Surgical Management of the Difficult Neck

Author: M. Sean Freeman, MD

General Considerations

The ideal neck consists of a clean cervico-mandibular line, a defined break point near the level of the hyoid, a well positioned chin and a submandibular gland that is not visible in the digastric triangle (fig 1). Specifically the cervicomental angle or break point of the neck should be around 90 degrees with the hyoid at the apex of the angle. Ideally the thyroid notch is perceived as a subtle protrusion below the level of the break point and no horizontal rytids are noticeable.

A working knowledge of the fibromuscular layers of the neck is necessary to understand the surgical concepts to be presented. The superficial musculoaponeurotic system (SMAS) invests the face and neck from the galea (to which it is continuous), through and around the superficial muscles of facial expression in the midface and lower face and then down into the neck where the SMAS is continuous with the platysma muscle. The platysma muscle itself, which comes from the Greek word “plate”, is a quadrangular sheet of muscle originating from the fascia of the pectoralis major muscle inferiorly, ascending superiorly to attach at the level of the mentum medially, the body of the mandible and SMAS lateral to the midline and laterally sweeps up to and around the risorius and related structures (fig 2).

Based on the anatomy of the platysma muscle Vistness1 proposed several anatomical observations which he felt had surgical consequences:

1. “The platysma is intimately attached to the skin by fibrous septa, which must be completely separated to mobilize the skin independently of the platysma muscle. Because of this relationship, redundancy of the skin usually implies redundancy of the platysma muscle.” This implies that one must always separate and tighten the neck skin and platysma separately in order to improve neck laxity (author’s interpretation). The author will show that this is indeed not true for patients without medial platysmal banding, significant submental fat deposition and/or an anterior hyoid.

2. “If the platysma is tightened by changing the direction of its fibers, the change in vector may forcibly affect other muscles.” The worry is that the depressor anguli oris and/or risorius functional pull on the lips during animation may be affected should the platysma vector be changed appreciably or in an un-natural direction. The author has found that indeed this can be the case should the direction of pull laterally be other than at the typical breakpoint of the neck. Otherwise the author has not found this point to be clinically significant.

3. “If the anterior fibers do not decussate, prominent vertical bands in the anterior neck may form. The submandibular fat pads and submandibular glands (SMG) will not be supported well and may become ptotic, blunting the contour between face and neck. Treatment requires approximation of the medial borders of the platysma.” The author agrees that medial platysmal

banding requires aggressive management of the medial platysmal border, a technique that will be reviewed later in this chapter; however ptosis of the SMG is more commonly seen in patients with a weak chin with or without an anterior hyoid. To reliably treat this problem one needs to consider more then simply tightening the medial border of the platysma.

4. “Transection of the cervical branch of the facial nerve may have a detrimental affect on some people with a full smile should the platysma work in synergy with the depressor anguli oris.” The author agrees that transection of the cervical branch of the facial nerve is a poor surgical maneuver. I would add that full horizontal sectioning of the platysma from lateral to medial is similarly a poor surgical choice. Anything that causes this muscle to atrophy over time will ultimately result in an unusual withered look to the neck, an appearance that is difficult to improve.

Classification of the Aging Neck

When discussing correction of the aging neck it is somewhat helpful to attempt to classify necks into categories which relate to anatomical findings. Many factors would need to be taken into account to make this exercise useful; things such as patient age, skin quality, relative abundance and location of fat, chin position especially as it relates to the hyoid, as well as other skeletal and muscular anatomical findings. Dedo2 proposed a classification system of the neck based on anatomical layers which can be summarized as follows:

1. Class 1: an essentially normal patient who needs no surgical intervention.

2. Class 2: A patient with normal anatomy but with skin laxity of the neck only.

3. Class 3: A patient that is otherwise normal but has an excess of fat in the neck.

4. Class 4: Patients that primarily have platysmal banding as the main finding but may indeed have excess skin and fat as well.

5. Class 5: Patients with retrognathia which contributes to their other problems.

6. Class 6: Patients with an abnormal hyoid position which is either too low or too anterior to obtain the desired end result. These patients will typically present with other problems as well.

This classification is useful but somewhat muddled in that most patients that present for rejuvenation of the neck fall into more then one of the above classifications. The author tends to think of these patients in terms of degree of difficulty which directly relates to the surgical plan. With that in mind the author proposes the following classification system:

1. Class 1: Patients in this class require an easy surgical plan. They either have simple laxity of the skin and require lateral support of the SMAS/platysmal entity via a short flap approach or a lateral platysmal lift (should the surgeon deem this necessary) or they simply have excess submental fat but with good tone and need submental fat recountouring only (fig 3). Should

they need a chin implant in addition, this will not change the complexity of the approach. This is added as needed and should be encouraged by the surgeon should the patient vacillate, since adequate anterior mandibular support will give better short term and long term results.

