How the evidence was selected

For this review, a targeted PubMed search was conducted, including only systematic reviews and meta-analyses published up to 2025. Only studies reporting data on clinical complications, the incidence of adverse events and factors associated with facial fat transfer in aesthetic or reconstructive surgery were considered. Particular attention was given to the quantification of adverse events, their classification according to severity and the methodological quality of the studies, in order to provide a clear and reliable overview of the safety and risks associated with the procedure.

Incidence and severity of complications in facial fat transfer

Evidence from the most recent meta-analyses indicates that facial fat transfer is generally safe, with a low overall complication rate, although it is not free from clinically relevant risks. In one review including more than 6,200 patients, the overall incidence of adverse events was estimated at approximately 4.2%, with most complications being mild to moderate and only a few cases classified as severe.

The most frequently reported complications include fat necrosis, infections, induration, calcifications, oil cysts and hematomas, the frequency of which may vary according to the injection technique, the anatomical site treated and the criteria used to evaluate adverse events. These findings emphasize that, although the overall risk is generally low, precise techniques and rigorous safety protocols remain essential.

Classification and severity of complications in facial fat transfer

Facial fat transfer may be associated with a range of complications that vary in type and severity. Meta-analytic evidence shows that most adverse events are mild to moderate; however, rare but potentially severe complications have also been reported, particularly in anatomical regions with a high vascular risk. The systematic evaluation of the studies demonstrates that the severity and frequency of adverse events are closely related to surgical technique, operator experience and the anatomical characteristics of the treated area, highlighting the importance of rigorous safety protocols.

Local and mild adverse events

Evidence from meta-analyses and systematic reviews indicates that the most common local complications are generally mild to moderate. These include contour irregularities, prolonged edema, asymmetry, ecchymosis and lipogranulomas. In one systematic review involving more than 1,000 patients, the most frequently reported adverse events were asymmetry and contour irregularities.

Although not severe in most cases, these complications may require touch-up procedures or additional clinical interventions to optimize the aesthetic outcome and reduce patient dissatisfaction.

Rare but severe complications: neurovascular and visual risk

In addition to mild local complications, rare but severe adverse events have also been documented, including neurovascular injury, arterial embolization, vision loss, stroke and hemiplegia. These events are primarily associated with injections performed in areas rich in vascular structures, such as the forehead and temporal region.

The possibility of permanent complications highlights the importance of adopting rigorous surgical techniques, a thorough knowledge of anatomy and well-defined safety protocols to minimize the risk of serious adverse events during facial fat transfer.

Factors influencing the incidence and severity of complications in facial fat transfer

Meta-analytic evidence indicates that the incidence and severity of complications in facial fat transfer depend on several factors. The main factors include:

– Injection volume and anatomical site: Areas such as the forehead and temples, where arterial vessels are more superficial or more exposed, have a higher likelihood of vascular complications than deeper or less vascularized regions.

– Injection technique: Injection depth, direction of injection and the selection of appropriate cannulas, together with the use of standardized techniques, significantly influence the risk of adverse events.

– Operator experience: Larger studies show that more experienced surgeons report a lower incidence of severe complications, highlighting the importance of specialist training.

– Definitions and complication criteria: Heterogeneity in the definition of “complication” and differences in follow-up duration limit direct comparisons between studies, emphasizing the need for standardized outcome measures in future research.

These factors demonstrate that the safety and outcomes of facial fat transfer are closely related to surgical technique, operator experience and methodological considerations, making careful management and rigorous surgical protocols essential.

Relationship between complication rates and volume retention in facial fat transfer

In addition to evaluating complications alone, several meta-analyses have examined the relationship between complication rates and the percentage of facial fat graft retention. The available data show that mean volume retention is approximately 40–50%, while clinical complication rates are significantly lower than those reported for other filler techniques or non-autologous injectable materials.

These findings suggest that although volume loss or fat resorption represents an inherent challenge of facial lipofilling, these phenomena are not directly associated with the occurrence of major complications. Nevertheless, long-term follow-up and individualized strategies remain essential to optimize both safety and aesthetic outcomes.

Prevention and practical strategies to reduce complications in facial fat transfer

Systematic reviews indicate that many complications associated with facial fat transfer, particularly severe complications, can be prevented or mitigated through targeted clinical strategies. The main recommendations include:

– Detailed anatomical knowledge and safe injection techniques to reduce the risk of intravascular injection and injury to surrounding tissues.

– Standardization of fat harvesting, processing and reinjection procedures to ensure consistency of outcomes and reduce technical variability that may contribute to complications.

– Careful patient selection and preoperative consultation to inform patients about potential risks and align expectations with realistic outcomes.

– Intraoperative monitoring to ensure correct fat placement and prevent vascular adverse events.

The systematic adoption of these strategies helps minimize risks, optimize aesthetic outcomes and improve the overall safety of the procedure, thereby enhancing both patient experience and satisfaction.

Clinical management and practical considerations

In clinical practice, facial fat transfer requires a careful balance between aesthetic objectives and patient safety. Although severe complications are rare, their potential occurrence highlights the need for rigorous surgical protocols, precise injection techniques and specialist training.

It is essential to provide patients with detailed information regarding potential risks and realistic expectations in order to promote informed decision-making and improve postoperative satisfaction. The adoption of a systematic and well-informed approach helps minimize risks, optimize aesthetic outcomes and ensure a high standard of safety in all clinical settings.