Introduction

While skin rejuvenation dates back to the Egyptian era, laser facial rejuvenation is a recent innovation. It is said that Cleopatra used soured milk (lactic acid) to rejuvenate her skin. Thus chemical peels as well as a variety of mechanical exfoliations have been practiced for thousands of years. The laser, however, is a recent addition to the skin rejuvenation armamentarium. In 1960, Theodore Maiman produced the first laser energy, utilizing a Ruby crystal.¹ New laser development was primarily a product of the communications industry, and in fact much of the early work was done in Bell Laboratories. Many of the lasers used in medicine today were developed for industrial use and later adapted to medical applications. Patel published his discovery of the carbon dioxide laser in 1964.²

Laser application in medicine gained momentum in the late 1960s and early 1970s. Dr Leon Goldman commonly considered ‘the father of laser medicine’ and many other pioneers recognized the value of the laser in treating a variety of medical conditions.³ Ophthalmology was one of the early adopters of laser energy for treating intraocular neovascularization. The technology was soon applied to vascular birthmarks, such as port-wine stains. These early lasers, however, were very crude devices with poor control of the laser parameters, thus leading to mixed results. Commonly a port-wine stain was exchanged for a scarred, hypopigmented area of skin. The satisfactory treatment of many skin conditions awaited the development of new technology and understanding.

The concept of selective photothermolysis (SPTL) was introduced by Anderson and Parrish in 1983 and proved to be a turning point in the laser treatment of skin conditions.⁴ This theory recognized that the optimal treatment of a variety of skin disorders was dependent on optimization of several factors related to the target tissue and the laser parameters. The target of vascular disorders for instance, was the hemoglobin inside the vessels. The laser wavelength that was preferentially absorbed in hemoglobin was that wavelength which was heavily absorbed by hemoglobin and minimally absorbed by other competing pigments in the tissue. Absorption curves which plot percent absorption versus wavelength for a single tissue are not linear but have many peaks and troughs. When the absorption curves for the various absorbers, termed chromophores, in the target area are overlaid it is possible to choose optimal wavelengths that are heavily absorbed by the target (e.g. hemoglobin) and minimally absorbed by other chromophores such as water, xanthophyll, and melanin that would compete with the hemoglobin to absorb the laser energy. Since nearly all lasertissue interaction is thermally induced, the controlled heating of the target tissue is created by the absorption of the laser energy which is induced by photons impacting the molecules of the tissue. Vibrational energies disrupt the molecules and the cells of the tissue target.

As part of the SPTL theory, the concept of thermal relaxation time was introduced to explain the selective heating of the various tissue components. In essence, this concept states that the confinement of energy (heat) within a structure can be controlled by limiting the exposure time. This thermal relaxation time is proportional to the size of the structure, meaning that extremely small tissue components such as melanosomes have an extremely short thermal relaxation time, and thus should be treated with extremely short pulse duration. Typically these nanometer structures would be treated with a nanosecond pulse duration. By limiting the pulse duration the energy is thus inhibited from spreading to surrounding structures causing unwanted damage.

Energy loading or heating of target tissue to achieve a specific goal such as disruption of the cells tends to be an all-or-none phenomenon. Thus, like the high jumper who has to jump 6 feet to clear the bar, the ablation threshold has to be reached in order to achieve cell disruption. Below the ablation threshold nonselective heating of the tissue can occur, which will lead to untoward results. This ablation threshold is also related to the size of the target structure. The concept of selective photothermolysis (SPTL) opened the door to many successful laser treatments.

The result of the SPTL theory led to the development of the first laser which was specifically designed and produced to treat a medical condition. This was the pulsed dye laser used for treating port-wine stains. The pulsed dye laser was almost instantly accepted in treating port-wine stains in very young patients which had hitherto been very problematic.⁵ It was not long before new lasers were introduced, having been designed according to the theory of SPTL for treating a variety of ailments such as lentigines, tattoos, and skin aging.^5,6

Unfortunately the theory of selective photothermolysis is not ideal in every situation. While it has led to a greater understanding and thus more effective treatment in most lesions, there are exceptions to this generalization. For instance, the original flash lamp pulsed dye laser was designed to deliver energy at 577 nm, a peak in the absorption curve of hemoglobin. Because of the considerable variation in size, color, and depth of vessels within a port-wine stain, the newer lasers have emitted wavelengths at 585 to 595 nm. In addition the pulse duration of the original pulsed dye laser, 450 ns has been extended to the millisecond range for the same reason. This compromise from the SPTL theory ideal has led to a much improved outcome while minimizing undesirable side effects.

