Development of a retrobulbar injection technique for ocular surgery and analgesia in dogs

Abstract

In dogs, retrobulbar administration of anesthetic agents via the ITP technique is a potential alternative to systemic administration of neuromuscular blocking agents for ophthalmic surgery and provides the additional benefit of local ocular analgesia.

A comparison of retrobulbar and two peribulbar regional anesthetic techniques in dog cadavers

“…It has been proposed that in dogs the RB injection provides better distribution into the orbital muscle cone than does PB injection (Accola et al 2006). However, in that study, the injectate volume for both techniques was 2 mL, whereas in humans the volume used for PB anesthesia is 2e4 times that used for RB anesthesia (Nouvellon et al 2010).…”

“…These were deemed unsuccessful, and were omitted from further investigation. In comparison with findings in dogs by Accola et al (2006), distribution of 6 mL of colored latex within the EOMC following PB injections was considered excellent in 10 orbits of human cadavers (Ripart et al 2001). Likewise, CT evidence in cats suggested that PB injection of 4 mL bupivacaine combined with a contrast agent achieved excellent intraconal delivery in 11 out of 13 cat cadaver orbits (Shilo-Benjamini et al 2013).…”

“…The first report of PB injectate distribution in dogs used four cadaver orbits each injected with 2 mL of latex material divided between two injection locations (1 mL per location): dorsal (superior) and ventral (inferior) (Accola et al 2006). These were deemed unsuccessful, and were omitted from further investigation.…”

“…The RB injections were performed using a technique similar to that described by Accola et al (2006). A 22 gauge, 8.9 cm spinal needle (Shanghai KDL Co. Ltd, Shanghai, China) was bent at the proximal end to achieve an angle of approximately 20 .…”

“…However, in that study, the injectate volume for both techniques was 2 mL, whereas in humans the volume used for PB anesthesia is 2e4 times that used for RB anesthesia (Nouvellon et al 2010). Therefore, the goals of the present study were to develop a reliable method for PB injectate delivery, to describe potential complications of two PB injection techniques and to compare, in dog cadavers, the injectate volume of distribution achieved using these two PB techniques versus the distribution achieved using the more commonly used RB injection technique (Accola et al 2006;Giuliano 2008;Hazra et al 2008;Myrna et al 2010). Our hypothesis was that the distribution of injectate produced by PB and RB techniques would be similar.…”