The greatest fear of using lasers subcutaneously in the face is that facial motor nerve injury will occur. With SmartLifting procedures, this is not a complication that occurs provided the laser and surgical guidelines are followed. We have seen several short-term, marginal mandibular neuropraxias in several patients, all of which resolved within weeks. There have been no permanent nerve injuries in any patient undergoing SmartLifting procedures. There is temporary interruption of cutaneous sensory nerves during the rhytidectomy, and the resolution of the temporary sensory deficits is identical to the resolution of non–laser-elevated rhytidectomies.
History of laser lipolysis and internal aesthetic fiber laser–assisted surgery
The history of laser lipolysis is brief and has been summarized well by DiBernardo, who notes that Apfelberg is credited for describing the laser-fat interaction in 1992, and that publications by Blugerman, Schavelzon and colleagues, and Goldman and colleagues followed in which each showed their own experience with lasers on adipose tissue. Badin and colleagues also highlighted the important tissue retraction that he noted with his technique of laser lipolysis. Ichikawa and colleagues published on the histologic evaluation of tissue treated with laser lipolysis, showing the destructive changes of heat-coagulated collagen fibers and degenerated fat cell membranes with dispersion of lipid after laser irradiation of human specimens. These histologic changes correlate with clinical changes seen by both physician and patient. Further, the hemostatic properties of the 1064-nm wavelength have been well documented and are discussed later. The thermal effect produced by the neodymium-doped yttrium-aluminum-garnet (Nd:YAG) laser (1064 nm) in the adipose tissue promotes better hemostasis, resulting in less surgical trauma and wound healing with fewer adverse sequelae. In addition to the histologic evidence, the clinical evaluation shows improved postoperative recovery, resulting in a more rapid return to daily activities with an excellent aesthetic result. The application of laser lipolysis to facial and neck rejuvenation, in conjunction with the advanced facial rejuvenation techniques of SmartLifting, were introduced by Gentile in 2007. The initial procedures were performed with the SmartLipo 1064-nm laser but, on introduction of the SmartLipo MPX, the 1064/1320-nm multiplexed laser was used. Although these lasers were introduced for the purpose of lipolysis, it became evident that, for the facial plastic surgeon, the lasers had significant hemostatic and tissue-tightening effects. External laser treatment of human skin does produce a remodeling of dermal collagen and elastin fibers as well as the stimulation of neocollagen. In other aesthetic devices, the epidermis and dermis presented itself as an obstruction to getting optical or electrical energy into the deeper dermal and subcutaneous layers. Internal aesthetic lasers bypass this obstruction and hence are better positioned to perform thermodermoplasty or shrink-wrapping of the facial and neck skin envelope. The use of internal aesthetic lasers is a new modality and the benefits of these innovative or technology-enabled techniques can be assessed by examining the factors listed in Table 1 regarding the potential benefits provided by introduction of a new technology-enabled technique. New technology should not only introduce another particular technique, it should be proved to offer the specific benefits that are detailed in Table 1 .
| Criteria for assessing improved outcomes in aesthetic surgery resulting from technology innovations | Reduces anesthetic requirements for procedure |
| Reduces operating time for procedure | |
| Reduces complications or morbidity for procedure | |
| Reduces recovery time for procedure | |
| Facilitates new technical approaches lacking in conventional or existing techniques | |
| More than 1 novel application is possible with the new technology |
The introduction of internal laser use for aesthetic facial and neck rejuvenation
The Cynosure SmartLipo laser was the first laser to be approved by the US Food and Drug Administration for laser lipolysis. In addition to the laser lipolysis indication, the laser is approved for the surgical incision, excision, vaporization, ablation, and coagulation of soft tissue. All soft tissue is included, such as skin, cutaneous tissue, subcutaneous tissue, striated and smooth tissue, muscle, cartilage meniscus, mucous membrane, lymph vessels and nodes, organs, and glands. Since the 2006 introduction of subcutaneous laser-based lipolysis techniques, other laser companies have introduced similar products and many have introduced different wavelengths for the specific indication of laser lipolysis. Other wavelengths for laser lipolysis include 980 nm, 1440 nm, and 1444 nm.
The introduction of internal laser use for aesthetic facial and neck rejuvenation
The Cynosure SmartLipo laser was the first laser to be approved by the US Food and Drug Administration for laser lipolysis. In addition to the laser lipolysis indication, the laser is approved for the surgical incision, excision, vaporization, ablation, and coagulation of soft tissue. All soft tissue is included, such as skin, cutaneous tissue, subcutaneous tissue, striated and smooth tissue, muscle, cartilage meniscus, mucous membrane, lymph vessels and nodes, organs, and glands. Since the 2006 introduction of subcutaneous laser-based lipolysis techniques, other laser companies have introduced similar products and many have introduced different wavelengths for the specific indication of laser lipolysis. Other wavelengths for laser lipolysis include 980 nm, 1440 nm, and 1444 nm.
