Evidence-Based Medicine: Augmentation Mammaplasty

Frank Lista, M.D.

Jamil Ahmad, M.D.

Mississauga, Ontario, Canada

From The Plastic Surgery Clinic.

Received for publication April 19, 2013; accepted May 14, 2013.

DOI: 10.1097/PRS.0b013e3182a80880

Learning Objectives: After studying this article, the participant should be able to: 1. Recognize the role of biofilm in breast implant surgery and possible ways to reduce the incidence of capsular contracture. 2. Describe the advantages and disadvantages of various surgical approaches including the incision placement and implant location. 3. List the advantages and disadvantages of implant characteristics including implant fill, shell surface characteristics, and implant shape. 4. Take steps to avoid the phenomena of double capsule and late seroma.

Summary: This article was prepared to accompany practice-based assessment with ongoing surgical education for the Maintenance of Certification for the American Board of Plastic Surgery. It is structured to outline the care of the patient presenting for cosmetic breast augmentation. (Plast. Reconstr. Surg. 132: 1684, 2013.)

Breast augmentation continues to be one of the most frequently performed aesthetic surgical procedures, with 286,724 breast augmentations performed in 2012.¹ There are many surgical approaches and different implants that are available. Substantial clinical data exist regarding breast augmentation to assist with evaluating the various options. The purpose of this article is to provide a summary of the best available evidence on augmentation mammaplasty. When combined with clinical expertise, this evidence will assist the plastic surgeon in clinical decision making to provide the patient with a safer and better aesthetic result.

Evidence on Preoperative Assessment

Despite the multitude of publications over the past half a century, few describe the process of decision making in breast augmentation. Tebbetts and Adams²,³ described a decision support process that enables surgeons to address all preoperative assessment and operative planning decisions by prioritizing five critical decisions in breast augmentation: (1) optimal soft-tissue coverage/pocket location for the implant; (2) implant volume (weight); (3) implant type, size, and dimensions; (4) optimal location for the inframammary fold; and (5) incision location (Reference 3, Level of Evidence: Therapeutic, III). This “high five” system was developed based on analyzing data from more than 2300 breast augmentations planned using the TEPID system.⁴

Choudry and Kim⁵ surveyed current preferences of plastic surgeons regarding preoperative assessment and its effect on clinical outcomes in primary breast augmentation. Breast base diameter and implant volume were the two most important considerations in choosing an implant for breast augmentation. Reported reoperation rates for size change were significantly lower for surgeons who regarded breast base diameter as more vital than those who valued implant volume more.

Evidence on Antibiotics

Adams et al.⁶ performed a retrospective review of 335 patients that underwent aesthetic and reconstructive
breast implant procedures using pocket irrigation with triple antibiotic solution (including bacitracin, cephazolin, gentamicin), and reported a 1.8 percent capsular contracture rate for patients undergoing breast augmentation, which was lower than previously reported rates. They concluded that the use of triple antibiotic solution is associated with a low capsular contracture rate and recommended use of this technique. Araco et al.⁷ performed a retrospective review of 3002 patients that underwent cosmetic breast augmentation with or without mastopexy. They found that implant brand (Mentor compared with Poly Implant Prothèse or Eurosilicone) and pocket irrigation with antibiotics were protective against infection, whereas the use of drains significantly increased the risk of infection. Pfeiffer et al.⁸ reviewed 414 patients that underwent pocket irrigation with or without cephalothin added to the pocket irrigation fluid. The frequency of infections and seromas was substantially higher in patients where the pocket irrigation fluid did not contain antibiotics; there was no significant difference in the incidence of capsular contracture. Khan⁹ performed a retrospective review of 3256 breasts after augmentation mammaplasty. Patients received prophylactic antibiotics as a single intravenous dose, a single intravenous dose with an oral course for 24 hours, and a single intravenous dose with an oral course for 5 days. The incidence of infection was lowest with a single perioperative dose of intravenous antibiotics. Mirzabeigi et al.¹⁰ performed a retrospective review of 605 implants used in cosmetic breast augmentation. They compared patients who received 3 days of postoperative antibiotics and those who did not. They concluded that there was no reduction in infection, capsular contracture, or total complication rate with postoperative prophylactic antibiotics for either primary or secondary cosmetic breast augmentation. Hardwicke et al.¹¹ published a systematic review to examine the role of the prophylactic systematic antibiotics on surgical-site infections in augmentation mammaplasty. Two randomized controlled trials¹²,¹³ and two controlled trials⁹,¹⁰ were included. A meta-analysis of surgical-site infection incidence after augmentation mammaplasty showed no effect on infection rates with any antibiotic regimen (i.e., antibiotic versus none, single dose versus postoperative course). The overall infection rate with no prophylaxis was 0.3 percent, and that with any antibiotic regimen was 1.5 percent. Data concerning incidence of capsular contracture or implant removal did not allow for meta-analysis.

