Partial orbital rim resection, mesh skin expansion, and second intention healing combined with enucleation or exenteration for extensive periocular tumors in horses

Use of a chronic soft tissue expansion device to facilitate blepharoplasty in a horse with lower-lid cicatricial ectropion with a 14-year follow-up

A 3-year-old Thoroughbred filly presented to a referral equine hospital for surgical correction of a severe cicatricial lateral lower eyelid ectropion OD, with secondary exposure keratitis. The severity of the ectropion deemed that conventional ectropion repairs would be unsuccessful. Therefore, a soft tissue expansion device was used to create sufficient local tissue for a rotational graft with tension-relieving horizontal incisions to be performed to facilitate closure and acceptable eyelid apposition. The keratitis had resolved by two months postoperatively. There were no long-term complications and only mild recurrence of the keratitis observed 14-years postoperatively.

Rhomboid blepharoplasty and cryotherapy for the treatment of a squamous cell carcinoma on the lower eyelid in a horse

A rhomboid blepharoplasty can be used to achieve functional and cosmetic eyelid reconstruction at the medial canthus in the horse. Combination of a rhomboid blepharoplasty with cryotherapy is a treatment option for eyelid ocular squamous cell carcinomas.

Periocular Neoplasia in the Horse

Periocular neoplasia is common in horses. Treatment of the periocular skin and ocular adnexal structures can be technically challenging. Common neoplastic conditions, a treatment algorithm, surgical principles, and therapeutic modalities are reviewed. Regardless of the type of neoplasia found or the treatment that is applied, success is most likely when the neoplastic tumor is small.

Orbital reconstruction in the dog, cat, and horse

OBJECTIVE

To describe an adaptable method for reconstruction of the orbit following partial orbitectomy.

ANIMALS STUDIED

One horse, one cat, and four dogs.

PROCEDURE(S)

Following partial orbitectomy for removal of bone and soft tissue affected by pathologic processes, reconstruction was achieved. Cerclage wires were used to reconstitute the orbital rim and other salient facial contours involved in excisions. These wires were then covered with a prolene mesh, first inside the orbit and then outwards over the affected extraorbital areas. Thereafter, a collagen sheet was placed over the mesh. Finally, subcutis and skin were closed over the construct.

RESULTS

All operated eyes remained visual with normal position, direction, and mobility. Eyelid function, tear production, and nasolacrimal function were preserved. Side effects were mild and temporary, but animals requiring a lateral-posterior surgical approach experienced concavity to the side of the head posterior to the orbital ligament region. One bone tumor out of three recurred.

CONCLUSIONS

The reconstruction method presented offers excellent results tectonically, cosmetically, and functionally, even following extensive orbitectomy. By adapted application of three reconstruction steps using readily available materials, large defects may be surgically repaired. Once orbitectomy is mastered, reconstruction requires no additional specialized techniques or equipment.

Modified Kuhnt-Szymanowski surgical procedure for secondary cicatricial ectropion in a horse

A 1-year-old Dutch Warmblood gelding was presented to the University of Florida's Large Animal Hospital (UF-LAH) for correction of ectropion of the right lower eyelid. The ectropion was the result of a lower eyelid laceration. A primary repair was performed by the referring veterinarian; however, the horse prematurely removed the sutures and the wound healed with inversion of the eyelid margin. Surgical correction of the entropion, with removal of tissue from the lower eyelid, resulted in cicatricial ectropion. During the initial evaluation at UF-LAH, a corneal ulcer was noted in the right eye because of exposure from the anatomically nonfunctional lower eyelid. A modified Kuhnt-Szymanowski procedure was performed to correct the ectropion and repair the eyelid margin. The surgical site healed appropriately with an acceptable cosmetic and functional result. No recurrences of corneal ulcers in the right eye were reported in the 18 months following surgical correction of the ectropion.

Return to work following unilateral enucleation in 34 horses (2000-2008)

REASONS FOR STUDY: The effect of unilateral enucleation on vision and potential loss of performance in horses has received little study.

OBJECTIVE

To evaluate the likelihood of return to prior discipline following unilateral enucleation in horses, assessing the role of age at enucleation, equine discipline, reason for enucleation, time to vision loss and eye enucleated.

HYPOTHESIS

Unilateral enucleation has no significant effect on likelihood of return to work in horses, for both right and left eyes, across age and discipline.

