**Abstract**

Permanent esthetic buttocks augmentation is on the rise. Fat augmentation or Brazilian butt lift (BBL) cannot be a solution for patient with a lean body and poor subcutaneous fat deposit. Hyaluronic acid (HA) infiltrations for volume enhancement, when used in big volumes, tend to form foreign body granulomas and cysts, which are visible and palpable with a poor esthetic result. On the other hand, implant-based augmentations have been proposed since the late 1960 of the past century. Buttocks implants can be placed in four different planes according to distinct surgical techniques: subcutaneous, subfascial, intramuscular, and submuscular. An alternative to the widely proposed intramuscular technique is described in the chapter. Submuscular positioning of a biconvex silicone implant is a safe and valuable alternative to other gluteal augmentation techniques with a different plane for implant positioning. Depending on implant volume, submuscular gluteal augmentation has the benefit to perfectly conceal the implant making it almost impalpable and invisible as well.

**Keywords:** gluteal implant augmentation, retromuscolar, buttocks implants, gluteoplasty, biconvex silicone implants

### **1. Introduction**

Gluteoplasty with implants is a growing trend within surgical esthetic procedures. Endpoint of the procedure is enhancement of the roundness of buttocks, volume augmentation along with outward projection. Permanent and stable results are obtainable only with fat grafting and/or gluteal implants placement. Patients with a lean body and low gluteal projection have no choice but to undergo gluteal implant surgery, since conspicuous donor areas are needed for fat grafting. Gluteal implants may be sufficient or can even be associated with fat transfer in a combined procedure [1]. Techniques for implant-based buttocks augmentation are divided into subcutaneous, subfascial, intramuscular, and submuscular, according to the depth of the plane in which the implant pocket is made. The gluteus maximus muscle can be uplifted to expose the "subgluteal

#### **Figure 1.**

*Skin and subcutaneous tissue have been removed to show the superficial anatomy of the gluteal region. Palpable landmarks are coccyx (X) greater trocanther (T) and Ischial tuberosity (I). Gluteus maximus fibers run diagonally from the origin (lateral margin of sacral bone and coccyx) and insert into the iliotibial band and on the gluteal tuberosity.*

#### **Figure 2.**

*Gluteus maximus has been elevated and detached from his origin from sacral bone and coccyx. Deep face of implant pocket may be seen, with piriformis muscle (blue triangle) and ischiatic nerve (blue dot). G Med: gluteus medius.*

*Perspective Chapter: Gluteal Augmentation with Complete Retromuscular Placement… DOI: http://dx.doi.org/10.5772/intechopen.107387*

cellular space," as described by Robles et al. in 1984 [2]. To better understand the anatomy of the gluteal region, a cadaveric dissection was made by second author (A.S.). Ischial tuberosity is an important landmark for the surgery planification, along with sacrotuberous ligament; both structures delimit the medial border of the implant pocket, in order avoid dissection into the ischioanal space. The deep face of the pocket is represented by muscle piriformis, superior and inferior gemelli, internus and externus obturator, and quadratus femoris. Ischiatic nerve origin is just below piriformis muscle in more than 85% of the population [3]. **Figure 1** shows superficial anatomy of the gluteal region. **Figure 2** depicts relevant anatomy of the deep gluteal region.

#### **2. The retromuscolar technique for implant-based gluteal augmentation**

Complications of every gluteal implant-based surgery such as seroma formation, wound dehiscence, implant extrusion, and/or implant visibility and palpability can be greatly reduced with the choice of a submuscular placement of the implant [4–6]. Advantages of this surgical technique are short length of skin incisions, very low rate of implant exposure or extrusion, short operative time, and full implant concealing, making it much less visible and palpable. Downside may comprehend longer learning curve, blind dissection, and little range of implants size.

