Facial Nerve Palsy

Understanding Facial Nerve Palsy (Bell's Palsy)

Facial Nerve Palsy, commonly known as Bell’s Palsy, is a sudden condition characterized by the paralysis or weakness of one side of the face due to the improper functioning of the facial nerve. While approximately 80% of patients experience symptom resolution within a short period, those with long-term effects may face challenges in everyday activities such as closing their eyes and smiling.

Course of the Facial Nerve

The facial nerve that controls facial muscles passes through a narrow corridor of bone under the ear on its way to the face.

Bell's Palsy and Its Causes

Bell’s Palsy is often related to viral infections that cause inflammation and swelling of the facial nerve. The exact cause is frequently unknown, but potential factors include:

• Shingles and infections like Herpes.
• Lyme disease.
• Facial trauma.
• Cold sores.
• Infectious Mononucleosis.
• Cytomegalovirus Infections.
• Respiratory illnesses.
• Mumps.
• Flu.

Symptoms of Facial Nerve Palsy

Symptoms of Facial Nerve Palsy include:

• Sudden onset of mild weakness to total paralysis on one side of the face within hours to days.
• Drooping of facial musculature and an asymmetrical smile.
• Drooping of the eyebrow leads to an inability to close the eye completely.
• Collapse of nasal sidewalls, causing difficulty in breathing.
• Excessive drooling of saliva.
• Increased sensitivity to sound on the affected side.
• Loss of taste.
• Changes in the amount of tears and saliva produced.
• Vision obstruction.

People at Risk for Facial Nerve Palsy

Certain groups of people are more susceptible to facial nerve palsy, including:

• Pregnant women, particularly during the 3rd trimester or the 1st week postpartum.
• Individuals with respiratory diseases like flu or cold.
• Diabetic and cardiac patients.
• Obese patients.

Complications Associated with Facial Nerve Palsy

Complications of facial nerve palsy can include:

• Irreversible damage to the facial nerve.
• Irregular regrowth of nerve fibers leads to involuntary muscle contractions when attempting to move other muscles (synkinesis).
• Partial or complete blindness of the eye due to excessive dryness and scratching of the clear protective covering (cornea).

Reconstruction for Facial Palsy

Reconstruction techniques can be employed to address facial palsy, including:

Treatment at an early stage:

It includes the following procedures:

Direct Facial Nerve Repair with or without Grafting : This method is suitable when the facial nerve is damaged. A nerve graft is used to bridge the gap between the cut ends of the nerve. Typically, the sural nerve from the calf is used as a nerve graft.

Cross-Facial Nerve Grafts : In cases where one side of the face is affected, a nerve graft is used to connect unaffected facial nerve branches from the healthy side of the face to the paralyzed side. Nerve fibres grow across the graft, restoring function to the paralyzed muscles over time.

Nerve Transfers : When both sides of the face are affected, nearby nerves can be used as a source for facial muscle innervation. The masseteric nerve is often used for this purpose. It does not require the use of a nerve graft.

Nerve Transfer Surgery for Facial Palsy

Nerve transfer surgery for facial palsy involves rerouting nerves to restore facial movement. This procedure is used to address asymmetrical smiles resulting from Bell’s Palsy. The surgery is similar to a facelift, with incisions made in the hairline and along the ear. Key steps include identifying specific facial nerve branches responsible for smiling and connecting them to the masseteric branch of cranial nerve 5. Patients typically experience improved smiles within 4 to 6 months as the nerves heal.

Treatment at Late Stage

Late-stage treatment is considered for patients who have experienced facial palsy for more than 12 to 24 months. In such cases, original muscles may no longer accept nerve connections and alternative muscles must be used.

1. Static Reconstruction :

This type of reconstruction provides support to the muscles but doesn’t help in movement.

• a) Slings are constructed from other regions of the body, like fascia from the thigh, forearm, or temple, or from surgical products.
• b) Gold weight insertion for eyelid closure.

2. Dynamic Reconstruction :

This technique provides movement in the paralyzed muscles.

• 1. Regional Muscle Transfers- Functioning muscles like temporalis on the paralyzed side of the face (innervated by the trigeminal nerve) can partially be transferred to provide movement for the face.
• 2. Free Functional Muscle Transfers- With the help of microsurgical/microvascular advanced surgeries gracilis muscle from the inner thighs is transferred with its blood vessels & nerve. This muscle is positioned such that after 4 to 9 months approximately the muscle can contract giving a smile-like movement to the corner of the mouth & upper lip .

Consultation with a specialist, such as Dr. Amit Agarwal , is essential to determine the most appropriate treatment approach based on the individual’s specific condition and needs.