Although the standards to define a beautiful buttock region may vary slightly from culture to culture, there is little debate about the allure of the hourglass female figure. Singh [4] proposed that there is one female body shape (full buttocks and a narrow waist) that men universally find attractive; and this is defined by an ideal female waist to hip ratio (WHR) of 0.7. The waist to hip ratio is defined as the ratio of the circumference of the waist at its narrowest point to the circumference of the thighs at the level of maximal lateral projection (level of the trochanteric depression). (See Chap. 7 for more details.) A successful gluteal augmentation procedure is therefore defined as one in which the surgeon successfully brings the woman as close to the ideal WHR of 0.7 as possible [5].

Since the advent of body contouring surgery, many different ways of evaluating the gluteal region have been proposed to help surgeons achieved optimal results in contouring of and around the buttocks. In 2004, Cuenca-Guerra et al. [6] first reported their analysis of more than 24,000 images of the gluteal area taken from various media sources. He defined four recognizable characteristics of an aesthetically pleasing gluteal region (Fig. 6.3):

Centeno in 2006 [7] described one of the other primary methods for evaluation of the buttocks to help plan body contouring procedures. From the posterior-anterior view of the patient, he defined eight gluteal aesthetic units that help form an aesthetic bottom. By his estimation, the gluteal region consists of two symmetrical “flank” units, a “sacral triangle” unit, two symmetrical gluteal units, two symmetrical thigh units, and one “infragluteal diamond” unit (Fig. 6.4). Accentuation of these units with liposculpture, buttock implants, or hip implants would aid in producing a more aesthetically pleasing contour to the buttock region. When considering procedures that involve incisions, Centeno recommended careful incision placement to respect the junctions of these aesthetic units.

Mendietta in 2006 [8] described a gluteal evaluation system where he analyzed the underlying bony framework of the buttocks, the skin, and the subcutaneous fat distribution, in addition to the musculature of the region. First, he recommended an evaluation of the pelvic frame. Next, the gluteus muscle is evaluated in its height and width. He divided the buttock into four quadrants: upper inner, lower inner, upper outer, and lower outer. Determination of volume addition should be based on analysis of these four quadrants of the buttock. Any additional procedures that need to be performed (e.g., buttock lift or liposculpture) can then be determined by the analysis of these defined criteria.

Many surgeons on many continents have added to the knowledge base and growing amount of literature on gluteal augmentation procedures. Gluteal augmentation surgery began in 1965 when Bartels first used a mammary prosthesis (Cronin prosthesis) in the gluteal region to produce a more round and supple bottom side [9]. Subsequently, Cocke in 1973 [10], Douglas in 1975 [11], and Buchuk in 1980 [12] described their early experiences with aesthetic gluteal augmentation. Robles in 1984 [13] reported on his placement of a submuscular gluteal implant with an incision in the medial sacral line. In 1991, Gonzalez Ulloa [14] described his 10-year experience with buttock augmentation. Recently, Vergara [15] presented his 15-year experience with the procedure.

