Introduction

Gluteal augmentation has become increasingly common due to a rise in bariatric surgery in North America as well as because of ingrained cultural ideals, combined with increasingly easy access to esthetic surgery in South America. Projection of the gluteal region has become a sign of a well-sculpted body, and consequently, is a goal of individuals who seek body contouring procedures. While Bartels et al were the first to report silicone gluteal augmentation in 1969,¹ more recently, numerous autologous procedures have been developed, including fat grafting, dermal-fat grafting, and, more recently, dermal-fat flaps.^2–10 Indeed, fat grafting plays an important role in gluteal augmentation in selected patients with low complication rates; however, it may not work well in patients after weight loss. Excess of skin combined with muscle hypotonia and skin flaccidity in patients after significant weight loss may contraindicate fat grafting procedures. For these patients, Agris,¹¹ based on the work of Pitanguy,^12,13 proposed the use of dermal-fat suspension flaps for thigh and buttock lifts. In addition, Gonzalez-Ulloa,¹⁴ Guerrerosantos¹⁵ and many others have proposed several types of adipocutaneous flaps to improve contours in this region.^16,17

Flaps proposed in the past have provided little projection to the upper gluteal region and are based on de-epithelialization of the gluteal region commonly discarded after major body contouring and circumferential body lift procedures. Pascal and Le Louarn¹⁸ should be credited for noticing the importance of preserving the de-epithelialized upper excess of soft tissue to better shape the gluteal region, avoiding the hollow aspect of the upper pole seen in patients with a lack of gluteal muscle tone. Progressive understanding of perforator anatomy in the gluteal region allows surgeons to respond appropriately to patient complaints and desires.¹⁹ The superior gluteal region, which is either discarded in body contouring procedures or simply de-epithelialized, can now be used to offer additional augmentation to the gluteal sagittal projection, treating the ptotic and sagging buttock. The edges of the superior gluteal dermal-fat flaps can be rotated to the midline to add volume to the gluteal region.

The purpose of this article is to describe our 8-year experience with gluteal augmentation using dermal-fat rotation flaps and to discuss the indications, proper location of the flaps, pitfalls of preoperative markings, postoperative complications, and instruments to both determine the success of surgery and to evaluate the flaps postoperatively.

Preoperative Preparation

With the patient in a standing position, we pull the excess skin cephalad with our open hand on the hip region. Then, beginning about 4 cm above the coccyx, a line is marked in the direction of the iliac region, usually a little bit below the anterior iliac spine. This line will join a classic abdominoplasty scar at some position where it curves anterolaterally. When an abdominal scar does not exist, the line is marked on the projected scar of a supposed abdominoplasty. With the fingers pinching the skin at the lumbar region, we determine the amount of skin excess to be resected. Next, on the lumbar region, we mark a second line at the superior aspect of the skin excess. The second line is initially parallel to the first, but then continues laterally to the upper anterior iliac spine to be joined with the first line at either the classic abdominal scar or its supposed projected position. These markings result in a long fusiform-shaped area between two points, both beginning and finishing inferior to the anterior superior iliac spine (Fig. 37.1). The direction of this line depends on the skin excess and is usually asymmetric. Occasionally, the union point of these two lines extends as far as the hemiclavicular line or even into the pubic region.

FIG. 37.1 Preoperative markings.

(A) The pinch test is used as a helpful maneuver in the preoperative markings section. (B) The markings are based on the preoperative excess of skin in each patient and may change according to individual patient characteristics.

Surgical Technique

Under general or epidural anesthesia, the patient is placed in a ventral decubitus position. The fusiform-shaped area is de-epithelialized, and an incision is made along the inferior edge of this area to the gluteal muscle fascia and then in a direction near the gluteal fold, producing an adipocutaneous flap (a pocket to receive the dermal-fat rotation flaps) (Figs 37.2 and 37.3). Next, incisions are made along the superior edge of the fusiform-shaped area down to the lumbar–hip musculature aponeurosis. A sagittal incision along the midline of the fusiform-shaped area is then made. The medial and lateral segments of the dermal-fat flaps are undermined, maintaining a large pedicle in the region corresponding to the position of the gluteal perforator’s vessels. The two segments are rotated and either sutured together in the muscle plane or alternatively fixed with a Reverdin needle, and transcutaneous fixation sutures are tied to gauze and buttoned over the transfixed skin near the gluteal region (Fig. 37.4). The inferior adipocutaneous flaps are brought over the dermal-fat flaps in an upward direction and sutured to the upper lumbar–hip skin border using biplanar wound closure. The same procedure is performed on the contralateral side. We also perform numerous quilting sutures to fix the gluteal skin flaps to the aponeurosis after rotation of the dermal-fat flaps. This maneuver has proven to be efficient in diminishing the seroma rate in abdominoplasty and has similar effects in the gluteal region. Another maneuver used during the undermining of the dermal-fat skin flaps is to leave a fat layer over the gluteal fascia to decrease seroma formation. These technical details have been responsible for decreasing the duration of drainage.

FIG. 37.2 (A) Illustration of the fusiform-shaped area being de-epithelialized. (B) Intraoperative photograph showing the dermal-fat flaps before elevation.

