The increase in the use of filler treatments within minimally invasive cosmetic surgery has correspondingly escalated the variety and frequency of associated side effects. Initially, unregulated procedures led to primary side effects such as infections, foreign body reactions, and granuloma formation. However, severe vascular complications like skin and tissue necrosis and blindness have emerged as recognized risks. Side effects from filler treatments can range from mild to life-threatening, including edema, pain, tenderness, numbness, bleeding, bruising, hematoma, redness, erythema, pigmentation, allergic reactions, itching, pruritus, the Tyndall effect, asymmetry, irregularity, migration, skin and soft tissue infections, nodules, granulomas, and vascular compromise. These side effects are categorized into early and delayed types. Many complications, particularly those related to vascular abnormalities, are frequently linked to procedural issues, emphasizing the importance of understanding filler properties, injection techniques, and facial anatomy. Preventing side effects is ideal, but early detection and treatment are crucial. Recognizing potential side effects based on their timing and understanding appropriate preemptive treatment methods is essential. This discussion addresses non-vascular side effects, highlighting their onset, symptoms, and management strategies. The comprehensive understanding and careful management of these side effects are vital for minimizing complications and ensuring patient safety in filler treatments.

Clarification is needed regarding the definitions and classification of groove and hollowness of the infraorbital region depending on the cause, anatomical characteristics, and appearance. Grooves in the infraorbital region can be classified as nasojugal grooves (or folds), tear trough deformities, and palpebromalar grooves; these can be differentiated based on anatomical characteristics. They are caused by the herniation of intraorbital fat, atrophy of the skin and subcutaneous fat, contraction of the orbital part of the orbicularis oculi muscle or squinting, and malar bone resorption. Safe and successful treatment requires an optimal choice of filler and treatment method. The choice between a cannula and needle depends on various factors; a needle is better for injections into a subdermal area in a relatively safe plane, while a cannula is recommended for avoiding vascular compromise when injecting filler into a deep fat layer and releasing fibrotic ligamentous structures. The injection of a soft-tissue filler into the subcutaneous fat tissue is recommended for treating mild indentations around the orbital rim and nasojugal region. Reducing the tethering effect of ligamentous structures by undermining using a cannula prior to the filler injection is recommended for treating relatively deep and fine indentations. The treatment of mild prolapse of the intraorbital septal fat or broad flattening of the infraorbital region can be improved by restoring the volume deficiency using a relatively firm filler.

Vascular complications arising from dermal filler treatments pose significant risks, including ischemia, tissue necrosis, and severe outcomes like blindness and pulmonary embolism. This study investigates the mechanisms of vascular complications, categorizing them into extravascular compression and intravascular emboli. Extravascular compression occurs when injected fillers compress adjacent blood vessels, leading to ischemia and potential necrosis, while intravascular emboli result from fillers entering blood vessels, causing blockages. The study emphasizes the importance of anatomical knowledge, careful injection techniques, and early intervention. Management strategies include the use of hyaluronidase to dissolve HA fillers, vasodilators to improve blood circulation, and hyperbaric oxygen therapy. The regions most susceptible to complications align with major arterial pathways, particularly the nasolabial folds and nasal region. The study also highlights the need for meticulous injection techniques, the use of cannulas over needles in high-risk areas, and the aspiration test to detect vessel penetration. Early detection and immediate intervention are crucial to mitigate adverse outcomes. Continuous education and training for practitioners, along with advancements in filler materials and injection methods, are essential for improving the safety of cosmetic procedures. This comprehensive understanding aids in preventing and managing vascular complications, ensuring better patient outcomes. The field of dermal filler treatments is advancing with new techniques and technologies, such as High-Resolution Ultrasound, Infrared Imaging, self-crossing hyaluronic acid filler, biodegradable microspheres, and microinjection.

Hyaluronic acid (HA) fillers are extensively utilized in aesthetic medicine due to their biocompatibility, reversibility, and effectiveness in enhancing skin hydration, volume, and overall appearance. These fillers are predominantly produced through microbial fermentation, followed by a critical cross-linking process that enhances their longevity by resisting enzymatic degradation. This review provides a thorough examination of the manufacturing processes that differentiate HA fillers, with particular attention to the distinctions between biphasic and monophasic variants. Unlike previous studies, this review emphasizes the specific cross-linking techniques and their substantial impact on the fillers’ rheological properties, such as elasticity and cohesiveness, which are crucial to their clinical performance and patient outcomes. Additionally, the review offers a comprehensive comparison of HA fillers with non-HA alternatives, including calcium hydroxylapatite, poly-l-lactic acid, and polymethyl methacrylate, highlighting the unique advantages and potential complications associated with each type. By presenting novel insights into the latest advancements and challenges in filler technology, this review aims to provide clinicians with a deeper understanding of filler properties, thereby guiding them in making informed decisions to optimize patient safety and aesthetic results.

The classification of nasolabial folds into three types, each with distinct causative factors and mechanisms, is explored. Age-related changes in facial skin and connective tissues are examined in detail, revealing variations across different facial regions due to variances in tissue firmness and thickness. The innovative ‘Reverse Technique,’ involving cog threads to enhance tissue traction and effectiveness in thread-lifting procedures, is introduced. Detailed technical guidelines, anatomical considerations, and safety measures are provided, emphasizing the importance of identifying optimal vectors and fixing points to achieve maximum lifting effects while minimizing potential risks, particularly those associated with vascular structures. Additionally, the ‘Cross Technique using volumizing thread’ is discussed, designed to smooth tissue boundaries and rejuvenate sagging areas. Facial anatomy, including the positioning of arteries and ligaments, is underscored as essential for ensuring the safety and efficacy of procedures. In conclusion, this review stands as a comprehensive guide for practitioners, offering insights into innovative thread-lifting methods and their applications in addressing nasolabial folds. The primary focus is on achieving optimal aesthetic results while prioritizing patient safety.

Hyaluronic acid (HA) fillers are widely used in esthetic medicine and are categorized into biphasic and monophasic types based on their manufacturing processes. To evaluate the quality of these fillers, it is essential to understand their rheological properties, which reflect their viscoelastic nature. Rheology, the study of material deformation and flow, reveals how fillers behave under stress, combining properties of solids and liquids. This study explores the fundamental principles of elasticity and viscosity, rooted in Hooke’s law of elasticity and Newton’s law of viscosity, to explain the complex behavior of viscoelastic substances like HA fillers. The distinction between biphasic and monophasic fillers lies in their chemical cross-linking processes, which impact their molecular weight, structure, and ultimately, their clinical performance. Biphasic fillers with minimal cross-linking rely on natural molecular entanglements, exhibiting lower modification efficiency and greater elasticity. Conversely, monophasic fillers, which undergo extensive chemical cross-linking, demonstrate higher modification efficiency, firmer texture, and enhanced resistance to enzymatic degradation. The study emphasizes the importance of thoroughly removing residual cross-linking agents to ensure filler safety. Understanding these rheological characteristics aids clinicians in selecting appropriate fillers based on injection sites, tissue conditions, and desired outcomes, balancing viscoelastic properties and safety for optimal esthetic results.