Until now, no publication has been published with the words “evidence based” and “cosmetic breast surgery ” in the same title. The problem is, “evidence based” has become a cliché. “Evidence-based medicine” is a phrase coined by Guyatt in 1991 [15]. Sackett et al. [16] defined evidence-based medicine as “the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients through integrating clinical expertise with the best available external clinical evidence from systematic research and the patient’s values.” This definition is subject to interpretation as to what exactly constitutes the best available clinical evidence.

In reviewing the plastic surgery literature, it would appear that evidence-based medicine was introduced to plastic surgery in about 2009 [17, 18]. However, physicians have known about the importance of rigorous methodology and study design for decades. These are not new concepts. They have simply been neglected. For example, Brody and Latts [19], in 1981, wrote “established techniques for the conduct of drug trials are well-described in the literature, but none of our plastic surgery writing on this subject betrays any familiarity with a controlled study.” In discussing the etiology of capsular contracture, the authors [19] called for prospective studies, concurrent controls, and reproducible diagnostic criteria. They emphasized the need for “well-established, scientifically valid analysis rather than artistic ‘impressionism’” (i.e., conclusions based on clinical impressions) [19].

Scientific study of cosmetic breast surgery has suffered from a lack of accepted definitions and terms relating to breast shape, and a practical measurement system. There has been a noticeable reluctance to use measurements, or even to standardize photographs [20]. As I took my seat after a presentation at the 2016 meeting of the American Society of Plastic Surgeons, a senior co-panelist leaned to me and whispered, “too scientific.” The irony is that I do not make detailed measurements that I follow precisely in surgery. I rarely adhere exactly to my preoperative markings. My final decision regarding nipple placement is made in surgery. I do not use tissue measurements to determine implant size. The time I spend making markings is just a few minutes. The system I developed is used after surgery , for comparison of before-and-after photographs using the same reference plane [21]. It is a means to evaluate and quantify surgical changes later, when I have an opportunity in my office to match photographs and make the measurements. This analysis is the foundation of my work to scientifically evaluate cosmetic breast surgery (Fig. 1.1). In many ways, evidence-based cosmetic breast surgery is measurement-based cosmetic breast surgery.

The lack of science in plastic surgery is well recognized [17, 22–25]. Efforts to incorporate evidence-based medicine [15, 26] in plastic surgery are justified. Both the Level of Evidence [27] and Grade [23] concepts originated in a seminal Canadian Task Force Report published in 1979 [28]. Evidence-based medicine challenges traditional clinical practice based on unsystematic clinical observations, basic principles, common sense, experience, and expert opinions [16, 26, 29, 30]. Ironically, the Level of Evidence classification [27] itself is a product of experience and expert opinion. Evidence-based medicine is not intended to be static, but rather a dynamic, lifelong process [30, 31] that recognizes the need to evolve [16]. There is no grandfather clause that shields it from scientific scrutiny [32]. When analyzed, medical practice guidelines often fall short in meeting methodological standards [32]. About half the guidelines are outdated in 6 years [33].

In 2013, the author used the components of evidence-based medicine [24, 30], including “tracking down the best evidence” and “critically appraising that evidence” to investigate evidence-based medicine in plastic surgery [34]. A 2-year period of cosmetic surgery publications in the Journal of Plastic and Reconstructive Surgery, July 2011 through June 2013, was retrospectively evaluated. All articles with a Level of Evidence rating published in the Cosmetic Section were included. Each paper was designated a quality rating by the author using a new Cosmetic Level of Evidence And Recommendation (CLEAR) scale (Table 1.1). This classification modifies the traditional Level of Evidence ranking [7] and grade of recommendation (Table 1.2) [17, 23–25]. Table 1.3 and Fig. 1.2 compare the classifications. Table 1.4 summarizes the findings.

Forty-eight studies (55%) were designated a Level 4 using the Journal of Plastic and Reconstructive Surgery’s Level of Evidence rating . Three articles were assigned a Level 1. Forty-one articles (48%) evaluated consecutive patients or consecutive patients subject to inclusion criteria. Thirty-five studies (40%) consisted of chart reviews and a recording of complication and reoperation rates. Twenty-five studies (29%) reported physical measurements on patients or images. An equal number of studies (29%) featured subjective evaluations of the result by the investigators. Patient-derived data were collected in 18 studies (21%).

A Level 1 study is often considered the “gold standard” of evidence [16, 29, 35, 36]. A Grade A recommendation is usually assigned to such studies [24, 31]. A Level 5 study, on the other hand, constitutes expert opinion that is often open to question. A Level 2 study is a prospective comparison of treatment cohorts, a Level 3 study is a retrospective case-control study, and a Level 4 study is a case series [24].