Recent innovations in the major facial rejuvenation have involved other wave lengths and other sources of radiant energy. Examples of these would include the intense pulsed light (IPL) as well as radiant energy sources such as microwave and radiofrequency excited sources. The intense pulsed light is a noncoherent light source consisting of a broad spectrum emission of relatively modest energy. The function of the microwave and radiofrequency sources is to stimulate collagen tightening and deposition.

The carbon dioxide (CO₂) laser with a wave length of 10,600 nm in the far infrared portion of the spectrum is capable of coagulation and ablation of tissue. Thus it is used to remove lesions by evaporation as well as to thermally stimulate the tissue. The normal response can therefore be quite varied, depending on a large number of factors such as tissue hydration as well as the laser parameters such as pulse duration and energy density. Although the traditional carbon dioxide laser does not meet any of the parameters of the theory of selective photothermolysis, nevertheless this laser can be designed to achieve satisfactory ablation or cutting while minimizing thermal damage.⁸

As an ablative instrument the carbon dioxide laser has been used to remove a variety of benign and malignant lesions.⁹ These include verrucae, syringomas, seborrheic keratoses, and other benign lesions. Actinic keratoses as well as superficial basal cell carcinoma can be removed with these lasers, however, due to a lack of histologic confirmation one can never be certain that the lesion is totally removed by the laser.¹⁰

Two conditions which respond extremely well to the carbon dioxide laser treatment are rhinophyma and actinic cheilitis.^11,12 A generic treatment regimen for these types of lesion would include the use of a 1 mm handpiece with a focused and defocused beam, usually pulsed mode with sufficient energy to evaporate the tissue. Coagulated tissue may require removal by wiping between passes. Commonly some minor scarring and hypopigmentation can be seen at the site of treatment.

Methods

As mentioned above, a variety of chemical and mechanical processes have been used in the past to rejuvenate the skin. Most of these required removal of a large portion of the epidermis as well as portions of the dermis, anticipating that the healing process would rejuvenate the epidermal elements including pigment, and contraction of the dermal collagen elements with additional collagen being deposited during the healing process. It was quickly recognized that the laser could produce a similar effect. In particular the carbon dioxide laser was used for treating photoaged skin in the 1980s. Early attempts with conventional carbon dioxide lasers however led to many unsatisfactory results, including scarring.¹³ With the advent of high peak power, rapidly pulsed or scanned carbon dioxide lasers, this difficulty was overcome in accordance with the theory of SPTL, mentioned above.

There are generally two methods of achieving the necessary energy in a sufficiently short time frame in order to achieve evaporation/ coagulation with minimal thermal damage. These would be the extremely short pulsed, high energy lasers as well as the rapidly scanned continuous-wave laser. The super pulsed carbon dioxide laser was a step in the direction of satisfactory laser rejuvenation. The UltraPulse laser by Coherent Inc. was capable of delivering 5 j/cm² in a sufficiently short period of time in order to allow vaporization of 20 to 30 μ of tissue and residual thermal damage of 40 to 120 μ depth after two or three passes.¹⁴ Most of the laser resurfacing is accomplished with a robotic scanner which Coherent termed the computerized pattern generator (CPG). Histologically much of the epithelium is removed. Although elastin may persist, type I collagen is denatured between 60 ° and 70 °C, causing it to shorten.¹⁵ Epithelialization was complete in seven days, but total healing as indicated by an abating of the erythema required several weeks. In fact, collagen deposition may be seen for many months following the laser resurfacing. Comparison of laser resurfacing with chemical peel and dermabrasion showed similar healing and results, with the exception of the phenol peel which required considerably longer to heal. No scarring was observed in this treatment study.¹⁶

A competing technology for laser resurfacing is the rapidly scanned carbon dioxide laser produced by Sharplan called the Silk Touch. This continuous wave CO₂ laser is rapidly scanned across the skin surface, thus reducing the swell time and therefore the effective pulse duration.

