Composite Platysmaplasty and Closed Percutaneous Platysma Myotomy: A Simple Way to Treat Deformities of the Neck Caused by Aging

“Danger Zones” Under the Platysma 

Platysma undermining, or platysma myotomy, must be performed so as to avoid damaging the cervicomandibular stem branches of the facial nerve, the mandibular marginal nerve and the cervical nerve that proceeds between the deep cervical fascia (investing fascia), and the platysma itself. The marginal mandibular and cervical nerves proceed within the parotid gland and exit at its lower border. The cervical nerve is always posterior to the mandible angle; the mandibular nerve may be either posterior and follow parallel to the mandibular border and below it, or it may cross the mandibular ramus and proceed above it.

The pathway of the mandibular and cervical nerves and the number of branches—and any potential anastomosis between them and other nerves (such as the large auricular nerve and cervical plexus branches)—are subject to much variation. Therefore, studies involving a large number of cadaver dissections were important to define the “danger zones” for incisions that approach the subplatysmal structures, regardless of any anatomic variations found.17, 18, 19, 20, 21, 22, 23

Most textbooks describe the mandibular nerve as being cephalad to the mandibular border at the point where it crosses the facial vessels24, 25; however, Seward20 and later Ziarah and Atkinson18, 19 found the mandibular nerve proceeding below the mandibular border but very close to it, slightly before a vertical line that passes posteriorly to the second premolar tooth in 6% of the cases. Among the described “danger zones,”17, 18, 19, 20, 21, 22, 23, 24 we chose to use the one described by Ziarah and Atkinson19 because it was the most encompassing (based on more than 100 dissections) and because it included the study of the cervical nerve. The cervical nerve is responsible for the mobility of the platysma muscle, which includes a segment that expands to the angles of the mouth and, by contracting, draws down those angles, thereby serving as an aid to mimicry and smiling. The marginal mandibular branch is a motor nerve that innervates the depressor muscle of lip and the depressor muscle of the angle of the mouth. Ellenbogen26 stressed that transient paralysis of the movements that lower the angles of the mouth might not be caused by an injury of the marginal nerve, but rather by an injury of cervical nerve filaments that leads to partial paralysis of the platysma, and because the platysma has numerous terminal filaments, such “pseudoparalysis” was transient. In order to avoid damage to not only the mandibular nerve but also the cervical nerve, the author chose to use the “danger zone” that also provides protection to that nerve.

“Danger Zone” for the Cervical and Mandibular Nerves 

The limits of the “danger zone” for the marginal mandibular and cervical nerves18, 19 was traced by taking the mandibular angle, the lower mandibular border, and the second premolar tooth as reference points. Starting at the mandibular angle, we measured 3 cm in the caudal sense, drawing a vertical line (line P; Figure 1, A). A vertical line was drawn from the second premolar tooth to the mandibular border and then up to 4 cm below the mandibular border line, following the muscle fibers (line A; Figure 1, A). The lower tips of the two lines were joined by a horizontal line, closing the “danger zone.”

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Figure 1. A, “Danger zone” for the mandibular marginal and cervical nerves according to Zairah and Atktinson.19 Line P starts at the mandibular angle and runs vertically down for 3 cm. Line A starts at the second premolar tooth and runs up to the mandibular border; at that point, it runs caudally 4 cm in the direction of the platysma fibers. B, On the skin marks for surgery, line A goes below the hyoid bone and line P extends up to sternocleidomastoid. A line passing 1 cm below the lower mandibular border connects lines A and P.

Skin Marks 

A line was traced line parallel to the mandibular border and 1 cm below it. That line was then extended vertically from the mandibular angle to meet the sternocleidomastoid muscle border, as an extended line P shown in Figure 1. A second line was drawn from the second premolar tooth, extending vertically up to the mandibular border and then following the course of the platysma fibers (as with line A in Figure 1, but extending until it intersected the hyoid bone). That line indicated the anterior limit of the “danger zone” described by Ziarah and Aktinson19 for the protection of the mandibular and cervical nerves. These lines were termed the posterior line (P) and anterior line (A) by this author to designate not only the skin marks, but also the lines used on the platysma after the undermining.

