Key points

Introduction

The aging neck is characterized by platysmal bands, lipodystophy, and jowls that extend into the neck. As jowls develop, the chin and jawline lose definition and horizontal and radial necklines become more noticeable. Like the face, the neck is subject to photodamage. For these reasons, patients who seek facial rejuvenation often want their neck treated as well to obtain a homogenous, natural appearing improvement in photodamage. Surgical approaches to addressing these and related cervical deformities have been described. Nonsurgical modalities, such as botulinum toxins, chemical peels and dermabrasion, radiofrequency energy, plasma skin regeneration (PSR), lasers, and light, have also emerged to rejuvenate the skin of both face and neck. Resurfacing of the neck combined with facelift and other surgical procedures must be executed carefully and with significant caution due to the inherent healing limitations of the neck.

Introduction

The aging neck is characterized by platysmal bands, lipodystophy, and jowls that extend into the neck. As jowls develop, the chin and jawline lose definition and horizontal and radial necklines become more noticeable. Like the face, the neck is subject to photodamage. For these reasons, patients who seek facial rejuvenation often want their neck treated as well to obtain a homogenous, natural appearing improvement in photodamage. Surgical approaches to addressing these and related cervical deformities have been described. Nonsurgical modalities, such as botulinum toxins, chemical peels and dermabrasion, radiofrequency energy, plasma skin regeneration (PSR), lasers, and light, have also emerged to rejuvenate the skin of both face and neck. Resurfacing of the neck combined with facelift and other surgical procedures must be executed carefully and with significant caution due to the inherent healing limitations of the neck.

Botulinum toxins

Botulinum toxins have been used to treat vertical platysmal bands and horizontal neck rhytids. Results appear within several days and persist for up to 6 months. Potential complications are minimal but include dysphagia and immunoresistance, which may be avoided by using the smallest effective doses, injecting at intervals of at least 3 months, and avoiding booster injections. Careful injection technique is critical to avoid diffusion of toxin to nontargeted muscles near the injection site.

Patients likely to benefit from botulinum toxins should have good cervical skin elasticity, well-defined platysmal bands, and minimal fat descent. The treatment is suitable for older patients who are either poor candidates for surgery or have already had neck rejuvenation surgery. Younger patients with strong platysmal bands that do not require surgery are also candidates. No improvement is expected, however, in the appearance of photodamaged skin.

Peels and dermabrasion

Although inexpensive, chemical peels and dermabrasion have produced variable results in photodamaged facial skin due to the difficulty in controlling the depth of tissue removal. In the neck, dermabrasion and chemical peels are associated with a high risk of scarring, although this risk may be smaller with superficial peels. Roy uses α- and β-hydroxy acid peels to treat vascular and pigmented lesions and fine rhydids on the neck and chest because these peels can be used on all types of skin and there is no downtime. Roy cautions, however, that results are less dramatic than with light and laser treatments. When resurfacing the face with medium to deep peels, Roy uses the Jessner peel on the neck and chest to minimize the transition between the face and neck. Despite side effects and complications, chemical peeling and dermabrasion have produced dramatic, long-lasting clinical and histologic improvements in the face. Superficial peels (eg, α-hydroxy acids) and medium-strength peels, however, have little effect on fine wrinkles. With α- and β-hydroxy peels there is no downtime and these peels can be used on the necks of all skin types. These peels provide no lasting change to skin ultrastructure. When using medium to deep chemical peels to rejuvenate the face, the use of Jessner peel on the neck may minimize the transition from the treated face to the untreated neck. (The neck often remains untreated with medium or deep peels for fear of scarring or hypopigmentation.)

One type of chemical peel has received considerable study by Hetter and Bensimon. The croton oil peel has been shown to produce consistently excellent cosmetic results, even in the neck. This peel evolved from the classic Baker-Gordon peel (phenol and croton oil) reported in 1962 and is still used by some physicians. Although the Baker-Gordon peel provided dramatic improvement, its use was sometimes limited because hypopigmentation and a waxy porcelain appearance often resulted after treatment. In 2000, Hetter showed that the active ingredient was croton oil rather than phenol. Hetter further showed that lowering the concentration of phenol, varying the concentration of croton oil, and using a specific application technique permitted surgeons to control the depth of penetration during treatment. Thus, surgeons could treat facial areas of different skin thickness, even the eyelids. A complete protocol for the modern croton oil peel in facial rejuvenation (including the neck) has been published and is summarized.

