History

Traditional suction-assisted lipoplasty (SAL) became popular in the United States in the 1980s. Although initially met with scepticism, it was eventually embraced and quickly became the gold standard tool for liposuction. The introduction of the tumescent technique by Jeffrey Klein further increased the safety and efficacy of the procedure by reducing fluid and electrolyte shifts, thereby allowing larger volumes of fat removal with considerably less blood loss. The concept of applying ultrasonic energy to adipose tissue was first conceived by Zocchi of Italy in the late 1980s. Ultrasound-assisted lipoplasty (UAL) involves the application of ultrasonic energy to adipose tissue, which effectively “liquefies” the fat by cellular fragmentation, causing release of cellular contents into the intercellular space. A combination of triglycerides, normal interstitial fluid, and the infused tumescent fluid forms a stable fatty emulsion, which can be extracted from the subcutaneous space by low-vacuum suction. The specificity of the ultrasonic sound waves for low density tissues such as fat allows selective targeting of fat cells with minimal effect on intervening connective tissue and neurovascular structures. Ultrasonic medical devices have been used in a variety of other medical fields (neurosurgery, general surgery, ophthalmology, and urology) and proven to be extremely useful and safe. A variety of UAL surgical devices are available on the market today and it is beyond the scope of this chapter to discuss the differences in the various machines.

We have used a variety of ultrasonic generators as the technology has developed over the years. Our early experience was with the first generation devices which delivered continuous wave ultrasound via a solid, blunt-tip probe which effectively fragmented fat before evacuation. Second-generation UAL machines used 5-mm diameter hollow cannulas that would allow for simultaneous fat fragmentation and aspiration. Reported complications with second generation ultrasound lipoplasty devices were thought to be related to the amount and duration of energy applied to the adipose tissue. Third generation devices were therefore developed with “pulsed” delivery of ultrasonic vibration to allow increased control of the ultrasonic energy.

Physical evaluation

A liposuction consultation should begin by asking the patient, what would they like to change about their body?

Anatomy

One of the most important factors to consider when evaluating a patient’s candidacy for liposuction is their patient’s skin tone, or dermal quality. It is important to pinch and palpate the skin, assessing for the degree of laxity and dermal thickness (Fig. 65.1). Young thick undamaged dermis is more likely to retract after liposuction and give a desirable result. Thin, stretched skin with striae is unlikely to retract and may look worse after liposuction. If it is determined that the skin quality is not suitable for liposuction, alternative procedures, such as skin excision, may be indicated. Liposuction does not improve cellulite, thus one should not make promises to this effect.

Fig. 65.1 A patient with a protuberant abdomen with paucity of subcutaneous fat. A, The patient’s protuberance is due to muscle laxity and poor posture. B, When the patient is asked to “pull in” the muscles, protuberance lessens. C, Pinch thickness is minimal.

The quality of the fat should also be assessed because it may also affect the outcome. Generally speaking, firm, fibrous fat is more “forgiving” than soft, loose fat. The softer fat has large lobules with wispy intervening fibroconnective tissue. This type of fat is removed readily and is easy to over-resect; as a general rule, the overlying skin is thin. The fibrous type of fat tends to be densely packed between tightly woven intervening fibroconnective tissue. This type of fat is less readily removed. The overlying skin tends to be thicker and can be expected to retract well. The better retraction is theoretically due to the retractile properties in the fibroconnective tissue and in the dermis itself.

The anatomy of the subcutaneous adipose tissue varies through the body. Some areas of the body have both a deep adipose compartment and a superficial adipose compartment, which are separated by the discrete subcutaneous fascia. The superficial fat in the trunk and thigh consists of smaller lobules, tightly organized within the vertically oriented thin, fibrous septa and the zones of adherence differ between males and females (Fig. 65.2). The deep fat consists of larger lobules arranged more loosely within deeply spaced and more irregularity arranged septa. In these areas, the deep layer of fat is the target for liposuction. The overlying superficial fat is relatively thin and will act as a protective layer to hide small contour deformities, especially for the in experienced liposuction surgeon. In contrast, other areas of the body that are commonly suctioned (arms, lower legs) have only one layer of fat. Suctioning these areas with smaller cannulas will help to avoid contour irregularities.

Fig. 65.2 Diagram of superficial fascial system anatomic variations in men (left) and women (right). The superficial fascial system zone of adherence is at the iliac crest in men and several centimeters inferior to the iliac crest in women.

From Lockwood T. Superficial fascial system (SFS) of the trunk and extremities: a new concept. Plast Reconstr Surg 1991;87:1011.

Technical steps

Marking and positioning markings provide a necessary “topographic map” that allows the surgeon to visualize the targeted convexities, to avoid concavities, and to address asymmetries when the patient is lying on the operating table. Markings should be done immediately before surgery with the patient in a standing position (Fig. 65.3). A permanent marking pen is recommended so the markings will not wash off when the patient is prepared. Asymmetries should be carefully marked and brought to the attention of the patient. Depressions and indentations are marked with a different color marker so these areas can be avoided or fat grafts can be planned.

