Ophthalmic procedures and surgery in the standing horse

Topical ropivacaine hydrochloride 0.5% and lidocaine hydrochloride 2% significantly reduce corneal sensitivity without short-term negative side effects in horses

OBJECTIVE

To evaluate corneal sensitivity and acute side effects following application of ropivacaine hydrochloride 0.5% and lidocaine hydrochloride 2% on the healthy equine cornea.

ANIMALS STUDIED

Eight healthy adult horses.

PROCEDURE

A randomized, masked, crossover study design was utilized. Baseline Semiquantitative Preclinical Ocular Toxicology (SPOT) scores and corneal touch thresholds (CTT) using a Cochet-Bonnet esthesiometer were recorded and measured, respectively, for eight healthy adult horses before medication application. Commercially available eyewash was used as a negative control. Ropivacaine hydrochloride 0.5% or lidocaine hydrochloride 2% solution was sprayed on a randomly selected eye, and the contralateral eye received eyewash. CTT was measured in both eyes at 1, 5, 15, 25, 35, 45, 55, 65, and 75 min post-application. Post-application SPOT scores were recorded immediately following the trial. Linear mixed model statistical analyses (mean ± standard error) were performed (p < .05).

RESULTS

Mean eyewash CTT (3.41 cm ± 0.464) was significantly different from ropivacaine-treated (1.44 cm ± 0.562) (p = .008) and lidocaine-treated eyes (1.75 cm ± 0.562) (p = .024); CTT was not significantly different between drug groups (p = .88). Time to maximum anesthesia was not significantly different between ropivacaine (13.25 min ± 3.353) and lidocaine (16.25 min ± 3.353) (p = .40). No side effects were appreciated as confirmed by SPOT.

CONCLUSIONS

Ropivacaine and lidocaine similarly decreased corneal sensitivity when applied topically without clinically evident short-term ocular side effects. Lidocaine may be preferable in clinical settings due to its large, multi-use vials and similar effects to ropivacaine.

Dorsally placed commercially available subpalpebral lavage systems have low complication rates in horses

OBJECTIVE

To retrospectively evaluate the complication rate following dorsal placement of a commercially available 1-hole subpalpebral lavage system (SPL) at a veterinary teaching hospital.

ANIMALS

102 client-owned horses with ophthalmic disease.

PROCEDURES

Medical records of horses (2010 to 2020) with ophthalmic disease were reviewed to determine whether a commercially available SPL system was dorsally placed. Data collected from the medical record included signalment, presenting complaint(s), diagnosis, ophthalmic procedures performed, SPL laterality, hospital service that placed the SPL, anesthetic technique for placement (general anesthesia or sedation with local nerve blocks), duration of SPL management while hospitalized or at home, type of enclosure for the horse, use of eye protection, duration of time the SPL was in place, location of SPL management (home vs hospital), types and numbers of medications administered, recorded complications, and outcome of the globe. Complications experienced during treatment were categorized as either ocular or nonocular. The χ2 test for independence test and Fisher exact test were performed to examine the relationship between the department that placed the SPL, method of anesthesia, antimicrobial administration, type of facial protection used, and complication type and rate.

RESULTS

Overall complication rate for SPL systems was 29.1% (37/127), with 21.2% (27/127) being ocular complications and 7.9% (10/127) being nonocular complications. SPL complication rate was not affected by any variable that was examined.

CLINICAL RELEVANCE

Commercially available SPL systems placed dorsally have a low ocular complication rate. These SPL systems may be placed by veterinarians with varied training backgrounds and managed at home without significantly increasing complication rate.

Intrasinus bolstering of traumatic maxillary sinus fractures by using Foley catheter balloons in two foals

OBJECTIVE

To describe the repair of unstable facial fractures by using Foley catheter balloons as intrasinus bolsters.

STUDY DESIGN

Case report ANIMALS: Two weanling foals with unilateral fractures of the sinus and orbit secondary to kick injuries. Preoperative imaging that included positive contrast dacrocystorhinography and computed tomography confirmed severe comminution of facial fractures and nasolacrimal duct disruption in both foals.

METHODS

Small bone fragments were surgically removed, and large fragments were retained even when denuded of periosteum. Repair procedures included nasolacrimal canaliculosinusotomy and suturing fracture fragments together with polydioxanone sutures. After fixation, the fracture fragments could be depressed into the sinus with manual pressure, so two intrasinus Foley catheters were placed to bolster the sinus wall, with the tubing exiting through a frontal sinus trephine. The skin was completely closed over the fractures. Catheters and nasolacrimal stenting were maintained in place during fracture healing.

RESULTS

One foal prematurely dislodged catheters and nasolacrimal stent 11 days after fixation. The catheters and stenting were removed as planned 4 weeks after surgery in the second foal. Wound, fracture healing, and overall cosmesis was good in both foals, and epiphora resolved. Surgical site infection, sinusitis, and sequestration did not occur. Both foals became high-level performance horses with acceptable cosmetic outcome and good bilateral nasal airflow.

CONCLUSION

Foley catheter balloons supported sinus fracture repair and maintained stability of the surgical reconstruction during convalescence.

CLINICAL SIGNIFICANCE

Suture repair of comminuted sinus fractures can be supported by using Foley catheters, which are readily available.

The use of a combined sliding skin graft and a free labial mucocutaneous graft for reconstruction of the equine upper eyelid after full-thickness excision of a melanoma

A melanoma of the upper eyelid was resected in a gray warmblood gelding. A full functional eyelid could be obtained by completion a sliding skin graft with a free labial mucocutaneous graft transplantation to restore the mucocutaneous junction and to decrease the risk of postoperative trichiasis.