Gluteal free flaps for breast reconstruction

Introduction

Replacing tissue loses in kind is essential to achieve functionally and aesthetically pleasing outcomes in all aspects of plastic surgery; therefore, the ideal tissue for breast reconstruction is fat with or without skin. In the last two decades, with advancement in microsurgical techniques, perforator flaps have allowed the transfer of a patient’s own skin and fat in a reliable manner for breast reconstruction.

Although gluteal soft tissue is usually not a first choice in autologous breast reconstruction, it has been considered as a viable option when the abdominal donor site was not available, whether because of a thin body habitus or prior surgical procedures. Consistent vascular anatomy, good skin color match with donor site, excellent thickness and texture of subcutaneous fat that provides desired breast projection and volume are clear advantages of gluteal perforator flaps. On the other hand, difficulty in dissection of perforators to their source vessels, short pedicle length, patient positioning concerns and the potential need for a second surgeon in bilateral cases has made both superior gluteal artery perforator (SGAP) and inferior gluteal artery perforator (IGAP) flaps less favorable choices in our practice when compared with the new generation of perforator flaps such as transverse upper gracilis (TUG) and profunda artery perforator (PAP) flaps.

Despite the technical and logistical demand, the superior gluteal donor site consistently serves a reliable flap option in microsurgical breast reconstruction with adequate and high quality soft tissue, and robust vascular anatomy. With increasing microsurgical experience, a plastic surgeon should be able to perform this procedure safely and consistently. Therefore, we believe that gluteal free flaps are still an important part of the reconstructive breast surgeon's repertoire.

History

The first free flap described for breast reconstruction was the gluteus maximus myocutaneous flap by Fujino et al . in 1975. Although the technique was further developed and popularized by Shaw in the early 1980s, the modern total muscle-sparing SGAP flap was reported by Allen and Tucker in 1993 in a nine-patient case series. Without sacrifice of muscle, a much longer pedicle was obtained, which in turn eased both the flap inset and performance of the anastomosis with internal mammary or thoracodorsal recipient vessels. The same technique was also applied for development of the IGAP flap; however, close proximation of pedicle harvest to the sciatic nerve and aesthetically unpleasing scar location made this flap less favorable compared with the SGAP flap.

Patient selection and considerations

For patients who opt for autologous-based breast reconstruction, the deep inferior epigastric perforator (DIEP) flap is considered the best option by most microvascular surgeons. However, insufficient abdominal subcutaneous fat or previous abdominal surgeries may preclude abdominal based autologous flap reconstruction. Gluteal-based free flaps can be a reliable options for these patients desiring a natural look with acceptable donor site comorbidity and scar formation.

As it is important for all microsurgical reconstruction cases, general rules of patient safety should be taken into consideration by performing a thorough preoperative evaluation as well as a history and physical examination. Active tobacco use, potential need for radiation therapy, uncontrolled diabetes mellitus and hypertension are considered relative contraindications requiring patient optimization prior to proceeding with microsurgical reconstruction. If the likelihood of radiation therapy is high, the reconstruction can be staged by placing tissue expanders immediately following the mastectomy. In the event of active tobacco use, we prefer to perform microsurgical reconstruction once the patient stops smoking for at least 6 weeks prior to surgery. Advanced patient age is not a contraindication and there is no upper age cut-off for microsurgical breast reconstruction as long as patient is considered an appropriate candidate by the surgical and anesthesia teams for an operation that can be 10–12 h in duration. Surgeons should keep in mind that performing gluteal-based free flaps can be challenging in obese patients (body mass index [BMI] >30) due to increased flap thickness in addition to a short pedicle length. Although there is a clear BMI cut-off in our practice, other free flap options should be considered in this patient population.

During the physical examination, assessment of overall body habitus and breast symmetry plays an important role for surgical planning. With regards to recipient site, patient’s native breast size, presence of ptosis, nipple and breast asymmetry, previous scars, soft tissue deficits, and radiation-related skin changes should all be taken into account while discussing both reconstruction and contralateral symmetry procedure options with the patients. Donor sites should be assessed for surgical and post-traumatic scars as well as adequacy of soft tissue and skin. Previous liposuction and fat injection procedures at the donor site can complicate the surgery and warrant preoperative vascular imaging using magnetic resonance or computed tomographic angiography for evaluation of the perforators.

Patient education is very important and should include demonstration of photographic images of previous patient outcomes to appreciate the potential scars and contour changes. Whether a patient prefers to undergo an SGAP or IGAP flap is usually influenced by the trade-offs of each gluteal flap procedure. SGAP scars can be covered by a bathing suit but the scar on the buttock is prominent. IGAP scars can usually be hide at the gluteal crease but especially the lateral portion can be visible in a bathing suit. Although both scars might be concealed with well-designed flaps and clothing, harvest of these flaps can potentially disrupt the aesthetic units of the buttocks and cause unfavorable contour changes. We found that some patients from certain ethnical backgrounds can find the post-surgical donor site appearance unacceptable; therefore, discussion about the change in buttock volume and shape should always be a part of patient-centered preoperative decision-making process before proceeding with a gluteal free flap reconstruction.

In cases where gluteal free flap reconstruction is not feasible during surgery due to inadequate recipient vessels or damaged perforators, the need for secondary options, if they exist, should also be discussed in advance with the patient. Timing of reconstruction and revision procedures should be explained as well as the length of hospitalization and the recovery period. Patients who desire a larger breast size than a gluteal free flap can offer can still undergo an implant placement as early as 6 months after the original free flap surgery. We do not recommend simultaneous implant placement at the time of the free flap procedure due to the short pedicle length.

Preoperative perforator mapping

Although anatomical landmarks of the perforators zones for SGAP and IGAP flap are well known, the highly variable anatomy of gluteal vessels can make the flap design challenging. Knowledge of perforator location, caliber and trajectory results in improved operative efficiency and flap design.

In experienced hands, gluteal free flaps can be designed and harvested safely by locating perforators on the gluteal skin using a hand-held Doppler. This avoids both additional cost to reconstruction and patient exposure to radiation. When surgeon experience is limited to only a few cases per year, preoperative perforator mapping can help the surgeon to efficiently identify a centrally located, larger caliber perforator that allows sufficient pedicle length for insetting.

Options for perforator mapping includes Doppler US, CT-angiogram and MR-angiogram. CT- angiogram can be obtained quickly and images can usually be interpreted by the surgeon independently. Radiation exposure and need for contrast injection are the disadvantages of CT- angiogram. MR-angiogram can give superior imaging results with no radiation risk; however, it can be costly, time-consuming and hard to independently view by the surgeons.