Chronic Facial Paralysis
Stanford Facial Nerve Center
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What is Chronic Facial Paralysis?
Facial paralysis is the loss of facial muscle movement due to a weakened or damaged facial nerve, usually occurring on one side of a patient’s face. Causes of facial paralysis that require surgical treatment include trauma, tumor, complication from surgery, among other causes.
Diagnosis of chronic facial paralysis is performed by a clinician. This may include electrodiagnostic testing, if the injury is recent and the prognosis for nerve recovery is unknown.
Facial Paralysis may be treated through a variety of surgical approaches. All techniques, however, share a common goal: to restore facial symmetry, improve essential functions of the face (such as speech and drinking liquids).
Nerve Transfer Surgery for Facial Paralysis
In cases of facial nerve paralysis that have lasted, in general, 1.5 years or less, a nearby motor nerve can be connected to a portion of the facial nerve in order to restore movement. Please see detailed descriptions of each procedure with Before and After results in the “Reanimation Surgery” section.
Nerve to Masseter Transfer
One of the most common nerve transfer procedures is called the nerve to masseter transfer . This involves the use of the nerve to the masseter muscle as a donor nerve to supply input to the paralyzed facial nerve in order to restore a patient’s smile. Facelift-type incisions are used to access both the nerve to masseter and the main trunk of the facial nerve. The branch of the facial nerve that commonly produces a smile, the buccal branch, is carefully divided and connected to the masseteric nerve. The nerve to masseter is then connected to the facial nerve, thereby providing nerve input to the paralyzed facial nerve. After 6 months, patients will be able to initiate facial movement by biting down (activating the masseteric nerve).
Patients usually stay in the hospital for one or two days following this procedure. This is a relatively reliable method to restore movement to the corner of the mouth. In order to simultaneously provide better resting symmetry to the face, a Fascia Lata Sling or Hypoglossal nerve transfer may be performed simultaneously (see below).
Hypoglossal Nerve Transfer
In order to restore resting symmetry or “tone” to the face, the hypoglossal nerve may be used as a donor nerve to resupply the injured facial nerve. The hypoglossal nerve assists with movement of the tongue. Due to the importance of tongue movement to speech and swallowing, the hypoglossal nerve is not cut completely, but is instead partially cut to allow nerves to grow into the facial nerve without sacrifice of the entire hypoglossal nerve. This typically preserves normal tongue mobility.
Dual Nerve Transfer
The main advantage of the nerve to masseter transfer is that it can restore impressive movement to the corner of the mouth. Its main weakness is that it does not provide sufficient resting tone or symmetry at rest. By contrast, the advantage of the hypoglossal nerve transfer is that it restores symmetry at rest, but movement or smile is extremely limited. Taking advantage of these strengths and limitations, the two nerve transfers may be combined together in one surgery to provide both smile reanimation and restoration of tone. In the combined hypoglossal nerve and nerve to masseter transfer, both the hypoglossal nerve and the nerve to masseter are employed simultaneously.
Gracilis Free Muscle Transfer for Chronic Facial Paralysis
The gracilis muscle transplant procedure has the ability to restore moving, functional muscle to the face. This is particularly useful in cases of long-standing facial paralysis or paresis (weakness). The procedure involves harvest of muscle from the inner thigh through a surgical incision. The gracilis muscle is detached, along with its blood vessels and nerve. The muscle is then transplanted to the paralyzed side of the face and connected to a nerve and blood vessel in the face.
Once the gracilis muscle is transplanted to the paralyzed side of the face, it must be connected to a new nerve, so that it can move the paralyzed side of the face. The gracilis muscle may be connected to the nerve to master (which is normally used for biting/chewing), to a cross-facial nerve graft harvested from the leg, or to both nerves simultaneously. These options are decided based on a discussion between the surgeon the patient. In general, the gracilis may be performed in a single surgery if connected to the masseteric nerve, or in two surgeries if connected to a cross facial nerve graft. Patients usually stay in the hospital for approximately three or four days after this surgery. The advantage of the gracilis free tissue transfer surgery is that it can, if successful, restore movement to the corner of the mouth in any patient with facial paralysis, regardless of the duration of paralysis. Nerve transfers, discussed above, are typically used only within 1-2 years from the onset of paralysis. A gracilis free muscle transfer can be used even many years after the onset of paralysis or weakness. In the case of facial weakness with some movement, but no smile, the gracilis free muscle transfer is an effective way to restore smile but also preserve whatever function is left.
Static Sling (Facelift and Sling to Support the Corner of the Mouth)
The most time-tested treatment for facial paralysis involves a facelift on the paralyzed side of the face, combined with a soft tissue from the leg that is used to hold up the corner of the mouth. In this procedure, tissue from the leg (fascia) is removed from the thigh through a surgical incision. Fascia is a form of connective tissue that wraps our muscles in a fibrous sheath. Using a facelift incision, this tissue is then attached to the muscles at the corner of the mouth and used to lift it into symmetric position. This provides relatively quick improvement in facial symmetry, speech, and helps keep food in the mouth.
Temporalis Tendon Transfer and Lengthening Temporalis Myoplasty
The temporalis muscle is situated on the side of the head, and is one of four major muscles used for chewing. It attaches to the jaw bone (mandible), and helps to close the jaw when chewing. The muscle, and its bony attachment, can be cut through a skin incision that is placed in a natural skin crease between the lip and cheek. The tendon and bone are then attached to the muscles at the corner of the mouth. This results in the corner of the mouth being pulled upwards in a more symmetric position. This procedure provides a very long-lasting suspension of the face, and immediately results in improved symmetry at rest, and often improves speech and eating. There is mild to moderate discomfort in the jaw after this procedure, but this improves with time. This is also a relatively quick procedure that can last for years.
Cross Facial Nerve Graft
In some cases of facial nerve injury, a nerve graft is obtained from the lower leg. This is a sensory nerve that gives sensation to the outside of the calf and outer portion of the foot. Using this nerve causes numbness in these areas. The nerve graft can then be connected to the non-paralyzed side of the face, providing nerve supply to the paralyzed side of the face. Due to the length of these grafts, they may not provide a reliable source of nerve supply and are used only in select cases or in certain situations.
Some patients with facial weakness may benefit from a facelift (rhytidectomy) on the side of their facial paralysis. The goal of this facelift, as in all facelifts, is the elevation of redundant and drooping soft tissue near the jawline and neckline. This is not a facial reanimation surgery, but can improve resting symmetry and have a pleasing effect on the appearance of the face. Facial incisions for a facelift are shown below.
The deep tissue of the face that is often repositioned in a facelift is called the superficial superficial muscular aponeurotic system (SMAS). The SMAS is released and repositioned, in a manner called a “SMAS flap facelift” which is a well-established technique 2. The SMAS flap facelift may be combined with other procedures.
 Pepper, J.-P. and S. R. Baker (2011). "SMAS flap rhytidectomy." Arch Facial Plast Surg 13(2): 108-108.