Prevention of Implant Malposition in Latissimus Dorsi Myocutaneous Flap Breast Reconstruction Using an Acellular Dermal Matrix With Pectoralis Muscle Following Mastectomy for Breast Cancer: A Clinical Review

With over 250,000 new cases each year, breast cancer is the second most common cancer amongst women in the United States. Whereas a mastectomy is a common treatment option,¹ reconstructive options can vary based on the individual’s postmastectomy status.^2,3 In women with inadequate soft tissue coverage, the latissimus dorsi myocutaneous (LDM) pedicled flap is a well-established method for breast reconstruction, utilized for its reliable blood supply and minimal donor-site morbidity. Unfortunately, the LDM flap can often lack the necessary or desired volumes for unilateral or bilateral reconstructions. Whereas the robust nature of the latissimus blood supply can accommodate immediate placement of implants to allow for increased reconstruction volumes,⁴ this subjects the patient to the potential known risk of implant malposition.^5,6

Malposition of an implant, which most commonly occurs in the inferior and lateral directions, has a prevalence of 6.8% in breast augmentations.⁷ In the setting of breast reconstruction, implant malposition has been identified in up to 16.1% of cases (Table 1).^5-12 Major causes of implant malposition include inadequate or overly extensive pocket dissection, selection of inappropriately large implants, and compromise of local breast tissue.¹³ In latissimus-based flap reconstruction, a frequently used technique to prevent lateral malposition is suturing the flap laterally to the chest wall.¹⁴ Despite this, malposition is a leading cause of revisional surgery. In a study evaluating LDM reconstruction, 30% of the patients who underwent reoperation required revision for implant malposition.⁸

One method to mitigate implant malposition involves using an acellular dermal matrix (ADM) for structural support. An ADM is a tissue matrix that can act as a biological scaffold to induce tissue growth, angiogenesis, and tissue regeneration. Its first use in implant-based breast reconstruction was reported in 2005.¹⁵ It can be utilized to create a subpectoral pocket if the pectoralis major does not provide complete inferolateral coverage and is commonly used to recreate the inframammary fold. This improved support of the lower breast pole has been shown to reduce rates of capsular contracture and postoperative pain as well as provide superior aesthetic outcomes.^16,17

The use of ADM in breast augmentation^13,18 and reconstruction with implants^15,17 is well documented. There is a paucity of literature, however, describing use of ADMs with latissimus flaps and their impact on implant position. By utilizing an ADM in implant-based latissimus flap reconstruction, it is hypothesized that patients will experience a lower incidence of implant malposition and experience improved aesthetic outcomes. This 13-year retrospective review aims to evaluate the effectiveness of breast reconstruction using a LDM flap with a subpectoral implant and ADM after mastectomy for breast cancer.

Design and Study Population

A single-center retrospective chart review, approved by the University of Louisville Institutional Review Board, was performed to identify all patients who underwent breast reconstruction following mastectomy with a LDM pedicled flap, subpectoral implant, and an ADM over a 13-year period from 2007 to 2020 by the senior author (BJW). Demographic and clinical data were collected including patient age, race, body mass index (BMI), smoking history, comorbidities, pathology, concurrent treatments (radiation, chemotherapy), and postoperative outcomes.

Operative Technique

Inclusion criteria included women with inadequate soft tissue coverage for an implant-based reconstruction alone. Indications included prior failed attempts at expansion because of infection or radiation and women with aggressive tumors requiring excessive skin resection for curative therapy.

All patients were evaluated and all surgical markings were made by the senior surgeon preoperatively. Great care was taken to assess for breast asymmetries and the patients’ desired outcome. Marks were all made in a standing position (Figure 1). Skin pedicle size was variable, depending on the size of the defect, and always oriented diagonally from the medial cephalad origin of the latissimus dorsi to the ipsilateral lateral iliac crest.

