Facial overfilled syndrome

This trend is largely driven by technological advancements, such as the introduction of exosomes, and by a deeper understanding of patients’ aesthetic needs. In the early years of aesthetic medicine, these needs were often overlooked and overruled by the preferences of the health care provider or by the offering of the pharmaceutical companies. If no biostimulator existed, it simply could not be offered.

Today, patients have access to a wide range of aesthetic treatments and can choose which modality bests fits their budget and desired outcome. The latter has (luckily) shifted away from exaggerated transformations to more natural-looking, individuality- preserving results.

This shift is reflected in the financial trends of the filler market, with many practitioners noting a significant decline in soft tissue filler requests compared to pre- and peri-pandemic years. It is difficult to speculate why such a drastic change has occurred, but unpublished data from a community-based survey may offer insight. When asked, ‘What would deter you from receiving aesthetic injections?’, the most common patient response was: ‘I don’t want to look overfilled’—when referring to cheeks and lips. This finding is both interesting and concerning, and warrants further investigation.

The discovery of the transverse facial septum in 2019 prompted a deeper exploration of facial biomechanics – specifically, how facial mobility contributes to natural expression and outcomes.

Anatomic background

In 2019, a new anatomic structure was introduced to the scientific community: the transverse facial septum¹. This connective tissue sheet lies in the lower midface, right beneath the cheeks, spanning the distrance between the underside of the zygomaticus major muscle to the maxilla. It forms the inferior boundary of the superficial and of the deep midfacial fat compartments and resembles a hammock-like membranous configuration.

Since this membrane is connected to a muscle, it moves in synchronicity with the muscle and can assume different levels of tension depending on when the muscle is contracted or relaxed.

When the muscle is contracted, the septum is tensed; when the muscle is relaxed, the septum is loose and relaxed as well.

This conformational change between tensed and relaxed results in a positional change of the midfacial fat compartments – appearing lower (more caudal) when the transverse facial septum is relaxed and higher (more cranial) when the transverse facial septum is tensed.

Because the zygomaticus major muscle is the most important muscle for smiling and contracts when a smiling facial expression is assumed, the transverse facial septum tenses when smiling and, consequently, the midfacial fat compartments become relocated into a higher position. This results in a greater skin surface projection during a smiling facial expression, often termed ‘apple cheeks’.

Clinical consequences

The discovery of the transverse facial septum prompted a deeper exploration of facial biomechanics – specifically, how facial mobility contributes to natural expression and outcomes.² The following clinical implementations were emphasised (because they were already practiced) or newly introduced after the transverse facial septum was published:

1. Injectors started to evaluate midfacial volume loss at rest but also during smiling.
2. The volume of soft tissue filler material that injectors applied to the midface was determined at rest and when smiling (termed ‘dynamic filling’).
3. The volume deficiency of the infraorbital region, including the tear trough, was addressed, starting from the midface and only secondarily via direct tear trough injections.

Gradually, the aesthetic medical community started to make a connection between overfilled cheeks and unnatural facial expressions, a reduced ability to smile naturally, or even to express various emotions in a physiologic way. This connection was possible through greater understanding that too much product within the upper midface affects the natural mobility and flexibility of the midfacial soft tissues. Despite the fact overfilled cheeks were being treated with hyaluronidase, robust scientific validation for the link between the transverse facial septum, natural facial expressions and overfilled cheeks did not arrive until December 2023.

Latest research

A clinical case series³ was published at the end of 2023 investigating a total of 28 aesthetic patients complaining about their unnatural smile following cheek soft tissue filler injections.

Ultrasound imaging revealed filler pockets lodged within the midfacial fat compartments in all patients. The study also measured the vertical and horizontal position of the oral commissures, given the relationship between smiling, the zygomaticus major muscle and the transverse facial septum.

As part of the study, an average of 81.6 IU [range: 75-150] hyaluronidase was injected, after which it was revealed that the position of the oral commissure increased vertically by 0.60cm 0.30cm horizontally (both p < 0.001).

The latter finding indicated that the removal of filler material from the upper midface allowed the transverse facial septum to be more flexible and, as a consequence, allowed the zygomaticus major muscle to contract more freely. This resulted in a more natural smile with a wider and higher amplitude of the oral commissures.

An additional but very important finding was that lateral canthal line severity decreased following the removal of the cheek filler. This intriguing finding was initially difficult to understand but made sense when connecting the dots between the zygomaticus major muscle and orbicularis oculi muscle; the latter is causative of lateral canthal lines.

The orbicularis oculi muscle is also involved in the facial expression of smiling, termed ‘Duchenne-type smiling’, and signals a truthful and honest smile, ie When someone ‘smiles with their eyes’. If the zygomaticus major muscle can contract more because less filler is inhibiting the transverse facial septum to freely swing during smiling, then the orbicularis oculi muscle does not need to work as hard because the majority of the work is carried out by the zygomaticus major muscle. Therefore, a reduction in lateral canthal line severity was observed in the recently published study.

Respecting facial biomechanics

Natural facial expressions, such as smiling, have structural correlates on which they depend. In the midface, this structure is the transverse facial septum. Understanding that soft tissue filler injections or neuromodulator treatments along the jawline can influence the interplay between facial structures and thereby influence facial biomechanics is crucial for achieving natural-looking facial outcomes.

Understanding facial biomechanics is more important than ever in the aesthetics industry – and with deeper anatomical insight, practitioners can better honour patient preferences, ensuring their voices are heard and their aesthetic needs are respected.