METHOD

A retrospective review of medical records identified 92 horses that underwent unilateral enucleation at the University of Pennsylvania New Bolton Center from April 2000-April 2008. Case variables determined from the medical record included breed and sex of horse, age at enucleation, which eye was enucleated, reason for enucleation and onset of vision loss. Pre- and post operative occupations were determined by telephone interview with the owner or trainer of each horse.

RESULTS

Based on hospital surgery logs, 92 enucleations were performed over the 8 year period and 77 records were available for review, with follow-up information available for 34 horses. Of these, 29/34 (85%) horses returned to work in pleasure or trail riding (11/13), flat racing (7/10), hunter/jumpers (4/4), dressage (3/3), group lessons (1/1), eventing (1/1), steeplechase (1/1) and as a broodmare (1/1). Four of 5 horses (4/34, or 12% sample) that did not return to work (2 pleasure and 2 racing) were retired due to anticipated or perceived decrease in performance or behaviour change following unilateral enucleation, with the remaining horse retired from racing for lameness issues unrelated to enucleation. Twenty-two of 25 horses (88%) with acute vision loss and 7/9 horses (78%) with gradual vision loss returned to their previous discipline.

CONCLUSIONS

Horses are able to return to a variety of occupations after unilateral enucleation.

Imaging Features and Decision Making in Retrobulbar Neuroendocrine Tumours in Horses ? Case Report and Review of Literature

A 25-year-old Haflinger gelding was evaluated for chronic-progressive unilateral exophthalmos. Ultrasonographic investigation and magnetic resonance (MR) imaging revealed a retrobulbar space-occupying mass to be the cause of eyeball displacement. Ultrasonographic features were not sufficient to specify the type and extension of the lesion. Magnetic resonance scans, however, clearly displayed an infiltrative intracranial growth pattern but sparing of orbital soft tissues. Based on MR appearance, tentative diagnosis of an orbital soft tissue neoplasia was made and subsequently confirmed by histopathological investigation. The latter revealed a poorly differentiated neuroendocrine tumour. Retrospectively, MR changes resembled those seen with neuroendocrine neoplasms of the human skull. Even if histopathology remains to be elucidated by cytological or histological inspection, MR imaging of equine orbital tumours should provide the criteria necessary for evaluating the therapeutic options and associated prognosis.

Amniotic membrane transplantation for corneal surface reconstruction after excision of corneolimbal squamous cell carcinomas in nine horses

OBJECTIVE

The purpose of this study was to evaluate the usefulness and effectiveness of permanent amniotic membrane transplantation as an adjunctive treatment to superficial keratectomy alone or combined with strontium-90 irradiation for treatment of equine corneolimbal squamous cell carcinoma (SCC) to decrease corneal scarring and recurrence rate.

STUDY

The retrospective case study included 11 horses (n = 12 eyes) diagnosed and treated for ocular SCC that involved the limbus and cornea. Nine of those horses (n = 9 eyes) were treated between 2002 and 2006, with superficial lamellar keratectomy alone or combined with strontium-90 irradiation and followed by placement of a permanent amniotic membrane graft in the surgical defect. The level of scarring (i.e. the clarity of the cornea) resulting with the use of amniotic membrane was subjectively compared to cases where a permanent bulbar conjunctival graft was performed following keratectomy combined with strontium-90 irradiation or cryotherapy (n = 3 eyes). Recurrence was defined as the postoperative and postirradiation regrowth of SCC in the same site and globe.

RESULTS

The nine horses that received an amniotic membrane graft after keratectomy alone or combined with irradiation showed a minimal level of scarring in a cornea that regained a greater transparency in comparison to the horses that were treated with a bulbar conjunctival graft. All of the horses that received an amniotic membrane graft had 226 +/- 218 days of follow-up without tumor recurrence (mean +/- SD), ranging from 21 days to 778 days.

CONCLUSIONS

The combination of superficial keratectomy alone or associated with beta-irradiation and permanent amniotic membrane transplantation is an effective treatment of corneal or corneolimbal SCC in horses. The placement of an amniotic membrane material represents an alternative surgical procedure to bulbar conjunctival grafts, especially if there is a lack of bulbar conjunctiva tissue available after tumor resection or if a particularly large corneal resection is necessary. The amniotic membrane is incorporated into the corneal defect and seems to create noticeably much less scarring than a corneal defect covered by bulbar conjunctiva.