Buttock shaping with fat grafting and liposuction

Who is a good candidate for autologous fat grafting of the buttocks?

Every patient has different aesthetic goals and volume preferences; therefore the patient has to have enough fat to deliver the desired shape and size of buttock. This will vary in every patient, but the goal is to graft between 500 and 1500 cc per buttock (in some cases more), depending on patient frame and goals. There is no foolproof way of assessing how much fat is available other than surgeon experience and the pinch test. Using body mass index (BMI) has not been helpful since some patients are skinny-fat (thin with a thick layer of fat on pinch test), while others may have a large BMI but the fat is mostly visceral. In cases where you may be in doubt if enough fat is available, the patient can gain 10–20 lb (4.5–9.0 kg). Chapter 35.2 discusses buttock augmentation with implants. For a detailed summary of the advantages and disadvantages of the various techniques for buttock augmentation, see Table 35.3.1 .

Aesthetic goals

Research by Singh, as well as other authors, has documented the importance of an ideal waist-to-hip ratio of 0.7. In the senior author’s experience, in some cultures a 0.6 ratio can be extremely desirable. There is a tremendous synergistic effect of liposuction of the lower back, waist, and flanks in conjunction with buttock augmentation to achieve this ideal waist-to-hip ratio. This is clearly evidenced by the fact that fuller, more shapely buttocks appear more attractive when the waist is slender rather than fuller.

A specific goal is achieving a cleavage of the buttocks superiorly, along with lordotic curve. Buttock height should be short, as this is more of an aesthetic shape than a vertically long buttock.

Pre-surgical markings

There are two essential points regarding appropriate marking for buttock augmentation by autologous fat grafting. The first is to thoroughly sculpt the flanks, lumbar area, and lumbosacral area to create an inward sweep, which will synergistically emphasize the new fullness of the buttocks after fat grafting. This includes performing liposuction to create a deep sacral “V”, which will enhance the superior gluteal cleavage. This is further accentuated by grafting the upper medial buttocks, immediately adjacent to the sacrum. Second, it is important to have adequate donor sites. Clinically, we have discerned no difference of fat survival from the various areas that are used for donor fat. The vast majority of buttock augmentation procedures range from grafting 500 cc (small-framed petite patients) to 1500 cc (larger-framed patients) per buttock. Up to one-third of the fat that is harvested may become damaged during the harvesting process, meaning that 3000–4000 cc must be available for the body.

The areas of maximum prominence should be at the junction of the middle and central thirds transversely and the mid and upper poles of the buttocks. The patient is asked to bring a favorite bathing suit and markings are made outlining the borders of the swimwear and, during the surgical procedure, every effort is made to place liposuction incisions within the boundaries of these markings.

Surgical technique

This is a three-dimensional procedure; therefore, liposuction as well as the fat injections will be performed by placing the patient in the supine, lateral decubitus, and prone positions. In preparation, the patient will have a warming blanket placed on the surgical table, which is covered by a sterile sheet; pneumatic stocking compressions are placed prior to induction and a Foley catheter inserted once under general anesthesia. Therefore, after marking, the patient undergoes a standing circumferential povidone–iodine prep; if allergic, then Hibiclens or chlorhexidine may be used. Antibiotic prophylaxis is clindamycin 600 mg intravenous (IV) (30 min prior to procedure), and cefazolin (Ancef) 1 g at the end of the procedure. A sterile towel is placed in the small of the back to help facilitate turning. Since constant turning is being performed, there are no drapes on the patient except for the anesthesia end. The procedure takes about 1 h 30 min to 2 h.

Maximum effort is made to maintain sterility and prevent infection. With the patient in the supine position, tumescent solution is infused to all of the fat donor sites and is warmed up to 110–115 °F (43–46 °C) just prior to infusion. This is an excellent method of maintaining the patient at appropriate body temperature during the surgical procedure.

Harvesting and preparing fat is a multiple-step process. A 4 or 5 mm harvesting cannula is used with the power-assisted liposuction device (PAL, MicroAire Surgical Instruments, Charlottesville, VA). Since incorporating the use of the PAL hand-held device, the authors feel there has been a reduction in the time required to harvest the appropriate amount of fat without compromising fat survival. It is essential that the vacuum used to provide negative suction be maintained at <24 inches of mercury, otherwise “gassing-out” of oxygen and nitrogen can disrupt cell membranes and markedly decrease fat survival.

The collection and reinjection technique has changed as the procedure has evolved. Many different systems are available to collect and reinject, and the surgeon can use what he or she is most comfortable with. The current preparation system used by the senior author for fat involves a decanting method. This preserves the smaller fat cells but at the expense of having more liquid in the injected fat. This is a drawback of this system, but hopefully, as technology advances, we will have a better preparation system.

In the past, syringes were used to inject fat, but due to technical advancements, a reinfusion pump with a closed system is used. This facilitates injections tremendously and makes the procedure extremely efficient. Therefore, two systems are involved in the reinjection process. The first is the cannula system to inject the fat; this is a power-assisted reciprocating 4–5 mm vibrating basket cannula system (MicroAire Surgical Instruments, Charlottesville, VA). If you do not have a power-assisted vibrating system, then a regular liposuction cannula system can be used. The reciprocating power-assisted vibrating cannula will expand tissues, pre-tunnel the area allowing for release of tight dermal attachments, and create space for the fat to be injected. The second equipment used is a reinfusion pump, this pump system will reinject the fat directly from the canister; this way the fat is not manipulated or exposed to air. Several systems are available. The system described is the Wells Johnson High Volume Precision Auto-Graft System (HVP; Wells Johnson, Tucson, AZ).

The fat is collected in a large 2–3 L canister that has a bottom port with a Y-connector that allows removal of the liquid through one of the tubes. The extraction end of the tubing can then be clamped and the reinjection tubing used to reinject through the pump. The reinjection cannula used is the 5 mm basket attached to the reciprocating PAL. Prior to transferring the fat, 10 mL of an antibiotic solution (3 g ampicillin/sulbactam and 80 mg gentamicin plus 1 g cefazolin in 1000 mL of saline) are injected into the canister at every 500 cc (500 mL) mark of fat collected.

Any grafting to the anterolateral areas is performed at this time with the patient in the supine position. The patient is then placed in the lateral decubitus position to complete the liposuction of the flanks, lower thoracic, and lumbosacral areas. Injections will also occur in the lateral decubitus position to work on the lateral buttock zones, prior to placing the patient in the prone position to finalize the suction. The prone gluteal fat injections will be performed only in the subcutaneous tissue layers, consistent with current safety guidelines. Additionally, it is strongly recommended that real time ultrasound be used during the injection to ensure that the grafting is being performed in the subcutaneous tissue and not the muscle. Recent history has taught us that patients suffering from fatal fat embolism have been found to have grafted fat within and below the muscle.

Final contouring is performed by judicious liposuction to achieve the desired contour. Virtually all areas that are dimpled or flat and resist distension are tethered down by a fascial band to the muscle. Even if you can hydraulically pump these areas up, they will reappear postoperatively unless the tethering bands are selectively released. This is performed with a J-shaped dissector and should only be done after fat has been forcefully grafted into the area. The J-dissector may need to be passed extensively, but only in a radial fashion; a sweeping motion can accomplish complete subscission and must be avoided, as this can result in a bulge. A compressive garment is applied. A 3-inch-thick gauze triangle made from Kerlix rolls is applied to the lower lumbar/sacral area to help facilitate skin adherence to the sacrum and maintain the superior gluteal cleavage and inward sweep of the lumbosacral area. The sacral incision is left open to allow for drainage as well as both groin access incisions.