Flat Aesthetic Mastectomy Closure with the Angel Wing Technique to Address Lateral Adiposity: Technique and Outcome Analysis

Introduction . Oncologic mastectomy in the setting of obesity poses challenges in achieving a fat closure that includes the lateral adiposity. Te angel wing (AW) technique was developed to address this issue. We aim to demonstrate the safety of AW by evaluating incidence of arm lymphedema (AL) and decreased range of motion (dROM) in patients postmastectomy with and without the AW closure. Methods . We performed a single-center retrospective cohort study at an academic referral center of patients who underwent mastectomy with and without the AW technique from May 2014 to October 2022. Tose who received breast reconstruction (immediate or delayed), partial mastectomy, and male patients were excluded. Te presence of postoperative AL and dROM was evaluated. Subgroup analysis was performed for patient factors including BMI, extent of axillary surgery, PMRT


Introduction
As mastectomy rates have changed over the years, there is a growing interest in patients who desire mastectomy without reconstruction ("going fat") [1].However, oncologic mastectomy in the setting of obesity poses challenges in achieving an aesthetic fat closure (AFC) that include the lateral fat pad or fold, defned as the lateral adiposity.Tis lateral adiposity can cause chafng, pain, range of motion limitation, challenges in prosthetic ft, and dissatisfaction of appearance.
Several techniques to address lateral adiposity have been described.Tese techniques include the Y-shaped incision by Szynglarewicz et al. [2], the modifed V-Y advancement technique by Gibbs et al. [3], the Fish-tail plasty by Hussien et al. [4], the modifed M-plasty by Meybodi et al. [5], the double S technique by Stefens et al. [6], the tear-drop incision by Mirza et al. [7], and the L incision and lipoaspiration by El Hajj et al. [8].Te angel wing (AW) technique was frst described by Hill and Henry-Tillman et al. in 2018 [9].It is novel in that it avoids the frequently seen watershed area resulting in an increased risk of posterolateral junction skin ischemia or fap necrosis as well as providing an aesthetic linear scar.Te previously described Y-shaped incision added two oblique incisions (two triangular-shaped faps) to the traditional transverse Stewart mastectomy incision at the lateral part forming a Y-shape [2], and the modifed V-Y advancement technique retracted the lateral apex of the mastectomy incision medially and secured the apex to the approximated transverse incision, followed by excision of the redundant superior and inferior tissues, forming a Y-shaped confguration upon closure [3].Te fsh-tail plasty was similar.A stay suture is used to approximate the superior and inferior skin fap just lateral to the anterior axillary line, the lateral end of the mastectomy incision is brought medially to the existing stay suture, and the redundant skin is excised superiorly and inferiorly [4].Within the modifed M-plasty, the lipodermal fap of the Mplasty is de-epithelialized, pulled medially and secured to the pectoralis fascia according to the desired lateral contour fattening, also resulting in Y-shaped closure [5].Of note, with these techniques employing a Y junction, skin necrosis is not infrequent.Tis occurs in 1.7-3.6% of patients, and they additionally exhibit an increased risk of dehiscence [2][3][4][5].Other techniques avoid this Y junction, such as the double S technique [6], the tear-drop incision [7], and the L incision and lipoaspiration [8].Tese all have their advantages and drawbacks.Te double S technique employs two S-shaped incisions, superior and inferior to the nipple areolar complex.Tis enables the surgeon to shift the incision medially or laterally depending on the tumor location and the amount of lateral adiposity [6].Te tear-drop incision results in a broader incision laterally, including a segment of the axillary fat pad [7].Of note, the double S technique and the tear-drop incision do not address the posterior aspect of the lateral adiposity.Conversely, the L incision and lipoaspiration include removal of a portion of the axillary fat pad and liposuction of the posterior axillary fat; however, the incision extends to the axillary crease resulting in an increased risk of lymphatic disruption [8].
Te AW technique pioneered by Henry-Tillman at the University of Arkansas Medical Sciences (UAMS) was developed to minimize the risk of posterolateral junctional skin ischemia or fap necrosis while addressing lateral adiposity, creating a linear scar that is aesthetically pleasing.Te preliminary study revealed increased patient satisfaction and improved functional outcomes [9].Te AW technique consists of two parts, a lateral incision with superior and inferior faps development to address the lateral adiposity and the mastectomy incision (see Figure 1).Preoperatively, the patient is evaluated in a standing or upright sitting position with her arm relaxed in front.A pinch test is done to assess the amount of lateral adiposity to be excised; with the lateral adiposity "pinched," the patient is asked to raise her arm to avoid the range of motion dysfunction.Te posterolateral end point is outlined based on the amount of lateral adiposity; therefore, the posterior end of the angel wing varies between patients.Te AW portion of the procedure is composed of two parallel curvilinear lines with the superior line inferior to the axillary hairline and the inferior line extending from the posterior point to the sternal border along the entire inframammary crease.An anterior axillary line marking is drawn to ensure proper alignment during skin reapproximation.Te mastectomy incision is then marked in the standard width to length ratio of 1 to 3, with the superior marking typically created at the level of the inframammary crease for a fat closure, yet without tension (see Figure 2).
In the operating room, the patient is positioned in the supine position with arms extended 90 degrees, and sterile covers are used for the arms to allow medial arm retraction by an assistant.Te AW incision is performed via a separate incision to the anatomical borders of the mastectomy.Tick subcutaneous faps are developed superiorly and inferiorly, and the excess lateral adiposity is excised superfcially to the latissimus dorsi fascia, keeping the fascia intact.Of note, during fap reapproximation, it is important to shift the ipsilateral abdominal wall medially to restore neutral body alignment.Skin staples are used to temporarily approximate the lateral skin for ease of fap alignment and to minimize blood loss.Te mastectomy ± axillary portion of the procedure is then completed in a standard fashion, and a drain is placed in the mastectomy cavity.Te incisions are closed with a single layer of 3−0 absorbable suture followed by skin adhesives (see Figure 3).Before and after photos are shown in Figure 4.

