Commentary on: Static Injection, Migration, and Equalization (SIME): A New Paradigm for Safe Ultrasound-Guided Brazilian Butt Lift: Safer, Faster, Better

See the Original Article here.

This study deals with an interesting and innovative technique that could enhance the safety of the Brazilian butt lift (BBL) procedure.¹ With the increasing popularity of BBL procedures, many safety issues have been raised and many alarms sounded.² Many studies have been published and task forces built with the aim of increasing safety.^3–6 Through autopsy findings, cadaver studies, and recommendations from multiple plastic surgery societies (The Aesthetic Society, American Society of Plastic Surgeons, International Society of Aesthetic Plastic Surgery, International Society of Plastic Regenerative Surgeons, and International Federation for Adipose Therapeutics and Science), regulatory bodies have identified the muscular and submuscular planes as the probable cause of death and the subcutaneous plane as the safe site for fat grafting.^2–6

However, there is no reliable way to be sure that the grafting is indeed in the subcutaneous plane, and not the muscular plane, except for the general recommendation about the feeling of the tip of the grafting cannula, overlooking the gluteal anatomy. Indeed, some of the medical records regarding surgery in patients deceased from pulmonary emboli indicated that grafting was performed in the subcutaneous fat; however, fat was found to be grafted intramuscularly in the specimen.⁵ The importance of finding a method to safely perform subcutaneous fat grafting is vital, and it is the challenge that this paper seeks to address. Despite a general decrease in the death rate from pulmonary fat embolism due to increased caution, the need to identify a method in which the surgeon—and especially the new surgeon—has a sure plan for fat grafting remains.⁷

I agree with the authors that not doing the procedure at all is far more harmful to our specialty, in reference to the British experience of patients seeking care from surgeons in other countries with less oversight.⁸ This study is trying to raise the safety bar with a simple ultrasound device method, previously investigated, employed simultaneously during fat grafting.⁹ The device guides the tip of the cannula to the subcutaneous space into which the fat should be injected.

The strengths of this study include the large total number of patients with complete BBL cases (4150) and the many figures with anatomical descriptions about the 2 fascia and the 2 fat layers, which excellently illustrate the fat grafting plan. The superficial subcutaneous space is below the dermis and above the superficial gluteal fascia, and the deep subcutaneous space is below the superficial gluteal fascia and above the deep gluteal fascia.¹ Ultrasound allows the surgeon to accurately enter each space and manipulate it, while always remaining above the deep gluteal fascia. These findings give us a new understanding of the anatomy of the subcutaneous layer of the buttock, specifically above the gluteus maximums, thereby contributing to the increased safety of the procedure.

However, although the number of cases is large, the sample of the comparison between expansion vibration lipofilling (EVL) with and without ultrasound guidance is too small, with only 10 patients being compared. Some conclusions of the study are therefore not warranted, including the conclusion made in the title. Furthermore, the selection criteria for these 10 patients remain uncertain, and it is unclear whether the characteristics, indications, and total amount of fat grafted of these groups were comparable.

Another limitation is the fact that the overall indications, features, and follow-up outcomes are not included for the 4150 patient group, assuming that those patients are included in the study. The authors state that patients were followed for 6 months to 1 year. In addition, some of the more recent patients were included in the study in September 2022 (the date of the procedure), allowing only limited follow-up for patients who underwent their operations in 2022.

The words faster, safer, and better mentioned in the title Static Injection, Migration, and Equalization: A New Paradigm for Safe Ultrasound-Guided Brazilian Butt Lift: Safer, Faster, Better indicate a comparison with other techniques, which in the article is only true for 10 patients. Additionally, some queries for clarification include: What is the total operation time? How does it compare with other techniques? What about the effect of fatigue for these patients? These questions are not answered, or need to be explained in more detail. There is no comparison of operation time or successful fat grafting with other methods. What was the resorption rate? It is uncertain if the injection time includes all 3 stages: static injection, migration, and equalization. The duration of grafting is not necessarily longer with the syringe technique if you have a good routine with good assistants.¹⁰

Furthermore, there is a big concern about the viability of this technique because it is based on static grafting, which accumulates the fat in bolus or bulk in one area, without consideration of how the thickness of the fat tissue might affect fat survival. In addition to the risk of necrosis, there is a significant possibility that much of the grafted fat will not survive. Also, because the equalization is not controlled entirely by the ultrasound, as in the static injection phase, that might increase the risk for the cannula to be placed under the subcutaneous space. Traditional grafting includes multichannel retrograde grafting, which keeps most of the blood circulation and structure in the septa and maintains a reasonable thickness between the skin and subcutaneous fascia, where an increase in fat has little chance to survive. Furthermore, it remains to be proven whether the effect of equalization is the same as in traditional grafting in the matter of creating the necessary tunnels and the expansion needed in the recipient area. Concerning the shorter time for grafting itself as a factor favoring this technique, we should also consider that if surgeons are highly trained we might anticipate that utilizing this gadget will take longer for less experienced surgeons.

We believe that the safety of BBL is multifactorial and not related to a single procedure, one caution, or a single device. We have explained this idea in 2 publications with 20 safety recommendations; we believe that they provide a comprehensive guideline that will improve the safety of BBL, and that ultrasound-assisted grafting should be an integral part of the procedure.¹⁰

A multicenter analysis of patients undergoing gluteal fat grafting is needed. The take-home message is that safety is of the utmost importance, and safety is multifactorial, to include preoperative assessment, perioperative considerations regarding technique and fat grafting amount, and postoperative follow-up. The necessity of using the ultrasound device is increasing over time, especially for younger colleagues, for whom its use is advised. However, the fat grafting technique should not be a bolus graft with its big risk of necrosis, it should be performed in a retrograde manner in parallel tunnels to keep most of the septa intact for the best of fat take. The challenge is, therefore, to find an optimal method to keep the grafting cannula in motion while the ultrasound device continues to control the level of grafting.

In the search for this optimal method, the use of a mobile ultrasound-guided cannula will be a good way to safely and effectively achieve good results.

Disclosures

The author declared no potential conflicts of interest with respect to the research, authorship, and publication of this article.

Funding

The author received no financial support for the research, authorship, and publication of this article, including payment of the article processing charge.

REFERENCES

Author notes