Polypropylene Mesh Complications in the Sublay Position After Abdominally Based Breast Reconstruction: Les complications des treillis de polypropylène en sous-couche après une reconstruction mammaire par voie abdominale

Abstract

Introduction:

Abdominal wall morbidity after microsurgical breast reconstruction is an important consideration for patients and surgeons. Previous studies are limited by multiple mesh locations or types. In this study, we evaluate specifically subfascial polypropylene mesh placement to determine a more definitive complication rate and basis for objective comparison.

Methods:

A retrospective review was performed for patients undergoing microsurgical breast reconstruction at our institution by 3 surgeons from 2015 to 2018. All patients with sublay placement of polypropylene mesh were included. Patient demographics, medical comorbidities, type of reconstruction, and postoperative abdominal wall complications were recorded.

Results:

A total of 114 flaps were performed on 81 patients who met the inclusion criteria. Of these, 48 were deep inferior epigastric artery (DIEP) flaps (42%), 43 were MS-2 TRAM flaps (37.8%), 20 were muscle sparing (MS-1) transverse rectus abdominus muscle (TRAM) flaps (17.5%), and 3 were free TRAM flaps (2.6%). Average follow-up was 392 days (range: 29-1191). Average body mass index was 30.7. No patients developed hernias. Two patients (2.5%) complained of post-operative bulges, neither of which required operative treatment. Two patients experienced superficial abdominal wall infection, one of which required admission and intravenous antibiotics. Ten patients (12.3%) had abdominal incision dehiscence, 3 of which required operative intervention. There were no cases of mesh exposure, contamination, or removal.

Conclusion:

Polypropylene mesh is safe and effective, with subfascial placement resulting in low morbidity and low rates of bulge/hernia formation after microsurgical breast reconstruction. Consideration should be given to using polypropylene mesh for fascial repairs after microsurgical breast reconstruction, particularly in high-risk populations.

Introduction

Breast reconstruction is increasingly common after mastectomy, and autologous-free tissue transfer continues to be popular, particularly using abdominally based flaps.¹ Since its initial description by Hartrampf et al in 1982, the abdominally based flap for breast reconstruction has undergone significant evolution to improve patient satisfaction and minimize patient morbidity.² Examples of this is the progression of the pedicled transverse rectus abdominus muscle (TRAM) to full-muscle-free TRAM flaps, to muscle-sparing TRAM flaps, to deep inferior epigastric artery (DIEP) flaps, with more rectus muscle spared in each iteration. Taking less muscle during flap harvest reduces abdominal morbidity including pain, loss of strength, and rates of hernia or bulge formation, all of which significantly impact patient satisfaction post-operatively.³ An important consideration in the management of the abdominal donor site is the method of closure. One variable is the use of mesh, which can impact these complications rates.

There is substantial evidence in the hernia literature that the use of mesh can reduce hernia recurrence rates, particularly using synthetic mesh.^4-8 Although the entirety of the abdominal fascia is not intentionally violated during abdominally based free flap harvest, the relatively high rates of hernia or bulge formation, particularly with flaps that include more muscle, have led to increased use of mesh for abdominal closure.⁹ However, there are few established guidelines for the use of mesh in abdominally based flap harvest, and mesh is often placed or avoided at the preference of the reconstructive surgeon or patient. Oftentimes the decision is made intra-operatively, based on the perceived integrity of the fascia, the extent of the fascial incision, and/or amount of fascia sacrificed or risk of complications. Additionally, there are several options for the location of mesh placement, including retrorectus, sublay (posterior to the anterior sheath, anterior to the rectus abdominis muscles), and onlay (anterior to the anterior sheath).¹⁰ The variety of options for location of mesh placement and few high evidence studies evaluating mesh use in abdominally based free flap breast reconstruction make it difficult for reconstructive surgeons to find guidance when choosing whether or not to place mesh, in which patients, or in which location.