With regard to the effects of pocket irrigation with antibiotics on capsular contracture rates, there is significant experimental¹⁴–¹⁶ and clinical evidence³,¹⁷–²³ that biofilm is a significant cause in the development of capsular contracture. Over the past 15 years, with increased recognition of this relationship and use of interventions such as antibiotic pocket irrigation, there has been a marked decrease in the reported rates of capsular contracture after breast augmentation. Other measures such as the use of funnels for insertion²⁴ and nipple shields²⁵ have been proposed to prevent contamination of the implant.

Evidence on Surgical Approach

A multitude of surgical approaches for breast augmentation have been described. Surgeon preference along with patient characteristics and wishes seem to be largely the deciding factors in treatment planning. Many published articles include data collected in a retrospective manner or opinions that are based on anecdotal experiences of the authors. Experiences with inframammary,²⁶–²⁸ transaxillary,²⁹–⁴⁰ and periareolar⁴¹ incision placement have been reported. With respect to implant location, experiences with subglandular, subfascial,⁴²–⁴⁷ submuscular,⁴⁸,⁴⁹ dual plane,⁵⁰ and muscle-splitting biplane⁵¹ have been reported. Outcomes with respect to safety and complication rates seem to be more objectively measured than aesthetic results. A review of comparative studies for incision placement and implant location is presented.

Incision Placement

Momeni et al.⁵² compared 78 patients that underwent breast augmentation through either an endoscopic transaxillary or inframammary approach. The complication rate was low for both groups, but patient satisfaction was higher in the transaxillary incision group, and they felt that this approach was useful for patients that preferred to have the incision at a distant site. Wiener⁵³ retrospectively reviewed the incidence of capsular contracture for breast augmentations performed through a periareolar incision versus an inframammary incision and found that the capsular contracture rate was significantly higher using a periareolar incision. Jacobson et al.⁵⁴ conducted a retrospective review of 183 patients that underwent breast augmentation and found that transaxillary incision had the highest incidence of capsular contracture followed by periareolar and inframammary incisions. Stutman et al.⁵⁵ retrospectively reviewed 619 patients who underwent breast augmentation to examine the relationship of postoperative complications to incision. Postoperative complications including capsular contracture were not associated with any particular incision. Reoperations were significantly higher with inframammary incisions; however, these were for size/style change, asymmetry, and ptosis.

Okwueze et al.⁵⁶ studied 33 patients after breast augmentation through both subjective questionnaires and objective sensory measurements to evaluate changes in breast sensation between inframammary and periareolar incisions. They found that the inferior region of the breast had significantly poorer sensitivity thresholds than the periareolar incision at 6-month follow-up and concluded that the periareolar incision may produce less sensory loss in the lower pole of the breast. However, Mofid et al.⁵⁷ evaluated 20 women that had breast augmentation through either inframammary or periareolar incisions and found no difference in sensory outcomes. Araco et al.⁵⁸ retrospectively evaluated 1222 patients for risk factors associated with alterations of nipple-areola complex sensitivity after breast augmentation. They found that, compared with an inframammary incision, a periareolar incision increased the risk of nipple-areola complex sensitivity alterations almost threefold and the risk of areolar pain by more than threefold.

