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Caudal Mandibular Regional Blocks

For additional information on other dental nerve block techniques, see the 2019 AAHA Dental Care Guidelines for Dogs and Cats.

Intraoral approach:

Extraoral approach:

Caudal mandibular (inferior alveolar) regional blocks 

INDICATIONS: Dental and orofacial surgery on the mandible (i.e., dental extractions, mass removals, fracture repair, etc.) This desensitizes all tissues to midline on the ipsilateral side. 

INSTRUCTIONS:

 1.  Select and calculate the full dose of a local anesthetic, i.e., lidocaine (cats = 2–4 mg/kg, dogs = 4–6 mg/kg), bupivacaine (cats = 1 mg/kg, dogs = 2 mg/kg), or ropivacaine (cats = 1 mg/kg, dogs = 2 mg/kg).*

 2.  Prior to the procedure or extraction is performed, choose intraoral vs. extraoral approach, based on clinical indication, and personal preference.

3. The mandibular foramen or nerve can often be palpated on the lingual side of the mandible, just rostral to the angle of the mandible and just caudal to the last molar in approximately the middle 1/3rd of the mandible (as measured from dorsal to ventral). NOTE: The foramen is often difficult to palpate in very small patients like cats and small dogs.

  • Intraoral:
    • With the mouth temporarily propped open, insert the needle through the gingiva at the distal and lingual aspect of the last molar. 
  • Extraoral:
    • Pass the needle through the skin along the medial aspect of the mandible to a point where the tip of the needle is at the site of the foramen (again, aiming for a site just caudal to the last molar on the lingual side of the mandible).
      • Place a finger in the oral cavity with the tip of your finger at the landmarks described for the injection site. This is done so that the needle can be felt as it is inserted under the gingiva and to insure that it is not accidentally passed through the gingiva (in which case the drug would be squirted into the oral cavity instead of being injected over the nerve). Inject when the tip of the needle is correctly placed under the gingiva.

      3. Aim the tip of the needle towards the foramen or towards the foramen landmarks. The foramen cannot be entered so the drug is merely infused under the gingiva at the site of the nerve. Aspirate to assess whether the needle is in a vessel. 

      4. Inject the local anesthetic (0.1 - 1.5ml) uni- or bilaterally, staying below the total recommended dose, and apply pressure to the injection site to allow diffusion within the tissues.

      5. Recover the patient in sternal recumbency to decrease the risks of patients biting their tongues if the lingual branch is anesthetized. 

      *Although bupivacaine or ropivacaine provide a longer duration than lidocaine, some clinicians are more comfortable with lidocaine because it has a higher safety margin if accidentally injected IV. Thus, personal comfort with the drugs dictates final drug choice for this block.

      If blood is aspirated and bupivicaine is the local anesthetic selected by the clinician, withdraw the needle, change the needle, and reposition. Once in the new location, aspirate again. If blood is noted again, distinguish between whether the needle is in an vessel vs. aspirating a small amount of blood from the previous injection.

      Artwork by Lauren D. Sawchyn, DVM, CMI.

      These guidelines are supported by generous educational grants from IDEXX Laboratories, Inc., Midmark, and Zoetis Petcare.