Operative Technique 

The cervical detachment was performed over the platysmal fascia in the area delimited between lines P and A, as previously marked on the skin. The platysma was exposed, leaving as much adipose tissue as possible adhered to the skin flap. The caudal limit of the undermining varied depending on the degree of flaccidity, but in most cases of moderate laxity, a line parallel to the mandible passing slightly below the hyoid bone usually served as a guide for the caudal detachment (Figure 2, A and B).

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Figure 2. A, B, The dissection along the skin marks as shown in Figure 1 exposes the platysma up to line A, leaving as much fat as possible on the skin flap. C, D, On line A, an incision is made opening the platysma in the direction of the muscle fibers and a small blunt dissection is made under the platysma adhered to the skin.

Taking line A (at the platysma undermining anterior limit) as a guide, a vertical incision was made on the platysma, running about 3 to 4 cm along the course of the fibers, from 1 cm below the mandibular border to the hyoid bone (Figure 2, C), leaving the anterior border of the incised platysma attached to the skin. This incision gave access to the subplatysmal plane; a small, blunt detachment of about 1 to 2 cm was required to loosen it and enable traction of the composite flap that was created (Figure 2, D). In cases of severe laxity and lack of tone, the caudal detachment had to be increased, but the vertical incision on the platysma did not follow this increase along its entire length; 0.5 or 1 cm was usually sufficient. Long vertical incisions were not performed in order to avoid excessive cutting of the cervical nerve terminal branches.

The cervical composite flap was tractioned and anchored only after the midface area was detached. In order to calculate the appropriate anchorage site, it was necessary to traction the skin flap of the previously-released cheek area (simulating a facelift traction) while the assistant kept the traction in place. The composite flap was pulled by the surgeon using a Kocher or Allis clamp, taking the anterior border of the incised platysma attached on the flap. The muscle was taken with the forceps at the spot where the cervicomandibular angle was to be placed (Figure 3, A and B). With the forceps pulled firmly, the first anchoring suture was made. In most cases, this anchoring procedure was performed by taking the platysma border located on the composite flap and fixating it with a 2-0 Vicryl suture on the platysma right below the mandibular angle, almost approximating line A to line P (Figure 3, C). The platysma muscle tissue below the mandibular angle is quite firm and deeply adherent, and therefore it makes for an excellent anchoring point. This tissue was always included in the anchoring procedure because, in addition to being firm enough to ensure that anchoring was maintained, the tensile strength adjustment and the tightening of the platysmal tissue immediately below the mandibular border immediately produced a marked definition of the mandibular line. The improved definition of the mandibular line and cervicomandibular angle were apparent as soon as this first anchoring was complete. New sutures were placed between the borders of the muscle flap, or between the adjacent adipose tissue and this firm tissue right below the mandibular angle to fixate the anchoring more securely (Figure 3, D).

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Figure 3. A, B, The muscle on the composite flap is pulled with a Kocher forceps toward a point just below the mandibular angle (several attempts may have to be made to choose the best point for traction). C, D, Two or three sutures secure the composite flap muscle on the tissue below the mandibular angle. A few more Vicryl sutures are used to secure the flap to the area next to the sternocleidomastoid.

In cases in which little loss of tone was present, the border of the platysma tied to the skin–muscle flap did not reach the firm tissue near the mandibular angle. In such cases, the first suture was made on the platysma tissue somewhat anteriorly, but the following anchoring sutures were placed between the adipose tissue of the flap and the platysma, below the mandibular angle.

The tightening obtained by this method of platysmaplasty produced such a good repositioning of the cervicomandibular angle that liposucton was considered only in cases involving truly heavy necks. Moreover, when dissection was performed keeping all the fat attached on the skin, the fat moved together with the traction, shifting to a higher and more posterior position where it was less apparent. When liposuction was indicated, it was performed at the subplatysmal level in order to avoid loosening of muscle–skin adherence. Such subplatysmal liposuction was performed only on the medial area, between the two vertical platysma incisions.

There was no need to thin the area below the mandibular angle by performing lipectomy or liposuction because the dissection left the fat attached to the skin, so it was no longer in the area when the the skin-fat-muscle flap was pulled. However, in some cases, an open lipectomy by scissors over the sternocleidomastoid area was necessary in order to obtain a thinner neck.

