Prevention of Fat Embolism in Fat Injection for Gluteal Augmentation, Anatomic Study in Fresh Cadavers

A Bibliometric Analysis of the Top 100 Papers on Gluteal Augmentation

Background

Gluteoplasty or gluteal augmentation is a popular cosmetic procedure that is used to improve the volume, shape, and contour of the buttocks.

Objectives

This bibliometric analysis aims to characterize emerging research trends and to assess the methodological quality of the highest impact gluteoplasty research.

Methods

The 100 most-cited publications in gluteoplasty were identified on Web of Science, across all available journal years (from Inception to August 2023). Study details, including the citation count, main content focus, and outcome measures, were extracted and tabulated from each publication. Oxford Centre for Evidence Based Medicine level of evidence (LOE) of each study was assessed.

Results

The 100 most-cited publications regarding gluteoplasty were cited by a total of 2375 publications. Citations per publication ranged from 5 to 176 (mean 23.75 ± 25.86), with the highest-cited study being authored by Simonacci, discussing autologous fat grafting (n = 176). Most publications were LOE 5 (n = 55), representative of the large number of case series and reports. The number of publications for LOE 1, 2, 3, and 4 was 1, 9, 13, and 22, respectively. The main content focus was "surgical technique" in 38 publications, followed by "outcomes" (n = 34) and "risk factors/prognosis" (n = 10). Patient-reported outcome measures (PROMs) were used in 20 publications, and 33 publications reported aesthetic outcome measures.

Conclusions

This analysis demonstrates a need for improvement in research methodologies regarding gluteoplasty research. This advancement would be facilitated by robust, high-quality research through randomized control trials and multicenter studies, as well as the further development of validated PROMs for gluteoplasty.

Level of Evidence 2

The S-Curve®: Clinical Importance of the Gluteal Ligaments in Efficacious Fat Transfer

Liposuction cannulas are versatile tools in a plastic surgeon's armamentarium useful for dissection, deep subcutaneous ligamentous release, fat extraction, and lipofilling. Experienced surgeons develop the ability to navigate subcutaneous anatomy through real-time tactile feedback of the cannula's depth, angulation, excursion, and resistance. Peripheral gluteal ligaments acting as anatomic boundaries must be understood and protected. However, central ligaments tether the dermis to deeper structures precluding expansion. Appropriate, targeted ligamentous weakening improves focal capacitance allowing precise gluteal contouring while staying in safe planes. This maneuver is critical during subcutaneous lipofilling of the S-Curve® procedure to create an aesthetically pleasing, convex gluteal silhouette.

Gluteal Augmentation with Fat Grafting: Literature Review

BACKGROUND

The buttock is the second sex feature of the human body, and the graceful buttock curve gives people confidence. Although the safety of gluteal augmentation with autologous fat grafting is still controversial, the proportion of operations is increasing year by year.

PURPOSE

To provid a comprehensive and detailed review of the literature on gluteal augmentation with fat grafting.

METHODS

A comprehensive review of the published literature through September of 2020 was performed in PubMed database, with the search terms "gluteal augmentation," "buttock augmentation," "Brazilian buttock lift," "fat grafting," "fat transfer," "gluteal AND aesthetic," "gluteal AND anatomy."

RESULTS

A total of 64 articles were included. On the basis of the information obtained, surgical recommendations are proposed to achieve buttocks as close as possible to aesthetic standard and improve surgical safety.

CONCLUSION

With a good grasp of the anatomical structure of the buttocks, complications can be reduced. At the same time, based on the theoretical basis of buttock aesthetics, better postoperative results can be obtained.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Personal Strategy to Avoid Fat Embolism During Fat Grafting: Brisk Withdrawal of Cannula While Injection

INTRODUCTION

Complications of fat grafting by means of injection may lead to unwanted passage of substrate into vessel lumens resulting in catastrophic complications. Likewise, a similar trend of complications is observed with non-autologous fillers regardless of an almost generalized use of blunt cannulas, the latter being implicated in the majority of serious vascular complications of hyaluronic acid injection. This report is the product of investigation to review all cases that underwent an original technique of fat injection: "The smart fat injection" during the cannula's brisk withdrawal technique. The aim of this research was to document the safety of this technique by searching if fat embolism had occurred and if yes, its incidence in this group of fat injection surgeries.

