The Carbon Dioxide Laser in Oculoplastic Surgery and Sliced Bread

The Carbon Dioxide (CO2) laser has been used by ophthalmologists for well over 10 years. We have performed CO@ laser blepharoplasties on the oculoplastic service at the Jules Stein Eye Institute, Los Angeles, Calif, since the mid 1980’s, initially using underpowered continuous wave machines, including one with a cumbersome flashlight-sized handpiece designed for podiatry. The machines have advanced significantly since then, particularly in their ability to perform controlled ablation of the superficial layers of the skin (laser resurfacing); however, the technological advances have been outpaced by the striking advances in media interest in laser cosmetic surgery. Laser aesthetic surgery, which has always been a popular topic for both physicians and the lay public, has recently had a firestorm of publicity, including, for example, a notable television personality having his own laser resurfacing performed live on his talk show. Marketing of laser blepharoplasty by physicians is now mainstream as well: 5 or 10 years ago advertisements for laser surgery were typically placed by physicians without formal surgical training, but now it is common for respected ophthalmic, facial plastic, and general plastic surgeons to market CO2 laser surgery.

It does not take a rocket scientist (or laser physicist) to grasp that the recent media interest in CO2 laser surgery is substantially generated and fueled by the successful public relations of laser surgeons and laser manufacturers. For the ophthalmologist trying to decide whether to train in and begin to perform CO2 laser surgery, it is incumbent, but difficult, to try to sort through the hype and determine the advantages and disadvantages of the CO2 laser over other modalities. I will focus on the 3 promary applications of the CO2 laser in oculoplastic surgery: laser blepharoplasty, laser resurfacing, and laser marketing.

LASER BLEPHAROPLASTY

The CO2 lasers used for blepharoplasty are delivered through a handpiece on an articulating arm (the beam travels through a series of hinged mirrors). The patient must be draped in a special fashion: the face is surrounded by wet cloths and shield to prevent fires (if the laser strikes dry cotton) or burns (if the beam strikes inadvertent areas of skin). Instruments have special nonreflective surfaces to minimize unwanted reflections, and the surgeon and all operating personnel wear protective glasses. The patient’s globes are protected with stainless steel shields. A filtered smoke evacuation system is needed to evacuate the laser plume. Typically, at least 1 extra person is needed in the operating room to monitor and run the extra equipment, and all personnel receive extra training in laser safety. Naturally, there is additional training and a learning curve for the surgeon.

Once the laser is armed, a red aiming beam identifies the laser focus. The CO2 laser beam itself is invisible. For blepharoplasty, a focused handpiece is typically used. For cutting, a fine laser spot can be used (0.2 mm), but the handpiece can also be drawn back to defocus the beam to create a less intense burn that will cauterize vessels without cutting through them.

A CO2 laser cut is characterized by minimal bleeding, because the intense heat of the laser cauterizes small vessels as it cuts. Equivalent hemostasis can be achieved with standard cutting electrocautery, but, particularly for skin incisions, cautery may cause more collateral heat damage than the precise cutting of the laser (especially with some of the newer ultrapulsed cutting modes). The laser is very effective for vaporizing fatty tissue. The depth of the laser cut is potentially unlimited, so care must be taken to avoid inadvertent injury to deep structures in the wound and to protect the globe.

To our knowledge, there has been no large double-blind study comparing the use of the laser for cutting and hemostasis in blepharoplasty with other techniques. Anecdotal reports and small series of cases suggest that the use of the laser in blepharoplasty decreases postoperative swelling and bruising and possibly decreases intraoperative and postoperative pain. The theoretical basis for decreased swelling and bruising is that the laser seals small capillaries and lymphatics with minimal collateral damage; decreased pain may be related to sealing of nerves and decreased collateral damage. Histologically, laser wounds are characterized by decreased inflammation and increased hyaluronidase activity. Not all surgeons agree, however, that the CO2 laser is associated with more rapid healing in blepharoplasy surgery, and most authors suggest that the long-term results are equivalent regardless of the technique used for cutting and hemostasis. At our institution we followed up 20 patients who underwent traditional blepharoplasty on one side and CO2 laser blepharoplasty on the other. Masked observers felt that there was decreased ecchymosis and swelling over the first 6 postoperative weeks with the CO2 laser technique; there was no appreciable difference between the sides at 3 months (unpublished data, 1995).

