Deepplane Dissection

We keep referring to this as an "opportunistic technique" since the extent of the dissection of the deep flap is not based on anatomic landmarks, but rather on determining what is required to give the elevation necessary for the patient. Dissection of the deep-plane usually begins in the neck.

The first step is to identify the posterior border of the platysma. If this structure is not clearly evident, we use a technique of open liposuction to remove the fatty tissue off the posterior extent of the muscle. A No. 6 spatula type liposuction cannula is attached to standard wall suction and, using an open technique, the fatty tissue is suctioned off of the muscle. Once the posterior border of the platysma is evident, a flap is started. It is developed by incising along its posterior border from the lower edge of the parotid inferiorly to the level of the upper thyroid cartilage. This incision can be made with a knife or elec-trosurgically, but we prefer the laser because of its precision and hemostasis. Once the incision is complete, scissors are used to undermine the posterior platysma for about 4 or 5 cm. A lower transverse incision is then made across the platysma to create a flap that can be advanced posteriorly. The anatomic development of the platysma muscle varies considerably from individual to individual. In some patients, the platysma can be clearly identified, extending upward into the face, whereas in other individuals it attenuates at the level of the mandible. Even in cases where it attenuates, a fibrous remnant usually persists.

The posterior incision in the platysma is continued upward into the face following the posterior border of the muscle to the angle of the jaw. From there, it continues upward in the midface, about 2 cm in front of the helix.

Flap elevation is then carried out using the laser. The deep-plane of the dissection is either the thin areolar tissue overlying the parotid gland, or, if that layer is not apparent, the parotid gland itself. The upper level of the incision is slightly below the zygomatic arch. At this point, the incision curves forward, proceeding anteriorly toward the true zygoma.

In this fashion, a deep flap is elevated that is continuous with the lower platysmal flap. Superiorly, the anterior dissection extends into the fibro-fatty tissue of the cheek. Further inferiorly, a discrete plane is clearly apparent. Ideally, this plane is within the loose areolar tissue immediately overlying the parotid gland.

Anterior dissection is carried forward with the laser to and beyond the anterior border of the parotid gland. As the dissection proceeds forward, beyond the anterior limit of the gland, the masseter muscle is apparent, and one usually sees fibers of the facial nerve resting on that muscle within a thin layer of areolar tissue.

Here again, the use of magnification facilitates the dissection. As mentioned before, we are more comfortable when we actually see the nerve fibers. Similarly, we can also sometimes see Stenson's duct with an associated buccal branch.

The nerve fiber that is probably most at risk is the marginal mandibular. Although we do occasionally see this nerve, it is usually not apparent. Careful meticulous laser dissection is carried out, and flap elevation is most conservative over the angle of the mandible.

The important decision to make is just how far we need to elevate this flap. Again, the answer depends on the individual patient. As we proceed with the dissection, we are constantly pulling on the flap to see whether we get the desired lift. Once we reach a point where there is a general freeing of the flap, we can usually see the desired pull on the cheek, nasolabial fold and the corner of the mouth. In simple terms, when we get the pull that we need, the dissection is complete.

Most commonly, we find that it is the malar portion of the flap that binds us down the most. This is the most difficult area of the dissection, because we are working within the bulk of the malar fat pad and not in a true anatomic plane. We like to make the flap fairly deep in this area because we feel that by staying deep, we actually lift up the malar fat pad itself. This gives a natural form of malar augmentation.

Once the flap is elevated and hemostasis maintained the flap can be secured. Using a strong permanent suture (3-0 braided silk), the upper part of the flap is attached to the tem-poralis fascia, exerting a strong pull. Next, the platysma muscle is pulled back, attaching it to the mastoid fascia. Immediately, we can see a marked tightening of the face and neck. These are the two primary anchoring sutures. We continue to suture the posterior border of the platysma to the fascia overlying the sternocleidomastoid muscle using interrupted 3-0 silk suture. The pull is actually in a posterior superior direction, such that the platysmal flap actually forms a sling that supports the ear lobe and tends to prevent subsequent inferior migration of the ear, which can result in the deformity commonly called "pixie ear." In the facial region, the flap is attached to the parotid fascia in the preauricular area. A firm pull is applied, as this forms the primary support of the facelift.

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