Subcutaneous Plane

First attempts at gluteal augmentation placed implants in the subcutaneous space (Fig. 40.2); breast implants were used until the first implant designed by González-Ulloa specifically for gluteal augmentation was released by Dow Corning. However, this subcutaneous space had numerous anatomic restrictions, making it unsuitable for this operation. Results were unnatural, and the visibility of the implant restricts the usefulness of this space for gluteal augmentation (Fig. 40.3A, B, C).

FIG. 40.2 First attempts at gluteal augmentation placed implants in the subcutaneous space.

FIG. 40.3 Results were unnatural, and the visibility of the implant restricts the usefulness of this space for gluteal augmentation.

The system that maintains the skin attachment to the gluteal region is composed of aponeurotic expansions running from the gluteal aponeurosis to the dermis; when a gluteal implant pocket is developed in this space, these aponeurotic expansions are divided, skin will be loose, and the implant will not have the correct anatomic position. Thus a very obvious implant will result.

Complications with this subcutaneous approach consisted of extrusion, infection, and inferior displacement of the implants. The second generation of implants included Dacron patches on the back, with the goal of affixing the implant to the pocket; however, these patches were not sufficient to maintain implant position. The next generation design had an area on the implant that could be sutured to the deep tissues. Results with this approach were still unnatural, with implant visibility an ongoing problem.

Correction of these cases implies having to change the dissection plane to either intramuscular or subfascial and closing the subcutaneous space permanently. In Fig. 40.4A, B, and C the correction of the patient shown in Fig. 40.3 has been performed, placing a polyurethane covered gluteal implant in a subfascial plane (photos were taken 6 weeks postoperatively).

FIG. 40.4 Correction of the patient shown.

Submuscular Plane

In 1984, Dr. Robles from Argentina described a new technique for gluteal augmentation that used a submuscular approach. This approach preserved the aponeurotic system that holds gluteal skin in position; however, it introduced a new anatomic problem with the potential risk of injury to the sciatic nerve. This nerve emerges from the submuscular space, at the level of the proximal lower third of the gluteal region and at the inferior border of the piriform muscle. To avoid injury to this nerve, an implant could not be placed below this level (Fig. 40.5). Furthermore, implants had to be small in diameter and could not be placed close to the infragluteal fold.

FIG. 40.5 Submuscular plane.

This technique was used for many years. In patients who had good volume in the lower third of the gluteus, small implants could be placed in a relatively snug pocket. However, in slender patients the esthetic results were not good and patients were often left with a double bubble deformity, similar to the phenomenon sometimes seen when mammary implants are placed below the inframammary fold.

Tailoring the pocket for the gluteal implant through the submuscular approach preserved the aponeurotic expansion system uninjured, but the implant was positioned high in the gluteal region. Therefore projection was higher than normally expected, and the lower third of the gluteal region was empty, with the loose skin hanging over the upper thigh. This space, which was named the “subgluteal cellular space” by Dr. Robles, is developed deep on the depression of the osseous pelvic bones, and projection of the implant is lost. This technique was probably the most well known for gluteal implants, until the subaponeurotic technique was developed.

Intramuscular Plane

Another anatomic space described for gluteal implants was the intramuscular space (Fig. 40.6), which was developed by disrupting the gluteal muscle fibers. The goal was to leave a 3 to 4 mm thickness of gluteus maximus muscle attached to the aponeurosis. Ideally, this could help to minimize risk to the sciatic nerve, but disruption and avulsion of the muscle fibers produced a high incidence of seroma. It was also very difficult to estimate the quantity of muscle on top, and the possibility of injuring the sciatic nerve was not totally eliminated because undermining was done blindly with no anatomic landmarks to guide the surgeon.

FIG. 40.6 Intramuscular plane.

Additionally, skin markings for this operation were done with the patient in a sitting position; thus the inferior part of the gluteal region would remain empty. Although the threat of injury to the sciatic nerve was remote, the esthetic result, similar to that of the submuscular approach, was suboptimal. The inferior border of the implant was high, and the lower part of the gluteal region was empty and loose with the appearance of a double contour (Fig. 40.7A, B, C). Furthermore, the operation was painful, with a difficult postoperative period, because the patient had to maintain a vertical position for several days.

FIG. 40.7 The inferior border of the implant was high, and the lower part of the gluteal region was empty and loose with the appearance of a double contour.

Subfascial (Subaponeurotic) Plane

To solve the problems encountered with the subcutaneous, submuscular, and intramuscular anatomic dissections, a new anatomic plane was sought that could hold a gluteal implant. Extensive anatomic dissections were performed in which we studied the gluteal aponeurosis. Our technique is based on these anatomic studies.

