The inferior alveolar nerve block is a Mandibular nerve block given to anesthetize the Mandibular teeth, due to its proximity to other Nerves and muscles and salivary glands it has many complications if the technique in which it is given is wrong. Here we have mentioned the most common to some of the rarest complications which have arisen due to an improper technique of Inferior Alveolar Nerve block. 

Complication Specific to Inferior Alveolar Nerve Block: 

Undesirable Never Block: Due to the proximity of the Inferior alveolar nerve block needle position to the facial nerve and the Parotid through which it passes is the result of this complication where we can see the characteristic complications when the Facial nerve is anesthetized:

Transient Hemifacial Paralysis: In this, we can see from the image below that the muscles being supplied by that side of the facial nerve is affected and cannot contract, and this results in loss of muscle action of the affected side of the face.

  • Where the eyelids cannot be closed by the patient
  • Loss of maintaining of lips position on the affected side and drooping of the lips on the affected side is seen in the image below.

Inferior alveolar nerve complications

How to manage Transient Hemifacial Paralysis due to the complication of Inferior alveolar nerve block

  1. If this condition is ever encountered be calm and explain the patient about the problem which has occurred and assure him/her that it is temporary and will be back to normal in 3 hours after the effect of local anesthesia is gone.
  2. Prescribe any Lubricating Eye drops and ask the attendant or the patient to keep putting 2 drops for every 15 mins on the affected eye to keep the eyes wet as the eyelids cannot be closed due to paralysis of the facial nerve.
  3. Ask the patient to use a clean cloth to keep over the eye to prevent dust from entering the open eye.
  4. Lastly, ask the patient to stay in the clinic for 3 hours if possible to monitor the condition after the effect of local anesthesia wears off.

The General Complications of Inferior Alveolar Nerve Block which is common with other nerve blocks:

  1. Muscle Trismus: It is due to muscle spasm which is caused when the injection is given into the Medial Pterygoid muscle causing tearing of the muscle fibers. It is called as Medial Pterygoid Trismus or Myospasm. The onset of Muscle trismus in inferior alveolar nerve block is after 24 hours of the injection and it resolves by itself without any treatment. In some cases, anti-inflammatory drugs and muscle relaxants might be required. 
  2. Hematoma: It is also caused when there is an accidental injection to the Blood vessel which in turn leads to Hematoma formation.
  3. Mucosal Irritation: The Irritation of the Mucosal tissue can be either due to allergic reaction to the needle itself or the anesthetic agent. 
  4. Infection: 
  5. Needle Breakage: If care is not taken in maintaining the proper position of the needle or excess force is applied, there have been instances of needle breakage during IAN block. 
  6. Numbness of Auricle or Ear Lobe: This is a very rare complication which has been reported where the patient has experienced numbness of the auricle on the side of Inferior Alveolar injection which lasted for an hour. This is seen due to the accidental anesthetic injection to the auriculotemporal nerve resulting in numbness. 

Click here for: List of Complications due to Nerve Block