Retrograde maxillary nerve perineural injection: A tomographic and anatomical evaluation of the infraorbital canal and evaluation of needle type and size in equine cadavers.
Authors: Nannarone S, Bini G, Vuerich M, Menchetti L, Arcelli R, Angeli G
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary: Retrograde Maxillary Nerve Perineural Injection in Equine Surgery Maxillary nerve blocks are essential for orofacial surgical procedures in horses, yet conventional techniques targeting the maxillary foramen via the zygomatic arch carry considerable risk of iatrogenic injury to sensitive neurovascular structures. Nannarone and colleagues explored an alternative retrograde approach using the infraorbital foramen on 13 equine cadaveric skulls, employing computed tomography scanning and anatomical dissection to characterise the infraorbital canal's dimensions, morphology and relationship with its neurovascular contents, followed by systematic evaluation of seven different needle types for their ease of insertion, tissue trauma and contrast distribution characteristics. Their findings revealed that the infraorbital canal follows a serpentine curved pathway with anatomical gaps present between the nerve, vessels and canal walls—a configuration that protected these delicate structures when appropriately sized Tuohy needles were passed retrograde, with CT confirmation of successful anaesthetic solution spread toward the maxillary nerve without complication in the validated approach. The retrograde infraorbital technique offers farriers and veterinary surgeons a potentially safer alternative to traditional maxillary blocks for horses requiring orofacial work, provided careful attention is paid to needle selection and injection technique, thereby reducing the risk of neurovascular trauma during dental and sinus procedures.
Read the full abstract on PubMed
Practical Takeaways
- •Retrograde maxillary nerve blocks via the infraorbital foramen offer a safer alternative to traditional zygomatic arch approaches, reducing risk of injury to delicate surrounding structures during orofacial surgeries
- •Tuohy needles are the preferred choice for this technique; proper needle selection and insertion technique are critical to limiting complications
- •This approach may expand your surgical options for conditions requiring maxillary nerve anesthesia, though further clinical validation in live horses is needed before widespread adoption
Key Findings
- •Infraorbital canal has a serpentine-curved pathway with anatomical gaps between the nerve, vessels and canal wall
- •Tuohy needles successfully navigated the infraorbital canal and preserved integrity of enclosed neural and vascular structures
- •Retrograde approach via infraorbital foramen is anatomically feasible with appropriate needle selection and technique
- •Contrast medium spread verified by CT imaging confirmed successful distribution toward the maxillary nerve target area