Adapting Dermal Fillers in Clinical Practice

Yates Yen-Yu Chao, Sebastian Cotofana, Yates Yen-Yu Chao, Sebastian Cotofana

• Publisher: CRC Press
• Year: 2022
• ISBN:
  9780429536137
• Edition: 1
• Topic: Medicine
• Subtopic: Dermatology

There have been many different brands of dermal fillers approved for use for soft tissue augmentation in the US market alone, comprising four different types of temporary fillers and one permanent type, with several other brands and types also available elsewhere in the world. Against such a potentially bewildering variety and range of choices, this new text offers a scientific and an anatomic rationale for why a particular filler should be selected as optimal for each individual location and indication and how it should best be used in treatments. International experts share their clinical knowledge and expertise to guide all levels of aesthetic practitioners toward the best results for each individual patient.

CONTENTS: Fundamentals of Injectable Filler Procedures * Basic Injection Techniques * Modified and Advanced Injection Techniques * Novel Injection Techniques * Aesthetic Filler Injection Pearls * Adapting Injection Techniques to Different Regions * Adapting Injection Techniques to Special Indications * Adapting Injection Techniques to Different Filling Materials * Adapting Injection Techniques to Different Genders * Adapting Injection Techniques to Different Age Groups * Adapting Injection Techniques to Patients of Different Ethnicity * Prevention and Management of Complications.

1Fundamentals of Injectable Filler Procedures

Yates Yen-Yu Chao, Sebastian Cotofana and Nicholas Moellhoff

DOI: 10.1201/​9780429260520-1

Contents

• 1.1 Introduction
• 1.2 Preparation of Fillers
  • 1.2.1 Temperature
  • 1.2.2 Dilution and Additives
  • 1.2.3 Repackaging
  • 1.2.4 Needles and Cannula
• 1.3 Preparation of Patients
  • 1.3.1 Cleansing
  • 1.3.2 Pain Control
  • 1.3.3 Marking
  • 1.3.4 Positioning
• 1.4 During the Procedure
  • 1.4.1 Illumination
  • 1.4.2 Antiseptics
  • 1.4.3 Bleeding Control
  • 1.4.4 Assistants
• 1.5 Aftercare
  • 1.5.1 Pain Control
  • 1.5.2 Skincare
  • 1.5.3 Medications
  • 1.5.4 Massages and Molding
  • 1.5.5 Follow-Up
• 1.6 Touch-Up and Refill
• 1.7 Ultrasound Imaging
• Bibliography

1.1 INTRODUCTION

The practice of aesthetic medicine has experienced dramatic changes in the way we deliver our service. In a digitalized world, patients can easily research their problems and possible solutions, evaluate their budget, imagine the treatment outcome, and invest in the appropriate quantity and types of products they want. Doctors usually then plan and combine products according to the individual characteristics of each product and the clinical indications of different patients.

Minimally invasive cosmetic procedures have become mainstream. Among them, injectable soft tissue fillers are prepackaged products with different characteristics indicated for different purposes in a certain quantity. These handy packs of a product are ready for use, can be delivered quickly, and mostly give immediately visible effects (Figure 1.1). Any error occurring during the process of delivery can result in severe consequences, which is why these materials are strictly regulated in most countries and should be administrated by registered medical professionals, but even the safe placement of soft tissue fillers in tissue does not guarantee satisfactory aesthetic results.

FIGURE 1.1 Some of the commercially available injectable fillers. One manufacturing technology usually can be varied in concentration, degree of modification, particle size, and physical differences, within several subtypes in a single range.

The professional use of injectable fillers is not entirely medicine or even science. Every procedure for correction or enhancement using fillers should be performed or regarded as a form of art. Three-dimensional (3D) morphology, structural diagnosis, knowledge of anatomy, filler property, rheology, injection techniques, skills and soft tissue biomechanics, filler biology, immunology, and a sense of art or beauty are all important ingredients for a successful result.

This book will focus on injection techniques with only a succinct description of related subjects necessary for completing a safe and successful injection job; this chapter concentrates on the important physicochemical parameters involved.

1.2 PREPARATION OF FILLERS

Although most filler materials are prepacked as commercial kits with pre-paired needles or cannula, it is suggested some filling materials be kept under certain conditions that need to be prepared before they are applied to patients. Some of the fillers can be modified before injection to have varied physicochemical properties adapted to different purposes.