The gluteal aponeurosis is very strong at its origin and insertion. This fascia covers the gluteus maximus muscle (Fig. 40.8A, B), the larger and more superficial regional muscle responsible for projection of the gluteal area, and the anterior two thirds of the gluteus medius muscle, which shows on the upper third of the gluteal region. The gluteal aponeurosis insertions are on the posterior iliac bone, the sacral bone, and the coccyx bone, and on the lateral limit inserts on the greater trochanter and extends to the iliotibial line.

FIG. 40.8 Subfascial (subaponeurotic) plane.

This large aponeurosis covers the entire gluteal region and at the same time molds the gluteal augmentation; it is stronger at the insertion sites and softer in the middle, helping to achieve a natural result (Fig. 40.9A, B).

FIG. 40.9 This large aponeurosis covers the entire gluteal region and at the same time molds the gluteal augmentation.

The aponeurosis expansions are distributed in a transverse direction, along the axis of the muscle fibers throughout the gluteal region. Because they originate on the deep part of the gluteal aponeurosis, the attaching fibers convert the superficial surface of the gluteus maximus into a uniform space shaped like the muscle. The aponeurotic expansions to the skin are preserved, and the subaponeurotic space allows proper positioning of an implant without risking injury to the deep neurovascular structures (Fig. 40.10A, B).

FIG. 40.10 The aponeurotic expansions to the skin are preserved, and the subaponeurotic space allows proper positioning of an implant without risking injury to the deep neurovascular structures.

Implant Decision

This procedure employs small anatomic implants for gluteal augmentation, as well as bigger implants for larger patients who want a better contour of the gluteal region. Gluteal contour is gained by insetting anatomic implants on top of the gluteal maximus muscle and under the gluteal aponeurosis. The anatomic decision making system designed for this operation consists of templates (Fig. 40.12A) for the preoperative skin markings, sizers for transoperative measurement (Fig. 40.12B), and gel-filled implants (Fig. 40.12C). Further explanation of decision making for individualized implant selection will be elaborated in the technique portion of this chapter.

FIG. 40.12 Implant decision.

FIG. 40.12 Implant decision.

FIG 40.2D, E Appears ONLINE ONLY

Implant Characteristics

Implants have a textured surface with the maximum softness available; these implants are highly cohesive gel–filled implants with texturized surfaces and/or a polyurethane cover. It has been demonstrated that polyurethane can lower the incidence of capsular contracture in breast augmentation and currently we have an ongoing study to demonstrate its benefits in gluteal augmentation.

New designs of gluteal implants have been launched onto the market recently. The design recommended can vary depending on the desires of the patient and their anatomy but the most important factor to keep in mind when deciding on a type of implant is making sure that the transverse length of the buttocks is not increased, that is why a narrow base with adequate projection is desired (Fig. 40.12D, E; De la Peña Design implants on the left with a polyurethane cover).

Incision

The skin incision has changed over the years. At the beginning a midline incision was used over the sacrum all the way to the coccyx as described by Robles and colleagues in 1984. This was followed by de-epithelializing an ellipse of skin to maintain the skin and fat of the midline and perform the subcutaneous undermining independently. Despite this modification the incidence of small wound dehiscence remained high. With the use of two separate incisions the rate dropped to 4%.

Using two incisions provides a better anatomic preservation of the crease, isolates the pocket if a complication in the other side should occur and has a lower incidence of dehiscence and hypertrophic scarring because of lesser tension in the scar.

The paramedial incisions are 4 to 6 cm in length and 2 cm apart (Fig. 40.13), each beveled in an oblique fashion from the skin edge down to the gluteal aponeurosis at the lateral border of the sacrum. The subcutaneous tissue at the midline is left intact.

FIG. 40.13 The paramedial incisions are 4 to 6 cm in length and 2 cm apart.

Markings

With the patient in the upright position, skin markings are made using a custom-designed template. The template must fit perfectly into the gluteal region leaving 2 cm above the infragluteal sulcus and 2 cm lateral to the external rim of the sacral bone (Fig. 40.14). The sacral triangle must be preserved; it is an esthetic landmark of this region. The implant should never be placed on top of the sacral bone.

FIG. 40.14 Markings.

Laterally the template will extend to the external border of the gluteal region, leaving at least 2 cm from the external line (Fig. 40.16A); this is the line that continues up from the iliotibial line of the thigh. Liposculpture lines are drawn at the same time when indicated (Fig. 40.15B).

FIG. 40.15 Degrees of ptosis.

Some of the same principles used in breast surgery can be applied to the gluteal region. When evaluating a gluteal augmentation candidate it is important to take into consideration the following aspects:

If redundant skin exists in the lower back and gluteal area due to excess laxity of the skin or important weight loss, introducing a gluteal implant will improve the volume of the buttocks but it will not correct any drooping, sagging, or ptosis of this area. This is the same phenomenon seen with the breast; it will continue to be a ptotic buttock, only bigger in volume.

For the correction of this problem, resection of the excess skin is necessary, reposition of the anatomical structures and the restoration of the volume and projection desired.

