Shaped Versus Round Silicone Breast Implants in Breast Augmentation: Prospective Data through 8 Years

Goals/Purpose: The development of different styles of silicone gel breast implants offers an increasing variety of choices for surgeons and their patients undergoing breast augmentation. In addition to round profile implants, anatomically shaped, "form-stable" implants have recently been approved for use in breast augmentation, revision, and reconstruction. Further, silicone gel implants are available with smooth and various textured surfaces.  Despite widespread use, long-term, prospective evidence is needed to define how different device types influence key safety and aesthetic outcomes. The purpose of this analysis was to characterize the long-term clinical outcomes associated with round and shaped silicone breast implants in women undergoing primary breast augmentation.

Methods/Technique: The MemoryGelª (NCT identifier NCT00753922) and MemoryShapeª/CPGª (NCT identifier NCT00812097) Core studies are non-randomized, open-label clinical trials designed to assess the long-term safety and efficacy of round and shaped breast implants, respectively. The cumulative incidence of selected complications and reoperations was estimated using the Kaplan-Meier method. Cox regression analyses were conducted to examine whether specific patient, device, and surgical characteristics are risk factors associated with clinical outcomes. Global patient satisfaction was assessed by asking the patient if she would decide to have the breast implant surgery again.

Results/Complications: Five hundred fifty-two and 572 women were included in the primary augmentation cohorts of the MemoryGel and MemoryShape Core studies, respectively. The overall baseline demographics of women implanted with round devices was comparable to the profile of women who received shaped implants as well as the general US population of women undergoing augmentation procedures utilizing breast implants. Overall, shaped implants were associated with significantly lower cumulative incidence rates of Baker Grade III/IV capsular contracture compared with round implants (Figure).  The most common reasons for the 146 reoperations performed through 8 years in patients with round implants included capsular contracture (n=44 reoperations), size change (n=20 reoperations), and hypertrophic scarring (n=16 reoperations). The most common reasons for the 130 reoperations performed in patients with shaped implants included breast mass (n=24 reoperations), patient request for size change (n=16 reoperations), and calcification (n=10 reoperations), with breast mass and calcifications both generally associated with biopsies to assess potential breast cancer. Among patients with round implants, Cox regression demonstrated a statistically lower risk of Baker Grade III/IV capsular contracture with textured-surface round implants compared with smooth-surface implants, and with submuscular placement compared with subglandular placement.  The risk of capsular contracture in patients with shaped implants was not significantly associated with surgical approach, placement, incision size, or irrigation solution. At the 8-year follow-up, 273 of 280 (97.5%) primary augmentation patients in the MemoryGel Core Study and 313 of 320 (97.8%) patients in the CPG Core Study indicated patient satisfaction.

Conclusion: Eight-year cumulative incidence rates of complications and reoperations support the overall comparable safety of round and shaped devices in patients undergoing primary augmentation. Both devices are associated with high levels of patient satisfaction, with the overwhelming majority of patients reporting they would make the same decision to have breast surgery. With the availability of softer-and-round or firmer-and-contoured silicone-gel breast implants, continued analyses of specific differences in clinical outcomes will help surgeons to knowledgably counsel patients about the most suitable implant for their desired aesthetic outcome.