Methods
We performed a single-center retrospective cohort study at an academic tertiary referral center, evaluating all patients who underwent mastectomy with and without the AW technique, encompassing an 8.5-year period from May 1, 2014, to October 31, 2022.As this was a retrospective study employing deidentifed data, the study was determined to be institutional review board (IRB) exempt as nonhuman subject research, and a waiver of consent was obtained by the University of Arkansas for Medical Sciences IRB. Eligible patients included all women who underwent mastectomy during the selected timeframe.Patients were identifed through an EMR query of all who underwent a mastectomy  d-f ) With the lateral adiposity "pinched," the patient is asked to raise her arm to ensure that the lateral adiposity removed would not restrict full range of motion.

Right lateral adiposity
During faps approximation, the abdomen is shifed medially to restore neutral alignment skin staples

Results
A total of 390 patients met the inclusion criteria.Te overall dROM rate was 13.3% (n � 52/390), seen in 11% (n � 19/173) undergoing AW vs. 15.2%(n � 33/217), and did not signifcantly difer between the technique utilized (p � 0.22).When subgroup analysis was performed, there was no statistical diference in dROM development within patient populations undergoing the AW technique compared to the non-AW technique (see Table 3).

Discussion
Lateral adiposity in obese patients often conveys a challenging aesthetic fat closure in oncologic mastectomy.Tis lateral adiposity is often exaggerated and bothersome to patients postprocedure.Redundant soft tissue and lateral adiposity postmastectomy may cause decreased range of motion, chafng, poor self-image, and difculty with prosthesis (see Figure 5).
Many techniques have been developed to address this issue, including the M-plasty, Y-plasty, double S-plasty, advancement faps, and staged liposuction.However, these procedures are often done by a plastic surgeon as a separate procedure after the mastectomy and are often associated with complications such as wound dehiscence and necrosis with a Y-shaped closure.Te AW technique was developed at the University of Arkansas for Medical Sciences as another option to address lateral adiposity at the time of mastectomy.Te angel wing technique is diferent from an extended dog ear revision in that it includes the entirety of lateral adiposity to the fold/crease, instead of just addressing the dog ear at the apex of the closure.Te extension to incorporate the fat fold makes this technique a unique and novel approach in addressing the lateral adiposity.As it is performed at the time of mastectomy, it eliminates unnecessary additional visits and surgeries that may be seen as "cosmetic" Te Angel Wings technique: before and afer photos   Te Breast Journal procedures and may not be covered by insurance.Tis can have large repercussions upon patient satisfaction and quality of life, as many with lateral adiposity postmastectomy are reluctant to undergo additional procedures despite experiencing poor bra ftting, decreased range of motion, poor body image, and dissatisfaction after surgery.In addition, the AW technique is reproducible and simple, enabling those without formal plastic surgery training to easily adopt, with a learning curve of 4-5 cases.Te AW is an excellent technique for mastectomy scar revision as well (see Figure 6).As surgeons evaluate the potential of incorporating this technique into their practice, it is worth noting that the AW technique does increase the operative time depending on the amount of lateral adiposity.However, there are current procedural terminology codes (14301-14302) which may be used to compensate for the added time and efort of employing this technique.Te AW technique does require a separate incision with faps.While it does not prevent future breast reconstruction, if desired by patients, a latissimus dorsi fap may not be feasible, as some of the soft tissue over the latissimus has been removed.A previous study by Hill and Henry-Tillman et al. noted increased patient satisfaction and improved functional outcomes with use of the AW technique [9].However, the rates of procedural complications such as lymphedema and decreased range of motion remained largely unknown.
Complications such as lymphedema, wound healing, and range of motion postmastectomy are known to be afected by age, BMI, stage, the extent of axillary surgery, chemotherapy, and postmastectomy radiation in addition to the procedural technique.Terefore, we set out to determine the incidence of these functional outcome complications within those undergoing mastectomies with and without the AW technique as related to these factors.Notably, this study confrmed the AW technique to be noninferior, without  With regards to AL, the overall incidence was slightly higher in the AW cohort; however, there was no statistical signifcance between those undergoing the AW and non-AW techniques (p � 0.18).When subgroup analysis was performed, evaluating subpopulations within the cohort with varying BMI, extent of axillary surgery, presence of radiation therapy, and pathologic stage, there was no statistical difference in AL development within patient populations undergoing the AW technique compared to the non-AW technique, with the exception of an increased rate of AL in those undergoing the AW technique and subsequent postmastectomy radiation therapy (35% vs. 19.2%,p � 0.04).Tis could be explained by several factors including low number of patients, the possibility of extended radiation feld to include the AW incision, and the compounding risk factor of obesity, as those within the AW cohort unsurprisingly exhibited a higher BMI (p > 0.0001).
It is important to discuss with the radiation oncology team to prevent extensive radiation at the AW incision beyond the anatomic borders of the breast and axilla.Obesity is a known risk factor for AL development [10,11], and others have proposed the relationship between obesity and lymphedema is reciprocal, as obesity impairs lymphatic transport and impaired lymphatic function promotes adipose deposition [10].In addition, in our experience, the extension of the incision into the angel wing does not lead to any additional neurosensory changes or sequelae.Te extension incorporates only subcutaneous adipose tissue and overlying skin.It does not extend to the depth of nerves in this portion of the dissection, and there have been no additional neurosensory impacts related to this portion of the surgery.
As the AW technique involves removal of lateral adiposity and skin inferior to the axilla, there lies an inherent risk of dROM.Of note, the technique includes performance of a "pinch test" in preoperative marking, with the arm elevated to ensure an aesthetic fat closure without conveying risk for tension and dROM postoperatively.Notably, dROM was seen less frequently within the AW cohort, seen in 11% (n � 19/173) undergoing AW vs. 15.2%(n � 33/217); however, this diference was also not signifcant (p � 0.22).When subgroup analysis was performed, there was no statistical diference in dROM development within patient populations undergoing the AW technique compared to the non-AW technique.
Of note, the current study is restricted by its singlecenter, retrospective design.Terefore, these results may not extend to difering populations and providers less familiar with the technique.Tis technique has been taught to over 20 breast surgical oncology fellows trained at UAMS, and future studies may include their outcomes.In addition, as a large portion of our patients complete their adjuvant treatments elsewhere, data regarding adjuvant treatments such as chemotherapy and the extent of radiation treatment were limited and thus not included in this study.In addition, incorporation of additional techniques such as axillary reverse mapping, which has been reported to reduce risk of lymphedema, can also be evaluated in future studies.

