INTRODUCTION

Inadvertent intra-arterial injection of local anesthesia in maxillofacial region has subjective and objective symptoms: dizziness, light-headedness, palpitation, vision alternation, diplopia, burning sensation, and facial blanching.[123] Most of these complications are reported during inferior alveolar nerve block, but they can occur in every intraoral injection, when the local anesthesia is injected into the lumen of artery.[45] The blanching follows certain principles:

1. Terminal branches of maxillary artery are affected.[6]

2. It is reversible end-organ phenomenon.[7]

3. Sympathetic vasospasm is the accepted theory for this phenomenon.[8]

4. Facial blanching occurs in the distribution of infraorbital artery.[9]

CASE PRESENTATION

Case 1

The patient was a 28-year-old woman without any systemic disease. She attended for the removal of mandibular right wisdom tooth. On the basis of palpitation report, plain mepivacaine had been used. Gow-Gates injection was used for this purpose, and immediately after injection, blanching occurred in the infraorbital, buccal, and palatal regions [Figure 1].

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Figure 1

Facial, buccal, and palatal blanching after Gow-Gates injection

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Case 2

The patient was a 25-year-old man and ASA class I [Figure 2]. Mandibular inferior alveolar nerve block (Halsted’s technique) and long buccal nerve were used for dental implant insertion in the mandibular right quadrant. Facial blanching and palatal–buccal mucosa whitening occurred.

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Figure 2

Facial blanching and palatal whitening after inferior alveolar nerve block injection

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Case 3

The patient was a 63-year-old man who attended for right maxillary sinus lift procedure. On the basis of previous heart problems, epinephrine was not used in the local anesthetic cartridge. Maxillary block injection from greater palatine canal approach was used for obtaining profound anesthesia. Facial and palatal blanching occurred immediately after the injection, and the patient felt burning and itching sensation on the face [Figure 3].

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Figure 3

(A) Facial blanching and (B) palatal ischemia after maxillary nerve block via greater palatine canal

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Case 4

The patient was a 22-year-old woman who referred for mandibular right wisdom tooth removal. Lidocaine 2% and epinephrine 1:80,000 were used for inferior alveolar nerve block. Facial, buccal, and palatal blanching occurred on the side of injection. She felt numbness in the periorbital and lower lip. The color of the face returned to preinjection condition after 10minutes [Figure 4].

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Figure 4

(A) Facial blanching immediately after inferior alveolar nerve block injection and (B) 10 minutes later

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Case 5

A 32-year-old female patient in healthy conditions attended for extraction of second maxillary right premolar. Immediately after buccal infiltration, a white patch appeared lateral to the nasolabial fold [Figure 5].

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Figure 5

Partial blanching of the face subsequent to buccal infiltration for extraction of maxillary second premolar

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DISCUSSION

Intra-arterial injection of local anesthesia in dentistry occurs most commonly in inferior alveolar nerve block injection.[10] In this article, five cases have been reported, where in two cases, other injections caused reversible facial–mucosal blanching. Other causes of facial blanching include neurotoxin (botulinum toxin) injection, intravascular injection of cosmetic fillers, and superpotent topical corticosteroids.[111213]

In oral cavity, every artery is at the risk of intra-arterial injection. Maxillary artery (proximal segment) is penetrated in Gow-Gates injection, especially if the loop variant of proximal segment is present.[14] Greater palatine artery injection was the reason for facial and palatal blanching in the third case [Figure 6].

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Figure 6

Diagram of maxillary artery and its branches, sympathetic nerve, and facial blanching in infraorbital area (PSA, Posterior Superior Alveolar artery; ASA, Anterior Superior Alveolar artery)

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Lower frequency of administering maxillary nerve block and inherent low incidence of positive aspiration in Gow-Gates conduction nerve block are the reasons for low reported facial blanching after these injections.[1516]

Vasoconstrictors are not necessary for facial blanching. In two cases (1 and 3), plain mepivacaine had been used.

Mucosal blanching occurs in the distribution of buccal, greater palatine, and soft tissue posterior superior alveolar artery but not in the arterial distribution of inferior alveolar artery. Inferior alveolar artery terminates to the mental artery and nourishes the lower lip chin and alveolar mucosa.[17] Anastomosing branches between submental and inferior alveolar artery within the mandible may compensate for the hypoxic effect of inferior alveolar artery spasm. Thus, lower lip blanching did not occur in the case where maxillary artery proximal segment or inferior alveolar artery was penetrated.[18] The size of the blanching area on the face depends on the presence and percentage of infraorbital artery terminal branches (zygomaticomalar, nasal, and superior vestibular arteries). Existence of anastomosis with angular and transverse facial arteries is the other important factor.[1920]

In PubMed search for local anesthesia and blanching, the majority of reported cases were young individuals. In our report, 1 of 5 cases had an age past the third decade of life. This may be attributed to the impaired sympathetic control of the peripheral cutaneous vascular system.[21]

Facial blanching is not always accompanied by positive aspiration. This and the fact that local anesthesia failure was not observed in reported cases in this article suggest that the contact of the needle with the perivascular sympathetic plexus or bypass of the artery by the needle is sufficient for triggering facial blanching. In the case of positive aspiration in the inferior alveolar nerve block and numbness in skin pallor area, other theories should be considered.

With selection of local anesthetic techniques in less vascular regions, risk of this complication can be reduced.

Cutaneous surgeon should be aware of this complication of local anesthesia because this phenomenon also occurs after extraoral injection of local anesthesia. Transient nature of facial blanching after local anesthesia injection differentiates it from facial blanching after injection of cosmetic fillers. The latter needs prompt treatment with hyaluronidase, topical nitro pastes, and warm compress.[22]

Anxiety for the patient and physician and unnecessary treatments may occur if the surgeon is not familiar with this complication.

CONCLUSION

Periorbital and palatal whitening is the constant feature of the blanching subsequent to inadvertent arterial penetration in intraoral local anesthetic block techniques. Mucosal blanching in the distribution of buccal artery occurs in Gow-Gates mandibular nerve block as well as inferior alveolar nerve block injections.