Fig. 65.3 Schematic of markings. A, Anterior view. B, Lateral view. C, Posterior view.

Most body areas can be suctioned from the prone supine positions; however, some surgeons prefer the lateral decubitus position for the hips and lateral thighs.

A large soft hip roll placed under the slightly flexed hip facilitates excellent exposure of the back, posterior hips, lateral, posterior and medial thighs. (Figs 65.4, 65.5) Abdomen, breast, arms, anterior and medial thighs, knees, calves and ankles are all best addressed from the supine position. (Figs 65.4, 65.6, 65.7) Patients are prepared with a 3-minute povidone-iodine (Betadine^™) scrub, followed by povidone-iodine paint. Bair Hugger^™ warming blankets are recommended on unexposed body parts. A Foley catheter should be placed when aspirations of more than 5 liters or multiple procedures are planned. When liposuction is combined with an open surgical procedure or when large-volume liposuction is performed, compression hose and sequential compression boots for prophylaxis of deep venous thrombosis are recommended.

Fig. 65.4 A, The primary access incision for medial thigh liposuction is in the upper groin crease. The patient’s legs should be prepared so that they can be abducted and externally rotated. This usually involves a circumferential preparation as shown. An additional incision is made at the distal two thirds of the medial thigh to allow crosshatching and access to the posterior fat. B, The posteromedial thigh fat can also be accessed from the prone position through a medial gluteal crease incision.

Fig. 65.5 A&B, Liposuction of the back. Note access by midline and gluteal crease incisions.

Fig. 65.6 Small stab incisions can be made at the posteromedial knee or the anteromedial knee as shown. These incisions allow access to the medial knee as well as to the medial subpatellar area. Suctioning of the subpatellar area can significantly improve the aesthetics of the lower leg.

Fig. 65.7 A, Markings for male gynecomastia. The inframammary crease incision is used only in patients with abundant chest hair. B, Access incision in the axillary hair.

UAL Technique can be broken down into 3 distinct phases: Infiltration, Application of Energy and Evacuation.

Infiltration of tumescent solution: Standard wetting solution recipes are used for UAL. If large volume removals are planned, the amount of xylocaine is decreased so as not to exceed the recommend 35 mg/kg maximum subcutaneous dose. Our experience and research support the use of room temperature tumescent fluid to minimize the risk of ultrasound induced subcutaneous tissue elevation while maintaining stable core body temperature. The authors recommend infiltration of wetting solution at a 1 : 1 ratio, i.e. Superwet Technique. Accurate record-keeping of the amount infiltrated into each area is recommended.

Application of Ultrasonic Energy: Ultrasonic energy is applied to the subcutaneous tissue using either a solid probe or hollow cannula. Solid probe technology offers the advantage of more efficient transmission of ultrasonic energy and therefore theoretically less tissue trauma, but the disadvantage of no simultaneous evacuation of fat. A hollow cannula offers the advantage of simultaneous fat evacuation, but at the expense of some decrease efficiency in the actual liquefaction process. In either case the hand piece is held in the dominant hand while the opposite hand is placed on the overlying skin to “feel” or monitor what is going on beneath the surface. The ultrasonic probe or cannula is generally passed in and out the skin incision at a slightly slower pace than with traditional SAL. A surgical assistant is asked to drip water or saline solution over the incision site during application of energy to avoid frictional injury at the incision site. The use of skin protectors as previously described has been abandoned by the authors.

Ultrasonic energy is ideally applied until the appropriate amount of fat has been liquefied so that once the liquefied fat is evacuated the patient will have the ideal final contour. Thus the “endpoint” is reached when the appropriate amount of fat has been liquefied. Passage of the ultrasonic probe will gradually loose resistance indicating emulsification of the fat. Additional endpoint criteria for achieving symmetry are time of energy applied to the tissue and the volume extracted.

Evacuation Phase: Even when a hollow ultrasonic cannula is used for application of ultrasonic energy there will still be some fatty emulsion left in the SQ space. (The internal diameter of a standard 5 mm hollow titanium cannula is 1.8 mm). The evacuation phase is performed using traditional liposuction cannulas of the surgeon’s choice. When using a solid probe, the entire volume of fat and fluid will be removed during the evacuation phase. When using a hollow cannula, it is common to remove 50–60% of the total volume during application of energy and the remaining 40–50% during the evacuation phase. Again, careful record-keeping of volumes removed from each area is important. Once all the fatty emulsion is removed one must evaluate the adequacy of treatment based on contour above all other data. Final contouring may be done at this point with small diameter cannulas, using traditional SAL technique. Once the final contouring is performed, the incisions are closed. Drains are recommended in the male breast, and when greater than 2 liters are suctioned from the abdominal area. The patient is dressed in a compression garment that covers the areas that have been suctioned. The author favors the use of compression foam (TopiFoam^™) under the garment which seems to decrease bruising and swelling in the early postoperative period.

