Comparing Round and Anatomically Shaped Implants in Augmentation Mammaplasty: The Experts' Ability to Differentiate the Type of Implant

Plast Reconstr Surg. 2017 Jan;139(1):60-64. doi: 10.1097/PRS.0000000000002896.


Background: The purpose of this study was to determine whether the aesthetic results of subpectoral augmentation mammaplasty using anatomically shaped versus round prostheses are differentiable.

Methods: Thirty observers (i.e., plastic surgeons and nurses) assessed preoperative and postoperative photographs (frontal and oblique views) of 30 patients who had undergone subpectoral augmentation mammaplasty with cohesive silicone gel implants, with an average implant volume of 295 cc (range, 220 to 340 cc). The observers classified each case as round or shaped on two different occasions with a 12-week time interval. A statistical concordance analysis was performed, calculating the overall concordance rate, the interobserver, the intraobserver, and the overall intraobserver kappa indexes, to evaluate the expert observers' capacity to differentiate the implant type.

Results: Among the total of 1800 observations (30 observers assessed 30 cases on two occasions), the overall concordance rate was 50.33 percent (95 percent CI, 47.99 to 52.67). The interobserver kappa value was 0.010 (95 percent CI, 0.0025 to 0.04). The overall intraobserver kappa value was 0.0602 (95 percent CI, 0.0025 to 0.123). The observers were unable to recognize the type of implant used, nor was interobserver concordance noted. An agreement was not reached before the different observers, nor was an intraobserver concordance seen between the first and second classifications of the same cases by each observer.

Conclusion: The results obtained from subpectoral augmentation mammaplasty using anatomically shaped and round prostheses with a volume of 340 cc or less are indistinguishable, not justifying the systematic use of anatomically shaped implants in this patient.

Clinical question/level of evidence: Therapeutic, III.

Publication types

  • Comparative Study

MeSH terms

  • Breast Implantation / instrumentation*
  • Breast Implantation / methods
  • Breast Implants*
  • Esthetics
  • Female
  • Humans
  • Observer Variation
  • Photography
  • Prosthesis Design
  • Silicone Gels


  • Silicone Gels