Over the past three decades of advancements in gluteal augmentation, surgeons have proposed various methods of performing the augmentation to achieve the most aesthetic result with minimal complications. Gonzalez Ulloa [16] is regarded by most as one of the great pioneers and grandfathers of buttock augmentation, having begun his work late in the 1970s and presenting his work in Mexico City in 1977. A large portion of his early procedures were performed on patients who had suffered severe damage and/or deformation of the gluteal region due to silicone, collagen, or guaiacol injections. In his early reports of the procedure, he recommended placement of the implant above the gluteus maximus muscle with an incision in the subgluteal sulcus. This subcutaneous plane has largely been abandoned by many surgeons as it can produce an unnatural look and has a large risk of implant migration. Robles in 1984 [13] reported on placement of implants in the submuscular plane with an incision along the medial sacral line. In 1995, the primary author evaluated Robles’ work and felt that the potential for injury to the sciatic nerve was too great and began working to place gluteal implants in a more superficial submuscular space, which would later be termed the “intermuscular” space. His initial work on 22 gluteal augmentations performed in the intermuscular space was published in early 1997 as a “modification of buttock augmentation” [17]. The intermuscular space was defined as the potential space that was visualized between the gluteus maximus above and the medius and minimus below during surgical dissection. An implant could easily be placed into this position, thereby minimizing trauma to the gluteus maximus muscle and avoiding injury to deeper muscles and neurovascular structures. Vergara and Marcos [15] later described their use of the “intramuscular” plane for gluteal implant placement based on cadaver dissections which showed an intramuscular anatomic space available for augmentation, larger in size than the submuscular space previously noted by Robles [13]. This paper validated the placement of a silicone prosthesis between the fasciculi of the gluteus maximus muscle and avoided the deeper plane which would put the patient at greater risk of sciatic nerve injury. However, this description differed from that of the primary author in that Vergara attempted placement of the implant within the gluteus maximus muscle rather than placing the implant fully under the maximus muscle. Vergara, along with other authors that use the intramuscular plane, emphasizes the need for maintaining a superior muscle flap covering the implant that is at least 3 cm thick [17–19]. Later in 1997 Peren et al. [20] described their work with augmentations done in the subfascial plane. This was then revisited in 2004 by de la Pena [21]. The limitation of the subfascial plane is that large volume implants with significant projection increase cannot be used due to the tightness of the pocket. Additionally, because of its more superficial position, there is a greater chance of implant palpability. Most recently, Gonzalez [22] introduced the XYZ method for gluteal augmentation. Gonzalez uses the same intramuscular plane as described by Vergara but introduces a means of orienting the gluteal implants to maximize symmetry and aesthetic results. He defines a point X as representing the center of the gluteus maximus muscular mass at the site of access to the submuscular plane. He performs dissection cephalically up to a point Y which is just past the lower iliac spine. Then along a vector named line G, he dissects caudally down to a point Z which is at the level of the trochanter and still beneath the gluteus muscle. Gonzalez asserts that his technique is important in gluteal augmentation as natural and reliable pelvic landmarks are used for dissection as preoperative cutaneous markings often provided a distorted view of the anatomy when the patient is in the prone position for surgery, helping to produce more reliably aesthetic outcomes [22].

In considering incision placement for the procedure, early surgeons worked through bilateral infragluteal sulcus incisions [9–12, 14]. This was then followed by bilateral coccygeal incisions as used by Gonzalez Ulloa [9]. Later surgeons felt that less incisions could lead to less postoperative morbidity. For this reason, incision placement turned to use of a single 5–7 cm incision hidden in the intergluteal cleft [13–15, 17, 18]. Mendietta in 2005 [23] presented his approach to gluteal augmentation, suggesting two paramedian incisions in order to decrease the risk of wound dehiscence. By placing two incisions, there was less trauma to the incision and tension was minimized. Most recently, in 2007, Badin and Vieira [24] discussed their experience with a small intergluteal crease incision with pocket dissection using endoscopic technology aimed at minimizing the risks of sciatic nerve injury and maximizing aesthetic gain.

In 2006, De la Pena [25] described the history of gluteal augmentation and briefly discusses the differences in implants used for buttock augmentation between the United States and countries outside it. He notes that there are two primary types of buttock implants available commercially: semisolid elastomer implants and cohesive gel implants. In 2012, Bortoluzzi Daniel [19] sought to evaluate the durability of gluteal prostheses and noted that cohesive gel implants, as used in his native Brazil, had a high failure rate and risk of rupture when compared to the semisolid elastomer-type implants used by surgeons in the United States. Cohesive gel implants have a shortened useful lifespan due to the fact that creases can sometimes fold in the implant itself combined with the significant force of compression produced by sitting on the implants. Studies performed on breast augmentation patients suggest that cohesive gel implants may need replacement in 20–40 % of patients at 8–10 years. Based on the research of Bortoluzzi Daniel, this half lift is considerably shorter for gluteal implants because of the constant tension that they are subjected to. Although the search for the ideal implant continues, the semisolid elastomer implant and cohesive gel implant have underscored the major developments in buttock augmentation surgery.

The large majority of the US companies are making implants that are semisolid and rigid. Implantation of these types of implants does have the advantage of not rupturing; however, it can lead to a more firm buttock region. This is in contrast to the implants frequently used in Latin American countries that are often made of a cohesive gel within a thick and resilient silicone shell (Fig. 6.5). These implants are softer and have a more natural feel according to physicians that use them. The major downside of these implants, however, is the risk of rupture. In our own practice, it is our feeling that implants made by AART (Aesthetic and Reconstructive Technologies, Inc., Reno, NV) not only provide rigidity needed to provide a solid augmentation but are pliable enough to make them natural in their look and feel when implanted.