The present grade classification used by the Journal [24] provides recommendations based on current knowledge irrespective of the study. A deficient study could receive an “A” grade if there are existing high-level studies that support its conclusion. The CLEAR grade rates the overall quality of the study itself, regardless of conventional wisdom [34]. A low-quality study that concludes, for example, that smoking increases the complication rate may receive a low grade of recommendation, despite support in the literature. Because methodology is considered in the CLEAR numerical rating (1–5), the grade tends to be closely linked. In this study, the CLEAR Level and Grade always matched (2A, 3B, 4C, and 5D). The traditional Level of Evidence rating does not correlate well with the recommendation grade (ρ = 0.11, not significant) because it does not consider several important quality parameters (Table 1.3).

Only three studies were designated Level 1. Paradoxically, all three Level 1 studies arrive at unreliable conclusions that encourage the reader to needlessly (1) purchase a six-figure instrument [37, 38], (2) compromise the aesthetic result of an abdominoplasty [39, 40], and (3) deny surgery to one-third of prospective cosmetic rhinoplasty patients [41, 42]. These three Level 1 studies represent just 3% of the total number of publications, equal to the percentage of Level 1 studies published in three major plastic surgery journals from 1998 to 2007 [29]. The frequency of highest-level studies does not appear to be increasing as hoped [29, 36]. It is reasonable to ask whether a randomized trial (the additional descriptors, “controlled” and “prospective,” are redundant) is the ideal model [34].

Randomized trials balance known and unknown confounders and avoid selection bias [17, 43]. In drug-testing, the need to identify a true benefit from a medication, without the influence of other factors, is well known. However, surgery is a much different discipline [29, 44–47].

Unlike a pill, a procedure is not identical from patient to patient [29, 48], placebos and blinding are usually not possible, and randomization is not well accepted by patients [29, 35, 43], surgeons [35, 43, 47], or referral sources [45]. Patients are particularly averse to randomization when the choice involves an operation with irreversible consequences [35, 36, 49]. Solomon and McLeod [50] report that most surgical questions would

not be suitable for randomized trials, citing patient resistance, uncommon conditions, and lack of clinical equipoise as the most common reasons. Other shortcomings include a lack of external validity (generalizability) [17, 18, 43, 49], the fact that surgeons are rarely equally proficient in and enthusiastic about two different techniques [46, 49], and cost [18, 43]. Funding is an issue for cosmetic surgeons in practice [35]. Such studies need to be cost effective [50]. Lack of funding can lead to methodological compromises [51]. Randomized trials suffer from low inclusion rates and recruitment biases, and may be underpowered [18, 49]. In surgery, by the time a randomized trial is conducted, the novel procedure has often been improved [45]. Techniques evolve quickly, particularly in plastic surgery [46].

In recent years, the presumed supremacy of the randomized controlled trial has been challenged [34, 49]. Two review articles published in the New England Journal of Medicine showed that observational studies usually produce results similar to randomized trials, and may be more consistent and less prone to reporting contradictory results [53, 54]. Their greater homogeneity provides a broader representation of the general population [53].

Randomized trials are inflexible and do not allow modifications that might better suit individual patients [34]. Inadequate concealment of randomization and treatment assignments can cause serious bias that may exceed the magnitude of the treatment effect [56–58]. Bhandari et al. [52] report that two-thirds of randomized orthopedic trials did not use proper techniques of randomization or concealment. Reviews of randomized trials in plastic surgery uniformly report low quality [36, 59–63].

Randomized trials are beyond the capability of most plastic surgeons [34]. Fortunately, well-done observational studies can work as well or better [34]. Important considerations

include a prospective study design, controls, and sound methodology, including consecutive patients, high inclusion rates, clear eligibility criteria, and consideration of confounders [34]. Because observational studies are less expensive than randomized trials, there is less need for outside funding, which avoids commercial bias – a major problem in plastic surgery today [55].

The CLEAR (Cosmetic Level of Evidence And Recommendation ) classification includes important methodological criteria that are left out of the existing Level of Evidence classification and a grade system that rates the reliability of a study based on its merits rather than whether the conclusions are supported by the literature [34]. A Grade A recommendation is now shared by randomized and high-level observational studies. The CLEAR classification preserves the same categories from Level 1 to Level 5, but adds overdue modifications [34]. This process is simply the application of the principles of evidence-based medicine to actual evidence-based medicine [34, 49].

Ethical considerations prohibit randomization of patients into two groups, one of which constitutes a known inferior treatment [43]. Cognitive dissonance may prevent a surgeon from finding that one half of his or her randomized patients received an inferior treatment [34, 44]. The investigator may be confronted by a catch-22 [34]. If the surgeon does not believe there is an advantage for the newer method, why is he or she conducting the study in the first place? For example, two studies compared different facelift techniques on each side of the face in the same patient [64, 65]. If the investigators had found that one facelift method was superior, they would be also conceding that one side was treated inferiorly. Not surprisingly, the authors found the techniques to be similarly effective, avoiding this ethical dilemma. If the difference is so slight that there is no consistent evidence one way or the other, the study is probably pointless.