Mastering the Maxillary Nerve Block in Equine Dentistry

The maxillary nerve block is an essential technique for veterinarians performing standing dental surgeries on horses, especially extractions. Developed over 16 years ago by Dr. Bernie Fletcher, this technique has revolutionized the way veterinarians manage pain during these procedures. Here, we'll explore how to perform the maxillary nerve block effectively and safely.

Understanding the Maxillary Nerve Block

Before Dr. Fletcher's work, equine dentists struggled with sedation alone, as it often wasn't sufficient to keep horses still during procedures. The upper first molar, known for its challenging extraction, is frequently targeted with this nerve block. The aim is to numb the maxillary nerve to ensure the horse remains comfortable and calm throughout the surgery.

Key Anatomical Landmarks

To perform the block, it's crucial to identify the correct anatomical landmarks:

1. Frontal Bone and Nasal Bone: Draw a line connecting these two bones.

2. Lateral Canthus of the Eye: From this point, draw a perpendicular line (90 degrees) to the previous line.

3. Facial Crest: The needle insertion point is just below the facial crest, directed toward the maxillary foramen.

The needle must reach the maxillary nerve as it enters the infraorbital canal, ensuring effective anesthesia.

Performing the Procedure

Preparation

• Sterile Technique: Use a new bottle of anesthetic, sterile gloves, and perform a thorough scrub to avoid complications like septic meningitis.

• Horse Positioning: Keep the horse’s head elevated during preparation to minimize the risk of blood vessel distension and hematoma formation.

Injection Technique

1. Equipment: Use a 3.5-inch, 22-gauge spinal needle. This size reduces the risk of creating larger puncture wounds if you accidentally hit a blood vessel.

2. Visualizing the Injection Site: Brace your hands to stabilize your technique and minimize the risk of injury.

3. Needle Insertion: Insert the needle quickly until you hit bone, then withdraw slightly to inject the anesthetic (typically 8-12 ml of lidocaine).

4. Aspirate: If you encounter a flashback of blood, pull back slightly and ensure you’re not in a vessel before proceeding with the injection.

Aftercare

Following the injection, apply firm pressure to the injection site for about five minutes to minimize swelling and potential complications. It’s common for the horse to exhibit minor swelling, but proper technique will prevent significant issues.

Common Complications and Considerations

While complications are rare, they can occur. The most common issues include:

• Hematomas: These can develop if blood vessels are inadvertently punctured. Typically, they resolve quickly if pressure is applied.

• Corneal Ulcers: Some horses may rub their eyes post-procedure. While superficial, these ulcers usually heal rapidly with appropriate treatment.

Veterinarians should focus on technique and efficiency to minimize the likelihood of complications. The maxillary nerve block, when performed correctly, is safe, effective, and crucial for pain management in equine dental procedures.

Conclusion

With thousands of successful maxillary nerve blocks performed, the technique has proven to be an invaluable tool in equine dentistry. By mastering this procedure, veterinarians can enhance their practice, ensuring horses remain comfortable during necessary dental surgeries. As always, confidence and proper technique are key to delivering optimal care in veterinary practice.