Local complications of local anesthesia

Muscular and vascular complications

If the needle is inserted medially to the pterygomandibular raphe during mandibular anesthesia, injury to the medial pterygoid muscle is possible. This leads to the development of mandibular contracture—limitation of mouth opening, the treatment of which requires prolonged physical and mechanical therapy, as well as pyrogenal injections. In addition, misadministration of the anesthetic causes numbness of the pharyngeal tissues.

Vascular complications include trauma to blood vessels by the needle, causing hemorrhages and the formation of hematomas. The anesthetic solution may also enter the bloodstream directly. Ischemia zones occasionally appear on the skin of the chin and lower lip.

Neurological complications

Injury to a nerve trunk (e.g., lingual, inferior alveolar, or mental nerve) by the tip of the injection needle leads to the development of neuritis. Physical therapy procedures (galvanization, diathermy) are used as treatment.

A rare complication is facial nerve palsy, which occurs as a result of unintended blockade of the facial nerve branches.

Injection needle fracture

Needle breakage usually occurs at its most vulnerable point—at the junction of the metal shaft and the hub.

Causes of fracture:

• sudden change in syringe position with a deeply inserted needle;
• insertion of the needle into the space between muscle and bone tissue;
• penetration of the needle into a tendon (most commonly the temporalis muscle).

Physician tactics: If the needle fragment is completely hidden in the soft tissues, it is strictly forbidden to attempt extraction in an outpatient setting. Surgical removal is performed strictly in a maxillofacial hospital after radiographic diagnostics and only in the presence of clinical symptoms (pain at rest or during mouth opening, inflammation, contracture). If the broken needle has encapsulated and causes no discomfort to the patient, it is left in the tissues.

Complications of trunk anesthesia

Blockade of the maxillary and mandibular nerves at the skull base carries the risk of specific complications:

• penetration of the needle into the nasal cavity or auditory tube;
• mechanical trauma to the oculomotor and abducens nerves;
• diplopia (double vision);
• transient vision loss (upon infiltration of the optic nerve with a vasoconstrictor-containing anesthetic solution);
• injury to major arteries and veins of the skull base.

The primary prevention of all local complications is strict adherence to the injection technique.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Anesthesia zones for various types of local anesthesia
• Technique of mandibular anesthesia according to Lagarde and Vazirani-Akinosi
• Techniques for mental nerve anesthesia (extraoral and intraoral approaches)
• Blockade of motor branches of the mandibular nerve (Bersche and Egorov methods)
• Trunk anesthesia: approaches to the pterygopalatine fossa according to Weisblatt

Other topics in "Chapter 12. Dental Anesthesia"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.