BACKGROUND: The increasing number of fatalities caused by gluteal fat grafting is concerning; thus, there is a need to determine ways to obtain the ideal aesthetic effect while ensuring a safe operation. In this study, three-dimensional (3D) measurements combined with B-ultrasound were used to evaluate the effect of gluteal fat augmentation in Asians, whose safety and effectiveness were confirmed using quantitative data.
METHODS: Thirty-five consecutive female patients were evaluated in this prospective clinical study. All patients underwent B-ultrasound-assisted gluteal fat augmentation on the subcutaneous plane alone. 3D imaging and B-ultrasound analysis of the adipose tissue thickness in the gluteal region were performed preoperatively and at 1 week, 3 months and 6 months post-operatively.
RESULTS: The waist circumference of the patients decreased, gluteal circumference and length of the gluteal crease increased and average waist-to-hip ratio improved from 0.78 to 0.74. At 3 months and 6 months post-operatively, the adipose tissue thickness decreased by 5.1% and 15.1%, respectively. The fat retention rates calculated using 3D imaging measurements at 3 months and 6 months post-operatively were 77.9% and 64.7%, respectively. According to the BODY-Q scale scores, patients reported a high level of satisfaction post-operatively.
CONCLUSIONS: B-ultrasound guidance can effectively prevent the occurrence of fatal fat embolism during gluteal fat grafting and maximise the augmentation effect. The quantitative data obtained using 3D measurements and B-ultrasound confirmed the safety and effectiveness of fat injections for gluteal augmentation under B-ultrasound guidance.

OBJECTIVE: Fat grafting has been widely used for soft-tissue augmentation. External volume expansion (EVE) is a favorable tool for improvement in the rate of fat graft retention. However, few studies have focused on the most appropriate time for its implementation. In this study, BALB/c nude mice were used to investigate the effective time for the implementation of external volume expansion to improve the rate of fat retention.
METHODS: Sixteen mice were divided into four groups, and EVE was performed at different time points before or both before and after fat grafting. Fat tissue from a human donor was injected into the mice following EVE. Visual assessment, micro-computed tomography analysis, and histopathological evaluation were used to assess fat retention.
RESULTS: After 10 weeks, the group that underwent EVE 5 days before fat grafting demonstrated a significantly higher preserved fat volume, as determined by micro-computed tomography (p<0.05). Moreover, the group that received additional EVE after fat grafting exhibited a higher retention rate compared to the groups receiving EVE only before grafting (p<0.05). Histopathological analysis indicated that swelling, edema, and inflammation were more pronounced in the group with EVE immediately before grafting, while angiogenesis and lipogenesis were more active in the group with additional EVE after grafting.
CONCLUSIONS: EVE is a safe and effective approach for improving the rate of fat graft retentions. Furthermore, the timing of external tissue expansion plays a crucial role in fat retention. Based on our animal study, performing EVE immediately before and after fat grafting may be an effective strategy for enhancing the rate of fat graft retentions.