Indications and Contraindications

Although virtually every patient would receive some benefit from laser resurfacing, choosing the appropriate patient and preparation for treatment will achieve the optimal results. Most forms of photoaging including pigmentation disorders, as well as elastosis and laxity of the skin, will improve with laser resurfacing, although some lesions will not totally disappear. A sufficiently educated patient who has been informed of the procedure, alternatives and risks, and has a realistic expectation, is undoubtedly the best candidate. Patients who are prone to form keloids or aggressive scars are probably not good candidates. Other skin conditions such as scleroderma, and patients who have been treated within the past year with isotretinoin, are also probably not good candidates for laser resurfacing. In addition, patients who are receiving simultaneous cosmetic surgery such as facelifts are at risk of developing scars in the portion of skin that is undermined. Although there are reports describing treatment of the neck and other areas of the skin with the carbon dioxide laser, these generally require extreme care, because they are very susceptible to scarring and significant pigmentation changes. There are better modalities for treating these areas including the erbium laser, fractional laser or others.

The ideal areas for laser resurfacing would include the periorbital area as well as the perioral area. Neither of these areas is particularly improved by facelift procedures. A conservative approach is generally recommended, especially in instances where the patient response may be questionable. It is possible to repeat the laser resurfacing after three to six months and the results should be additive.

Preoperative Considerations

Preoperative treatment with tretinoin and possibly skin bleaching agents for a few weeks is frequently beneficial. It is generally thought to be beneficial to relax the muscles in the laser treatment area with botulinum toxin, for instance the ‘crow’s feet’ and glabellar frown lines a few days prior to the laser resurfacing procedure. However, there are no studies at present that have confirmed this benefit of muscle relaxation prior to the treatment.

Prophylactic treatment with antibiotics and antiviral medications preoperatively are advised.

As tretinoin preparations seem to speed epithelialization, many would administer these topically for a few weeks prior to the treatment. Patients with Fitzpatrick skin type IV and higher are subject to developing hyperpigmentation, particularly in low latitudes with heavy sun. For this reason a pre-treatment course of hydroquinone or other bleaching agent is advisable. Many patients unknowingly carry the herpes simplex virus and thus antiviral medications are almost always given, especially for treatment in the perioral area. These should be started a day before treatment, and continued throughout the healing phase. Antibiotics also are advisable as a number of bacterial infections have arisen after the treatment. In rare cases, hospitalization for intravenous antiviral drugs or antibiotics has been necessary. Although this is uncommon, the therapist should closely observe the patient in the post-treatment period. If the patient seems to be progressing nicely, but takes an abrupt turn for the worse by developing ulcers in a previously healing area, this is an indication that infection may be starting.

Laser resurfacing requires some form of anesthesia. While other laser procedures may be adequately performed with only topical anesthesia, the carbon dioxide laser treatment usually requires something more. Nerve blocks for limited resurfacing can be helpful, but if the patient is undergoing entire face or large areas of resurfacing, a heavy sedation is probably advisable. Even then, the patient will awaken with a stinging sensation which may necessitate oral pain medication. These medications should be given to the patient in the preop visit. It is also advisable to encourage the patient to minimize chewing, prepare ice packs or other cold compresses, as well as soaks and other postoperative necessities. These will be discussed below.

Operative Approach

After adequate anesthesia, it is necessary to protect the patient’s eyes. Especially when treating the periorbital area, intra-ocular eye shields should be used. These will necessitate an ophthalmic lubricant and perhaps an ophthalmic anesthetic. The area to be treated is usually prepped within antiseptic solution to cleanse the skin, chloroxyenol 3% being an excellent cleanser. It is obvious that at best this is a clean procedure and not a sterile procedure; nevertheless prepping the skin is advisable. Care should be taken to protect the airway, as well as any source of oxygen, as fires have resulted. Smoke evacuation of the laser plume is necessary.