Other gluteal augmentation techniques may have an highest rate of complications: implant is visible and palpable when placed in a subfascial plane, especially in patient with a thin subcutaneous layer; poor covering of the implant may lead over time to fat lamination and skin loosening with infragluteal fold displacement [7] and implant dislocation. When the implant is placed in a intramuscular pocket, advantage is better concealing, but still there's a moderate percentage of dislocation due to gluteal muscle contraction [8, 9], disadvantage is muscle atrophy and even longer learning curve. Submuscular undermining in first cases could be an intramuscular dissection, for the fear of damaging the deeper structures. Is such cases, one must remember the anatomy and the fact that he/she's not using any sharp dissection, so damaging structures while creating the pocket is seldom a possibility. Perfect dissection should be performed in a deep plane (under gluteus maximus muscles) with great safety for the sciatic nerve.

#### **3. Patient selection**

The retromuscolar technique is preferred by patients requesting a natural, sporty result. Both volume and projection of the buttocks may be improved. Patient with skin laxity of the gluteal area must be carefully advised that little change of this problem will be achieved, especially at the level of infragluteal fold.

Preoperative indications include patients with minimal gluteal flaccidity and a good gluteal muscle tone. Poor candidates may be patients with spinal disk herniation, sciatic nerve pain and thus should not undergo this kind of gluteal augmentation technique.

#### **4. Technique description**

Implant selection must be chosen along with patient desires, but first and foremost by carefully palpating muscle thickness, volume, and tension at the gluteal midpoint

area; the first two are essential to understanding what will be the gluteus maximus muscular implant coverage. Authors-preferred implants are biconvex implants from the French company Sebbin. Those implants are filled with a very high cohesive gel. Implant size range is quite narrow at the moment, presenting sizes of 370, 410, 480, and 530 cc. It is preferred to use an implant size ranging from 370 to 410 cc if the muscle is very thin or the patient has a narrow hip circumference.

Higher size from 410 to 480 cc should be used if the muscle has regular thickness or if the patient has a higher hip circumference. Drawing starts with the patient in the standup position (**Figure 3**). A horizontal line is drawn at the top of the intergluteal fold, since this feature will disappear when the patient is in prone position, thus ensuring that the incisions will be made entirely within the intergluteal crease to conceal the final scar. Subsequently, bone landmarks are identified to define the limits of the implant diameter. Those are the trochanter posterior border, i.e., the implant pocket lateral limit.

Another point of reference is the ischial tuberosity; from this point the sacrotuberous ligament runs toward the sacrum and the course of the lower limit of the gluteal muscle: this is the pocket inferior and medial limit. After drawing the point of desired maximum projection in which we want to place the implant, we obtained the radius of the implant according to implant diameter. Skin incision lines are then drawn with the patient laying over the operating table (**Figure 4**) placing them 1 cm lateral to the midline, with intergluteal fold and sacrodermal ligament complete preservation. Skin incisions are parallel and a little offset to lower the size of the area in between; length is 3–5 cm according to experience of the surgeon and implant choice of size.

#### **Figure 3.**

*Drawing in the standing position, horizontal line at the top of intergluteal crease and point of maximum projection of each buttock.*

*Perspective Chapter: Gluteal Augmentation with Complete Retromuscular Placement… DOI: http://dx.doi.org/10.5772/intechopen.107387*

#### **Figure 4.**

*Drawing in the prone position, offset of skin incision, 3–4 cm long, parallel, and 1 cm lateral to the midline. Skin around the anal region is highlighted in order to avoid incision in that area.*

