Clinical Exposures: Palpebral reconstruction after entropion surgery in a dog - Veterinary Medicine
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Clinical Exposures: Palpebral reconstruction after entropion surgery in a dog


VETERINARY MEDICINE


Causes of entropion

Before performing permanent surgical entropion correction, it is important to determine the cause of the entropion. There are two basic types of entropion in dogs: primary and secondary.

Primary, or conformational, entropion is due to a combination of hereditary factors including the shape of the dog's face, the length and shape of the palpebral fissure, and the depth of the orbit.1-6 Patients with this type of entropion often benefit from surgical correction once the head has reached its adult size.

Secondary entropion is either spastic in nature or due to cicatrix formation, atonic eyelids, or the loss of retrobulbar fat, which leads to enophthalmos and the rolling inward of the eyelids. Spastic entropion is caused by chronic blepharospasm, a consequence of ocular pain. Surgery should never be the first option in this type of entropion; everything should be done to resolve the primary cause of the pain (e.g. treating a corneal ulcer).1-6 To protect the cornea while the eye is healing, either temporarily tack the eyelid or place a third eyelid flap or bandaging contact on the cornea. If entropion is still present after the primary cause is resolved, then permanent surgery can be performed. If a permanent surgery is performed initially, it could lead to ectropion once the animal is no longer in pain.

Cicatricial entropion is caused by the contraction of scar tissue in the eyelids due to either an injury or surgery, which causes the eyelids to roll in.1-6 Surgery to remove the scar tissue and reconstruct the eyelid is usually required.

Atonic entropion is a rare form for which a specific cause has not been identified but which results in the loss of palpebral tone.6 Techniques used for correcting conformational entropion are often appropriate in these cases as well.2

Because previous medical records were not available in this case, it was impossible to determine the cause of the entropion. Since primary entropion generally manifests in young animals, it would be unusual to have it in an older animal such as this dog.1-6 This dog likely had spastic entropion and may not have needed surgical correction at all.

Eyelid evaluation and surgical plan

A detailed eyelid evaluation should be conducted and the surgical plan made before anesthetizing the animal for entropion surgery. When the animal is anesthetized, the eyelids relax, and if an eyelid evaluation is performed at this time, improper amounts of tissue could be removed. Careful measurements with a ruler or caliper should be taken and marked on the skin to determine the amount of tissue to be removed and the exact location of the incisions. This planning ahead will reduce the likelihood of iatrogenic ectropion in unaffected areas and the removal of too much tissue in affected ones.4 If in doubt, it is always better to undercorrect rather than overcorrect.

In this case, most of the length of the upper and lower eyelids of both eyes was included in the initial incisions. This approach was quite extensive and may have contributed to the postoperative pain initially experienced by the dog. The aberrant placement of the incisions and sutures undoubtedly led to irritation from rubbing on the surface of the eye, self-trauma, and the subsequent incisional infection.

The excessive granulation and scar tissue formation that occurred in this case is unusual and undesirable after entropion surgery. Its formation was due to the extensive tissue removal and subsequent postoperative inflammation and infection. Although we do not know what suture was used in the initial surgery, a potential cause of excessive scar tissue formation is incision closure with large or inappropriate suture material. These problems can be avoided by using small and closely placed bites, carefully handling tissue, and using small (no larger than 5-0) suture material. Nonabsorbable suture material, such as nylon or silk, is preferred as it causes less tissue reaction. With the Hotz-Celsus procedure, only skin sutures are required. However, with some of the more complex procedures such as Y to V blepharoplasty, subcutaneous small-gauge (5-0 or 6-0) absorbable sutures are necessary.1-6

Self-trauma

Self-trauma is a common postsurgical phenomenon that can lead to suture line dehiscence, infection, and scar tissue formation, and it may have contributed to the postoperative morbidity in this case. Avoiding this problem by decreasing irritation to the periocular area during surgery is important. Minimal delicate shaving of the periocular hair and a gentle scrubbing of this area are paramount for preventing irritation. Protecting the surgical site by fitting the patient with an Elizabethan collar or goggles before it recovers from anesthesia will help ensure that it does not traumatize the area while the anesthesia is wearing off. The collar should be kept on the dog at all times until the sutures are removed at about two weeks after surgery.


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Source: VETERINARY MEDICINE,
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