If there are specific lesions requiring ablation, these should be treated before generalized resurfacing. This may require a focused handpiece with either pulsed or continuous-wave energy. The robotic scanner or pattern generator may then be substituted to accomplish the generalized resurfacing. Entire aesthetic units of the face should be resurfaced before moving to other areas. Sometimes, starting on the forehead is easiest because of the broad flat surface area. Care should be taken to preserve the eyebrows and hair line, although these will certainly grow back during the healing phase. Usually two or three passes of aggressive resurfacing are necessary for each area.

After the first pass, the desiccated epithelium can be wiped away with a moist cloth. It has been shown however that vigorous rubbing of the skin deepens the effect of the laser treatment. Some therapists would leave the epithelium in place after the first pass as a dressing, which is acceptable unless one is pursuing an aggressive treatment. Experience gained from doing laser resurfacing is a valuable asset in recognizing the depth of treatment. Clinical indicators of the depth of penetration can be seen following each pass. Generally speaking, after the first pass when the epithelium has been wiped away the upper dermis will be pink and moist. Wiping the surface with saline soaked gauze not only removes the keratin debris but also rehydrates the skin. The skin area to be resurfaced should be dried prior to proceeding. When the second pass has been accomplished, this may turn gray and appear dry. A third or subsequent passes may lead to a tan or ‘chamois’ color which is as deep as the treatment should be pursued. This is in the deep reticular dermis. Further treatment beyond this point only contributes to the thermal wound and potential complications without adding to the benefit.

Care should be taken to feather or blend the edges of the laser treatment in order to avoid abrupt changes from rejuvenated skin to non-treated skin. This is of particular importance when doing only portions of the face or when resurfacing the face of a patient with a badly photoaged neck. The feathering can be accomplished by decreasing the energy, the density of the pulses, or by making fewer passes. Specific areas of need such as isolated perioral wrinkles, the lateral commissure lines, etc. may be addressed with an additional pass, usually with a single spot handpiece. At the conclusion of the resurfacing the skin should be cleansed again with a gentle antiseptic and rinsed.

Postoperative Care

The postop dressing or treatment is probably one of the more controversial issues of laser resurfacing. A variety of treatment protocols have been promoted over the years. In general they can be divided into two categories, open treatment which usually means topical ointment or cream, and a closed treatment which is frequently a membrane or mask. The open treatment will frequently consist of periodic soaks and or gentle cleansings followed by application of a topical antibiotic or burn cream/ointment. This should be done several times a day. Crusty areas can be soaked with cool compresses consisting of ¼% acetic acid in distilled water or saline. After the crusting and weeping has abated, the patient can start using a gentle moisturizer cream. The closed method consists of application of a mask or membrane in the immediate postop period. The skin is usually dried, following which the material is applied. This should be left in place for approximately 5 days, although some therapists advocate changing it the day following the resurfacing. The reasoning behind changing the mask is to detect any infections early.

A recent innovation is a silicone sealant which is applied immediately after the procedure. This is a two-part, epoxy-like, clear, flexible silicone material (Innovation Alley, Lyndhurst, OH). It is difficult to get this material to adhere to the skin, and the patient is advised to minimize movement such as talking and chewing. Frequently it will separate in the immediate postop period. Nevertheless, it is left in place for approximately 5 days unless it develops a green drainage underneath, possibly indicating infection, in which case it is removed and soaks are started with appropriate therapy. It is also sometimes removed around the mouth if food collects under the mask. The fifth day the patient is advised to sit in the shower soaking the face. The mask can be elevated from the skin with a cotton tip applicator lubricated with antibiotic ointment. Portions of the mask which are strongly adherent are left in place until they spontaneously loosen and fall off.

The results are often gratifying, especially when the laser resurfacing is combined with facial rejuvenation (Fig. 5.1A&B). In patients who undergo facial rhytidectomy at the time of facial laser resurfacing, the laser energy level should be reduced in the undermined area to minimize the potential for deeper thermal damage.^22,23 The fluence will be set at a lower level on the lateral portion of the face (settings such as a density of 3, 60 watts, and 100 mJ). The density will be increased as the laser is advanced medially. It is also be safer to minimize the undermining of the skin during the rhytidectomy.