For unilateral reconstruction, the patients were positioned in lateral decubitus to allow for ipsilateral harvest and inset. For patients with immediate reconstruction after mastectomy, the surgical wounds were closed with staples or a temporary adhesive dressing (if skin coverage was inadequate for closure) to allow for repositioning and appropriate surgical preparation and draping. For bilateral reconstruction, the patient was positioned prone to allow for bilateral harvest and placement into an axillary tunnel prior to being rotated supine for implant placement and flap inset.

LDM flaps were harvested to facilitate primary closure of the donor site, with beveled dissection to accommodate more dermal perforators and a smoother upper pole transition to incorporate more tissue bulk into the flaps. Once mobilized, the flaps were inset into an axillary tunnel to be delivered into the mastectomy defect (Figure 2). The donor sites were closed primarily over closed-suction drains, 2 per side.

Implants were selected to provide symmetry to the contralateral breast for unilateral reconstructions. For bilateral reconstructions, patient preference was utilized, which was further guided by predicted and actual mastectomy weights. Implants were placed in a submuscular plane, deep to the pectoralis major, and secured in place utilizing an ADM sling repaired to the chest wall and the free edge of the pectoralis major, acting as an internal bra. Prior to implanting the ADM, it was removed from its sterile packaging and soaked in a triple antibiotic solution. Full coverage of the implant was achieved, ensuring position of the implant without any stress or strain on the LDM flap. The LDM flap was delivered through the axillary tunnel and inset into a tension-free position. No mattressing sutures were placed in the latissimus dorsi muscle. A standard use of drains was applied for the 2 in the back and 1 in the breast.

Statistical Analysis

Descriptive statistics were used to report counts and frequencies for categorical data, and medians and interquartile range for non-normally distributed continuous data. Data storage and analysis were performed using Microsoft Excel (version 16.40, 2020).

A total of 40 patients met inclusion criteria and were included in the final analysis. Overall, 51 latissimus flaps with both implant and ADM were performed over the 13-year period. The cohort had a mean age of 50.25 ± 9.67 years at the time of surgery. Table 2 summarizes the demographic characteristics of the 40 patients. Nearly two-thirds of the patients were Caucasian, and a quarter were African American. The majority of patients were overweight (32.5%) or obese (42.5%) with an average BMI of 30.85 ± 6.15 kg/m²; 52.5% of patients were former or current smokers, 40% had hypertension, and 17.5% had diabetes. Average patient follow-up was 31.52 ± 29.51 months. All patients maintained follow-up for at least 3 months after their procedure, except 1 patient, who was lost to follow-up after 3 weeks.

Perioperative characteristics of this cohort are detailed in Table 3. The pathology of the breast cancer in the patient population were as follows: 22.5% ductal carcinoma in situ, 62.5% ductal carcinoma, 5.0% lobular carcinoma, and 2.5% adenocarcinoma. The pathology was not clear per the chart review in 8 patients. One patient in the study opted to undergo mastectomy and reconstruction prophylactically. Roughly half of the patients in this study underwent pre- or postoperative radiation (52.5%) and/or chemotherapy (52.5%). Most patients (72.5%) in this cohort underwent a unilateral mastectomy. The size of implant ranged from 100 to 500 mL, with an average implant volume of 249.13 ± 91.09 mL. Silicone implants were used in all patients. An ADM from the same manufacturer was used in all patients, although small modifications to the size and shape were made by the manufacturer over the 13-year period. Earlier models were rectangular in shape and required the surgeon to create the desired shape and add perforations prior to insertion. The currently utilized product is now ready in the correct shape and size for breast reconstruction with premade perforations in place.

