What are the New Anatomical Information on Lip Augmentation?


Lip augmentation is one of the most popular procedures in aesthetic dermatology. However, due to the dense vascular structure of the lips, there are important anatomical details that must be considered during the procedure. Findings from cadaver studies conducted in recent years have more clearly demonstrated the distribution, depth, and potential risk areas of the lip veins. This information is crucial for both reducing complications and developing safer techniques.

Why is the Vascular Anatomy of the Lips Important?
The lips are supplied by the superior and inferior labial arteries. The course and branching of these arteries vary considerably. Therefore, one of the most significant risks in filler procedures is intravenous injection and its associated complications. Inadvertent intravenous injections underlie serious complications such as necrosis, tissue loss, and, in rare cases, blindness.

Studies on the topography of lip veins indicate which areas are at greater risk and which techniques can be used for safe injection. In particular, the correct selection of vessel depth and tissue planes plays a critical role in minimizing the risk of complications for the clinician.

Anatomical Location of the Labial Arteries
Generally, labial arteries can be found in three different planes:

Submucosal plane: On the non-keratinized, "wet" side, between the mucosa and the muscle layer.

Intramuscular plane: Between the superficial and deep layers of the orbicularis oris muscle.

Subcutaneous plane: On the keratinized, "dry" side, within the subcutaneous fat.

Cadaveric studies have shown that:

In most cases, arteries are located in the submucosal plane (70–78%).

They are less commonly found in the intramuscular plane (approximately 17%) and, very rarely, in the subcutaneous plane (approximately 2%).

The smaller and more superficial location of the arteries in the lower lip makes the procedure relatively safer.

This anatomical variability necessitates the correct selection of depth and plane during injection.

Depth of Lip Veins
There are several important studies in the literature on the depth of lip veins. A study by Lee et al. revealed that the superior labial artery lies at an average depth of 3.3–3.9 mm at the vermilion border. This finding suggests that injections deeper than 4 mm may increase the risk of vascular injury.

Therefore, superficial injections (<4 mm) at the vermilion border are considered safer. Shorter, more controlled injections should be preferred over standard 13 mm needles for injections in this area.

Risks and Precautions in Lip Augmentation
Standard 13 mm needles increase the likelihood of reaching the lip veins.

Injections placed between the muscle layer and the mucosa increase the risk of complications.

Injections placed subcutaneously are safer than injections placed in the midline of the lip.

The lower lip is considered anatomically lower risk.

In clinical practice, it is safest to be cautious, avoid intramuscular or submucosal injections, and remain as superficial as possible.

New Approach: 4mm Technique
Based on anatomical data, one of the new techniques developed for lip augmentation is the use of a 4mm, 30-gauge needle. This approach was first introduced by Dr. Jean Louis Sebagh at a conference in Paris in 2015 and has since been adopted by many physicians.

In this technique:

The filler is placed very superficially, at the vermilion border.

It is inserted with a short 4mm needle, and under pressure, the hyaluronic acid flows forward (anterograde flow).

The number of entry points is reduced, resulting in less tissue trauma and less pain.

The filler is more safely distributed into the perioral fat tissue.

Advantages:
Reduces the risk of intravascular injection.

Reduces pain.

Provides more uniform filler distribution.

Preserves the natural contour of the lips.

The safety of this technique stems from the fact that the filler is likely to be advanced through an anatomical space or tube that has not yet been fully defined. Additionally, the hydrodissection effect created by the pressure during the procedure may direct the filler to a safer area, away from the blood vessels.

Clinical Experiences
Clinicians using the 4 mm technique have reported that patients experience less pain during the procedure and recover more quickly afterwards. This is due to the lower pressure applied to the dense nerve network of the lips.

Furthermore, the small number of entry points shortens the procedure time and reduces side effects such as post-injection swelling and bruising.

SEO-Focused Patient Information
The most important message for patients considering lip filler is that the risk of complications is extremely low when performed using safe techniques. Thanks to anatomical studies, especially in recent years, doctors have a better understanding of the location of lip vessels, making them more informed in their procedures.

People considering lip filler should definitely:

Choose an experienced dermatologist or aesthetic surgeon.