Applying RESTYLANE®: Cannula vs. Needle

With more and more people leaning toward swift and non-invasive procedures that promise instant results, dermal fillers like RESTYLANE® have become the go-to treatment for facial rejuvenation. Although a highly safe procedure, the type of approach used for administering dermal fillers can significantly impact the treatment outcome.

In this article, we will discuss the different techniques used in applying RESTYLANE® and their impact on the final results.

RESTYLANE® –  Enhancing Looks without Going Under the Knife.

Hyaluronic acid is a glycosaminoglycan in the human body, responsible for maintaining moisture and elasticity in the skin. RESTYLANE® is a Non-Animal Stabilized Hyaluronic acid (NASHA)-based1 dermal filler derived from the Streptococcus species of bacteria. Its gel-like consistency and chemical composition make it a valuable choice of filler material for correcting wrinkles, deep nasolabial folds, and marionette lines.

Unlike Botox, RESTYLANE® fillers can smoothen out moderate wrinkles and restore the skin’s volume with two important mechanisms. First, they easily blend with the surrounding dermal tissue to improve volume. Additionally, their hydrophilic nature helps bind to water molecules to replenish skin hydration levels, thus imparting a youthful and natural look to the skin.

Currently, the two RESTYLANE® products approved by the FDA for cannula use include – RESTYLANE® LYFT for midface enhancement and RESTYLANE® SILK for lip augmentation.

Needles & Cannulas – Tools of the Trade

Any dermal filler procedure is incomplete without the injection device. While RESTYLANE® fillers are usually supplied with their needles, of late, cannulas are making their way as the preferred delivery method among cosmetic specialists.

Needles are sharp with a pointed tip and typically of short length. Their unique shape makes them an excellent choice for transecting deeper skin tissue and delivering precise5 aesthetic results.

Cannulas, on the other hand, are flexible and long, with a blunt tip. They are preferred for their superb tactile control and less invasive approach. They are beneficial for contouring and volumizing procedures, such as cheek or jawline augmentation.

Therapeutic Aspects of RESTYLANE® Application

Irrespective of the methods for applying RESTYLANE®, any procedure follows the routine preparation protocol that includes cleaning the injection area and surrounding skin with antiseptics.

Precise injection site selection, depth accuracy, and careful product selection are crucial factors that significantly influence outcomes.

The clinician can ensure optimal anesthesia by adopting approaches like ice application, topical EMLA cream, and regional nerve blocks per the patient’s requirements (submucosal, maxillary, mental, or infraorbital). Additionally, massage and soothing talks can be valuable distraction tools to enhance patient comfort during the procedure.

The technique used for injecting fillers relies on a variety of factors2, such as:

• Intended use;
• Location;
• Filler substance;
• Size of the needle or cannula;
• Operator expertise.

Needle Technique

Typically, the clinician can use one or more of the following techniques2,3 for applying RESTYLANE® with a needle:

• Linear threading: Involves inserting the needle at the selected depth and depositing the filler slowly while retracting the needle (retrograde approach).
• Serial puncture: The filler is administered in multiple closely spaced small injections to treat wrinkles, fine lines, and volume loss.
• Fanning: The filler is deposited radially by changing the needle angle from a single entry point.
• Cross-hatching: Involves depositing the filler in a series of parallel and perpendicular lines.
• Depot: Unlike other techniques, the depot injection allows advancing the needle as far as the fat pads or periosteum, followed by depositing 0.1–0.2 cm3 filler bolus.
• Layering: Here, volume build-up is accomplished by injecting filler at various depths.

These techniques can also be used to administer the filler with a cannula. Additionally, approaches, such as the fern or cone technique, are used in exceptional circumstances. Advanced methods like skin boosting to treat superficial rhytids,6 linear periosteal threading for enhancing bone contours, and different approaches to the lip mucosa can be adopted to improve treatment outcomes.

Hyaluronic acid fillers can achieve better results by combining them with saline or botox (neurotoxin) for smoother distribution.

Safety Considerations

The cornerstone of a successful RESTYLANE® application is a thorough understanding of anatomy, including the facial planes and neurovascular bundles near the injection areas.