Implant Location

A meta-analysis by Barnsley et al.⁵⁹ examining the effect of texturization on capsular contracture noted the benefit of texturization on reducing the capsular contracture rate in the subglandular location. Texturization did appear to confer a protective effect in the submuscular location (Level of Evidence: Therapeutic, II). However, this subgroup consisted of a single study, which was dramatically underpowered. Data examined in a systematic review by Schaub et al.⁶⁰ loosely supported that implants in the submuscular location have a lower capsular contracture rate.

Strasser⁶¹ retrospectively reviewed 100 patients with subglandular implants and 100 with submuscular implants. Submuscular location provided better concealment of upper pole rippling than subglandular augmentation but had higher rates of muscle contraction–induced deformities and implant displacement; capsular contracture occurred in both locations. Pereira and Sterodimas⁶² performed a prospective study to compare outcomes following transaxillary breast augmentation using round, textured, silicone implants in the subglandular (18 patients), subfascial (18 patients), and submuscular planes (17 patients). Other than three patients with mild distortion of the implants during pectoral contracture, patients had similar rates of satisfaction independent of the implant location. Brown⁶³ retrospectively compared 200 subfascial implants with 83 subglandular implants and found no difference in complication rate or patient satisfaction. Tebbetts⁵⁰ described a dual-plane approach in 468 patients that attempts to make use of the benefits of both subglandular and submuscular planes while minimizing the potential risks of each. Three variations of the dual-plane approach were described to address the following: I, most routine breasts; II, breasts with mobile parenchyma-muscle interface; and III, glandular ptotic and constricted lower pole of breasts.

Evidence on Implant Selection

From 1992 to 2006, the U.S. Food and Drug Administration restricted the use of silicone implants for breast augmentation, making saline implants the only approved devices for breast augmentation.⁶⁴ Between 2006 and 2012, the U.S. Food and Drug Administration approved three premarket approval applications for silicone gel–filled implants produced by Allergan (Irvine, Calif.), Mentor (Santa Barbara, Calif.), and Sientra (Santa Barbara, Calif.). In 2013, Allergan also received approval for the Style 410 implant, which uses silicone gel with higher cohesivity compared with their previously approved implants. There are several key considerations when choosing an appropriate breast implant that warrant discussion. Several authors have published systematic reviews⁶⁰ and meta-analyses⁵⁹,⁶⁵,⁶⁶ examining the effect of implant characteristics on outcomes after breast augmentation.

Cunningham et al.⁶⁷ and Walker et al.⁶⁸ published outcomes data for saline-filled implants as part of the premarket approval process. Allergan,⁶⁹–⁷¹ Mentor,⁷²–⁷⁵ and Sientra⁷⁶ have ongoing premarket approval studies for silicone gel–filled implants with published follow-up data between 5 and 6 years. In addition, there have been several other large studies published reporting outcomes for these implants.⁷⁷–⁸⁹ These studies and key complication rates including capsular contracture, implant rupture/deflation, and reoperation are summarized in Table 1. Data reflecting primary breast augmentation are summarized, but in some studies, these data are not presented separately. Capsular contracture rates range from 0 to over 20 percent, with average follow-up as long as 13 years, and appear independent of the type of implant fill. Rupture/deflation rates are consistently low for all implants. Reoperation rates range between 0 and 36 percent and appear to increase with longer follow-up. Many of these studies include heterogeneous data sets representing results from multiple surgeons, a variety of surgical approaches, and significant differences in other variables such as the use of pocket irrigation, which can significantly affect certain outcomes. In addition, the premarket approval studies from the various manufacturers cannot be compared on a valid scientific basis because comparative patient cohorts were not established. Furthermore, many studies examining

specific implants report outcome measures combining both aesthetic and reconstructive in addition to primary and revision patients. However, key complication rates are significantly higher in revision and reconstructive patients; thus, these outcomes are likely not a true reflection of primary breast augmentation.¹⁷,⁶⁹–⁷⁶