Fig. 5.1 A&B, Pre and postoperative result, patient had laser resurfacing combined with facial rejuvenation.

Complications and Sequelae

As previously mentioned, pigmentation changes are the most common sequelae following a laser resurfacing. Hyperpigmentation is frequently seen in Fitzpatrick skin types III and greater, especially during the summer in the southern latitudes. This is frequently self-limiting, but should be treated with tretinoin and bleaching agents. In a few patients, typically Fitzpatrick skin types I and II, a delayed hypopigmentation is sometimes seen.^13–17 This may not appear until a year or more following the laser resurfacing procedure and generally is resistant to treatment. Inclusion cysts or milia are frequently seen, particularly in the periorbital area. These will usually spontaneously open, but sometimes have to be pricked. Infection, as indicated by ulcers or a worsening of the inflammation, may appear up to a week or more following the resurfacing procedure, and should be aggressively treated with cleansing, soaks and antibiotics in order to avoid scarring. Staphylococcus, Pseudomonas, Candida, and herpes simplex are among the more common pathogens. Conjunctivitis may result from the intraocular eye shields or topical ointments applied around the eye. In rare instances, these may require treatment with ophthalmic antiinflammatory drugs. Ectropion can result from aggressive resurfacing of the lower eyelid in susceptible individuals. Rarely, scarring results from overly aggressive laser treatment, secondary infections, or the patient traumatizing the skin. Pruritus is common in the postop period and should be treated with topical creams or antihistamines.

Laser Blepharoplasty

I have been using the laser in blepharoplasty for over 12 years and have done approximately 1000 cases with it.¹⁷ Almost all of my blepharoplasties involve carbon dioxide laser for excision, transconjunctival fat removal, and laser resurfacing of the upper and lower eyelids. Although this lengthens the healing time, there are many advantages to it. It is simpler, safer, and faster. The technique will be described below.

Operative Approach

The concept of laser blepharoplasty was introduced by Baker in 1992.¹⁸ Roberts collected a series of 907 laser blepharoplasties with a 95% satisfaction rate in wrinkle reduction and a 0.3% ectropion incidence.¹⁹ The advantages were pointed out that this procedure was faster, safer, with less bruising than conventional blepharoplasty. The disadvantages include the cost of the equipment, a learning curve and a longer healing time. The exceptional patient with considerable festooning or marked laxity of the lower lid may not be a candidate for transconjunctival blepharoplasty, but these patients may still be candidates for the standard transcutaneous lower lid blepharoplasty with a subciliary incision made by the laser. Seckel, using the CO₂ laser, was able to tighten the orbicularis oculi muscle through the transconjunctival approach.²⁰

The technique involved is very similar to conventional transconjunctival blepharoplasty. Selection of the patient involves screening for other eye conditions as well as laxity of the lower lid with a snap test. Appropriate tightening of the lax lower eyelid can be done in conjunction with the laser procedure. Based on the orbital anatomy, patients have to have realistic expectations as to the final result. Although removal of the ROOF tissue can be done easily with the laser, it is not possible to give a ‘deep set’ result in a patient with a shallow orbit and a full upper lid. Other adjunctive procedures for the lower eyelid could involve transconjunctival fat transposition utilizing the laser in the patient with a deep tear trough.

Under general anesthesia or intravenous sedation the face is prepped and draped. Local anesthesia is injected into the upper and lower eyelids including transconjunctival injection. Eye shields are placed to protect the eye. Laser resurfacing of the eyelid and periorbital skin is usually done prior to the blepharoplasty. Eyelid skin which is thinner shrinks much more than does other facial skin. It is not uncommon to see a 20-30% shrinkage of the eyelid skin which is frequently enough to avoid skin excision of the upper lid. Some of this shrinkage is reversible, perhaps 10%, for a few days following the treatment. Anticipating this relaxation of the skin tension, it is safe to tighten the upper eyelid skin somewhat more than the final desired result. Usually it is sufficient to have a small gap in the palpebral fissure of perhaps 2 to 3 mm, which will then allow adequate eyeclosure as the healing proceeds.