2. Class 2: Patients in this category require a more aggressive surgical plan due to the presence of medial platysmal banding. Full release of the skin from the platysma will be needed requiring a lateral and medial approach should significant medial platysmal banding be noted or subplatysmal fat contouring be required; medial platysmal plication is mandatory in these patients. Should a chin implant be necessary it is strongly recommended to the patient and inserted should permission be granted (fig 4). Should the patient not acquiesce to a chin implant when needed, they should be advised that the short and long term results will not be as gratifying. Many patients in this category will also require inferior fixation of the platysma to the hyoid with or without minimal resection or shortening of this part of the platysma, depending on the degree of banding and the strength of the chin. Many of these patients will require a degree of submental fat contouring. Lateral fixation of the platysma will always be needed and may be the only step needed to get an excellent result should medial platysmal banding be minimal, hyoid position be adequate and no fat contouring be needed.

3. Class 3: Patients in this category have anatomy that makes obtaining a satisfactory end result difficult if not unattainable (fig 5). These patients will invariably have a poorly placed hyoid. In addition it has been the author’s experience that a majority of patients with anterior hyoids will have a degree of SMG Ptosis, although that is not always the case. Patients with a good hyoid position but significant SMG ptosis are also in this category, although they are the exception rather than the rule. Many of the patients in this later category have a weak chin, which is easily corrected with an appropriate chin implant. The approach to patients with significant SMG ptosis and/or a poorly placed hyoid will be reviewed later in this chapter.

Surgical Management of Class 2 and Class 3 patients (Freeman classification)

Management of these patients can be broken down into four areas: management of the lateral platysma, management of the medial platysma, management of excess submental fat, and management of a ptotic SMG. The author has purposely left out management of an anterior and/or inferiorly placed hyoid as there is no known reliable safe method for changing the position of the hyoid for aesthetic reasons. There are many articles in the Otolaryngology literature concerning surgery on the hyoid for sleep apnea. However the goals of these approaches seek to move the hyoid in the opposite direction that facial plastic surgeons desire, in order to pull the tongue away from the posterior oropharynx.

The aesthetic literature is full of approaches for managing the lateral platysma during neck surgery. Skoog3 in 1974 advocated for extensive subplatysmal undermining with fixation of the lateral platysma to the mastoid. Guerrero-Santos4, 5 and others have proposed suspension sutures or a band of fascia lata running from one mastoid process to the other. The author’s preferred lift in this area is a figure-of-eight braided suture from the break point of the lateral platysma to the occipitomastoid fascia in conjunction with a deep plane lift of the parotid-masseteric fascia (when done in conjunction with a facelift). As

mentioned previously for class 2 and 3 patients a full release of the skin anterior to the platysma is also necessary when significant platysmal banding is noted, fat contouring required and/or medial platysmaplasty be necessary. The lateral platysma is only elevated enough beneath the platysma to allow for a strong double bite figure-of-eight stitch to be easily applied at the break point of the neck (fig 6). Care is taken to identify and preserve the external jugular vein and greater auricular nerve posterior to the lateral platysmal stitch. Use of this approach, angle and fixation point has resulted in an improvement of the mandibular line and sternocleidomastoid definition with less complaints of a long term choking sensation that used to occur too often with the suspension stitch. Extensive lateral dissection underneath the platysma is an unnecessary step.

Management of the medial platysmal border for class 2 and 3 patients will at times include plication of the medial border of the platysma. The author prefers a 3-0 braided stitch. The stitch is secured to the anterior-superior edge of the medial hyoid, a running stitch is then secured to the medial edge of the platysma (fig 7). The medial–inferior edge of the platysma is cut and shortened when there is laxity of this muscle as is typically seen in patients with an anterior hyoid, a small mandible, significant medial platysmal banding or a large amount of medial subplatysmal fat (fig 8). Should this area be shortened it is again secured to the hyoid in the same fashion as above. Failure to include this step will lead to less definition of the medial portion of the neck. The intent of this cut is only to put vertical tension back on the medial platysma so the horizontal inferior cut need be no longer then 2-3 centimeters. As long as this cut is made at the level of the hyoid the marginal mandibular nerve should not be at risk.

Submental fat contouring is an art rather then an exercise. Too much fat removal tends to give a thin look to the neck skin over the platysma. In addition, removing too much fat above and beneath the medial portion of the platysma can lead to a cobra deformity (fig 9). Alternatively, too little fat removal either in spots or in general will lead to less neck definition or a visible bump. The author prefers open fat sculpting with a scissors to closed liposuction, which tends to be too aggressive in removing fat between the platysma and the skin. All fat is not bad, nor should it all be removed. Experience over time with a careful critique of pre and post op results will help guide the facial plastic surgeon as to what is too much and what is too little. This concept is difficult to describe in words or portray with pictures. What the author looks for is a thin covering over the platysma when done with a healthy layer of fat left on the skin flap raised at the beginning of the dissection. In addition, having a 3-D picture of this area allows the surgeon to blend the fat above and below the medial borders of the platysma. At times open liposuction with a flat head canula of the lateral platysmal border is helpful at the end to smooth this area. Removing fat from underneath the platysma medially should be sparingly done; it is unusual to need aggressive removal in this area. Care must be taken to avoid the area of the digastric triangle as the marginal mandibular nerve can be injured in this area and aggressive fat removal is rarely needed in this area. Most patients who need subplatysmal fat removal tend to have early formation of submental fat that they have difficulty resorbing even with exercise and weight loss. It is important to remember that over time we all lose the thickness of our subcutaneous fat throughout the face and neck and therefore too aggressive an approach can lead to a deterioration of the patient’s appearance over time.