Postoperative outcomes based on a per-flap analysis can be found in Table 4. Most notably, no patients experienced implant malposition or flap necrosis (partial or complete), nor did they develop a hematoma or fat necrosis. Of the 5 patients that developed a seroma (9.8%), 3 were in the breast (5.8%) and 2 in the donor site (3.95). One breast seroma required aspiration, and the other 2 seromas were identified intraoperatively upon exploration. One was in a patient with a suspected infection, and the other was identified incidentally during reoperation of dehisced incisions related to chronic wound healing issues. No intervention was needed for the 2 back seromas. Three patients developed minor cellulitis (5.8%), 2 within the breast (3.9%) and 1 at the donor site (1.9%), which were all treated with local wound care and oral (n = 2) or intravenous (n = 1) antibiotic therapy. One patient, who continued using nicotine throughout the course of her treatment, had poor wound healing and eventually developed an infection of the breast (1.9%), which required removal of the implant. One of the irradiated patients developed grade 3 capsular contracture (1.9%) that required implant removal, capsulectomy, and placement of a new implant. No patients experienced grade 4 capsular contracture.

Most patients (70.0%) underwent at least 1 additional procedure after their initial breast reconstruction, as seen in Table 5. The most common additional procedure was a minor revisionary procedure, which 42.5% of patients underwent to further enhance the breast shape, volume, and/or symmetry. Four of these patients exchanged their implant (10.0%): 1 patient desired larger breasts and the other 3 experienced significant breast asymmetries after healing from their initial reconstruction. Additionally, 2 patients (5.0%) required implant removal: 1 patient developed an exposed implant after a traumatic injury and another patient developed infection of the breast as described above. Capsulectomies (15.0%) were performed in each of the 6 patients who underwent implant exchange or remova;. 42.5% of patients underwent nipple-areola reconstruction. Three patients had a subsequent mastopexy (7.5%), and 1 patient underwent reduction mammoplasty (2.5%). Additionally, 7 patients who complained of lateral soft tissue fullness (17.5%), which was a result of the tunneling and the pedicle, underwent a minor revision to restore a favorable contour. Figures 3 and 4 illustrate premastectomy and postreconstruction photos. Both patients were pleased with the postreconstruction symmetry and the resemblance to their premastectomy breast shape and volume. Moreover, no displacement of the implant was appreciated.

For patients undergoing mastectomy, an autologous latissimus flap with implant is a leading reconstructive option because of its reliable blood supply and additional volume. Complete coverage of the implant can be ensured with the addition of an ADM secured to the inferior border of the pectoralis muscle. This reconstructive option was preferred in this cohort, as the majority of patients were overweight/obese (75.0%) and current or former smokers (52.5%), which are both relative contraindications to an abdominal-based flap.

The most notable complaint in this subset of patients was lateral soft tissue fullness (17.6%) because of the tunneling and the pedicle of the flap. To reduce the risk of flap necrosis, a technique preserving the serratus and thoracodorsal arterial branches was used that contributed to a bulkier lateral volume. Among patients who had persistent fullness after the flap had healed, the skin envelope overlying the area was tightened in a later procedure to address this issue.

The axillary tunnel that is created for pedicled LDM flaps results in a large lateral defect, which could allow for implant migration into the donor site if the implant is not secured and isolated. One documented method to prevent implant malposition in an LDM flap–based breast reconstruction is to suture the muscle laterally to create a pocket to stabilize the implant.¹⁴ However, this technique was avoided because the sutures in this area can potentially lead to vascular compromise of the flap, either by injury to intramuscular vessels or by the tension required to stabilize the weight of the implant in an appropriate position on the chest. Securing the implant completely under the pectoralis muscle and ADM did not require lateral mattressing sutures and avoided additional risk to the pedicle and the LDM flap itself, increasing the likelihood of a successful reconstruction (Figure 5). Using this technique, none of the patients in the study experienced implant malposition (Table 1), nor partial or complete flap necrosis, supporting the use of this method to secure the implant.

Similarly, Cattelani et al⁵ identified a 0% implant malposition rate among their cohort of patients who underwent immediate reconstruction with implant-assisted pedicled LDM. All patients included in this study underwent postmastectomy radiation, which Fracol et al⁹ identified as a protective factor against lateral implant malposition. Their cohort, however, experienced large and superficial flap necrosis rates of 1.7% and 6.8%, respectively.⁵ The authors’ operative technique includes quilting stitches on the underside of the flap and sutures to secure the edges of the flap to the chest wall. This technique may have contributed to their increase in flap necrosis rate relative to the present study. This technique, which does not involve suturing the flap, prevents implant malposition without this additional risk of vascular injury and flap compromise.

