This is the digital version of the PhD Dissertation of Jani van Loghem.
The popularity of injectable treatments as a minimally-invasive method of aesthetic rejuvenation and enhancement continues to grow in concert with the number of treatment indications. With greater numbers of physicians practicing aesthetic medicine and increased numbers of treatments performed there will inevitably be a rise in the number and spectrum of adverse events. While most are mild and transient, more serious complications can occur that leave the patient with long-lasting or permanent injuries. This thesis has been developed as a resource to improve the safety of degradable filler injections for facial indications.
Chapter 1 provides an introduction to the new profile specialty of Aesthetic Medicine and an overview of the efficacy and safety of biodegradable fillers for facial aesthetic indications. The potential complications of filler injections are described in relation to facial anatomy.
Chapter 2 focuses on calcium hydroxylapatite (CaHA, Radiesse®), one of the most widely used dermal fillers with an established history of clinical use. We discuss the applications of this filler and provide advice based on experience gained in our clinic over the past 10 years. A standard treatment protocol for the reconstruction of a youthful facial anatomy is provided with the aim of achieving as natural a result as possible. CaHA can be used at various dilutions to treat a range of facial indications with injections performed at superficial (dermal) to deep (periosteal) anatomical levels.
Chapter 3 compares the instruments widely used for periosteal filler injection: sharp needles versus blunt cannulas. This was undertaken by injecting four cadavers with colored gels in five anatomical areas: the frontal region, the temporal region, the infra-orbital region, the mandibula and the mentum. The results of subsequent dissections of these regions revealed that blunt cannulas appeared safer than sharp needles and were more precise in predicting the anatomical level (periosteal) of final filler placement.
Chapter 4 examines the value of aspiration prior to injection as a standard safety test. While at first this might seem an effective method of determining whether the tip of a needle is positioned in a blood vessel, it is only applicable to fillers with low viscoelasticity. In an in vitro study we performed aspiration with a range of commonly used injectable fillers of varying viscoelasticity, injected with a range of needle lengths and gauges. The research showed that with a 1 second aspiration, 67% of the tested products injected with various needles showed false negative results. The sensitivity of aspiration as a safety test was dependent on both the filler product and the needle, and was generally low.
Chapter 5 describes the results of a retrospective 1-year analysis of 70 patients treated with CaHA in the upper third of the face: frontal region, temporal hollows and eyebrows. This is not a standard indication for CaHA and little has been published about injections in this area. The CaHA dilutions and cannula techniques used provided good aesthetic results with no serious complications. The results from this analysis are therefore a valuable addition to the literature.
Chapter 6 focuses on the perception of pain during injection treatments and describes the results of a study that compared pain perception measured with a visual analogue score on the left and right sides of the face in over 300 patients. The results showed that the left side of the face was statistically more sensitive to pain than the right. Furthermore, starting treatment on the left side of the face appeared to provide a significantly lower total pain experience than starting treatment on the right.
Chapter 7 describes the outcomes of an advisory board meeting attended by more than 400 experts from more than 60 countries. Participants discussed best practice for combining treatments including botulinum toxin, hyaluronic acid (HA), CaHA, microfocused ultrasound with visualization as well as other applications. The meeting also featured a number of presentations on best practice for treating a variety of facial and body indications with the aim of achieving harmonious and natural results.
Chapter 8 describes the potential complications that can occur after HA filler injections and the importance of an accurate diagnosis. The chapter’s algorithms provide clear guidance on how to diagnose and treat complications that may arise after HA filler injection based on their clinical presentation.
Chapter 9 focuses on vascular complications and in particular those arising after inadvertent intra-arterial injection of CaHA, which unlike HA does not currently have a reversing agent. For this reason, much emphasis is placed on prevention of vascular compromise, and on treatment of an embolization should it occur. A consensus document produced by 18 international experts in the field of injectables is described which provides both evidence-based and expert-based recommendations for the treatment of intravascular embolization with CaHA: early recognized peripheral embolization, late recognized peripheral embolization (resulting in necrosis and wounds), and retinal embolization. Embolization is solely due to injector technique and the chapter highlights the need for all practitioners to have a good knowledge of facial anatomy and appropriate injection techniques.
Chapters 10 and 11 conclude the thesis with a description of an expert consensus on the use of HA products from the cohesive polydensified matrix (CPM) Belotero range. The products in this range have been designed with specific rheological properties. The consensus provides recommendations on the optimal product and treatment technique for a range of facial indications based on underlying anatomy and anatomical risks.
Together these 11 chapters in this thesis should provide practitioners with a deeper understanding about how to optimize patient safety during filler treatments for facial aesthetic applications.