Croton oil peel

Patient selection is critical to the success of croton acid peels. Patients tolerate the peel better if they know what to expect, especially after a procedure is completed. Prospective candidates are shown photographs of patients in various recovery stages and the candidates may also have an opportunity to speak with previous peel patients. With the neck, the goal is to blend skin color with that of the more aggressively treated face rather than to remove wrinkles.

When a patient consents to treatment with a croton oil peel, the neck skin is first treated with tretinoin 1% once daily, beginning 4 to 6 weeks before peeling. If the skin becomes irritated, the frequency is reduced. Hydroquinone 4% is applied twice daily to prevent postinflammatory hyperpigmentation, and glycolic acid 8% is given once daily to facilitate exfoliation. These preparatory treatments are stopped 4 to 5 days before peeling. By that time, the skin is erythematous and flaky and patients have been told this is normal. Antiviral medication is routinely started 3 days before peeling and continued for 1 week after peeling to prevent herpetic complications.

For the thin skin of the neck, a croton oil 0.1% solution is prepared by dilution of the croton oil 0.2% solution, which is, in turn, prepared from a stock solution of phenol (35% by volume) and croton oil (4%) as described. The 0.1% croton oil peel is a light peel and affects only the epidermis. The peel solution is applied by sequential light applications with gauze and cotton-tipped applicators. The acid precipitates skin protein to form a white frost in 10 to 20 seconds. The depth of penetration is judged by the degree of frosting. As discussed previously, the concentration of croton oil and the application technique are the primary determinants of penetration depth. The endpoint of treatment is the degree of frosting, which is a subjective and experience-based judgment. Outcomes are optimized when practitioners have sufficient experience to recognize when the appropriate depth is reached as revealed by the frost. For the neck, the light peel results in a “light, wispy frost that is not at all organized.”

When the frosting subsides, an emulsion of Polysporin (Pfizer, New York, New York) and lidocaine jelly is applied over the peeled areas and given to patients for continued use. The mixture moisturizes the peeled area, prevents crusting, and provides analgesia. Postpeel medication includes a narcotic agent for pain, ibuprofen, Medrol Dosepak (Mova Pharmaceutical, Manati, Puerto Rico), and, if necessary, a sleep medication. Healing is complete in 2 weeks, although erythema persists for up to 12 weeks. If healing is delayed and the peeled areas thicken with mild scarring, peeling probably penetrated to the deep reticular dermis. In this event, triamcinolone acetonide and 5-fluorouracil are injected. Hyperpigmentation, if it occurs during recovery, is temporary and treated with tretinoin and hydroquinone 4%.

In summary, the croton oil peel is an inexpensive and effective modality for rejuvenating neck skin because the technique can be modified (ie, by varying the concentration of croton oil) to affect the depth of penetration, thus providing surgeons with unprecedented control of treatment depth and minimizing the likelihood of hypopigmentation. Bensimon’s current use of the croton oil peel is limited to the upper cervical skin just above the first cervical crease to prevent a noticeable transition from face to neck (Richard Bensimon, MD, personal communication, June 2013).

Plasma skin regeneration

PSR has been shown to improve moderately photodamaged skin of the face, neck, chest, and hands. Plasma is an ionized gas produced when electrons are removed from atoms. The PSR device includes an ultra–high-frequency radiofrequency generator that imparts energy to inert nitrogen gas in a hand piece. Energy is delivered to the target tissue at different depths without dependence on skin chromophores. Treatment requires the use of topical anesthesia, oral anesthesia, or both, depending on the amount of energy. Alster and Konda obtained mean clinical improvements of 41%, 48%, and 57% in the neck, hands, and chest, respectively, up to 3 months after a single treatment. Wrinkle severity and hyperpigmentation were significantly reduced and skin smoothness was significantly improved in all 3 areas. Side effects were limited to edema, erythema, and desquamation. To the author’s knowledge, the PSR device, although used by some physicians, is no longer commercially available.

Lasers

A variety of laser and light-based procedures have been used to rejuvenate neck skin ( Table 1 ). Considered the gold standard for rejuvenating skin, the ablative CO ₂ laser ushered in an era of precision and thus the possibility of better predictability compared with chemical peels and dermabrasion. As discussed later, early attempts at neck resurfacing were marred by complications due to treatment and technologic issues. With multigenerational improvements and better understanding of treatment nuances, however, successful treatments are now consistently achievable. The CO ₂ laser emits light at 10,600-nm and targets tissue water, which absorbs energy at this wavelength. A single pulse ablates the upper 20 μm of skin and collateral damage occurs at 0.2- to 1.0-mm depths. Advantages include control of tissue vaporization, minimal excessive residual thermal damage, dermal collagen contraction, and hemostasis.