Anesthesia can be general, deep sedation, or even spinal. We do not prefer the latter due to the fact of dilation of the vein system that could lead to a higher chance of bleeding. Patient decubitus is prone and completely flat. Incision lines are then drawn as described above and infiltrated with analgesic solution (2 mg epinephrine and 20 ml of ropivacaine 7.5 mg/ml for every 1000 ml of saline). This solution is infiltrated under the incision lines dermis, in the full thickness of subcutaneous fat and the medial border of gluteus maximus fascia; total volume is around 50 ml on each side. After that one must take time to wait for the drug onset, around 10–20 minute. Then a stab incision is made with a 15-scalpel blade in the middle of incision lines, a 2.5 mm infiltration cannula is inserted, and the submuscular plane is infiltrated with the same solution. This step is very important for the upcoming procedure of pocket dissection. The cannula must first pierce the gluteus maximus fascia (a perforating sound might be heard), then moved 2 cm deeper, and then turned laterally, to infiltrate the solution deeper to the gluteus maximus muscle, in the space between gluteus maximus and piriformis medially and between gluteus maximus and gluteus medius laterally. A first-time error could be a too superficial infiltration. Subsequently, time is taken to allow epinephrine to exert its vasoconstrictive effect. After scrubbing the skin with chlorhexidine and alcohol solution and sterile draping, a sterile gauze is tapered over the anal region to isolate it. The instruments required for submuscular gluteal augmentation have been designed by Petit F as described in his paper [9]. Those are a

mayo scissors, a Colin Hartman retractor, two long spacers (**Figure 5**), forceps, and a disposable funnel for implant insertion. No diathermic cutting instruments or bipolar forceps are routinely used. After the skin incision, opening continues bluntly in the subcutaneous tissue with the scissors to reach the insertion of gluteus maximus at the lateral border of the sacrum. In this, dissection is limited in the subcutaneous region and over the muscular fascia to keep at a minimum the dead space formation. After that muscolar fascia is perforated with the closed scissors, and this tiny hole is enlarged by the opening of the instrument while regressing it. Then the surgeon's index finger can access the submuscular cellular space. At this point, the surgeon should maintain the depth of the plane of undermining, which is performed bluntly by the fingers with a sweeping motion. Care is taken to maintain the undermining superior and lateral to the sacro-tuberous ligament, thus avoiding the posterior aspect of the obturator foramen. After creating a small cavity by fingers, the long spacers are used to free the pocket from the strongest fascial adhesions. A dry laparotomic gauze is then placed into it, to keep it wide open and to check for major bleedings. Same procedure is then done on the contralateral side, checking for pocket symmetry. With this technique

**Figure 5.** *Surgical instruments needed for pocket dissection and implant placement.*

#### *Perspective Chapter: Gluteal Augmentation with Complete Retromuscular Placement… DOI: http://dx.doi.org/10.5772/intechopen.107387*

the sciatic nerve is respected in its integrity because the narrow tunnel is made with fingers only as far as the fingers may undermine the muscle and open the pocket. This submuscular elevation allows the entire thickness of the muscle to be elevated, ensuring that the implant will be covered by the full thickness of the muscle. Thus, muscle fibers' morbidity is much less when compared to the one observed in the intramuscular technique. The implant will rest in a deep pocket with little chance of extrusion since muscle contraction will indeed force it to stay in its location. We should remind that


#### **Table 1.**

*Specific complication in order of frequency.*

#### **Figure 6.**

*(a) Preoperative posterior view of 38-year-old female patient. A 480 cc implant placement was planned. (b) Preoperative lateral view of. (c) postoperative posterior view. 3 month postop. (d) Postoperative lateral view. 3 month postop. (e) Close-up of scar placement and quality of patient shown in this figure.*

no sharp dissection is used in this surgical technique: Tissues are expanded: fascia and muscle are not cut, but once the tunnel is created, the tissues are dilated progressively. The disposable funnel allows insertion of the implant through the short skin incision and narrow muscular tunnel. Drains are not routinely used. The fascial opening is left untouched, and skin closure is performed in two layers: deep subcutaneous is brought together with a long, ½ circle needle, on a 2–0 braided absorbable suture, then a 3–0 absorbable monofilament close to the dermal plane, by a running bottom to top intradermal suture. The patient is allowed to stand up after being positioned in a supine position for 1 hour and then walk and sit with little restrictions for the first week postoperative. Patients are routinely discharged a few hours after surgery and go back home with a low waist elastic compression garment.