FIG. 37.3 Bilateral gluteal pockets are created above the gluteal muscle fascia plane to receive the dermal-fat rotation flap.

FIG. 37.4 (A) Intraoperative photograph showing the edges of the dermal-fat rotation flaps being elevated and prepared for rotation to provide projection to the upper pole of the gluteal region. (B) Illustration of the rotated dermal-fat flaps being sutured to the gluteal muscle fascia.

In cases in which the preoperative marking lines reach the anterior abdominal wall, the operation is begun with the patient in the dorsal decubitus position, and after rotation of the two anterior dermal flaps to the back, the patient is changed to the ventral decubitus position, and the lumbar-hip dermal-fat flaps are fashioned. Two large suction drains are placed in each side at the end of both the dermal-fat flap insertion and adipocutaneous flap rotation, and the patient is kept in the hospital in either the ventral or lateral decubitus position until at least the first postoperative day. Overall, patients were satisfied with the surgical outcomes as well as the longevity of the new shape of the gluteal region achieved with this operation (Figs 37.5–37.11).

FIG. 37.5 (A) Preoperative photograph of patient showing small gluteal projections. (B) Postoperative view after dermal-fat rotation flap gluteoplasty. Notice the projection and shape of the buttocks. (C) Long-term follow up (6 years after surgery) of the same patient. Notice the long-lasting results as well as improvements in the quality of the scar.

FIG. 37.6 Same patient as in Fig. 37.5: same photographic sequence: profile view.

FIG. 37.7 Same patient as in Fig. 37.5: same photographic sequence: oblique view.

FIG. 37.8 (A) Preoperative oblique view of a 52-year-old woman after a weight loss of 170 kg. Note the enormous amount of lax skin in the gluteal region. (B) Postoperative results, exhibiting the superior pole gluteal projection achieved by surgery.

FIG. 37.9 Same patient as in Fig. 37.8: same photographic sequence: oblique view.

FIG. 37.10 (A) Preoperative photograph of a patient after weight loss, with redundant skin in the posterior region and gluteal muscle hypotonia, seeking gluteal augmentation procedures. (B) Postoperative view at 4 years after surgery. The patient returned to our clinic, desiring additional projection of the gluteal region; thus, a repeated dermal-fat rotation flap was performed. (C) Final postoperative photograph at 3 years after the second procedure and 7 years after the first gluteal augmentation with autologous flaps.

FIG. 37.11 (A) Preoperative photograph of a patient with a very dysmorphic gluteal region after a bariatric procedure. The patient has a high accumulation of fat in the superior gluteal pole with flaccidity and hypotonia. (B) A challenging operation in which the patient benefited by the dermal-fat rotation flaps procedure. Postoperative view of the same patient in whom liposuction of the lateral thighs was performed as an ancillary procedure to improve final esthetic results. Restricted area where liposuction was performed should be preoperatively delineated to avoid complications.

Optimizing Outcomes

Understanding the Geometric Shape of the Gluteal Region

The beauty of the gluteal region involves the sagittal projection associated with the relative volume of and satisfactory fat distribution along the lower limbs. Several authors have developed a comprehensive classification system for the ideal fat distribution in the posterior region.^20–22 In patients with weight loss, skin flaccidity, and muscle hypotonia, we favor augmentation of the upper gluteal pole only. Long-term follow up has demonstrated its benefits (Fig. 37.12).

FIG. 37.12 (A) Illustration of the nonharmonic distribution of fat in patients seeking body contouring procedures. (B) Illustration of ideal fat redistribution, leading to a more harmonic, well-shaped body.

Postoperative Care

The drains are used for 3 or 4 days and are removed when output is less than 20 ml over 12 hours. Elastic garments are applied to the legs and buttocks, as well as to the abdomen at the level of the umbilicus, with a gauze dressing over the incision. Compression bandages are then applied over the elastic garments. If we are concerned about skin perfusion, we postpone the use of elastic garments until late in the postoperative period. Patients are seen every day until postoperative day 10 to 15, when the skin flaps can be monitored. If any sign of lack of perfusion is noticed, patients must remain in prone position for 10 consecutive days. Hemoglobin and metabolic profile are checked for at least 2 to 3 postoperative days. Patients are meticulously monitored for general clinical status (O₂ saturation, EKG, urine output, and blood pressure). Patients are instructed to not stand without professional assistance because of the potential risk of orthostatic hypotension and they are usually discharged at 3 to 4 days after surgery.

Complications and Their Management

We experienced both transient and major complications. We define transient complications as an event without serious consequences such as seroma, paresthesias, augmentation of the vertical dimension of the gluteal fold, and hypertrophic and malpositioned scars.

Seroma formation has decreased significantly with the routine use of drains and quilting sutures. Paresthesias of the gluteal region usually last from 2 to 3 months and are attributable to the wide undermining of the skin flaps. Their incidence also decreases when more selective undermining is performed, especially in patients after significant weight loss.

