Page 146 - WSAVA2017
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An Urban Experience
WSVA7-0414
OPHTHALMOLOGY
REGIONAL ANESTHESIA AS AN ADJUNCT TO YOUR OPHTHALMIC SURGERIES: WAYS TO IMPROVE YOUR SUCCESS
E. Giuliano1
1University of Missouri- Veterinary Medical Teaching Hospital, Columbia- MO, USA
Introduction
Local anesthesia can be a useful adjunct to multimodal analgesic surgical planning and improve post-operative analgesia. Retrobulbar blocks are routinely used for enucleation or evisceration/prosthesis surgeries and
may be used by some veterinary ophthalmologists for intraocular surgery (Accola et al. 2006; Myrna et al. 2010). Topical anesthesia is commonly used to facilitate ocular examination in the conscious small animal patient. Small animal patients typically require heavy sedation
or general anesthesia to perform regional anesthesia safely for both the operator and the patient. Potential side effects should be considered prior to performing local anesthesia. The possible effects on intraocular pressure are of particular concern, as this may affect the overall outcome of surgery and treatment. Knowledge of regional anatomy and physiology is essential to perform these techniques safely and effectively. Equipment needs are minimal; needles and syringes routinely available in small animal practice are sufficient.
Indications for use of ophthalmic local anesthesia
Numerous ophthalmic procedures may be performed with adjunctive local anesthesia. Examples include:
• Ophthalmic examination (application of topical anesthetic and rarely, an auriculopalpebral block unless examining a horse)
• Pre-operative analgesia
o Enucleation
o Evisceration with intrascleral prosthesis
o Corneal and/or conjunctival surgery
o Intraocular surgery where central rotation of the globe is desirable
o Immobilization of the eyelids to enable surgery while maintaining a light plane of anesthesia
• Post-operative analgesia
o As for pre-operative
o Infiltration anesthesia following eyelid surgery
Contraindications
As with performance of all loco-regional blocks, the underlying health of the target tissues should be taken into consideration. Large scale tissue disruption (i.e. infection) will affect onset and uptake of local anesthetic drugs such that there may be an increased chance
of systemic toxicity. Central nervous system toxicity is possible with direct injection of local anesthetic into the perineural optic nerve sheath. Due to space limitations required of the lecturers, the author will focus on those blocks most commonly employed in small animal practice and readers are referred to the reference list for additional information.
Retrobulbar block (RBB): Regional anesthesia for enucleation, evisceration/prosthesis and/or intraocular surgery
Equipment
• 1.5-inch 22 gauge spinal needle bent to approximately 20 degree angle, or a retrobulbar needle
• Maximum 2 mL local anesthetic (calculate maximum dose per patient and include other local blocks being performed)
• 5 mL syringe
Technique and step by step procedure
There are now several RBB described in the small animal literature. The author is choosing to describe in detail those drops she has most clinical experience with.
1. Inferior-temporal palpebral RBB
• The lower eyelid hair may be clipped at the injection site or a transconjunctival approach employed. Routine ophthalmic surgical preparation with dilute povidone-iodine solution is performed.
• A retrotrobulbar needle can be used or a 1.5 inch 22 gauge spinal needle can be bent to an approximate 20° angle
• Use the lateral canthus and the middle of the lower eyelid as landmarks. The needle should be positioned midway between those two points, along the inferior eyelid at the level of the orbital rim
• The needle is directed along the floor of the orbit and then redirected dorsally and towards the nose to reach the apex of the orbit
• A slight popping sensation may be detected (piercing of the orbital fascia)
• The needle should then be redirected slightly dorsally and nasally toward the orbital apex
• Aspiration prior to injection is warranted and strongly recommended
• Local anesthetic is injected into the orbit
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 42ND WORLD SMALL ANIMAL VETERINARY ASSOCIATION CONGRESS AND FECAVA 23RD EUROCONGRESS
  























































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