METHOD

This retrospective review included 3039 patients who underwent the smart fat injection at the facial or corporeal level between 2001 and 2019. The study focused on the search for complications linked to fat yet also cruorical embolism, as the latter may resemble the clinical symptoms of fat embolism.

RESULTS

The assessment of the 3039 patients who underwent the smart fat injection during cannula's brisk withdrawal, resulted in none presenting clinically detectable fat or a cruorical embolism.

CONCLUSION

This report documents the safety of the smart fat injection developed over a period of 22 years. It further explains the rationale of the technique for avoiding fat embolism while simultaneously enhancing fat take. This technique should not be implemented without appropriate in vitro training.

LEVEL OF EVIDENCE V

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine Ratings, please refer to Table of Contents or online Instructions to Authors www.springer.com/00266 .

How to Save a Life From Macroscopic Fat Embolism: A Narrative Review of Treatment Options

Macroscopic fat embolism (MAFE) has grabbed the attention of the plastic surgery community in recent years because of its high mortality rate. Many articles on preventing MAFE during gluteal fat grafting are available in the literature. However, total prevention is difficult: a number of factors, both technical and human, mean that MAFE remains a potential complication. This review was written with the main goal of providing a treatment plan. MAFE shares many similar pathophysiologic and hemodynamic features with massive thrombotic pulmonary embolism (PE), especially the associated cardiopulmonary decompensation. Lessons learned from PE management were used to devise a management algorithm for MAFE. The use of extracorporeal membrane oxygenation and its potential application as a main modality of treatment for MAFE was explored. The lack of evidence in the literature for the treatment of MAFE, and its high mortality, lent urgency to the need to write an article on the management aspect in the form of a narrative review, to ensure that every plastic surgeon practicing gluteal fat grafting is knowledgeable about the treatment aspect of this deadly complication.

Gluteal Vein Anatomy: Location, Caliber, Impact of Patient Positioning, and Implications for Fat Grafting

BACKGROUND

Deaths in gluteal autografting occur due to gluteal vein injuries, but data are lacking on the precise location and caliber of these veins.

OBJECTIVES

The authors sought to present the first in vivo study of gluteal vein anatomy utilizing magnetic resonance imaging.

METHODS

Magnetic resonance imaging venography of 16 volunteer hemi-sections was conducted in the supine, prone, prone with a bump (jack-knife), and left and right decubitus positions in 1 session after a single contrast administration. Caliber and course of the superior and inferior gluteal veins (SGV/IGV) were analyzed vs bony landmarks and position changes.

RESULTS

The SGV has a very short submuscular course before splitting into 2 smaller branches superolaterally. The IGV runs immediately deep to the gluteus maximus in the center of the buttock as a single large trunk, on average 56 mm deep (mean 27 mm of muscle belly and 30 mm subcutaneous fat). No intramuscular or subcutaneous branches greater than 2 mm were found. In the prone position, the IGV and SGV have an average caliber of 5.96 mm and 5.63 mm. Vessel caliber decreased by 21% and 27%, respectively, in the jack-knife position and by 14% and 15% in lateral decubitus.

CONCLUSIONS

The SGV and IGV are immediately deep to gluteus maximus approximately 6 cm deep with a caliber on the order of 6 mm in the prone position. The distribution of these vessels suggests there is no "safe zone" in the intramuscular or submuscular planes. The jackknife or lateral decubitus positions can decrease vein caliber by up to 27%, possibly reducing the risk of injury due to either traction or direct cannula impact.

Objectifying the Risk of Vascular Complications in Gluteal Augmentation With Fat Grafting: A Latex Casted Cadaveric Study

BACKGROUND

Fat transfer is the most popular means of gluteal augmentation. However, this procedure may be complicated by pulmonary fat embolisms (PFEs). Of 135 PFEs out of 198,857 cases reported by the Aesthetic Surgery Education and Research Foundation task force, 32 were fatal, contributing to the mortality risk of this procedure being as high as 1:2351.

OBJECTIVES

The aim of this study was to generate an anatomic map of the 3-dimensional location and variability in size of the gluteal region vessels.