The use of a LDM flap and an ADM are each well described in the literature regarding implant-based breast reconstruction. Lee et al¹⁹ compared a latissimus dorsi flap to ADM in implant-based reconstruction, finding improved aesthetic outcomes in regard to breast shape and symmetry using the LDM. Another study¹⁰ comparing the 2 techniques in expander-based reconstruction found that ADM performed as well as LDM in regard to complication and reoperation rates, patient satisfaction, and overall aesthetic outcomes. In this study, implant malposition rates of 6.4% and 4.9% were identified in procedures using ADM and LDM, respectively.¹⁰ Through our experience, these techniques can successfully be combined during reconstruction of oncologic patients with advanced breast disease to potentially avoid this complication all together.

In the same study mentioned above, incidence rates of capsular contracture (3.4% vs 4.6%), infection requiring removal (4.1% vs 5.5%), breast seroma (2.6% vs 3.7%), breast hematoma (1.1% vs 1.8%), breast cellulitis (4.5% vs 4.1%), and fat necrosis (1.1% vs 1.8%) were reported for LDM and ADM, respectively.¹⁰ The present cohort experienced lower rates of capsular contracture (1.9%), infection requiring removal (1.9%), breast hematoma (0%), breast cellulitis (3.9%), and fat necrosis (0%). Conversely, the present cohort had a higher incidence of breast seroma (5.8%).

Breast seromas have been shown to occur in up to 60% of latissimus-based breast reconstructions.^6,11,20 Similarly, donor site seromas after latissimus flap harvesting occur in 4% to 38% of patients.^21,22 It is important to note that ADMs, which were used in all patients for this study, have been shown to increase incidence of both infection and seroma formation. A systematic review of 9 studies using ADMs in implant-based breast surgery found a mean incidence of infection and seroma in 5.5% and 4.9%, respectively.²³ The infection rate (1.9%) for the present study was lower than this average, whereas the incidence of breast seroma (5.8%) was slightly higher. One patient with seroma had a BMI greater than 40 kg/m², and the other had several comorbidities, including hypertension and diabetes. A randomized control trial evaluating 2 types of ADMs found that BMI was an independent risk factor for both seroma and infection development in implant-based breast reconstruction.²⁴ This may explain the higher rate of seroma formation. Breast seroma in the third patient, however, was associated with minimal patient morbidity, only requiring aspiration.

There are some limitations to the present study inherent to its retrospective nature. Additionally, all patients included in the study were cared for by a single surgeon at a single institution. Relative to the authors’ experience with implant-based reconstruction, the sample size (N = 40) is small. The average follow-up period is adequate for most patients; however, 1 patient was unfortunately lost 3 weeks postoperatively.

Through this 13-year retrospective review of utilizing ADM to secure the breast implant in latissimus flap breast reconstruction, no incidence of implant malposition or flap necrosis was found, suggesting that this technique may prevent implant malposition and reduce the need for revisional surgeries. Given the slight increase in seroma formation, caution is advised for the use of ADMs in patients with BMI greater than 40 kg/m². Further studies directly comparing LDM with and without ADM may supply further supportive data for this technique.

Affiliations: ¹Division of Plastic and Reconstructive Surgery, Department of Surgery, University of Louisville, Louisville, KY; ²Division of Plastic, Maxillofacial, and Oral Surgery, Department of Surgery, Duke University, Durham, NC; ³Division of General Surgery, Department of Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ; ⁴Division of Plastic and Reconstructive Surgery, Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA

Correspondence: Milind Kachare, MD; milind.kachare@louisville.edu

Ethics: Written informed consent was obtained from the patients for publication of this manuscript and accompanying images.

Disclosures: This study received no means of outside funding. The authors report no known or perceived conflicts of interest regarding the material presented in this manuscript.