Evaluation of the Rostral Inferior Alveolar Nerve Block via the Mental Foramen in Equids: In Vivo Efficacy Testing.

The study tests the effectiveness of the rostral inferior alveolar nerve block (a type of anesthesia) delivered through the mental foramen (a hole in the jaw bone that allows nerves and blood vessels to pass) as sedation in horses during dental procedures. The study also examines if this type of anesthesia is more effective in any particular area of the mouth and if there’s a difference in effectiveness between applying the anesthesia to one or both sides of the mouth.

Methodology

• The researchers carried out a blind trial involving 10 horses.
• The horses were randomly assigned to receive either a left unilateral block, a right unilateral block, a bilateral block (anesthesia applied to both sides), or they acted as a control group.
• For the horses receiving unilateral blocks, the side of the mouth that didn’t receive anesthesia served as a control.
• The researchers applied a mechanical nociceptive (painful) stimulus to the horses’ mouths to check their response before sedation, after sedation, and then post-injection at 10, 30, 60 and 90 minutes.
• The results were assessed in four groups: unilateral blocks, unilateral controls, bilateral blocks, and bilateral controls.

Findings

• All test groups were notably less responsive to the painful stimulus after sedation, and at 10 and 30 minutes post-sedation.
• However, at the 60- and 90-minute marks, only the sites that had been blocked (received the anesthesia) were still less responsive to the stimulus compared to before sedation.
• The researchers did not observe any significant difference in the response to the stimulus between the three regions of the mouth at any time.
• Overall, though, the blocks were only successful in producing regional anesthesia in 73% of the sites at the 60-minute mark, and in 55% of the sites at the 90-minute mark.

Conclusion

• The study demonstrated that the rostral inferior alveolar nerve block has varied effectiveness when administered via the mental foramen in horses during dental procedures.
• In some instances, it only resulted in partial or incomplete anesthesia, which suggests that this technique may not fully numb the targeted area in all circumstances.