Proposed Classification for Gluteal Ptosis (Fig. 40.15C)

Skin markings in patients with ptosis is different (Fig. 40.15D–F) because there is an excision of skin in the upper part of the buttock and lower part of the back from where the surgery is carried out, but the subfascial plane is created in the same manner when compared with gluteal augmentation only.^1–4

Anesthesia

General or epidural anesthesia can be used for the procedure. If epidural anesthesia is used, the catheter may be left in place for pain control after surgery.

After the incisions are made and the subfascial space has been reached, tumescent infiltration with a modified Klein solution is performed (Fig. 40.16). This has two advantages: It produces hydrodissection of the subfascial plane, making it easier to create the pocket for the implant and produces vasoconstriction with less bleeding, giving a better visualization of the anatomical structures.

FIG. 40.16 After the incisions are made and the subfascial space has been reached, tumescent infiltration with a modified Klein solution is performed.

Patient Positioning

The patient is placed in the prone position. Special care must be taken to cushion the face and pressure sites such as the iliac spine and breast. The surgical procedure is done in this prone position. After the procedure, the patient is placed in a supine position. There is no need for a prone position during the postoperative period.

Surgical Technique

The surgical incision begins at a point 3 cm above the anus corresponding to the level of the coccyx and extends cephalad approximately 6 cm. The incision then proceeds laterally to the presacral fascia on the subcutaneous tissue until the external rim of the sacral bone is reached. At this time an incision is made parallel to the external rim of the sacral bone on the gluteal aponeurosis and reaching the subfascial space (Fig. 40.17A). Care is taken not to cut any of the muscle fibers. Infiltration of Klein’s solution is done under the aponeurosis; this facilitates identification of the avascular plane under the fascia. The multiple septae from the aponeurotic expansions are identified and infiltration is done between this network (Fig. 40.17B). Because these are aponeurotic expansions, they are not easily disrupted so they all need to be cut to ensure hemostasis (Fig. 40.17C). The goal is to raise a fasciocutaneous flap in the gluteal region.

FIG. 40.17 Surgical technique.

FIG. 40.17 Surgical technique.

FIG 40.17A Appears ONLINE ONLY

Sharp dissection continues; lighted retractors and long instruments for retraction, cutting, and coagulation are essential to divide all aponeurotic expansions over the muscle. Bleeding is minimal if undermining proceeds carefully, with simultaneous coagulation with dissection. Perforator vessels from the superior and inferior gluteal arteries are identified and legated (Fig. 40.17C). To facilitate undermining, it is advisable to maintain the dissection from medial to lateral and from cephalic to caudal, maintaining a wide field of exposure extending from the initial subfascial undermining (Fig. 40.18A). It is also important to remember to restrict the undermining to the level of the skin marking, thus preventing it from extending beyond the infragluteal crease.

FIG. 40.18 It is advisable to maintain the implant in saline solution with antibiotic until the end of surgery.

Once dissection is completed, we use implant sizers to confirm the size of the implants to be used and to determine if any further dissection is needed. These sizers are developed as part of the anatomic system for gluteal augmentation; they are white smooth-surfaced gel-filled implants, each with the corresponding size mark and with the “sizer legend” on top. These are not the definitive implants; however, they are handled with the same no-touch technique used for the final implants. It is advisable to maintain the implant in saline solution with antibiotic until the end of surgery (Fig. 40.18B).

Once the final implants are selected, closed suction drains are inserted to help maintain the adhesion of soft tissues to the implant. The selected implants are placed. These implants have a transverse line on their equator so that they can be seen through the incision and to ensure perfect placement and alignment (Fig. 40.19).

FIG. 40.19 These implants have a transverse line on their equator so that they can be seen through the incision and to ensure perfect placement and alignment.

The implant must fit loosely in the pocket, and closure of the aponeurosis must be without tension. Tissues are rearranged to comfortably drape over the implant. It is advisable to dissect both pockets before inserting any implant so that the augmented gluteus does not interfere with the dissection of the contralateral pocket (Fig. 40.20A, B).

FIG. 40.20 It is advisable to dissect both pockets before inserting any implant so that the augmented gluteus does not interfere with the dissection of the contralateral pocket.

Once the implants are placed, closure of the pocket begins by reinserting the aponeurosis under no tension; a watertight repair is done with absorbable sutures. Superficial and deep subcutaneous fascia are closed separately on both sides of the presacral fascia. Finally, the skin is closed and fixed to the presacral fascia to reconstruct the intergluteal crease. Tissue glue can be used to maintain the incision closed and dry. At this point any adjunctive procedures are begun.

Fat Grafting

Because of the added volume and contour that the implants provide it is not usually necessary to perform fat grafting to the buttock area. We recommend this procedure only for subcutaneous depressions that may have been present before the procedure and only in small amounts. Grafting large amounts of fat can lead to fat necrosis and infection that can compromise the entire operation.