An increased vertical dimension of the gluteal fold is a common error and it is not considered a complication. When photographs are taken of patients in their underwear, either the vertical dimension of the gluteal fold or the positioning of the scar cannot be appropriately appreciated. Both problems are related to preoperative markings. While a little redundant, it is of paramount importance to emphasize that the initial demarcation should never be started 6 cm above the coccyx region. The positioning of the upper marking should be slightly bowed toward the iliac region below the anterior iliac spine. In patients with skin flaccidity, scar descent may occur; we believe that its positioning, hidden by the underwear, is the final important detail of this technique. Dehiscence is also related to poor blood supply and high tension during placement of the suture.

We define major complications as events with serious consequences, mainly when related to systemic complications, infection, and ischemia of either the skin or dermal-fat flaps. Besides systemic complications, a lack of perfusion of the overlying skin of the gluteal region and dermal-fat flaps is the most significant and feared complication. With the mid-pedicle superior pole bilateral dermal-fat flaps, we reduce the undermining area (i.e., increasing the number of flap perforators) as well as decrease the area of the arc of rotation of the dermal-fat flaps. Verification of perfusion for each of the flap edges may reduce complications related to ischemia that may lead to fat necrosis and postoperative calcifications. Intraoperative resection of regions with limitation of dermal-fat flap perfusion is important for the reliability of this procedure, and although rare, such complications may occur in the extremities of the lateral segments of the dermal-fat flaps.

During our 7-year experience using this technique, we had only one patient with low perfusion of the skin flaps. Infection, even when proper antiseptic technique is performed, can be related to lack of blood supply and it was never seen in our patients. In order to avoid complications, procedures combined with gluteoplasty augmentation are rarely done. Liposuction of the lateral thighs might be performed to improve the shape of the gluteal region in selective patients (Fig. 37.13).

FIG. 37.13 Photograph of another patient in the prone position, 2 days after surgery, showing the lack of perfusion on the skin flap, marked with a blue pen. Ischemia of the flaps is indeed a major complication that can possibly result in a wide area of necrosis. This particular patient improved during follow up, and no major consequences occurred, besides an area of hyperchromia in the center of the gluteal region.

Assessment of Gluteal Projection and Possible Dermal-Fat Complications and Calcifications

The surgical outcomes of gluteal augmentation techniques have been assessed by clinical observations and comparisons between preoperative and postoperative photographs, which in many cases have not been standardized. We routinely photograph our patients using three or four spotlights and without any underwear to show the upper gluteal region as well as the position of the final scar. Three-dimensional photography is a good alternative to determine the final projection achieved by surgery, although not used in our practice.

Babuccu was the first to describe anthropometric measurements for gluteal morphology analysis after time, aging, and weight gain.^25,26 Radiographic and anthropometrical tools, however, have not been routinely used for surgical outcome validation.

We recently studied the accuracy and applicability of three different measurement methods (two radiological: computed tomography (CT) scan and ultrasound; one anthropometrical: goniometer) to assess gluteal projections after augmentation with bilateral dermal-fat rotation flaps from the lumbar–hip region. The CT scan and ultrasound measured the thickness of the subcutaneous tissue in the major gluteal region in the superior gluteal pole, and the goniometer measured the sagittal distance that corresponds to the major gluteal projection of the lumbar–hip region as determined by anatomic landmarks.

A simple equation was proposed to quantify the postoperative gluteal projection:

Although the three methods of measurement were technically different, the results should theoretically be the same. Nevertheless, the ultrasound method showed a lack of correlation between preoperative and postoperative gluteal projection measurements. This lack of accuracy using the ultrasound technique was probably due to a radical change in the soft tissue position when the patients were put in a prone position for the ultrasound examination. Standardized anatomic landmarks were difficult to establish clinically by the surgeon, and errors tended to occur. Recorded gluteal soft tissue changes were fewer when the patients were standing. The measurements taken by the goniometer in the standing position tended to avoid these errors, bringing higher accuracy to the measurements.

The overall conclusion of this study is that the goniometer method is preferred, since it shows less variability in each measurement (both before and after surgery). These measurements (both before and after surgery) correlated with each other and were equal to those measurements obtained using the CT scan method, which is much more expensive.²⁷ We did not observe calcifications and/or any sign of fat necrosis during the postoperative period. We conclude that the goniometer is a simple and reliable device for measuring gluteal projections after any type of gluteoplasty technique (Fig. 37.14).

FIG. 37.14 (A) Preoperative imaging (CT scan) of a patient in prone position. (B) Postoperative imaging of the same patient 10 months after surgery showing the dermal-fat flaps. This is one of the CT images performed in a series of 10 patients to screen flap status during the postoperative period. Although not routinely performed as a tool for flap screening, in this series, it was important to verify calcification and fat necrosis in addition to modifications of both gluteal shape and contour. In all exams, the dermal-fat flaps were integrated to local adipose tissue, confirming that the technique offered satisfactory and reliable results with low complication rates.

Conclusion

As gluteoplasty evolves, surgeons will no doubt face new challenges that require a refinement of current approaches. Rotation-flap gluteal augmentation represents an additional option for gluteoplasty, particularly in an ever-growing population of postgastroplasty patients.