METHODS

Twenty cadaveric gluteal regions were dissected. The aorta, venae cavae, popliteal, and saphenous veins were cannulated and injected with colored latex. Dissection was performed subcutaneously, in the gluteus maximus (GM), and submuscularly to evaluate the number and vascular distribution of all the vessels. Vessels were mapped on an XYZ axis.

RESULTS

The subcutaneous plane, containing 25 vessels on average, had the smallest vessel diameters (artery, 0.9 [0.3] mm; vein, 1.05 [0.22] mm). The GM vein diameter was 1.3 [0.3] mm. Branches of the inferior gluteal vessels had arterial and venous calibers of 2.2 [0.04] mm and 3.5 [0.99] mm, respectively. Superior gluteal artery and vein branches were 1.8 [0.2] mm and 3.85 [1.9] mm in diameter, respectively. Superior and inferior gluteal vein diameters were 7.61 [2.24] mm and 13.65 [6.55] mm, respectively.

CONCLUSIONS

The deeper and more medial planes of the gluteal region house larger, more prominent vessels. This research objectifies and is consistent with recommendations made by various recent task force reports to limit fat transfer to the subcutaneous plane.

The Role of Fat Grafting in Buttock Augmentation

Autologous fat grafting is now considered the gold standard for buttock augmentation. Although a variety of techniques are currently being used by surgeons around the world, methods of fat grafting to the buttocks remain unsystematized, poorly understood, and controversial in terms of their safety and efficacy. Nonetheless, buttock augmentation by fat grafting has a satisfaction rate of 97.1%, and its mean complication rate has been estimated to be around 7 to 10%, with serious complications occurring in less than 1% of cases. Fat emboli are one such serious complication, with several reports in the literature discussing morbidity and mortality, specifically with intramuscular injection. With the increasing popularity of fat grafting for buttock augmentation, it is more important than ever to continue researching and learning to safeguard the satisfaction and safety of our patients.

Autogenous Fat Grafting to the Breast and Gluteal Regions: Safety Profile Including Risks and Complications

Given the widespread utility and therapeutic potential of autogenous fat grafting, plastic surgeons should be familiar with its safety profile and associated adverse events. This article provides a critical review of the literature and delineates risk factors associated with various complications when grafting to the breast and gluteal regions. The majority of adverse events are related to fat necrosis and require minimal diagnostic or therapeutic intervention. Larger graft volumes, as in cosmetic augmentation, are associated with higher incidences of fatty necrosis. The oncologic safety of fat grafting is supported by multiple clinical studies with thousands of breast cancer patients, albeit predominantly retrospective in nature. Although less frequent, serious complications include fat emboli during gluteal augmentation. Identification of associated risk factors and implementation of proper surgical techniques may minimize the occurrence of life-threatening complications.

Searching for the Best Way to Assess the Risk of Thrombosis in Aesthetic Plastic Surgery; The Role of the Caprini/Pannucci Score

INTRODUCTION

There is concern regarding the high incidence of thrombosis in plastic surgery patients. For this reason, we wanted to compare the results of the Caprini/Pannucci score in patients with and without a past history of thrombosis admitted for aesthetic plastic surgery.

METHODS

This was a case-control study of 152 patients undergoing aesthetic plastic surgery procedures. We formed two groups: Group I had 70 patients who had thrombosis after aesthetic plastic surgery and group II had 82 patients without thrombosis. We studied the considered risk factors for thrombosis. We weighted the factors according to the OR and linear regressions. We then related them to the Caprini/Pannucci score.

RESULTS

Patients in group I had a score of 5.68 versus 3.45 in group II (p < 0.001). There was a 9.86% increase in thrombosis for each increased point in the rating. A higher effectiveness of the Caprini score was found in the high-score group; the greatest flaw was in the low-scoring group. The sensitivity was 75.71%, and the specificity was 70.73%. The factors with the greatest impact were the infiltration of fat in the buttocks, degree of obesity and time of surgery. There was an increased risk of thrombosis in patients with gluteal fat injections, varicose veins, obesity and immune disorders as well as those who had previously given birth.

