Hematoma consists of the formation of a blood collection in tissue, following vascular damage. The execution of local anesthesia by injection techniques involves trauma, even if it is slight. The accidental involvement of some small vascular structures is considered to be a complication in the formation of a hematoma at the level of intraoral soft tissues orextended to the extraoral skin site.
This is uncommon. Sometimes the extension is greater; it is sufficient that an arterial vessel, even a small one, remains affected, as it is subject to pressure by supporting a wide effusion. It is important that the dentist manages these problems and their course well to reassure the patient (who is probably worried; it is always advisable to specify this type of complication in risky interventions) and to prevent further harmful consequences.
A preventive measure of vascular damage is the aspiration test (the main purpose of which is to avoid direct intravascular administration of the local anesthetic) and, in addition, at the end of the injection, slow removal of the needle.
The approach is linked to the phase in which the complication is recognized and, secondly, to the location in which it occurs. The latter is indicative of the vascular tract involved and, therefore, of the anesthesiological technique adopted. First of all, consider the immediate approach, which presupposes the appearance of the hematoma in real time.
The general indication is to exert a prolonged local pressure (tending to be at least two minutes) to stop bleeding. In the case of the lower alveolar nervous block procedure, the site to be pressed is the internal aspect of the mandibular nerve.
The hematoma of the infraorbital region can have a large and rapid onset. Consequently, it is worthy of particular attention, even if it is in a skin region. The correct operating technique involves direct pressure on the area of the infraorbital foramen, which acts in a preventive manner to this complication.
The deferred treatment is usually based on the wait and see approach: the patient must be warned of possible soreness with the consequent form of trismus. It is also recommended to apply cold compresses, especially during the first hours. In the case of particularly important hematomas, found in case reports in the literature, an antibiotic cover can be put in place to reduce the risk of over infection.
The hematoma normally undergoes resorption within one to two weeks. This period and, in general, the potential seriousness of the problem is linked to the clinical history of the patient, especially the elderly.