Breast implants are either placed deep to the pectoralis muscle or superficial to musculature and under the mammary gland. A sub-muscular approach has the advantage of lower capsular contracture rates, but can result in a second breast contour or ‘double-bubble’ deformity in patients who have breast ptosis42–45. Additionally, many patients can experience breast distortion or ‘animation deformity’ during contraction of the pectoralis muscle after implantation46. Implants that are placed more superficially in the sub-glandular position avoid the double-bubble and animation deformity effects. However, if a patient does not have enough breast fullness superiorly, a sub-glandular implant is more likely to be palpable or show visible irregularities42. Subglandular implants can also have reduced stability, increasing the risk of rotation and extrusion below the inframammary fold. A subfascial implantation decreases the risk of both animation deformity and implant instability, allowing for better preservation of the inframammary fold and prevention of visible irregularities or rippling34. A total sub-muscular position, in which the serratus fascia is elevated as part of the implant pocket, requires dissection of an unnatural plane, which poses more operative challenges with minimal benefits and is thus infrequently used43,47,48.
A newer, ‘dual-plane’ approach places the superior portion of the implant sub-muscularly with the inferior aspect remaining in a sub-glandular position. The traditional sub-muscular approach often leaves a small portion of the inferior aspect of the implant in a sub-glandular position; however, the demarcation is much less significant than in the dual-plane approach. The dual-plane technique retains the advantages of both sub-muscular and sub-glandular implants, including less implant palpability and capsular contracture as well as a more natural breast shape42,43,49. Critics of the dual plane technique comment that it may lead to an increase in animation deformities and a visual muscle retraction. With varying degrees of sub-muscular versus sub-glandular coverage possible, dual-plane breast augmentation is becoming a more popular and attractive option for implant placement.
Seroma and haematoma
Common complications in any surgery where a cavity is created include haematoma (collection of blood) and seroma (collection of serous fluid). Both can cause localised swelling and pain. The rate of haematoma formation has been reported to range from between 0.9% and 3%50,51. The incidence of haematomas has not been associated with patient demographics, implant type or surgical approach. Although many seromas will resolve without intervention by being absorbed by the body, some will necessitate ultrasound guided aspiration. Ultrasound is often used as to not damage the implant during needle aspiration.
Higher rates of infection are observed with transaxillary approaches for breast augmentation, owing to the increased implant manipulation required for placement31. In addition to causing morbidity and potential implant loss, even mild infection can trigger capsular contracture, resulting in poor long-term aesthetic outcomes37. The Keller funnel™, which allows implant placement through a smaller incision, has been shown to reduce bacterial inoculation and thus likely infection in a cadaveric study, where the device reduced contact between the implant and patient’s skin by up to 27-fold52. Irrigation of the implant pocket with an antibiotic lavage prior to implant placement statistically reduces the risk of infection53. Additionally, anecdotal reports have suggested that using a transparent adhesive film dressing to cover the peri-incisional skin and nipple prior to implant placement may reduce the rates of infection54,55. Regarding systemic antibiotics, a recent meta-analysis revealed inconsistent reports of an association between preoperative antibiotic dosing and infection rate. As a result, no consistent recommendation is currently available regarding the role of systemic antibiotic administration in breast augmentation53.
Capsular contracture of the breast is defined as constriction of the fibrous capsule surrounding an implant, resulting in painful, palpable and visible irregularities of the breast. The hypothesis of capsular contracture centralises around inflammatory factors that are acutely protective, but can promote the growth of contractile cells with more chronic exposure56. Graded from I to IV in severity using Baker’s scale, capsular contracture is one of the most common and disfiguring complications of breast augmentation. Multiple surgical steps can be taken to prevent the development of capsular contracture, namely limiting handling of the implant, irrigation of the breast pocket with antibiotic solution, and sub-muscular implant placement. However, once capsular contracture has developed, definitive treatment involves removal of the implant, with less aggressive approaches including capsulotomy, capsulectomy, capsule expansion, and revision with acellular dermal matrix. Non-surgical options for reducing contracture and pain including capsule massage, ultrasound therapy, and pulsed electromagnetic field therapy, have all shown variable success57. More recent studies looking at the role of leukotriene inhibitors in increasing capsule compliance appear promising and consistent with the theory that capsular contracture is modulated by immunologic factors58–60.
First described in case reports in the 1990s, the literature shows a possible association between both saline and silicone implants, particularly textured salt-treated implants, and the development of anaplastic large cell lymphoma (ALCL), a rare form of non-Hodgkin’s lymphoma. Though breast implants and ALCL have been linked, no causation has been established owing to the exceedingly low rate of ALCL in the breast, estimated to be approximately 3 in 100 million women per year. It has been hypothesised that implant shell composition triggers pathogenesis of the condition; however, both implant type and characteristics are largely under-reported in clinical studies60. The most common presentation of ALCL is a late periprosthetic seroma developing months to years after implantation with malignant cells visible on cytology. Treatment of ALCL involves removal of the implant and capsule with no current consensus on the role of chemotherapy or radiation therapy61–63.