In Centeno’s [7] work, there are four superficial landmarks that should be identified and potentially accentuated in buttock augmentation/contouring. These four areas are the sacral dimples (overlying the PSIS), the sacral triangle (formed by the two PSIS and the coccyx inferiorly), the lateral depression correlating to the greater trochanters of the femur, and the short infragluteal fold. When performing buttock augmentation, one should be careful not to obliterate these landmarks and may even consider the adjunctive use of liposculpture to further enhance these landmarks in addition to performing the buttock augmentation.

The buttock region has investing fascia that helps prevent gluteal ptosis and provide structural support to the gluteal area. The superficial fascia as described by Lockwood [6] fuses with the deep gluteal fascia at the level of the infragluteal fold to create a tight adherence which needs to be respected in augmentation and liposculpture procedures [26]. A violation of this tight adherence can lead to significant gluteal ptosis which is difficult to reconstruct if lost. In addition to helping to create the infragluteal fold, the superficial fascial system along with the deep investing fascia of the gluteus muscle is key to providing a sound closure at the end of the procedure and should be employed in a layered closure of the midline buttock incision.

The muscles that comprise the buttock region are several, but the primary volume is formed by the three gluteus muscles (Fig. 6.6). The gluteus maximus muscle originates on the fascia of the gluteus medius muscle, the external ilium, the fascia of the erector spinae, the dorsum of the lower sacrum, the lateral coccyx, and the sacrotuberous ligament [27]. It inserts on the iliotibial tract and proximal femur. The muscle is a powerful extensor of the flexed femur and provides lateral stabilization of the hip. The gluteus medius originates on the external ilium and inserts on the lateral greater trochanters. It acts to abduct the hip and thigh and helps to stabilize the pelvis during standing and walking. During dissection, it can be differentiated from the gluteus maximus because of its vertically oriented fibers. The gluteus minimus originates on the external surface of the ilium and inserts on the anterior-lateral greater trochanter. This muscle abducts the femur and also serves as a pelvic stabilizer.

Blood supply in the gluteal region is rich and reliable. The musculocutaneous structures in the gluteal region are largely supplied by the perforating branches of the superior and inferior gluteal arteries, which are terminal branches of the internal iliac artery [28]. Accessory blood supply comes from the deep circumflex iliac, lumbar, lateral sacral, obturator, and internal pudendal arteries. The superior and inferior gluteal veins provide venous drainage of the region. When considering dissection of the gluteus muscle, one must be careful to avoid sharp dissection very close to the sacrum and sacrotuberous ligament as injury to the gluteal arteries can occur [22].

There is a rich complex of nerves that innervate the muscles of the buttock region and provide sensation to the overlying skin. They largely originate from the lumbosacral plexus. The gluteus maximus is innervated by the inferior gluteal nerve. This nerve comes from the pelvis to the gluteal area, crossing the great sciatic foramen posteriorly and in a way medial to the sciatic nerve. It divides into three collateral branches: the gluteus (motor nerve of the gluteus maximus), the perineal, and the femoral (sensory nerve). The branches of the inferior gluteal nerve are like a crow’s foot when dividing into its branches. These branches then course between the gluteus muscle and its anterior fascia, with the largest segments (fillets) of this nerve being close to the sacrum and sacrotuberous ligament. It is for this reason that undermining inside the gluteus muscle must never be performed to close to the sacrum, the sacrotuberous ligament, or the sciatic tuberosity [22].

The gluteus medius and minimus are innervated by the superior gluteal nerve. Sensation to the gluteal region and lateral trunk comes from several sources: the dorsal rami of the sacral nerve roots 3 and 4, the cutaneous branches of the iliohypogastric nerve, and the superior cluneal nerves that originate from the L1, L2, and L3 roots. The iliohypogastric and ilioinguinal nerves, branches of the L1 nerve root, supply the skin overlying the lateral gluteal region and can be injured with aggressive lipocontouring of the lateral buttock region. Lastly, the sciatic nerve is the largest nerve of the body and originates from the nerve roots of L4 through S3 (Fig. 6.7). It exits the gluteal region through the greater sciatic foramen below the piriformis muscle and above the superior gemellus muscle to enter the posterior compartment of the thigh. Compression or injury of the sciatic nerve may cause loss of function of the posterior thigh compartment muscles and all muscles of the leg and foot and loss of sensation in the lateral leg and foot as well as the sole and dorsum of the foot [29].

