Thanks to Drs. Webber, Orlansky, Lipton and Stevens for reviewing several case histories of intra-arterial injection complications and their management ("Complications of an Intra-Arterial Injection From an Inferior Alveolar Nerve Block," December JADA). This timely article underscores an important unintended reaction that probably occurs more often than is recognized in private practice.
As a younger practitioner in private practice for less than five years, I can attest that this has happened to me twice. However, the authors only review cases in which the reaction follows administration of local anesthetic with epinephrine after inferior alveolar nerve block.
Both cases in my practice involved administration of 1.8 milliliters of lidocaine with 1:100,000 epinephrine, and following careful aspiration for posterior superior alveolar, or PSA, blocks prior to maxillary molar restorations and root canal therapy. These cases involved a man and a woman with unremarkable medical histories and no known drug allergies.
After ruling out syncope, angina, acute asthma, hyperventilation or hypoglycemia, the conclusion was that the patients had suffered an intra-arterial injection. The clinical signs and symptoms suggested that this was the case, with both patients describing a burning sensation and tearing of the ipsilateral eye and infraorbital region.
The palpebral and forehead areas were not involved, ptosis did not occur, vision was normal and oculomotor disturbances were not noted with these patients. There was a slight blanching involving the infraorbital region of the face extending inferiorly to the nasolabial region on the same side. The palatal mucosa exhibited blanching and numbness. These reactions occurred within 60 seconds of the first dose administered.
I can only infer that the PSA artery was involved and the anesthetic traveled to the infraorbital branch of the internal maxillary artery. In both patients, blanching resolved after 10 minutes and tearing stopped within five minutes of injection.
I hope that my experience with these two patients reveals that these reactions can and do occur with any branch of the internal maxillary artery without necessarily involving the middle meningeal artery and its distal branches, the lacrimal and ophthalmic artery.
It also underscores the importance of careful aspiration following the injection and not just following an inferior alveolar nerve block. The tearing reported by the patients may have been a reaction to the burning sensation reported and not necessarily involvement of the lacrimal branch of the distribution of the internal maxillary artery. In both cases, the patients were reassured and continued treatment without further complications.