In addition to mesh location, the type of mesh used can have a significant impact on both cost and post-operative complication rates. Currently, one of the more popular meshes in use is polypropylene synthetic mesh.^11,12 Polypropylene mesh is resistant to enzymatic breakdown and induces a local inflammatory reaction in the surrounding tissues after placement, creating thick scar.¹³ The resultant scar causes the mesh to shrink but also decreases the pliability of the abdominal wall, reducing the likelihood of recurrent hernia.¹⁴ Given its overall lower cost, ease of use, strength, and durability, these factors have all contributed to polypropylene mesh being one of the most commonly used meshes in abdominal wall surgery.^11,12

The purpose of this study was to isolate as many variables as possible regarding mesh use during abdominally based free flap breast reconstruction to provide a framework for determining the efficacy of certain meshes and their ability to reduce hernia/bulge formation without significant complications. In this study, we retrospectively review patients undergoing abdominally based free flap breast reconstruction by multiple surgeons at our institution with polypropylene mesh placement in the sublay position. By isolating both mesh type and mesh location, we hope to provide more definitive baseline data on specific mesh use and complications in abdominally based free flap breast reconstruction as the basis of more rigorous, prospective studies in the future.

Methods

Institutional review board approval was obtained for this study. A retrospective review was performed of all female patients undergoing abdominally based free tissue transfer for breast reconstruction at a single institution, performed by 3 surgeons over a 4-year period (2014-2018). Inclusion criteria included polypropylene mesh placed in the sublay position, posterior to the anterior rectus sheath, at the time of breast reconstruction to address fascial defects, relative fascial weakness, or perceived/anticipated abdominal wall laxity. For each surgeon, mesh was placed according to the surgeon’s preference and perceived fascial laxity intra-operatively that would require re-enforcement to prevent a bulge or hernia. Patient demographics and characteristics were reviewed including age, body mass index (BMI, kg/m²), history of diabetes, smoking status, current use of immunosuppressive medications, history of prior abdominal operations, and presence of preoperative hernia or diastasis recti. Surgical characteristics such as type of abdominally based free tissue transfer performed, unilateral versus bilateral reconstruction, and laterality of mesh placement were reviewed. Post-operative complications including superficial and deep site abdominal infections, use of prolonged antibiotic therapy, the need for operative abdominal wall exploration and/or mesh explant, and reported hernias or bulges were also assessed. Hernia and bulge rates were determined based on patient-reported symptoms or findings reported on clinical examination in follow-up or repeat imaging, if available.

Results

Patient Demographics and Characteristics

After reviewing 187 patients during the time frame, 81 patients were found to have met the inclusion criteria and underwent abdominally based free tissue transfer for breast reconstruction and sublay polypropylene mesh placement during the study period (Table 1). All patients underwent mastectomy and reconstruction for a diagnosis of breast cancer. The average age of patients was 52 years (range: 31-73 years; SD = 9.0). The average BMI was 30.68 (range 21.4-47.0 kg/m2; SD = 5.34). Seven (8.64%) out of 81 patients were diabetic, and 2 (2.47%) of 81 were on long-term immunosuppressive medications. Of these 81 patients, 15 (18.52%) were actively smoking at the time of surgery and 24 (29.63%) had a history of previous smoking; smoking up to 3 weeks prior to the date of surgery was considered “previous.” Forty-nine (60.5%) of 81 patients had undergone prior abdominal or pelvic surgery. Surgeries included total abdominal hysterectomy, salpingo-oophorectomy, laparoscopic tubal ligation, laparoscopic appendectomy, laparoscopic cholecystectomy, umbilical hernia repair, and laparoscopic gastric band placement. Preoperative computed tomography angiography of the abdomen was obtained specifically to assess abdominal perforators and to aid in flap planning in 51 (62.96%) of 81 patients. Supra-umbilical diastasis recti were seen in 16 (19.75%) of 81 patients, and only 2 (2.47%) patients had true hernias, both of which were small peritoneal fat-containing umbilical hernias (Table 2).

Table 1.

Demographic Data for Patients Undergoing Breast Reconstruction Using Sublay Polypropylene Mesh.