A ptotic SMG is a difficult problem to address without aggressive measures. Certainly in some patients with adequate chin and hyoid location and good platysmal strength simply tightening the platysmal sling

may be enough to push the SMG back underneath the edge of the mandible. This however does not happen often, especially in patients with significant ptosis and poor anatomy of the hyoid and/or mandible. Certainly a chin implant will help but usually not enough. For these patients the author has been using an SMG shave technique since 2001. This approach was originally presented at the American Academy of Facial Plastic Surgery by the author. A thorough knowledge of the regional anatomy of the digastric triangle is needed but even with this the patient needs to know that attempting this approach puts the marginal mandibular nerve at greater risk. The boundaries of the digastric triangle are the anterior and posterior bellies of the digastric muscle inferiorly and the lower border of the mandible superiorly. The floor consists of the mylohyoid, hypoglossal and middle constrictor muscles while the ceiling consists of the platysma and marginal mandibular nerve. The facial artery and vein will sweep over the SMG from lateral to medial in a superior direction while above the gland one would see the hypoglossal nerve (fig 10). The approach is via a submental incision such as would be used normally to approach the mid-neck during facelift surgery. Blunt dissection is done on top of the posterior digastric muscle until the SMG and fascia are noted. The SMG is bluntly separated from the surrounding investing fascia thereby lifting the facial artery and vein away from the gland (and also from the marginal mandibular nerve). When the gland is free of all investing fascia below the level of the inferior border of the mandible then a suction cautery is used to slowly shave the gland from inferior to superior up to the level of the inferior border of the mandible. An insulated retractor should be used to hold the fascia, facial artery and vein (and related contents) away from the cautery; it must be insulated to prevent accidental electrical injury to the marginal nerve via the retractor (fig 11). Only remove enough of the gland such that it will no longer hang below the edge of the mandible. Following this approach for several years has improved the author’s results with no marginal mandibular nerve injuries to date. When the author first used this approach post operative drainage from the gland was also a concern. This has not occurred in any of his patients, possibly because the cautery seals the gland and prevents this from occurring.

Results

The author has specialized in facial plastic surgery since 1988 with an increasing majority of his practice focusing on aesthetic areas of the field over time. An average of over 100 facelifts/necklifts are done per year. The techniques described above have evolved over time with the goal of natural looking results and minimal post operative patient complaints. The author has tried other approaches mentioned in this chapter and has abandoned them because of less naturally appearing results or an unacceptably high frequency of post-operative patient complaints (such as with the mastoid to mastoid suspension technique). Using the suspension points and the other techniques as described has improved patient outcome in terms of both quality and lack of post op difficulties (fig 12).

Of course with any procedure post operative problems can be seen. Abnormal scarring can happen with any incision, but with careful closure and a deep plane technique, this problem is unusual and typically seen only in the post auricular area. The author does use a post tragal approach with the post-auricular incision extending into the hair behind the ear, allowing most patients to wear their hair up should they so desire. Infection has been seen but is rare and certainly has little to do with the approaches used to define the appearance of the neck. Nerve damage has also been rare, most commonly involving the

greater auricular nerve branches. About 3-5% of patients will complain of parasthesias of a small periauricular area up to a year after surgery; this is with dissection and identification of the greater auricular nerve during surgery. Facial nerve injury has also been rare even with the addition of the SMG shave technique. The author has performed the SMG shave technique on less then 80 patients since developing this approach in 2001; greater numbers have not been performed mainly because of patient fear of marginal mandibular nerve injury after the risks are explained. To date, however, the author has had no permanent injury to any of the branches of the facial nerve, although temporary weakness has rarely occurred. The most common branch with short-term weakness has been the buccal branch associated with the authors midface malar pad lift, not the SMG shave approach; all resolved within a week or two. Again, this weakness has nothing to do with the techniques described within this chapter since they are secondary to the deep plane and midface approach the author favors. Only a handful of temporary marginal mandibular nerve injuries have been noted over time, all resolved quickly and none have occurred in the subset of patients receiving a SMG shave. Seromas and hematomas are the most common problems seen in the post operative period. In all class 2 and 3 patients a suction drain is utilized post operatively, which has lowered the hematoma rate to less than 5 percent.

Conclusion

The techniques described above offer safe and effective improvement of the appearance of the neck for the majority of patients. Careful implementation of these approaches should be considered for facial plastic surgeons who feel they may benefit.