Having completed the resurfacing of the periorbital skin, the lower transconjunctival incision is made by retracting the lower lid margin and incising the conjunctiva approximately 6-8 mm inside the lash line. This was carried from one end of the eyelid to the other. With proper retraction, the bulging fat can be seen through the septum of the lower eyelid. The lower eyelid retractors can be gently teased from the wound. Incising the septum with the laser allows the bulging fat to protrude. The fat can then be grasped with the forceps and transected with the laser handpiece and a slightly defocused mode. Only that amount of fat which ‘volunteers’ should be excised, in order to avoid a hollow-eyed appearance. Defocusing the laser beam will allow coagulation of any vessels which can be seen as the fat is excised. Care should be taken to avoid injuring the inferior oblique muscle. Residual herniated fat which should be excised can be detected by allowing the lower eyelid to relapse into its normal position. Slight pressure on the globe will then reveal any bulging fat. After the fat is adequately excised, the eyelid is allowed to resume its normal position. No sutures are placed in the conjunctival incision.

Having completed the lower eyelid portion attention is turned to the upper eyelid. The amount of skin to be excised from the upper eyelid can be estimated by grasping the excess skin with the forceps and marking it with a skin marking pen. Utilizing an UltraPulse mode to incise the skin will minimize thermal damage at the incision site. Deeper tissue excision can be accomplished with a continuous wave beam. Portions of the orbicularis ocular muscle can be excised as part of the skin muscle island. The septum is then opened with the laser following which the excess fat of the upper eyelid is excised. ROOF fat can be excised with the laser at this time. Care should be taken to avoid the supraorbital nerve and the branch of the lachrymal artery in the lateral portion of the ROOF fat. Should the artery be injured, it usually can be coagulated with the laser. Only on a very rare occasion is cautery necessary during a blepharoplasty with the laser. Once the fat is excised, the upper eyelid incision can be closed in the usual manner. The incision can be closed with sutures. It has been recommended to leave sutures closing a laser incision a day or two longe to achieve greater wound tensile strength which might be retarded by the laser. This has not been my experience.

Postoperative care is the same as with conventional blepharoplasty, except that the laser resurfaced area should be treated as noted earlier with appropriate creams or mask dressings.

Methods Other Than Co₂ Laser Technique

The Future

It is fair to say that the laser skin rejuvenation is here to stay. Although we have come a long way in utilizing this new technology, there is still much to be learned. For instance, virtually all of the laser effects that have been utilized for skin rejuvenation in the past have been thermally mediated. That is the laser energy is absorbed by tissue which then heats it, thereby creating both desirable as well as undesirable effects. It has been termed a ‘controlled burn’. It has long been known that subcellular effects can regulate certain cell processes without heating the tissue. An example of this is blue light therapy for neonatal jaundice. The science of ‘low-power lasers’ which alter metabolic processes within the cell without physically damaging it, is emerging. In addition, new wavelengths as well as pulsing technologies will be developed to the extent that the laser can be finely tuned to treat specific entities. Side effects or sequelae will be minimized. Finally, the laser can be used in conjunction with topical medications to enhance their effects. This may be accomplished by increasing the penetration of the medication, activating the medication by the light interaction, or synergistically altering the tissue.

Many excellent articles and textbooks have been published, exhaustively discussing the concepts which have been superficially treated here. An example of these would be Lasers in Cutaneous and Aesthetic Surgery edited by Arndt, Dover and Olbricht.²¹ Clinicians wanting to become involved in laser medicine and keep abreast of the latest developments in this growing field would be well advised to attend the annual meeting of the American Society for Laser Medicine and Surgery (www.aslms.org).

Conclusion

In summary, carbon dioxide laser skin resurfacing remains the gold standard for skin rejuvenation. There have been many new technologies which have arisen to replace this, but none have measured up. The greatest problem with resurfacing is the healing associated with crusting and redness. This is because healing involves regeneration of not only the epithelium, but a large portion of the dermis. This of course involves complex metabolic pathways as well as increased circulation, and takes many months to complete. Patients should not be concerned if their result is not seen in the first few weeks following resurfacing. On occasion, it is wise to supplement the initial treatment with follow-up touch-ups, which may be of a lesser degree.