	Number of patients/flaps	Percentage
Average age	52 years old
Average body mass index	30.68
Length of follow-up	392 days
Diabetes	7	8.6%
Active smoker	15	18.5%
Former smoker	24	29.6%
Immunosuppression	2	2.5%
Previous abdominal surgery	49	60.5%
Preoperative hernia	2	2.5%
Reconstruction laterality
Unilateral	44	54.3%
Bilateral	37	45.7%
Reconstruction type
TRAM	3	2.5%
MS-1	20	16.9%
MS-2	43	36.4%
DIEP	48	30.7%

Abbreviations: DIEP, deep inferior epigastric artery; MS-1, muscle sparing.

Table 2.

Summary Data of Abdominal Complications in Patients Undergoing Breast Reconstruction Using Sublay Polypropylene Mesh.

	Number of patients	Percentage
Abdominal infection	2	2.5%
Mesh explantation	0	0%
Dehiscence	10	12.3%
Return to operating room for dehiscence	3	3.7%
Bulge	2	2.5%
Hernia	0	0%

Operative Characteristics

A total of 118 abdominally based free flaps were performed in 81 patients. There were 37 bilateral and 44 unilateral reconstructions performed. Of the 118 flaps, 48 were DIEP (MS-3), 43 were muscle sparing (MS-2) TRAM, 20 were MS-1 TRAM, 4 were superficial inferior epigastric artery (SIEA), and 3 were full muscle TRAM. In 4 patients undergoing bilateral reconstruction, an SIEA perforator flap was taken from one hemi-abdomen and no mesh was inset on this side. All patients in this series had polypropylene mesh placed posterior to the anterior rectus muscle (above the rectus muscle in muscle-sparing cases and between the anterior and posterior rectus sheaths in cases of full-muscle TRAM reconstruction). Mesh was inset using either running or figure-of-eight non-absorbable suture. Fascia was closed primarily overtop all mesh in the same manner and with the same suture material.

Postoperative Complications

The average length of follow-up was 392 days (range: 29-1191 days; SD = 265.91) after surgery. Postoperatively, 12 patients (18 flaps; 14.81%) experienced complications. The majority of patients with complications had either DIEP flap (50%) or MS-1 TRAM flap (33.3%) reconstruction, with the complications being evenly distributed between the groups. The average BMI of patients who experienced complications was 30.1, with 6 patients (50%) having a BMI >30. Four (33.33%) out of 12 were actively smoking at the time of reconstruction, and 5 (41.66%) of 12 had a history of smoking, accounting for 75% of patients who experienced a postoperative complication. There were 10 cases of abdominal wound dehiscence (10/81; 12.3%). Seven of 10 (70%) of these were managed with local wound care and allowed to heal secondarily. Three patients underwent operative debridement with either delayed primary closure or negative pressure wound therapy and secondary closure. There were 2 cases of superficial abdominal wall infection (2/81; 2.45%), one of which was managed with admission and intravenous antibiotic therapy and the other responding to a course of oral antibiotics as an outpatient. No patients in this series required a return to the operating room for deep space infection or mesh infection or required mesh explantation. Two patients complained of an abdominal bulge (2.45%), though in one patient this was not seen on physical examination and neither patient required a return to the operating room to address the bulge. Both patients had MS-1 TRAMs performed on the site of the bulge. There were no cases of postoperative hernia. One patient required a return to the operating room 2.5 years postoperatively for a palpable, painful deep suture at the site of mesh placement. This was removed and the mesh was confirmed intra-operatively to be well incorporated with no signs of infection or hernia.

Discussion

As abdominally based free flap breast reconstruction has become increasingly popular, more surgeons have progressively moved towards total muscle-sparing perforator flaps such as the DIEP flap, when technically possible. With muscle-sparing flaps, the hope is that abdominal wall morbidity and complications are reduced. Wan et al reported a decrease in bulge/hernia rate to 3.5% for DIEP flaps compared to 15.8% seen with free TRAM flaps.¹⁵ They also noted that with polypropylene mesh placement, the hernia/bulge rates of patients who had TRAM flaps or MS-TRAM flaps approached that of DIEP flaps (5.9% and 3.2%, respectively).¹⁵ In their cohort, mesh was placed in an inlay position, but the authors did not specify location relative to the rectus muscle. Additionally, they did not place mesh in any patients undergoing DIEP flap reconstruction.

