Consensus recommendations for surgical practice indicate preferred approaches to clinical problems as established by experts in the field. They are based on existing data or on a consensus of expert opinion when few or no data are available. The present recommendations apply to surgeons who use Natrelle 410 for primary breast augmentation. Users of other devices may not find these recommendations useful or suitable to their practice, as the surgeons’ feedback in this study was solicited specifically regarding Natrelle 410 and reflect their experience with this device and its specific characteristics. These recommendations indicate experienced surgeons’ preferred approaches with this device, although they are not necessarily the only approaches, owing to the complexity of aesthetic surgery.
Most of the surgeons surveyed seemed to have a well-defined perspective on appropriate patient selection and use of biodimensional planning with regard to Natrelle 410. Recommendations for patient selection indicated that Natrelle 410 may be used in a wide variety of patient types, although participants considered some characteristics more valuable than others in identifying the best candidates.
Several consensus items are worth noting. Participants agreed that the form-stable structure of Natrelle 410 is particularly beneficial for cases of tuberous breast, which was among the characteristics reaching the highest level of agreement (95.5%) and was most frequently mentioned in the top 3 characteristics for patients appropriate for augmentation with Natrelle 410 implants. Patient preference regarding shape in the upper pole (eg, more natural appearance) and breast shape asymmetry rounded out the top 3 characteristics. The latter 2 items were not among those receiving the most “agree” responses, but they were most often rated by the respondents as top characteristics in patient selection, specifically regarding the use of the Natrelle 410 implant.
Based on rates of participant agreement, the anatomic shape selections were considered well suited for patients with Regnault grade I ptosis, tight skin envelope, and/or acceptance of inframammary surgical scar (each reaching >90% agreement). Consensus was reached for treatment of pseudoptosis, where height options for the implant may be an advantage over round devices. In the authors’ opinion, patients with asymmetry related to size, shape, and/or projection of breasts or with chest wall abnormalities may be good candidates for Natrelle 410 implants, as the variety of available shapes makes it possible to compensate for these asymmetries.
Some characteristics did not seem to be key decision factors for the use of Natrelle 410. Lack of consensus regarding patients with Regnault grade II ptosis may represent a concern with rotation risk, double-bubble deformity, or the need for mastopexy in addition to augmentation. Prediction of postoperative nipple position and calculation of the amount of skin needed in the lower pole using the lower ventral curvature of the implant7 could be used to evaluate whether a ptotic breast may be corrected with an implant alone. In the authors’ opinion, lower height, higher projection implants are more suitable than others for correcting ptosis. Interestingly, consensus was not reached regarding patients with a higher-than-average propensity for capsular contracture, despite evidence in the literature indicating that Natrelle 410 implants are associated with a low rate of capsular contracture versus smooth surface and other anatomic implants.6,9,12 Participants commented that assessing whether a patient had a high propensity of contracture would be difficult in the setting of primary augmentation.
Previously published approaches to breast augmentation provide details on measurements and markings for anatomic breast implants that are generally in agreement with the consensus recommendations for Natrelle 410 reached in this analysis.6,7 Certain key measurements seem to be generally appropriate for any breast augmentation,4,13 but some are particularly important with shaped implants wherein the device must fit more precisely. Greater than 90% agreement was reached by participants for recommending breast base width, nipple-to-IMF distance, and nipple-to–new IMF distance measurements, and assessment for symmetry when using Natrelle 410 implants. The rates of agreement suggest that participants place more importance on analyzing implant width versus height. Indeed, breast base width was considered the most important measurement for Natrelle 410 by the greatest number of respondents. In the authors’ view, however, implant height is at least equally important to implant width, especially when assessing a breast with well-defined dense glandular tissue and a short lower pole. More than one-third of all participants indicated that they do not have access to 3-dimensional (3D) imaging, but among those who do, a recommendation for using results of this technology in preoperative planning with Natrelle 410 implants reached consensus. Computational modeling based on 3D surface scans has shown promising results for predicted outcomes14; however, commercially available systems do not take biomechanical soft-tissue behavior into account. Patients should be informed of the limitations of this imaging technique before consenting to undergo the assessment.
It is notable that participants did not reach consensus regarding recommendations for a pinch test in the lower pole and a skin stretch assessment, published by some experts to be high-priority measurements.4,7,13 Lack of consensus on assessment of skin stretch may be attributable to difficulty in obtaining an accurate objective assessment. There was also little agreement on the 3 most important measurement-related items specific to Natrelle 410. A recommendation for performing nipple-to-IMF distance measurement without stretching the breast did not reach consensus even though it was the item selected by the greatest percentage of respondents as top priority. Measuring nipple-to-IMF distance without stretch, in the authors’ opinion, is not reproducible and does not reflect accurate assessment. Determining the new nipple position with the patient’s arms behind her head also did not reach consensus; however, this measurement technique may be useful for determining preoperative markings and setting the new IMF. It has been demonstrated that arm elevation 45 degrees above the horizontal plane accurately predicts the new postaugmentation nipple position.7 It is possible that there are sufficient variations in performing new nipple measurements (eg, position of arms) that precluded the participants from reaching consensus. Participants were more united in their selection of the 3 most important markings for Natrelle 410: new IMF, width and height of pocket, and the incision location.