The goals of the liposuction surgeon are to remove specifically targeted fat, to leave a smooth body contour without deep or superficial contour irregularity, and to establish a smooth transition between the suctioned and the non-suctioned areas. The pinch test can help assess whether an area is nearing completion and can also assist the surgeon in finding missed adipose pockets or uneven areas of resection. The pinch test is most valuable if it is performed preoperatively to know the starting thickness of the adipose layer. The use of saline to wet the skin and glide one’s hand over the surface is helpful to assist in finding small contour irregularities. The old adage “the enemy of good is better” should be remembered during final contouring. Over-resection can occur quickly while chasing small contour irregularities.

Postoperative care

Patients should be informed that they will experience red-tinged, serosanguinous drainage from incision sites for the first 24–36 hours. It is not uncommon for a patient to experience a vasovagal response the first time the compression garment is removed, therefore the patient should be warned to have someone with them when they remove their garment for the first time! Patients may shower after 48 hours, and are instructed to replace compression foam over areas suctioned. Topifoam^™ is typically removed at 3–5 days and garments are recommended for 4–6 weeks, depending on the volume of suction. The patient is instructed to begin lymphatic massage of the areas suctioned approximately 2 weeks after surgery. This reduces edema and helps reduce small contour irregularities.

Patients should begin ambulating on the day of surgery. Oral fluids and a high-protein diet should be encouraged. Physical activity should be low for the first week, followed by a gradual increase in activity during the second week, depending on the amount of suction performed. At the end of the first or second week (depending on the amount of suction), the patient should be encouraged to get on a treadmill or walk outside (with compression garments on). Upper body conditioning can also begin. At 4–6 weeks, assuming edema and bruising are resolving appropriately, the patient should be advancing to full activity. These guidelines are general and must be tailored to the individual patient.

Return to work depends on many factors: the patient’s profession, the amount of liposuction, the patient’s general health, the patient’s physical and emotional recovery, and the patient’s desire to return to work. After an average medium-volume liposuction (2–4 liters), most patients return to work in less than 1 week. They feel tired and sore but can function appropriately. For large-volume liposuction (>5 liters), the average patient should schedule at least a week if not more. Many patients desire surgery on a Friday afternoon and plan to return to work on Monday. This can be done for appropriately selected patients, but anecdotally, those patients who do not plan any “recovery time” seem to have a lot of early swelling and their eventual total recovery time is prolonged.

Proponents of UAL contend that it is a safe method of body contouring with a number of advantages over traditional liposuction techniques. In addition to being less physically demanding for the surgeon, it is reported to allow greater suction volumes per patient with significantly less blood loss and better control of surface contour. Most long time users of UAL agree that it is not a replacement of traditional SAL techniques but an adjunct to be used in certain areas of the body. The authors feel that UAL is particularly useful in the male breast, the back, the posterior hip (flank) and the lateral thigh because these areas tend to have firmer, more fibrous fat (see Anatomy) and UAL offers the advantage of less surgeon fatigue and better control of surface contour. In areas like the abdomen, arms and anterior thighs, the main advantage of UAL is better control of surface contour, since these areas tend to have soft, loose fat. The authors prefer not to use UAL in the medial thighs, knees, calves and ankles, and neck. The reason for this is that UAL offers little advantage over SAL in these areas, may increase risk or may prevent disadvantages (e.g. ultrasonic probes don’t bend which is a disadvantage in calves and ankles).

Fig. 65C.1 A&C, Preoperative photographs of a 38-year-old woman with history of one prior pregnancy. B&D, Postoperative photographs one year following UAL and SAL of the abdomen, hips, flanks and circumferential thighs.

Fig. 65C.2 A&B, Preoperative photographs of a 42-year-old woman with history weight fluctuations. C&D, Postoperative photographs one year following UAL and SAL of the abdomen, hips, flanks and circumferential thighs.

Complications

Most of the potential complications of UAL are also possible with SAL. Risks and possible complications inherent to both include, but are not limited to, bruising, infection, asymmetry, contour irregularity, seroma, dyschromia and dysesthesia. Less likely complications include fluid imbalance, perforation of a major organ or vessel, lidocaine toxicity, DVT, PE, and fat embolism. UAL carries the additional risk of thermal injury, as heat is a potential by-product of ultrasonic energy. Temperature elevation can occur in both the subcutaneous space and at the incision site. Because the titanium probe is moving in and out at ultrasonic frequency, prolonged contact between the shaft of the moving probe and the stationary skin can cause frictional injury. For this reason, water or saline solution must be dripped at the incision site (or a skin protector can be used) to avoid thermal injury. A wet surgical towel is also recommended near the incision site to protect the skin from contact with the vibrating probe shaft. The two cardinal rules of UAL according to the Michael Zocchi, the father of liposuction, in prevention of thermal injury are: 1. Apply ultrasound energy only in a wet environment. 2. Always keep the ultrasound probe in motion. Thermal injury can be totally avoided with proper UAL technique!