Table 1. Summary of Breast Augmentation Studies

Reference	Study Design	Indication	Device	Implant Fill	No. of Patients	Length of Follow-Up	Capsular Contracture Rate (%) (Grade)	Implant Deflation/Rupture Rate (%)	Reoperation Rate (%)
Cunningham et al., 2000⁶⁷	Retrospective	93.9% implants were for breast augmentation	Various manufacturers	Saline	450	13 yr (9.8–20.0 yr)	8.4 (III/IV physician classified)	5.8 (excluding Surgitek implants because of higher deflation rate)	25.8
Brown et al., 2005⁷⁸	Retrospective	Breast augmentation data extracted	Allergan Style 410	Silicone	118	21 mo (16–36 mo)	0.0 (III/IV)	0.0	1.7
Hedén et al., 2006⁸⁰	Retrospective	Breast augmentation data extracted	Allergan Style 410	Silicone	124	6 years (5–9 yr)	5.6 (III/IV all indications)	0.3 (total)	Unreported
Tebbetts, 2006⁷⁹	Prospective	Breast augmentation only	Allergan Style 410	Silicone	50	97% at 3 yr	0.0 (III/IV)	0.0	0.0
Bengston et al., 2007⁷⁰	Prospective	Breast augmentation data extracted	Allergan Style 410	Silicone	492	87% at 3 yr	1.9 (III/IV)	0.7	12.5
Cunningham, 2007⁷²	Prospective	Breast augmentation data extracted	Mentor MemoryGel	Silicone	551	88% at 3 yr	8.4 (III/IV)	0.5	15.1
Cunningham, 2007⁷⁴	Prospective	Breast augmentation data extracted	Mentor CPG	Silicone	551	91% at 2 yr	0.8 (III/IV)	0.0	9.8
Spear et al., 2007⁶⁹	Prospective	Breast augmentation data extracted	Inamed Silicone-Filled	Silicone	455	81% at 6 yr	14.8 (III/IV)	5.5	28.0
Hedén et al., 2009⁸³	Prospective	Breast augmentation data extracted	Allergan Style 410	Silicone	112	8 yr (5–11 yr)	5.3 (III/IV all indications)	1.7 (total)	Unreported
Cunningham and McCue, 2009⁷³	Prospective	Breast augmentation data extracted	Mentor MemoryGel	Silicone	552	61% at 6 yr	9.8 (III/IV)	1.1	19.4
Walker et al., 2009⁶⁸	Prospective	Breast augmentation data extracted	Allergan Saline-Filled	Saline	901 for 5 yr 781 at 10 yr	97.2% at 5 yr 91.4% at 10 yr	11.4 at 5 yr (III/IV) 20.8 at 10 yr (III/VI)	6.8 at 5 yr 13.8 at 10 yr	25.9 at 5 yr 36.5 at 10 yr
Jewell and J ewell, 2010⁸⁵	Prospective	Breast augmentation and reconstruction data	Allergan Style 410 Mentor CPG	Silicone Silicone	118 117	42.5 mo (20–97 mo) 51.8 mo (16–77 mo)	2.5 0.8	0.0 0.0	2.5 5.9
Maxwell et al., 2012⁷¹	Prospective	Breast augmentation data extracted	Allergan Style 410	Silicone	492	72.9% at 6 yr	4.6 (III/IV)	5.0	19.4
Hammond et al., 2012⁷⁵	Prospective	Breast augmentation data extracted	Mentor CPG	Silicone	572	69% at 6 yr	2.4 (III/IV)	2.1	18.1
Stevens et al., 2012⁷⁶	Prospective	Breast augmentation data extracted	Sientra	Silicone	1116	5 years	8.8	2.0	16.6
Lista et al., 2013⁸⁹	Retrospective	Breast augmentation only	Allergan Style 410	Silicone	440	13 months (4 days–10 yr)	1.8 (III/IV)	0.0	10.7