1.2.1 Temperature

Most hyaluronic acid (HA) fillers are suggested to be stored under 25°C and not recommended to be frozen. In some regions with warmer climates, HA fillers are sometimes recommended to be stored in fridges to maintain their condition. However, an HA-based soft tissue filler – a substance with non-Newtonian fluid behavior – will have higher viscosity at low temperatures. Treatment should only be started when the content within syringes has been raised to room temperature. Sudden loosening of the needle, or (especially) the Luer-lock adaptor, with leaking or a burst of HA material can occur when the plunger forcefully pushes a body of cold HA material.

Calcium hydroxylapatite (CaHA) and polycaprolactone (PCL) are suggested to be stored at room temperature. Some practitioners reserve some filling substances (part of a complete kit) for a future touch-up or repack one syringe of filler for different patients; however, the rest of the half-used filler is no longer aseptic. Even storing in a fridge under low temperature is not safe, as a temperature of 4°C cannot kill or inhibit microflora after possible contamination during the repackaging process.

Poly-L-lactic acid (PLLA) suspension needs injectable sterile water for the reconstitution 2 days before injection, according to the product instruction. Some consensus guidelines suggest storage below 4°C but without specifying reasons. The fact is that fridge storage does not tackle the concern about product sterility after exposure to the water to be injected. Many of the reported hypersensitive reactions are cases of delayed biofilm reaction. The key to ensuring injection material safety is to be strict at every step during reconstitution to keep the injectable suspension clean.

1.2.2 Dilution and Additives

With advances in soft tissue filler technology, more and more filler products come in a different formula with lidocaine already added in. Most studies on physicochemical properties and clinical efficacy or longevity show not much difference between the original version of a product and the one with integral lidocaine. Before the launch of local anesthetics containing filler products, a trace of lidocaine was frequently added to products of fillers to reduce pain during injection. However, the liquid form of most commercially available lidocaine when added into prepacked syringes of fillers can change the physical properties of the filler substance, including its elasticity, viscosity, and lifting capacity.

HA fillers that are extremely hydrophilic are especially vulnerable to changes in character upon dilution with aqueous lidocaine. CaHA, when mixed with lidocaine in even a minimal amount, will be lower in viscosity rather than in elasticity (Figure 1.2). The preserved elasticity can be beneficial for contouring with a retained ability to lift tissue and give structural support, while the lowered viscosity facilitates filler spreading and enables the injectors to mold the tissue after injection more easily. Mixing with lidocaine has been approved by the US Food and Drug Administration (FDA) for relieving pain during procedures and has been modified for verified indications for biostimulation or soft tissue recontouring to achieve more satisfactory results. Now there are also lidocaine-containing CaHA products with similar physical properties as the original formulation. When lower viscosity is desired for certain purposes in these cases, the CaHA with integral lidocaine has to be diluted again and normal saline would be preferable to lidocaine or sterile injectable water.

FIGURE 1.2 CaHA is approved by the US FDA for dilution with injectable lidocaine, in addition to the lidocaine-containing CaHA that is now available on the market. The CaHA injectable product is diluted and hyperdiluted with lidocaine or normal saline by the injectors via a two-way or three-way connector to allow different functions of contouring and biostimulation.

Though often compared with CaHA because of similar ingredients and the percentage of sodium carboxymethyl cellulose (CMC) gel contained, PCL microspheres behave slightly differently when mixing with lidocaine. The injection of pure form PCL is painful, and minimal doses of lidocaine mixing are the usual practice for injecting PCL, although this is not evidence-based. Hyperdilution with lidocaine is not suggested for PCL, as that practice usually changes the structure and behavior of PCL gel too much and would interfere with its contouring function.

The reconstitution of PLLA with sterile water and lidocaine immediately before an injection is often misunderstood as the process dissolving PLLA particles (Figure 1.3). PLLA is grossly water-insoluble. Reconstitution and standing for 2–48 hours before the injection is intended to break down the aggregates of PLLA flakes. CMC inside each vial of PLLA helps to suspend the insoluble PLLA particles. However, the present usual practice of adding 5–6 ml water exceeds the suspension capacity of the formulated CMC but can temporarily prevent the concentrated substance from aggregating together after remixing and thereby reduce the risks of nodule formation. There is a trend in some areas to add more water (9–12 ml), expecting a thinner solution and less nodule formation. However, the reasons for PLLA injection nodule formation have complex mechanisms but are rarely related to the concentration of suspended PLLA particles, in the senior author's experience. These very diluted PLLA solutions can precipitate very quickly and result in injection with the suspension of very different compositions if the procedure has not proceeded quickly enough and each syringe is not completed soon or vortexed immediately before administration (Figures 1.4 and 1.5). The suspension inside PLLA vials gathers as sediment soon after remixing when being extra-diluted. The extracted suspension can be thinner in the initial syringes and thicker in the later ones. The same scenario can happen even in the delivery process of the solution when th...