Facial nerve palsy is a loss of function in the area innervated by the facial nerve after it exits the skull. It is also known as Bell’s palsy, facial neuritis, or peripheral facial paralysis.
The facial nerve (CN VII) is a mixed nerve. It exits the brainstem lateral to the abducens nerve (CN VI), enters the internal acoustic meatus, passes through the internal acoustic canal and the facial canal, emerges from the stylomastoid foramen, and runs forward into the parotid gland, where it divides.
It divides into several branches that interconnect to form the parotid plexus. This plexus gives off five branches: the temporal branches, zygomatic branches, buccal branches, marginal mandibular branch, and cervical branch. Each branch emerges radially from the anterior border of the parotid gland and distributes to the muscles of facial expression and the platysma.
**Etiology of Facial Paralysis** Most scholars recognize two possible causes of facial paralysis: pathological changes within the facial nerve itself, or compression and involvement of the nerve due to disorders in the surrounding tissues. In the first scenario, nutritional deficiency of the facial nerve itself, combined with invasion by Wind-Cold (Feng-Han), induces spasm of the nerve’s supplying vessels, leading to nerve ischemia, edema, and subsequent paralysis. In the second scenario, trauma or inflammation (bacterial infection, viral infection, or rheumatism) of the tissues surrounding the facial nerve causes local Blood Stasis (Yuxue), compression, and inflammatory involvement of the nerve. Facial paralysis may also result from periostitis within the stylomastoid foramen, which compresses the facial nerve or impairs its blood circulation. **Pathological Changes of Facial Paralysis** The primary pathological changes are edema and degeneration. If the condition persists and fails to respond to treatment, atrophy eventually occurs.
Key Diagnostic Points
Facial paralysis can occur at any age, but is most common in young women aged 18–25 years. It is usually unilateral with acute onset, often discovered upon waking in the morning or after a nap. The main manifestations include paralysis of the facial expression muscles on the affected side, inability to wrinkle the forehead or frown, upward and outward deviation of the eyeball, inability to close the eye (exposing the white of the eye), flattening or disappearance of the nasolabial fold on the affected side, deviation of the mouth to the healthy side (more pronounced when showing teeth, laughing, or crying), air leakage when puffing the cheeks, inability to whistle, and food easily lodging between the teeth and cheek on the affected side. Clinical symptoms vary depending on the site of facial nerve damage: if the lesion is at or below the stylomastoid foramen, only paralysis of the facial expression muscles on the affected side is seen; if the lesion is within the facial canal between the chorda tympani nerve and the nerve to the stapedius muscle, in addition to facial paralysis, there may be loss or reduction of taste on the anterior two-thirds of the tongue and dysfunction of salivary gland secretion; if the lesion is between the nerve to the stapedius muscle and the geniculate ganglion, hyperacusis may also occur; if the geniculate ganglion is involved, there may be reduction or absence of lacrimal gland secretion, and herpes zoster may appear on the external auditory canal, the lateral surface of the auricle, and behind the ear; if the lesion is in the internal auditory canal or the cerebellopontine angle, it is often accompanied by auditory nerve damage, as well as disturbances in lacrimal and salivary gland secretion and taste on the anterior two-thirds of the tongue due to involvement of the nervus intermedius.
【Treatment】
I. Acupoints and Needling Techniques
1. **Taiyang (EX-HN5) (affected side):** Located in the temporal region, in the depression approximately one finger-breadth posterior to the midpoint between the lateral end of the eyebrow and the outer canthus. Use two sterile filiform needles of size 30 gauge and 2.5 cun. After routine local disinfection, insert one needle toward GB8 (Shuaigu) with a penetrating puncture of approximately 2.2 cun. Insert the other needle from below the zygomatic arch to penetrate toward ST6 (Jiache). Needle sensation: distension and pain in the temporal area and cheek area.
2. Qianzheng (Extra point, affected side): Located 0.5 cun anterior to the earlobe, level with the midpoint of the earlobe. Use a 30-gauge, 2-cun filiform needle. After routine local disinfection, insert obliquely toward the tip of the nose to a depth of approximately 1.8 cun. Sensation: local distension and pain.
3. ST4 (Dicang) (affected side): Located at the intersection point of the horizontal lateral extension of the mouth corner and the extension line of the nasolabial groove. Using a 30-gauge, 2-cun filiform needle, perform routine local disinfection, then insert obliquely toward ST6 (Jiache) to a depth of approximately 1.8 cun. Needling sensation: local distension and pain.
II. Methods
Acupuncture is performed on the affected side with the patient in a sitting position. The above points are inserted according to the method, and electrical stimulation is applied for 1 hour before needle removal. Treatment is given once daily. Ten sessions constitute one course of treatment, followed by a 3-day rest before the next course.
【Commentary】
The clinical diagnosis of facial nerve paralysis is not difficult, but it is easily confused with central facial palsy. However, the acupuncture treatment methods for central facial palsy and peripheral facial palsy are completely different. The main differentiating points are as follows:
(1) Central facial palsy is caused by disorders of the central nervous system and is often accompanied by hemiparalysis of the upper and lower limbs and tongue paralysis, while the facial paralysis is limited to the muscles below the orbital region.
(2) Peripheral facial paralysis is caused by paralysis of the facial nerve itself, with the paralysis limited only to the facial muscles and not accompanied by paralysis of the limbs or tongue muscles.
The diagnosis and treatment of central facial paralysis can be referenced in the relevant chapters.
Electroacupuncture is particularly effective for treating simple facial nerve palsy without tumor compression or suppurative mastoiditis. This therapy is superior to other treatments (Chinese herbal medicine, Western medicine). The optimal time to initiate treatment is to start acupuncture within five days of onset. For patients whose condition has been delayed beyond three and a half months, the response to the aforementioned electroacupuncture treatment is slow and less satisfactory, though it still provides some benefit. For patients with secondary lesions, the secondary lesions should be resolved first while concurrently applying electroacupuncture; this approach consistently yields satisfactory results.