is not protective spasming. If blepharospasm and protection of the globe occurs, then proparacaine should be administered to eliminate any spastic contribution to the severity of disease. Assessment of how much tissue excision is made at this time.

Your surgical parameters are made while the patient is awake, not anesthetized. Patients under anesthesia have excess facial laxity that can interfere with outcome.

Patients can be positioned in sternal or lateral recumbency for this surgery. Sternal recumbency can push lips and face dorsally and change the tissue tension. Placement of a narrow chin rest that allows the face to hang normally is useful. Towel clamps and adhesive drapes can add tension to the region.

Appropriate suture selection 5-0 or 6-0 absorbable suture is most commonly used in our practice for simple and complex repairs. These small suture selections help avoid post- operative complications since suture placement near the eyelid margin is necessary.

For a typical Modified Hotz-Celsus procedure the incision should be 3-4mm from and parallel to the eyelid margin. Do not make your incisions 1cm away from the eyelid. Having the free edge of the incision near the margin allows the margin to be rolled away from the . If the initial incision is farther away from the eyelid margin it will pull the eyelid ventrally and create .

In many cases, the combination of a pentagonal excision can be combined with a MHC surgery to achieve better contact of the eyelid margin against the cornea. This is a challenging surgery since correct alignment of the eyelid is a must. Either figure 8 suture closure or a U-suture technique with 6-0 Vicryl is indicated. Meticulous alignment is required.

Avoid iatrogenic ectropion and suture contact against the globe.

Distichia and Ectopic cilia

These abnormal eyelid cilia occur in commonly in dogs and less commonly in cats. Distichia specifically are abnormal cilia emanating through the meibomian gland secretory openings in the eyelids. Ectopic cilia are also abnormal cilia, however these erupt through any other surface of the eyelid margin or conjunctival surface. Ectopic cilia tend to be more painful and can result in extensive corneal damage. Each of these abnormalities are most common in young animals, however, they can be discovered at all ages.

These cilia abnormalities are at times very difficult to find. Magnification is needed for not only identification but also during the treatment of each disorder.

Elimination of these distichia can be non-invasively achieved with cryoepilation, or more invasive high temp cautery. Ectopic cilia are excised to prevent return of discomfort and to eliminate the risk of repeat corneal damage.

Frustrating recurrences are experienced with distichia uncommonly. In most cases, more than 80% of the sites treated will not recur. Breeds and species that require repeat treatments are bulldogs and cats. The reason for the more common failures is not well understood.

Ectropion

Ectropion, whether from over-correction of entropion, or related to breed associated traits, can be complex and challenging corrective surgeries. Pentagonal excision and realignment of the eyelid margin may be possible. In more complex cases, advanced procedures such as Kuhnt- Szymanowski are performed. The KS procedure is commonly used in cases with euryblepharon, lateral canthal instability and ectropion. Many other surgical options exist, such as VY plasty, yet should be thoroughly researched before revision is performed.

Eyelid neoplasia Eyelid neoplastic disease management can threaten the overall structure and function of the eyelids. Addressing masses early will limit the amount of overall eyelid length that is threatened by surgery. Early onset meibomian gland masses rarely require full thickness excision of the masses. Partial thickness debulking and cryotreatment allow for full preservation of the eyelid length and are performed under sedation and local anesthetics. This technique of split thickness eyelid surgery and cryotreatment does not require suture and lessens patient recovery times.

Submitting tissue for histopathology is reasonable in establishing a definitive diagnosis.

When elimination of the eyelid mass cannot be achieved without reducing eyelid length, then basic plastics procedures can be performed to recreate eyelid length in an effort to prevent loss of blink or corneal coverage. Measure the amount of eyelid length that must be excised. If greater than 1/3 to ½ of the overall eyelid length is excised, then advancing skin from the lateral canthus is commonly performed to lessen tissue tension and preserve eyelid position. Closure of the new lateral canthus is required. Granulation of the new tissue edge will create a false eyelid margin.

Superior eyelid mass excision with significant tissue excision is an advanced surgical procedure given the need commonly for rotational flap harvest and closure.