What is a temporalis muscle transfer?
The temporalis muscle is a broad, flat muscle that originates on the side of the skull and passes its tendon down to the lower jaw (mandible), allowing it to close forcefully. It is one of the muscles using in biting and chewing. It is supplied by the fifth cranial nerve (trigeminal nerve), and is, therefore, unaffected in facial nerve palsy. The biting function allows for two unique advantages in the setting of facial paralysis. First, there are four muscles that are responsible for biting. This gives us a redundant system whereby one of the muscles can be used as donor for other functions without affecting the ability to bite normally. Second, biting is an analogous function to smiling. In other words, to a certain degree, when a person wants to smile, there is an element of biting or jaw closure that occurs. This is very important in planning smile reanimation.
The lengthening temporalis myoplasty (or, temporalis muscle transfer) is one option available in dynamic smile reanimation. This procedure is not to be confused with the “temporalis tendon transfer,” which is a more abbreviated version of the temporalis myoplasty or muscle transfer. The goals of a simple tendon transfer are limited in comparison. Dr. Panossian has spent nearly a decade refining the technique in order to produce natural and predictable results. The concept of using the temporalis muscle is not a new one. Dr. C.R. McLaughlin first described the temporalis tendon transfer in 1953. It was the first time the temporalis was used in an “orthdromic” fashion, meaning in its natural direction of pull. However, his technique did not produce significant lip movement. The lengthening temporalis myoplasty was developed later by Dr. Daniel Labbé on the basis of McLaughlin’s work. Significant improvements in the technique allowed for greater mobility of the muscle and eliminated the need for an intervening tendon or fascia lata graft. Dr. Panossian has made notable modifications on Labbé’s work that have greatly improved recovery time, predictability, and scarring.
How is a temporalis muscle transfer performed?
Incisions are planned along the hairline from the mid-forehead towards the sideburn. From there, they curve along the path of a standard facelift and end at the earlobe. A second incision is placed at the lip-cheek junction (nasolabial fold) to define this crucial landmark and to accurately anchor the temporalis tendon. After anesthesia and additional local medication is injected, the forehead and facial incisions are made. The temporalis is mobilized initially. The muscle is completely released inside in its natural position (within the temporalis fossa) so that it is suspended only on its nerve and blood supply. The zygomatic bone is temporarily disconnected in order to give access to the tendon of the muscle. The portion of the mandibular bone (coronoid process) to which the tendon is attached is then disconnected with the tendon intact. Next, through the nasolabial incision, a tunnel is created whereby the tendon and attached coronoid process are delivered. The bone is then separated from the tendon, and the tendon is inserted precisely along the corner of the mouth and upper lip.
The muscle is rotated where it normally sits by 90 degrees in order to give additional length to the tendon, hence, “lengthening” myoplasty. This maneuver allows the muscle to reconfigure along its new position and provide maximal excursion without requiring a tendon or fascia lata graft. After securing both the muscle and tendon in their new positions, the muscle is then stimulated to determine the adequacy and degree of movement. It also allows adjustments to be made prior to conclusion of surgery to get the best possible smile.
What is the recovery for a temporalis muscle transfer?
The surgery requires general anesthesia and takes approximately 3.5 to 4.5 hours to complete. It is frequently combined with other procedures, such as eyelid or brow surgery or lower lip depressor muscle excision on the opposite side to achieve excellent symmetry. Two drains are placed in addition to a thin pain pump catheter. The drains draw away extra fluid from the area of the temporalis muscle, while the pain pump limits muscle spasm and improves comfort. A bulky soft dressing and a facial support garment is applied. All drains and tubes are removed on the second or third postoperative day. A soft diet is started immediately after surgery. This includes soft foods such as soups, yogurt, well-cooked chicken, rice or pasta. Hard foods such as hard fruits, vegetables, steak, chips, and other similar items are to be avoided for 4 weeks.
Swelling of the face and eyelids can occur, but typically resolves over the first week. Bruising is not always present, but it will also improve during the same time period. Activity is restricted during the first 4 to 6 weeks to light walking and stationary activities. Heavy lifting, contact sports, and aerobic exercises are to be avoided during this time. Most adult patients elect to take 7-14 days off from work. During this time, make up can be used to mask any bruising.
In select individuals, the surgery is now an outpatient procedure and no longer requires hospitalization. Some patients elect to stay in an aftercare facility overnight for comfort or if there is no assistance at home.
Physical therapy is started at 3 weeks postop to encourage mobility of the temporalis muscle. This includes a visit to a facial paralysis therapist to initiate exercises, biofeedback, and massage techniques. Scar management is initiated to ensure excellent scar healing. Therapy may need to be continued for several months in order to improve mobility of the muscle and for developing spontaneity of the smile.
What are the risks and complications of a temporalis tendon transfer?
Complications are relatively rare when performed by a qualified and experienced facial paralysis surgeon, skilled in temporalis transfers. Standard risks associated with all surgeries apply. These can include bleeding (hematoma), infection, or adverse reactions to anesthesia. In adults, uncontrolled diabetes and smoking may affect healing and overall results. As a dynamic procedure, there is always a risk of minor asymmetry and excessive scarring underneath the skin, causing decreased movement of the lips. There is a small rate of revision required to loosen the scars to increase movement of the muscle. If this is required, it can be performed as an outpatient surgery that lasts 1-2 hours.
To minimize your risk, pay close attention to your surgeon’s instructions before and after surgery. The Facial Paralysis Center staff is available at all times to clarify any pre- or postoperative instructions that you were given. Please refer to the Pre- and Postoperative General Instructions for further details.