Early clinical studies and observations
The original SmartLipo laser ( Fig. 1 ) delivered 1064-nm optical energy though a 300-μm fiber at 6 W ( Fig. 2 A ). All subsequent Cynosure SmartLipo and SmartLipo MPX lasers use a 600-μm fiber (see Fig. 2 B) and now the 1000-μm fiber (see Fig. 2 C) for high-power laser lipolysis. The 600-μm optical fiber is introduced into a 1-mm diameter stainless steel microcannula of variable length and is used for facial laser-assisted procedures. The laser is fired through the distal end of the fiber, which protrudes 2 mm beyond the tip of the cannula. The distal end of the fiber interacts with the facial and neck soft tissue. For visualization purposes, an aiming laser source is provided in the beam path providing the precise location of the fiber tip, indicating where the laser is working. For most facial and neck anatomic regions, a 6-W to 12-W, 100-microsecond pulsed laser at 40 Hz and 150 mJ was used. The SmartLipo MPX laser, which is capable of blending both the 1064-nm and 1320-nm wavelengths, was used in more recent studies and is used today in completing these procedures. The Nd:YAG laser produced photomechanical and thermal effects that dissected the tissue quickly and easily. In addition, the hemostatic properties of the Nd:YAG laser allowed for the coagulation of small blood vessels in the subcutaneous plane with preservation of the dermal plexus of vessels. Multiplexing the 1064-nm and 1320-nm wavelengths provides some unique advantages. SmartLipo with MultiPlex (known as SmartLipo MPX, Fig. 3 ) allows individual as well as sequential emission of 1064-nm and 1320-nm wavelengths. The sequential firing of these 2 wavelengths in combination maximizes the positive properties of both. The combination of these wavelengths increases the efficiency of laser lipolysis and offers a more evenly distributed laser energy profile that benefits superficial and deep treatment. These 2 wavelengths emitted sequentially offer a more efficient vascular coagulation through the conversion of hemoglobin to methemoglobin. The 1320-nm wavelength heats the blood, converting hemoglobin to methemoglobin. The 1064-nm wavelength has a 3 to 5 times greater affinity for methemoglobin than for hemoglobin, thereby increasing absorption and resulting in more efficient coagulation, leading to enhanced skin tightening. SmartLifting is noted to permit easier flap separation in typically difficult-to-reach areas such as the buccal labial folds (BLF) and the corner of the mouth and infracommissural BLF, also known as marionette lines, when completing full rhytidectomy. The wavelength characteristics and thermodynamic photospectrum of the 1064-nm and 1064-nm/1320 multiplexed lasers and comparative thermal volumes are shown in Fig. 4 .
1064-nm wavelength characteristics (see Fig. 4 A)
1320-nm wavelength characteristics (see Fig. 4 B)
Multiplexing (see Fig. 4 C)
Comparative thermal volumes (see Fig. 4 D).
Hemostasis and fiber laser flap elevation
After the observations of early 2008 and on my discussions with Cynosure regarding the clinical hemostatic properties observed, we began to investigate the intrinsic hemostatic properties of other laser for facial flap elevation. What we wanted to determine was how the SmartLipo and SmartLipo MPX lead to the profound and desirable hemostatic effects when used before facial flap elevation, as shown in Fig. 5 . Do other fiber lasers show an equal or proportionate hemostatic effect? With proper patient consent, we compared the use of the pulsed 1064-nm and pulsed 1064/1320-nm laser with a 980-nm continuous-wave laser. In these clinical studies, the power was set to 10 W and the procedures were completed. The results of the studies indicated that, although the 980-nm laser glided through subcutaneous tissue more easily, the net hemostasis was poor and the procedure was about the same as performing a rhytidectomy without the benefits of laser-enhanced hemostasis. Photographs of the study are shown in ( Figs. 6 and 7 ). The study was quantified by sponge use when completing the procedure, and roughly 5 times as many sponges were used on the continuous-wave 980-nm side as on the pulsed 1064-nm and 1064/1320-nm lasers (see Figs. 6 B and 7 C). Other clinical findings were that the patients had longer bruising, swelling, and induration after the subcutaneous treatment with the 980-nm continuous-wave laser, which is most likely caused by more blood extravasating into the superficial soft tissues. SmartLipo was also compared with the 1444-nm pulsed laser, which also did not show hemostatic properties as significant as the 1064-nm and 1064/1320-nm multiplexed laser.
SmartLifting techniques
SmartLifting evolved from the application of 2 new technologies in facial surgery. The first is the use of subcutaneous laser techniques for hemostasis and for developing the facial flap in the most ideal plane. The laser helps define the facial flap and creates a dissection plane by creating multiple microdissection tunnels ( Fig. 8 ). We initially performed this with a low-wattage Nd:YAG laser fiber introduced through a stainless steel cannula and operating at 6 W. With the advent of more powerful laser lipolysis units, higher optical energy is possible, but rarely should the power settings exceed 15 W. We generally use 9 to 12 W for most areas of the face, and the higher settings can be used with caution in the very thin midline neck in patients with heavy necks. The second new technology that was introduced in the past few years is the barbed suture used in open surgeries differing from the previous closed techniques. One of the problems with barbed sutures in closed procedures was the inability of tissue repositioned to stay where it was placed because of the considerable dermal attachments of the skin to the deeper soft tissues and the tendency of these dermal attachments to return the tissues to their original position. The dermal attachments eventually led to a gradual descent of the tissues, which made the subtle results of these techniques very short lived. The ability to laser undermine the tissue and to elevate the skin flap off the dermal attachments in most of the procedures releases the deeper tissue and permits a more durable repositioning of the deeper soft tissues. Concurrent skin excision also contributes to more durable results in a minimally invasive procedure. The ability to use internal barbed sutures in the open technique is a work in progress and, now that we can release the skin from the deeper tissues in an atraumatic and hemostatic fashion, different suturing patterns will develop in search of the ideal pattern of suture plication or imbrication, the ideal being a technique that produces the longest-lasting and most aesthetically pleasing results and maintains quick recovery classification.