• Gradual injections with 0.05–0.2 cm3 of filler deposited every pass3 help gain optimal control during the procedure.
• A sharp needle or a blunt cannula ranging from 25–32 gauge in size has been shown to reduce trauma and improve patient safety.
• Aspirating for at least 5 seconds before each injection pass can be an added precaution against intravascular injections.
• Blanching or whitening of the injection site indicates potential vessel occlusion. If seen, the procedure should be halted immediately and treated with gentle massage or a reversal approach involving hyaluronidase injection.

Cannula Technique

Unlike a hypodermic needle, inserting a cannula often needs assistance from a needle before proceeding further. Here is a general guideline for applying RESTYLANE® with a cannula:

• Preparation: Before starting the procedure, it is essential to ensure you have the appropriate cannula size and filler product ready.
• Create the Pilot Hole: The pilot hole, usually created by a needle, is the first point of entry for the cannula. The location of the pilot hole must align with the direction of the pathway intended for the cannula. However, it must only puncture the dermis and not go any further.
• Size of the Pilot Hole: The needle gauge for the pilot hole should match or be slightly larger than the cannula.
• Insert the Needle: Insert the needle only about a third of the way into the intended direction. Stopping slightly past the dermis is a helpful landmark.
• Entering the Cannula into the Dermis: Using a cannula can be challenging to penetrate the dermis. Tap around the pilot hole and wait for the cannula to slide into place. Lubrication, such as a small amount of blood, can help make the sliding action smoother.
• Navigating Through the Dermis: After penetrating the dermis, the cannula tip should be in the hypodermic fat layer. The insertion angle can be gently modified to align with the intended cannula route. Remember that any rough handling can cause undue trauma.
• Overcoming Tissue Blockages: If encountering tissue that blocks the cannula’s path, it is best not to force it. Instead, repositioning the cannula or lifting the skin above the entry zone can help find a new pathway.
• Using Filler: Occasionally, a tiny amount of filler can create space within the tissue in case of any obstruction, allowing the cannula to continue its journey smoothly.
• Injecting Filler: Once the cannula is in place, the clinician can begin gently laying down the filler in retrograde or antegrade injections, or a combination of both, as needed to achieve the desired outcome.

Safety Considerations

The following can serve as valuable tips to ensure an atraumatic procedure using a cannula for RESTYLANE® fillers:

• Always prefer the path of minimal resistance during insertion. Avoid applying additional pressure.
• Avoid inserting the cannula into a bleeding entry point, as there is a likelihood of an arterial bleed.
• Observe the injection site for a slight elevation before going all the way in. This will help you understand whether the filler spreads outward rather than traveling down a blood vessel.
• Aspirating, irrespective of needle or cannula use, should be done at all times.
• Consider applying gentle pressure to vessels in high-risk injection regions to reduce complications.

With awareness of the potential risks and taking the necessary steps to avoid them, dermal fillers can be a safe and effective way to enhance one’s appearance.

Cannula or Needle for RESTYLANE®?

Here is a look at the pros and cons associated with the methods for applying RESTYLANE® fillers:

Complications Associated with Needle and Cannula Usage

When it comes to needles and cannulas, it’s important to be aware of the potential risks2,3 and complications:

Minor adverse events:

• Swelling;
• Redness (erythema);
• Pain;
• Bruising.

Severe adverse events:

• Vascular occlusion;
• Infections;
• Tyndall effect (bluish discoloration in the injection site).
• Asymmetry;
• Over and under-correction.
• Lumps;
• Dermatitis;
• Migration;
• Formation of granuloma;
• Skin necrosis;
• Pulmonary embolization;
• Stroke;
• Blindness.

The chances of adverse events can be significantly reduced by taking proper precautions and ensuring the correct injection of the filler material.

Needle vs Cannula – Some Food for Thought

A study by Murad Alam et al. revealed that needles in dermal fillers are associated with a much higher frequency of vascular events, while cannulas demonstrated a 77% reduction in frequency. However, the expert cosmetic surgeon, Dr. Tim Pearce, implores clinicians to think beyond numbers. The severity of vascular complications with a cannula may be more challenging to manage than those created with needles, owing to the former’s length and filler volume used. It is here when a sharp needle may deliver some of the product beyond the danger zone, reducing the severity of the initial injury and resulting in minor volume deposition.