Conclusion
In conclusion, the AW technique is a safe and efective method for addressing lateral adiposity and achieving an aesthetic fat closure, without conveying an increased risk of lymphedema or the efect on the range of motion.As we strive to provide our patients with improved surgical techniques for oncologic resection, we submit that this technique is a viable and safe option for achieving the goal of cosmesis with oncologic safety without incurring increased risk of functional complication.

Figure 1 :Figure 2 :
Figure 1: Te angel wing technique.Te AW technique consists of two parts, a lateral incision to address the redundant adipose tissue and the mastectomy incision.

Figure 3 :
Figure 3: Intraoperative angel wing technique.Te AW incision is created frst, and thick subcutaneous faps developed superiorly and inferiorly; the excess lateral adiposity is excised superfcially to the latissimus dorsi fascia, keeping the fascia intact.During fap reapproximation, it is important to shift the ipsilateral abdominal wall medially to restore neutral body alignment.Skin staples are used to temporarily approximate the lateral skin for ease of fap alignment and to minimize blood loss.

Figure 4 :
Figure 4: Mastectomy with angel wing technique: before and after.Te lateral body contour is smooth and fat.

Figure 5 :
Figure 5: Lateral adiposity and redundant soft tissue postmastectomy.Te patient presented after a simple mastectomy done at an outside facility.Te arm adduction range of motion is limited due to the lateral adiposity.
ALND).It occurred in 26.1% (n � 36/138) of those undergoing PMRT and 32.4% (n � 35/108) of those undergoing both ALND and PMRT.When subgroup analysis was performed, evaluating subpopulations within the cohort with varying BMI, extent of axillary surgery, presence of radiation therapy, and pathologic stage, there was no statistical diference in AL development within patient populations undergoing the AW technique compared to the non-AW technique, with the exception of an increased rate of AL in those undergoing the AW technique and subsequent postmastectomy radiation therapy (35% vs. 19.2%,p�0.04) (see Table2).

Table 1 :
Demographics of angel wing versus nonangel wing technique cohort.
Demographic information of those who underwent angel wing and nonangel wing technique.

Table 2 :
Subgroup analysis of angel wing vs nonangel wing technique and subsequent arm lymphedema development.

Table 3 :
Subgroup analysis of the angel wing vs nonangel wing technique and decreased range of motion.