Gluteal augmentation with implants is indicated in patients who suffer from insufficiency of the gluteal region. These patients are typically young and have good muscle and skin tone but lack volume or definition to the gluteal region. Gluteal implants are also indicated in patients who suffer from ptosis of the gluteal region and wish to have a perkier appearance to the buttocks. Another set of patients that benefit from gluteal augmentation with implants are those who have a congenital gluteal deformity or acquired asymmetry (due to trauma, postoperatively, or post-oncologic resection).

Relative contraindications to the procedure are few and typically deal with tissue irregularities in the area to be augmented. One such limitation is a depressed scar in the buttock area which may require adjunctive procedures to cause a release of the scar. Patients who have suffered from radiation to the area have a relative contraindication to surgery as their tissues may be indurated and healing may not be optimal postoperatively. Another patient who may have a relative or absolute contraindication to implant surgery is the patient who presents with deficiency of the lateral and inferior portions of the buttocks. When performing buttock augmentation with implants, the inferior pole remains largely unchanged as too caudal a dissection can put the sciatic nerve at risk of injury. For that reason patients who have a significant deficiency at the lower pole should be counseled to consider fat grafting and implant augmentation. Similarly, deficits in the lateral aspect of the butt are largely unchanged with implant augmentation. Although there will be a slight improvement in the lateral curvature of the buttocks, significant deficits may best be treated with fat grafting or possibly a hip implant. Patients who suffer from autoimmune diseases may be at increased risk postoperatively and should be counseled appropriately prior to pursuing any implant surgery. A patient who presents with unrealistic expectations or suffers from major psychological illness is not an appropriate candidate for buttock augmentation surgery.

A thorough history and physical are paramount to preventing complications at the time of buttock augmentation. Questions are posed regarding the patient’s reasonable attempts to build the muscle with conventional means. During the consultation, patient’s expectations are managed and assessment of the patient’s mental state is undertaken. It is made clear to the patient the expected augmentation that can be achieved, and limitations of the procedure are also explained.

After completion of the history portion of the consultation, an evaluation of the patient’s buttocks is made. Any asymmetries or defects are pointed out to the patient. The patient’s muscles are then evaluated. The skin and fat content are similarly assessed at this time as a patient with minimal adipose and thin skin is more at risk for implant palpability. Measurements of the patient’s buttocks in the transverse axis are then taken in the midportion of the gluteal region beginning 1 cm lateral to the intergluteal crease and ending at the lateral palpable edge of the buttock muscle. This measurement allows the physician to choose an implant that will adequately fill out the gluteal region and is analogous to determining the base width in breast augmentation. Measurement of the vertical height of the buttock is taken from its most cranial portion to its most caudal portion 2 cm short of the infragluteal crease.

The authors’ preference is the style 3, round implant.

On the day of the surgery, the patient is met in the preoperative holding area. It is here that the patient’s consent is verified and again risks, benefits, and alternatives are reviewed with the patient. With the patient in the erect position, the proposed site of incision is marked, measuring approximately 5–7 cm. The site of incision should be in the intergluteal cleft, starting at the apex of the cleft and proceeding caudally. This line of incision must be marked in the upright position preoperatively as the intergluteal sulcus loses its definition when the patient is in the prone position during surgery. The area around the anus should be respected, and incisions should not exceed a 5 cm boundary around the anus to avoid injury to the sphincter complex. Once the site of the incision is marked, the site of the proposed implant is marked taking into account the patient’s anatomy and existing deficit along with the desires of the patient (Fig. 6.8). The superior excursion of the buttock is marked with manual manipulation of the buttock in the cephalic direction if liposuction of the hips is to be done. The sacral triangle is marked for reference if liposuction of the sacrum/flanks is to be performed at the same time.