Ultimately, it is the clinician’s skill and expertise that primarily influence the chances of performing a safe procedure with minimal adverse events.

Conclusion

While dermal fillers are an integral part of facial rejuvenation, they are just one piece of a more comprehensive approach. Most cosmetic procedures are constantly evolving, which is why it gives ample opportunity for combining two or more approaches to accommodate individual cases.

Cannulas provide a compelling alternative to needles with their excellent track record of precision and safety. It’s worth remembering that even a cannula with a thin gauge can have a similar effect as a needle. That’s why it’s essential to modify the technique to ensure optimal outcomes.

As the demand for fillers rises, clinicians must ensure that safety protocols are followed and prompt intervention is done to manage potential complications. These simple measures can significantly maintain aesthetically pleasing results in the long term.

FAQ

Is a cannula better than a needle for fillers?

Cannulas are generally considered to be safer than needles for filler injections for the following reasons:

• Blunt-tipped and less likely to cause bruising or damage neurovascular structures;
• Provide excellent tactile feedback during the procedure;
• Allow for more controlled and precise placement of filler;
• Can be threaded deeper into the skin.

Is a cannula safer for a filler?

Yes, cannulas are blunt-tipped, longer, and less likely to cause vascular occlusion. Cannulas are also less likely to cause pain and bruising than needles. Additionally, the clinician can easily monitor the location and plane of filler deposition while using a cannula, thus providing better control during the procedure. However, the clinician’s skills and expertise are still the most important factor in ensuring successful results.

Why is a cannula safer than a needle?

Cannulas are safer than a needle as they:

• Need fewer entry points;
• Reduce discomfort;
• Have a blunt tip for safer use near veins and arteries;
• Come with minimal risk of bruising or swelling;
• Provide better control for doctors to avoid sensitive areas;
• Have greater reach.

References

1. RESTYLANE® Instructions for Use. [PDF]. https://www.galderma.com/us/sites/default/files/2018-11/RESTYLANE®_IFU.pdf. Accessed October 27, 2023.
2. Maya Vedamurthy, Amar Vedamurthy. Dermal Fillers: Tips to Achieve Successful Outcomes. J Cutan Aesthet Surg. Jul-Dec; 1(2): 64–67. 2008. doi: 10.4103/0974-2077.44161
3. Takintope Akinbiyi, MD, Sammy Othman, BA, Olatomide Familusi, MD et al. Better Results in Facial Rejuvenation with Fillers. Plast Reconstr Surg Glob Open. Oct; 8(10): e2763. 2020. doi: 10.1097/GOX.0000000000002763
4. Jani A J van Loghem, Dalvi Humzah, Martina Kerscher. Cannula Versus Sharp Needle for Placement of Soft Tissue Fillers: An Observational Cadaver Study. Aesthet Surg J

Dec 13;38(1):73-88. 2017. doi: 10.1093/asj/sjw220

1. Tatjana Pavicic, Konstantin Frank, Katharina Erlbacher et al. Precision in Dermal Filling: A Comparison Between Needle and Cannula When Using Soft Tissue Fillers. J Drugs Dermatol Sep 1;16(9):866-872. 2017.
2. Jani A J van Loghem, MD, Dalvi Humzah, MD, FRCS (Plast), Martina Kerscher, MD, PhD. Cannula Versus Sharp Needle for Placement of Soft Tissue Fillers: An Observational Cadaver Study. Aesthetic Surgery Journal, Volume 38, Issue 1, January 2018, Pages 73–88. doi: 10.1093/asj/sjw220
3. Murad Alam, MD, MSCI, MBA, Rohit Kakar, MD, Jeffrey S. Dover, MD, et al. Rates of Vascular Occlusion Associated With Using Needles vs Cannulas for Filler Injection. JAMA Dermatol. 2021;157(2):174-180. doi:10.1001/jamadermatol.2020.5102