The CO ₂ laser for neck skin rejuvenation has been studied by 4 groups. All used 1 or 2 passes with anesthesia and 100- to 500-mJ energy. Moderate improvements were noted in skin color, texture, tightening, and rhytids whereas adverse effects were transient and limited to erythema, hyperpigmentation, hypopigmentation, and, in the lower neck, scarring. In their 308-patient study, Behroozan and colleagues showed that a short-pulsed CO ₂ laser could safely rejuvenate the neck and the face at the same time with minimal risk of scarring or permanent pigmentary changes. Fitzpatrick and colleagues pointed out that wound healing of the neck, especially in the lower third, is noticeably less satisfactory than healing of the face. Healing is also more satisfactory in the upper neck than in the lower neck, so the lower part of the neck may require different treatment settings, as suggested earlier by Rosenberg. Consistent with these findings, Sasaki and colleagues reported average skin depths of 115 μm, 75 μm, and 70 μm for the upper, mid, and lower neck, respectively, and corresponding adnexal densities, all of which suggest that laser treatment settings for upper neck differ significantly from the treatment parameters used for the mid and lower neck.

The rationale for using the 2940-nm Er:YAG laser to resurface the neck is based on an anticipated reduction in thermal damage compared with the CO ₂ laser. Because 2940 nm is at the peak of water absorption, diffusion of heat to surrounding tissue is greatly reduced, thus lowering the risk of scarring and damage to pilosebaceous units. As shown in Table 1 , energies were higher (600–1700 mJ) than with the CO ₂ laser and 1 to 4 passes were made. Improvements were variable (0%–75%) and adverse effects included temporary erythema and hyperpigmentation. In 1 case, erythema was secondary to infection. Although use of anesthesia was not reported by 2 groups, patients of Jimenez and Spencer required topical anesthesia before treatment and local infiltration of lidocaine during Er:YAG laser resurfacing of the neck.

Goldman and Marchell treated the necks of 11 patients with a near-simultaneous beam of low-fluence CO ₂ and Er:YAG laser energies. The investigators had previously observed that nonspecific thermal damage with the combination beam was 14.8 to 37 μm, which is less than that of the CO ₂ laser alone (27.2–59.2 μm) or the Er:YAG immediately after CO ₂ resurfacing (22.6–37 μm). They found that improvement in skin texture and color was greater with the combined beam than with the Er:YAG alone. Patient satisfaction was also higher and adverse events were not observed, suggesting that the CO ₂ /Er:YAG laser beam was more suitable for neck resurfacing than the Er:YAG laser alone.

Weiss and colleagues reported a 4-year study of patients treated several times with intense pulsed light. Improvement was noted in skin texture, telangiectasia, and pigmentation while adverse effects included transient crusting, erythema, and purpura. Long-lasting hypopigmentation was noted in 2.5% of patients. Dahan and colleagues, using a nonablative Er:Glass laser, obtained improvement in skin texture and tone and increased dermal thickness, which they attributed to the growth of collagen fibers. Patients received 5 treatments. Adverse effects were not observed.

Using an ablative fractional CO ₂ laser, Tierney and Hanke obtained improvement in overall cosmesis as well as skin texture, laxity, and rhytids with minimal adverse effects. In fractional technology, the laser beam creates an array of microscopic wounds at specific depths rather than vaporizing the entire outer layer of tissue. Collateral damage is controlled and healing is rapid because the tissue surrounding each tiny wound is undamaged and keratinocytes have only short distances to migrate during re-epithelialization. Collagen contracts and neocollagenesis are initiated.

The advantages of fractional over fully ablative lasers are documented. Re-epithelialization after treatment is more rapid, post-treatment skin care is shorter, acneiform eruptions are less frequent, and postoperative erythema resolves more quickly. Adverse effects of fractional ablative lasers have only recently been reported. Avram and coworkers, for example, described hypertrophic scarring of the neck in 5 patients who had recently undergone fractional laser treatment. The investigators suggested that the scars might be attributed to the neck’s low wound-healing capacity, a “subtle fibrosis” due to damaged blood vessels after face or neck lift surgery, or a plastic surgery procedure in which underprivileged neck skin was placed on the face. Shamsaldeen and colleagues reported adverse events in 16.8% of 374 patients treated on the neck, face, and other nonfacial areas with a deep fractional CO ₂ laser. Adverse effects have also been found on the neck and other areas treated with the 1500-nm erbium-doped fractional laser.