CONCLUSION

To increase the effectiveness of the score and to use the score as a basis on which to decide upon prophylactic care, it is necessary to modify the score and add some factors.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Subcutaneous Migration: A Dynamic Anatomical Study of Gluteal Fat Grafting

BACKGROUND

Recent anatomical studies have demonstrated that fat placed subjacent to the fascia of the gluteus maximus muscle can migrate deep through the muscle into the submuscular space, possibly causing tears in the gluteal veins, leading to fat embolisms. The purpose of this study was to define and to study subcutaneous migration and to determine whether fat placed in the subcutaneous space under a variety of pressures and fascial integrity scenarios can indeed migrate into the deep submuscular space.

METHODS

Four hemibuttocks from two cadavers were used. Proxy fat was inserted using syringes with various fascia scenarios (1: fascia intact; 2: cannula perforations; 3: 6mm fascia defects) or using expansion vibration lipofilling (4: fascia intact). Subcutaneous pressures were recorded. After injections, anatomical dissections were performed to evaluate the migration of the proxy fat for each of the scenarios.

RESULTS

Scenario 1: pressure reached approximately 125 to 150 mmHg and then plateaued and all the proxy fat remained in the subcutaneous space. Scenario 2: pressure reached a 199-mmHg plateau and no proxy fat spread deeper into the muscle or beneath it. Scenario 3: pressure gradually rose to 50 mmHg then fell again and the submuscular space contained a significant amount of proxy fat. Scenario 4: pressure rose to a maximum of 30 mmHg and all of the proxy fat remained in the subcutaneous space.

CONCLUSIONS

The gluteus maximus fascia is a stout wall that sets up the dangerous condition of deep intramuscular migration with subfascial injections and the protective condition of subcutaneous migration with suprafascial injections. These persuasive findings are profound enough to propose a new standard of care: no subfascial or intramuscular injection should be performed, and all injections should be performed exclusively into the subcutaneous tissue.

Understanding Fatal Fat Embolism in Gluteal Lipoinjection: A Review of the Medical Records and Autopsy Reports of 16 Patients

BACKGROUND

Deaths secondary to gluteal lipoinjection are relatively recent events of major importance. However, little is known in relation to their behavior and clinical evolution. Therefore, an analysis was performed of case records from clinical cases that encountered this problem, correlating the results with the findings during autopsies.

METHODS

An analysis was performed of records from patients who died secondary to gluteal lipoinjection. Patient-specific data, surgical procedure, clinical picture, evolution, and outcome were analyzed. The findings of the autopsies and the involvement of other organs were also analyzed and correlated.

RESULTS

From 2000 to 2009, 16 files were obtained that fulfilled the indicated requirements. There were no statistically significant differences in the general characteristics of the patients, such as age, body mass index, or volume lipoinjected or liposuctioned. The clinical pictures were similar in all cases, and the autopsy findings showed the presence of microembolism in all cases and macroembolism in the most severe cases.

CONCLUSIONS

The most significant parameter of severity in patients who undergo gluteal lipoinjection is the presence of fat in macroscopic form in the circulation. The volumes of liposuctioned or lipoinjected fat have little influence. Hypoxemia, hypotension, and bradycardia are the characteristic clinical features. Although there is no specific treatment, immediate aggressive vital support to attempt to stabilize the patient is crucial.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

Where Does the Transplanted Fat is Located in the Gluteal Region? Research Letter

INTRODUCTION

Liposuction is one of the most popular plastic surgery procedures. As in any surgery, there are risks and complications, especially when combined with fat injection. Case reports of fat embolism have been reported. A possible explanation is the puncture and tearing of gluteal vessels during the procedure, especially when a deep injection is planned.

OBJECTIVE

To identify the places where fat can be located after injection during a fat graft in the gluteus.

METHODS

An experimental study was done in which colorant was injected in four directions using four different quadrants of the gluteus. We Injected 10 cc six times following clock hands until 60 cc were injected, and the cutaneous flap and the muscles were then elevated. Our main purpose was to describe where the colorant went and if it was in contact with the vessels (superior and inferior gluteal vessels). In total, four gluteus muscles were injected and dissected.

RESULTS

Injection in the lower lateral quadrant was mainly into the muscle, and colorant was observed in the hypogastric vessels. The injection in the upper quadrants stayed mainly in the subcutaneous tissue.

CONCLUSIONS

During surgery, it is important to identify the location of the perforators and to avoid a deep injection, especially from the lower lateral quadrant to the superior medial quadrant (Q4 to Q1), as the probability of puncturing and injecting fat into the main vessels from this direction is higher.