The patient is brought to the operative suite. Anesthesia is administered. The patient is then placed in the prone position. The buttocks and perianal region are prepped and draped in sterile fashion. The previously marked incision site in the intergluteal cleft is incised with a #15 blade scalpel, taking care not to violate the 5-cm safe zone proximal to the anus (Fig. 6.9). Dissection is carried through the subcutaneous tissues using electrocautery, using hooks in the skin to provide adequate visualization (Figs. 6.10 and 6.11). The incision is carried down to the level of the presacral fascia, making sure to maintain the presacral fascia intact as the closure will utilize this fascia as an anchor to recreate the intergluteal sulcus. Dissection is carried laterally to the gluteal fascia (Fig. 6.12). Dissection is carried laterally for approximately 3–4 cm to better expose the gluteal fascia. At a point found to be in the midsection of the gluteus maximus muscle, the gluteus is split in line with its fibers using a large Kelly clamp to achieve a plane below the gluteus maximus muscle (Fig. 6.12). The opening in the gluteus maximus muscle is then extended using electrocautery to create a 6–7 cm defect in the muscle. A spatula dissector and hockey stick dissector, along with finger dissection, are used to further develop this plane, in line with the proposed site of implant placement (Figs. 6.13 and 6.14). The pocket is created in such a way that the gluteus maximus adequately covers the position of the implant in the medial, lateral, and superficial levels. The gluteus medius and minimus then create the floor of the implant pocket (Fig. 6.15). When considering dissection of a buttock augmentation procedure, the medial extent of dissection should respect the sacral triangle. Care is also taken to minimize dissection in the lower third of the buttock which is the support zone of the buttock and supports the weight of the body when sitting. A key point for the novice surgeon at this stage is that one should err on the side of a tight pocket to minimize the risk of over-dissection and increased potential for implant migration that comes with too loose a pocket for the implant. The pocket is then packed with peroxide-soaked sponges, and attention is turned to the contralateral side for similar dissection (Fig. 6.16). Once all dissection has been completed, implant pockets are evaluated for hemostasis. Hemostasis is achieved as necessary with electrocautery. Next, the pocket is irrigated with an antibiotic solution containing Betadine, normal saline, 80 mg gentamicin, and 1 g of Ancef (if the patient is not penicillin allergic). The irrigant is then suctioned out. Ten milliliters of 0.5 % Marcaine is instilled into the pocket to allow for postoperative pain control. Drains are placed via stab incisions in the infragluteal fold using a #15 blade scalpel. Jackson-Pratt drains are then introduced into the pocket and laid into the base of the pocket and secured with 3-0 Nylon suture (Fig. 6.17). The appropriately selected gluteal implant is folded in half (like a taco) and introduced through the incision in the gluteus maximus (Fig. 6.18). The implant is placed in the contralateral side in the similar fashion. Symmetry is then assessed. Once this is deemed to be satisfactory, closure is begun. A 0-Prolene suture (or permanent suture of surgeon’s preference) is then used in interrupted fashion to close the gluteus muscle and fascia over the implant (Fig. 6.19). Once the implant has been fully covered, the intergluteal incision is closed in layers. First, 2-0 Vicryl suture is used to reapproximate the deep subcutaneous tissues and deep dermis to the presacral fascia to recreate the gluteal cleft. 3-0 Vicryl is used as necessary to fully approximate the dermis. 3-0 silk sutures in interrupted fashion are used to close the skin. The patient’s wound is dressed with Neosporin and absorbent pads. The patient is then placed in a compression garment. Anesthesia is discontinued and the patient is taken to the postanesthesia care unit (PACU).

Postoperatively the patient may begin ambulating starting on the evening of the procedure. They may shower POD 2, making sure to keep the dressings clean. The buttock region is dried and antibiotic ointment is applied in a thin layer. Patients are then allowed to begin light activity at week 2 and full unrestricted activity at weeks 4–6. Patients are asked to wear an elastic compression garment for 4 weeks postoperatively to prevent dead space, thereby helping to reduce the risk of seroma formation. The legs are to be elevated as much as possible to allow for better lymphatic/venous drainage. Narcotic analgesics are prescribed along with muscle relaxants (diazepam 5 mg every 8 h as needed for spasm) to assist with postoperative pain. Patients are placed on broad-spectrum antibiotics for 7 days. The authors’ preference is to use ciprofloxacin 500 mg BID for its broad coverage, both gram positive and gram negative. For 2 weeks postoperatively, the patient is asked to sleep on their abdomen or side and avoid direct pressure to the buttocks. After 2 weeks, the patient is cleared to sleep on their buttocks and sit on their new bottom side with the intention of slowly stretching the newly forming scar capsule. In the early postoperative period, patients may sit on their bottom side but favoring a “bird on a perch” position with the majority of bodily weight being focused on the posterior thigh region rather than directly on the midportion of the buttocks.

In performing buttock augmentation, there is a host of complications that can arise (Table 6.5).