The incisions and traction of the skin at the midface area and the remainder of the surgery can be performed according to each surgeon's habits and routine. However, because the anchoring of the composite flap creates a large amount of excessive skin, the surgeon must be prepared to accommodate or to remove such excess. In most cases, short incisions at the retroauricular area are not sufficient to resolve this issue, and incisions at the hairline or on the scalp are required.

Closed Platysma Myotomy 

The closed platysma myotomy technique using mini-incisions was introduced by Julien Bourguet, who was also the first to describe platysma bands. In 1926, he described how to treat platysmal bands that remained postoperatively after cervicofacial lifting.27 Using an extremely fine knife designed for cataract surgery, he performed mini-incisions to obtain transversal cuts on the platysma under the skin, thereby improving the more pronounced muscle bands. Zaylan28 revived this mini-incision approach by performing serial notching of the platysmal bands.

The author has performed the closed platysma myotomy together with composite platysmaplasty, placing 3-0 braided nylon sutures to lyse platysmal bands without incising the skin in the same fashion as described by Fournier and Carréra,29 who used metallic thread to perform this procedure. The lifting achieved with composite platysmaplasty is very efficient and, in most cases, no other auxiliary procedure is required to provide good results. However, if the patient has rigid and marked platysmal bands of McKinney grades III or IV,30 it is necessary to loosen the fibrotic muscle fibers. In these cases, as suggested above, the author has found the method introduced by Fournier and Carréra using nylon threads to be very efficient.

The platysmal bands were marked preoperatively with the patient awake and standing. Holding the platysmal band between the thumb and the index finger, a vertical line was drawn on top of the held band and two lines were drawn parallel to the first, one at each side, at the base of the tissue held between the two fingers. The distance between the line on the top of platysma band and the two parallel lines was about 1 or 1.5 cm on each side.

The anesthetic vasoconstriction solution was infiltrated at least 10 minutes before the procedure to avoid bleeding. Once again, the platysmal band was held between the thumb and the index finger and a large hypodermic needle (30 × 16) was introduced, entering at the previously drawn medial line and going out at the lateral line, so that the needle crossed the tissue held between the fingers (Figure 4, A). To expedite the process, several needles can be placed. A 3-0 braided nylon thread, without the needle, was introduced through the 30 × 16 needle's eye, following the same course as the needle, and pushed until the tip appeared on the other side, with the end of the thread being pulled about 10 cm (Figure 4, B). The needle was pulled with one hand, while the other hand maintained the thread in position. The needle was reintroduced through the other side (that is, from the lateral line to the medial line) using the holes made in the first pass. However, this time, instead of going very deeply and being aided by the finger pinch, the needle was pushed close to the skin, following a path anterior to the platysma (Figure 4, C). For this second pass, the finger pinch was not used; instead, the fingers were used to guide the needle through its new path until it exited through the hole previously made at the medial line. The nylon thread was reintroduced through the needle's sharp tip lumen, coming back in the opposite direction (Figure 4, C); when the thread appeared at the other end, it was pulled through and the needle was removed. Using this procedure, the platysma was caught up by the thread, which was tractioned with each end in one hand, alternating hands in a sawing movement. The thread cut through the entire platysma after a few such alternating movements (Figure 4, D). The same procedure was repeated in at least two other places on the marked area.

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Figure 4. A, After the marks are made, the platysmal band is held between the surgeon's fingers and a hypodermic 30 × 16 needle is deeply introduced until it crosses the tissue between the fingers. B, The braided nylon 3-0 thread (here replaced by a black 2-0 nylon to be better seen on the photo) without its needle goes through the 30 × 16 needle's lumen (the braided suture can be suctioned by a liposuction tube attached to the needle). C, The needle is removed and reintroduced through the same holes previously made, now in the opposite direction and superficial to the platysma. The thread is passed once again through the lumen in the opposite direction. D, The needle is removed and the thread is used as a saw to cut the platysma.

This procedure can be used as an isolated procedure in patients with minor skin laxity. The author has performed such procedures, but they are not part of this study. The results of closed platysma myotomy are different when performed alone versus when associated with a cervicoplasty. The rate of recurrent platysmal bands when performing closed platysma myotomy alone is higher and the analysis of the results deserve a separate study.