LASER RESURFACING

Skin resurfacing is performed to improve the quality of the skin surface. It is an important aspect of aesthetic facial surgery; incisional surgery can improve contours and remove excess tissues, but it cannot alter the texture and elasticity of the skin. Resurfacing, on the other hand, creates a superficial skin wound. The dermis reacts with a healing response characterized by new collagen formation and regeneration of a new epithelium. When the resurfacing is successful, the new surface is smoother and more elastic than the original. However, because an injury to the skin is created, there is potential for adverse scarring including hyperpigmentation or hypopigmentation, contraction (particularly worrisome in the periocular area), or hypertrophic scarring. Resurfacing can be characterized as superficial (epidermis), moderate (papillary dermis), or deep (midreticular dermis). The deeper peels trade an increased effect for an increased chance of adverse scarring. Finesse in resurfacing involves careful control of the depth of the injury.

Traditional resurfacing is performed using caustic chemicals that create a cutaneous burn. The depth of a chemical peel is influenced by many variables, including the type and concentration of the wounding agent, the type of application, skin type (such as dry vs oily), skin preparation, and regional anatomy. Experienced peelers can achieve fairly reliable results, but all of these variable can make it difficult, especially for occasional practitioners, to achieve uniform and reliable depth of injury.

The CO2 laser resurfacing procedure is performed by vaporizing the superficial layers of the skin. Modern laser technology achieves an accurate vaporization of controlled depths of epidermis and dermis (typically 100-150 micrometers per pass) with minimal damage to the underlying layers of skin. A spot size of about 3 mm is used; various pattern generators are available to automatically ablate larger areas. By adjusting the laser power and controlling the number of passes, the operator can achieve a fairly reliable and reproducible ablation. There is no residual dead tissue debris left on the surface as there is with a chemical peel; the fine white denatured collagen that remains is wiped away with wet cotton gauze.

The lay press seems to suggest, and patients would like to believe, that after a short painless procedure one goes home with new skin and that is that. Unfortunately, the procedure is not that simple. Identical to a chemical peel, a successful laser resurfacing causes a partial-thickness cutaneous burn injury that has to undergo a process of wound healing. Until reepithelialization occurs (typically 5-10 days), the skin has to be monitored carefully for herpetic or bacerial infections, which can lead to significant scarring. Some practitioners treat prophylactically for these infections. The skin must be kept moist until it epithelializes or else irregular scarring can occur. Patients may have pain, crusting, and significant redness at this stage, and reactions to the systemic and topical medications must be differentiated from the normal response to healing. Especially with a more aggressive resurfacing that extends into the reticular dermis, secondary intention healing can result in contraction and the most dreaded complication of resurfacing, full-thickness scar formation. In the late healing phase, which can last for 3 to 6 months, there is not infrequently persistent redness and hyperpigmentation or hypopigmentation; the redness eventually resolves but the pigmentary changes can be permanent. Practitioners, their office staff, and their patients have to be prepared to deal with these difficulties during the healing period.

Skin resurfacing can accomplish aesthetic improvement that is unattainable by other surgical interventions, and it plays an important part in the overall planning of aesthetic facial rejuvenation. Although the CO2 laser is not “magic” in its ability to avoid the problems and potential complications of resurfacing, it does produce a skin wound that is generally more reliable and reproducible than chemical peeling. It is far more expensive and time-consuming than a chemical peel, but the advantages related to control of depth of ablation probably justify its use.