One significant advantage of polypropylene mesh is its synthetic composition which translates to a much lower cost compared to, for example, biologic meshes.¹¹ In addition, synthetic meshes have a lower rate of hernia recurrence based on the ventral hernia literature, at the cost of limited ability to salvage the mesh should it become infected. However, in our experience, there were no instances of mesh infection requiring explantation, supporting the use of synthetic mesh over biologic meshes. Chatterjee et al performed a cost analysis for mesh use in abdominally based breast reconstruction and found that mesh was cost-effective if the mesh cost less than $5970 and resulted in a hernia/bulge rate of less than 7.25%.¹⁶ Our experience was substantially less than this, with a subjective bulge rate of 2.45% and a hernia rate of 0%.

Multiple studies have been performed comparing different meshes in abdominally based free flap breast reconstruction with the goal of minimizing complications as much as possible. Despite this, many of these studies have limited follow-up or do not specify mesh location to provide a more objective comparison. Messina et al compared polypropylene mesh (N = 20 patients) to poly-4-hydroxybutyrate mesh (N = 40 patients; Phasix; Bard Davol Inc) and reported a higher incidence of superficial dehiscence and seroma with the polypropylene group compared to the Phasix group. However, their follow-up time was limited, and they did not evaluate for hernia or bulge formation.¹⁷ Jordan et al compared their experience using polypropylene mesh (58 patients) to absorbable GORE Bio-A mesh (65 patients) in the subfascial plane and reported a bulge rate of 1.7% with the polypropylene group and 20% in the GORE Bio-A group.¹⁸ Boehmler et al compared the use of acellular dermal matrix (ADM) and polypropylene placed as a bridging inlay or underlay with and without primary fascial closure to primary closure alone.¹⁹ They reported bulge rates of 31% for ADM bridging inlay (26 patients), 20% for ADM plus primary fascial closure (5 patients), 10% for polypropylene bridging inlay (20 patients), 5% for polypropylene bridging inlay plus primary fascial closure (20 patients), and 5% for primary fascial closure alone (20 patients).¹⁹ Finally, Wormer et al reported their experience comparing Phasix onlay mesh for fascial reinforcement (160 patients) to primary closure alone (159 patients) and reported a bulge rate of 0% with Phasix onlay mesh compared to 5.0%.²⁰

Our objective with this study was to specifically evaluate patients who underwent polypropylene mesh placement in the sublay position (anterior to rectus muscle, posterior to anterior sheath) after abdominally based free flap breast reconstruction. To the authors’ knowledge, this is the largest cohort of patients with polypropylene mesh after abdominally based free flap breast reconstruction reported in the literature. Our large cohort using polypropylene mesh exclusively in one location allows for a more accurate assessment of complication rates for comparison to other meshes or locations. In addition, our results show that polypropylene mesh in the sublay position with primary fascial closure results in lower rates of bulge and hernia formation than previously reported. Additionally, there were no incidences of mesh infection or explantation in the study period, indicating the safety of using mesh in this cohort.

This study is not without limitations. The retrospective nature of the data collection allows for possible bias related to reporting, data collection, and data interpretation. Additionally, the cases were performed by 3 different surgeons. While this adds to the generalizability of these results and lends credence to the results being related to the mesh rather than surgeon-specific technique, it does introduce variability into surgical technique and intra-operative judgement for mesh placement between surgeons. Factors dictating placement of mesh versus no mesh or which type of mesh to use could not be gathered via retrospective review. Additionally, this is a study limited to one type of mesh in one anatomic location, which cannot be generalized to other mesh types or other anatomic planes.

Conclusion

Polypropylene mesh is a safe and efficacious option for fascial reinforcement after abdominally based breast reconstruction. Placement in the sublay position provides a relatively protected space from infection, resulting in zero mesh infections or explantations in our cohort. Additionally, polypropylene mesh in the sublay position appears to be effective in preventing bulge/hernia formation, with zero patients in our cohort requiring a return to the operating room to address these issues. Consideration should be given to polypropylene mesh in the sublay position for abdominally based breast reconstruction when the surgeon is concerned about abdominal integrity without significant concern for additional complications or significant cost.