Nearly all participants recommended inframammary incisions for experienced and first-time users of Natrelle 410. A significant percentage of participants disagreed with recommending the transaxillary approach for either first-time or experienced Natrelle 410 users (P < 0.01). Although the transaxillary approach is generally favored in certain geographic regions and can be effective in an experienced surgeon’s hands, its use, particularly with anatomically shaped implants, has some limitations.7,15–17 First, the remote incision may increase the occurrence of malposition, and an overdissection of the pocket could result in an implant-envelope disproportion that may allow the implant to rotate. Additionally, revision surgery often requires an inframammary incision, resulting in a second scar.
Participants significantly disagreed with recommending the periareolar approach for first-time users of Natrelle 410, although results for this approach by surgeons experienced with this implant were mixed. In the authors’ experience, the inframammary approach is well suited for the use of Natrelle 410 because of the ease of dissection and placement, particularly for surgeons without extensive experience with this implant. Additionally, the inframammary approach has been associated with a lower risk for capsular contraction versus periareolar and transaxillary approaches.18,19 Nonetheless, the authors believe that the periareolar approach is a reasonable option, especially in tuberous breast cases, and particularly in the hands of surgeons experienced with Natrelle 410. If it is not necessary to move the IMF, the periareolar incision may be as effective as inframammary incision.
Survey participants recommended consideration of multiple factors when choosing Natrelle 410 style and volume. Consensus was reached on using tissue-based implant selection considering height and width dimensions of the breast and quality of the skin envelope and breast parenchyma, both described as top priorities for Natrelle 410. However, the importance of patient preference was also considered a top priority for the selection of Natrelle 410. Thus, although the ideal implant based on tissue conditions may be determined, some divergence based on patient preference may be acceptable. It is important to emphasize that it is the surgeon’s responsibility to inform patients of what is and is not possible, and that the foundation for selecting proper implant volume and dimension relates to both tissue conditions and patient preferences.
Several limitations of this study should be noted. There are no universally accepted consensus thresholds for the Delphi method,20,21 which may make interpretation of results challenging. In this study, we chose a P < 0.01 level of significance to define the consensus threshold and provide statistical rigor to the analysis. Also, lack of consensus does not necessarily mean that the item is inappropriate for Natrelle 410; rather, it was not supported by the majority. Differences in the respondents’ geography, practice patterns, and patient distribution may substantially affect their experience with, and perceptions of, the Natrelle 410 implant, and therefore result in important differences in their recommendations that could appear as lack of consensus. Finally, participants did not supply rationales for their responses, as this level of information gathering is not generally part of the Delphi method. Nonetheless, this is the first time the Delphi method has been used to provide consensus recommendations for plastic surgery.
Conclusions and Implications for Clinical Practice
Experts in the field of breast augmentation surgery shared their approaches to optimizing surgical results achieved with the Natrelle 410 implant. Through the Delphi method, they provided consensus recommendations regarding patient characteristics and preoperative planning. Notably, the participants also provided feedback on what they considered the most important recommendations, specifically for the Natrelle 410 implant. These recommendations may serve as a basis for modification or refinement of a surgeon’s current procedures. They may also lend assurance to surgeons having less experience with the Natrelle 410 implant. Evolving information regarding the use of Natrelle 410 may have produced some important factors for patient selection and preoperative planning that are not included in the current recommendations. Such items may be worthy of future reassessment. Additional topics for evaluation could include ptosis management, revision and reconstruction procedures, and the use of Natrelle 410 implants in association with internal support matrices and fat, as well as detailed methods for carrying out the consensus recommendations reached in the current study.
The surgeon must choose the course best suited to individual patients based on a range of variables present at the moment of decision. However, the current consensus recommendations may play an important role in the optimization of aesthetic breast augmentation with Natrelle 410 implants.22
We thank Svetlana Pidasheva, PhD, and Damien Bates, MD, PhD, FRACS, who were employees of Allergan at the time of this study, for their contributions to the study design. We also thank Dr. Bates for data interpretation. Writing and editorial assistance was provided to us by Kathleen Dorries, PhD, of Peloton Advantage, Parsippany, N.J. All authors meet the ICMJE authorship criteria.
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© 2015 American Society of Plastic Surgeons
22. Natrelle Silicone-Filled Breast Implants [Directions for Use]. 2009 Santa Barbara, Calif. Allergan, Inc.