ASA Nerve Block Technique
What it numbs:
The anterior superior alveolar nerve block (ASA) also known as the infraorbital nerve block. Provides pulpal anesthesia to the maxillary anterior teeth on the side injected, the central and lateral incisors, and canine. In addition to the buccal soft tissue and bone the skin of the lower eye lid, the lateral side of the nose and the upper lip may all be anesthetized.
A 27 – gauge short for children or small adults or a 25-gauge long needle is recommended.
Patient position is supine or semi supine.
For the right ASA nerve block and right handed operator, sit at a 10 o’clock position facing the patient.
For the left ASA nerve block and right handed operator, sit at a 8 or 9 o’clock position facing the patient.
The landmarks are the infraorbital foramen, the mucobuccal fold , the apex of the canine and the canine eminence.
The target area and injection site is located at the height of the buccal fold adjacent to the maxillary first premolar, above the apex of the maxillary canine parallel with the canine eminence.
The bevel of the needle should be toward the bone and inserted until the bone is contacted at the roof of the infraorbital foramen.
Aspirate, if after two negative aspirations slowly inject 1/2 to 2/3of the cartridge over 30-40 seconds.
Observe patient after injection.
Document in patient record, what injection you gave, who gave it, what kind of anesthetic, how much anethetic, negative aspiration, no complications, ect.
Giving local anesthetic to patient requires the knowledge of anatomy of the skull, Head and neck nerves and tissues. There are many variations of anatomy among patients. To increase the success and reliability of administering local anesthetic you need to learn to rely on the visualization and palpation of landmarks and tissues while injecting.
For more information and references:
Handbook of Local Anesthesia by Stanley F. Malamed