Buttock Augmentation With Implants and Fat Grafting: A Comparative Study

The second reason for the difference in patient satisfaction with patients who underwent fat grafting is that sometimes a significant augmentation cannot be achieved because the patient has a paucity of fat for harvesting. Some patients believe only a small amount of fat is needed to achieve significant results. However, the amount of fat harvested directly correlates with the amount of augmentation that can be done, and when coupled with a less than 100% fat take, this results in a suboptimal result.

We did notice that there was a decrease in the amount of stem cells used in 2010 versus 2011 and attribute this reduction to financial considerations. Some patients elected to undergo fat grafting without stem cell therapy as it had a significantly lower cost.

In evaluating the rate of postoperative complications, there was a significant difference in the rate of seroma formation (3% in the fat-grafting group versus 17.7% in the implant group). This difference in seroma formation rates is likely due to the large amount of dissection that is performed in implant augmentation versus simple fat grafting. Literature from Mexico and South America points to an average seroma formation rate of 4% in patients undergoing implants and 6–-40% in patients undergoing autologous fat grafting. In our study, a seroma was defined as any fluid collection noted postoperatively after removal of drains. For this reason, perhaps our results are overly inflated. Although many small seromas may resolve without intervention, most require serial aspirations. When large seromas were noted, the buttock region was sterilely prepped, and aspiration was performed using an 18-gauge needle. Although it was never necessary to remove the implant, should a seroma fail to resolve, the surgeon and patient must be prepared for implant removal.

The rate of infection was noted to be higher in the implant group, and as mentioned before, this was defined as a positive wound culture with greater than or equal to 10^5 CFUs. The documentation of infection in the chart was not always clear cut and was determined by the reviewer’s evaluation of the patient chart. All patients having suspicion of infection were started on Cipro 500 mg twice daily for 14 days, pending final cultures and possible need for antibiotic modification. Another complication that was statistically significant between the 2 groups was the postoperative formation of lumps or dents (P – .0001; 95% CI, 17.9–51.8). Of the patients undergoing fat grafting, 33.3% had unsatisfactory results because of lumping in the area of fat injection. This may be due to inconsistency in fat take but it is also likely due to inadvertent injection of fat into the subcutaneous plane rather than directly into the muscle. For this reason that we prefer, as do our patients, the reliable results seen with silicone implant placement.

When looking at implant surgery specifically, we observed a 13.5% rate of contracture. This is significantly greater than the rate found in larger studies from South America and Mexico, which noted a contracture rate of approximately 2–5%. Although there is no standard for describing buttock capsular contracture, the author would propose that a system similar to the Baker breast implant contracture system be used. In the author’s greater than 20-year experience with buttock augmentation with implants, he has noted 4 degrees of capsular contracture in buttock augmentation patients, ranging from grade I contracture, which is consistent with a firmer buttock but no implant displacement or disfiguration, to grade IV, which shows evidence of marked deformity and clear implant displacement. (See Table 4.)

To minimize capsular contracture, we have now developed a sleep regimen for our patients, provide a week-long course of postoperative antibiotics, and continue Jackson-Pratt drainage of the implant pocket until output is minimal. Currently, we ask patients to sleep on their back 2 hours/night for 6 months beginning at week 2. This helps keep the implant pocket soft and allows the pocket to be stretched out adequately.

We also prescribe a 1-week supply of oral Keflex 500 mg every 6 hours to help keep the operative site as sterile as possible and have tended to keep drains in longer to minimize postoperative seromas, hematomas, and capsular contracture. Our policy is to leave
drains in until the 24-hour output is less than or equal to 15 mL. The longest we have kept a drain in place is 6 weeks. If the patient’s contracture is severe (grade III/IV), then our standard treatment is to remove the implants and then perform a reimplant 3–6 months later if the patient so desires. By minimizing the aforementione factors, it is possible to minimize the risk for capsular contracture. We have already seen a decrease in capsular contracture by 50% over the past 2 years, as noted when comparing 2008-–2009 data to 2010-2011 data (the average incidence per year has decreased from 4.5 to 2). (See Table 1.)

Another complication isolated to implant surgery is wound dehiscence, which we noted at a rate of 14.6%. This result is well within the accepted dehiscence rate of 14–30% as described in large series by Mendieta and Gonzalez. In our study, the dehiscences were not complete dehiscences but rather openings of the wound from 1 to 5 cm. These were all managed conservatively with debridement and healing by secondary intention. The risk of dehiscence is one to be aware of as it may require implant removal if the implant is compromised. We have minimized our wound dehiscence rate by paying careful attention to closure in layers and by carefully determining the implant size before surgery. In comparing 2008-–2009 to 2010–-2011 data, we noted a drop in the number of dehiscences from an average of 5.5/year to 1.5/year.

This is due primarily to our change in closure technique. It is currently our practice to close the muscle defect with 2-0 nylon in interrupted fashion, followed by closure of the deep dermis with 3-0 vicryl, and closure of the skin in subcuticular fashion using 4-0 vicryl. Previously, we had not been meticulous in closing the muscle defect and securing it to the deep sacral fascia but modifying our original technique has clearly yielded a lower dehiscence rate.

The rate of seroma formation, capsular contracture, and wound dehiscence seemed to directly correlate with larger implants being used in some patients. As the size of the implant increases, there is a greater chance of circulatory and lymphatic compromise. In addition, the larger amount of dissection required to create a larger envelope predisposes the patient to a higher risk of seroma formation and possible wound dehiscence. Finally, a larger implant results in more tension at the wound site, thereby increasing the risk of wound dehiscence.

Conclusion

Although fat grafting for buttock augmentation is rising in popularity among surgeons, its results are not as consistent as those seen with buttock augmentation via implant. Our research has definitely pointed toward inconsistency in the results of patients undergoing buttock augmentation with fat grafting. On the other hand, the consistency of results for implant augmentation is offset by the risk of capsular contracture and dehiscence, which are seen only in implant surgery. Regardless of the method of buttock augmentation chosen, surgeons can be confident that the results will be pleasing to the eye and to their patients as long as good surgical technique is used and the aforementioned perioperative risks are kept in mind.