Oral therapy for pain control consists of paracetamol 500 mg/codeine 30 mg bid and ketorolac oral drops along with a muscle relaxant such as diazepam. Steroids may be administered later in case of sciatic nerve irritation. Physical activity (i.e., gym

#### **Figure 7.**

*(a) Preoperative posterior view of 31-year-old female patient. A 370 cc on the left side and a 410 on the right side cc implant placement was planned. (b) Preoperative lateral view. (c) Postoperative posterior view. 4 month postop. (d) Postoperative lateral view. 4 month postop.*

*Perspective Chapter: Gluteal Augmentation with Complete Retromuscular Placement… DOI: http://dx.doi.org/10.5772/intechopen.107387*

workout and any other sport) is discontinued for 4 weeks after surgery. The first outpatient control is 7 days after surgery. The dressing pad is removed, and the incision site is cleaned with antiseptic solution.

Immediate and late complications are listed in **Table 1**. Cases photography are shown in **Figures 6**–**10**.

$$\mathbf{(b)}$$

#### **Figure 8.**

*(a) Preoperative posterior view 52-year-old female patient. A 480 cc implant placement was planned, along with liposuction of flanks and lipofilling of lateral depressed gluteal region (hybrid gluteoplasty). (b) Preoperative lateral view. (c) Postoperative posterior view. 4 month postop. (d) Postoperative lateral view. 4 month postop.*

#### **Figure 9.**

*(a) Preoperative posterior view 53-year-old female patient. A 480 cc implant placement was planned, along with liposuction of flanks. (b) Preoperative lateral view. (c) Postoperative posterior view. 3 month postop. (d) Postoperative lateral view. 3 month postop.*

#### **Figure 10.**

*(a) Preoperative posterior view 51-year-old female patient. A 370 cc implant placement was planned. Patient had a severe laxity of gluteal skin. (b) Preoperative lateral view. (c) Postoperative posterior view. 5 month postop. Improved skin laxity, with residual laxity at the inferior gluteal fold. (d) Postoperative lateral view. 5 month postop.*

*Perspective Chapter: Gluteal Augmentation with Complete Retromuscular Placement… DOI: http://dx.doi.org/10.5772/intechopen.107387*

### **5. Conclusions**

Due to retromuscular plane positioning, implants are invisible in every position of the buttock's region and almost impalpable, giving no clues that the operation was performed, for a natural **esthetic** result. Implant-based gluteal augmentation has a long surgical history, which started back in the late 1960s [1]. Intramuscular placement of the implant has gained popularity over time when compared with the subfascial and subcutaneous plane as it seemed to be the perfect "halfway" between deep and superficial placement [10, 11]. The submuscular placement had less appeal to surgeons for fear of damaging deep structures such as the sciatic nerve or gluteal vessels. This wasn't the case in our experience: sciatic pain is a postoperative complication that can manifest up to 3 week postoperatively, treatment includes oral steroid therapy for 10 days and common pain-controlling drugs. The submuscular technique for gluteal augmentation leads to advantages for both patients and surgeons. Patients seeking a more natural appearance are best candidates for this procedure. Surgeons can perform this technique in a short operative time and without complex preoperative analysis. Great care must be given to the surgical instruments and to the digital undermining, to avoid any damage to the sciatic nerve and the gluteal vessels.

## **Conflict of interest**

The authors declare no conflict of interest.

## **Author details**

Valerio Badiali1 , André Salval1 \* and Salvatore Giordano2

1 Istituto Estetico Italiano IEI, Private Practice, Roma, Italy

2 Department of Plastic and General Surgery, Turku University Hospital, Turku, Finland

\*Address all correspondence to: a.salval@istitutoesteticoitaliano.it

© 2022 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
