Investigating Facial Muscle Physiology Following Soft Tissue Filler Injections - A surface-derived Electromyographic and Skin Vector Displacement Analytic Study.

The use of hyaluronic - acid based soft - tissue fillers has often been reported to modulate the muscle i.e., to cause myomodulation. To our knowledge, there has been so far no scientific study investigating the potential of hyaluronic - acid based soft - tissue fillers to modulate or actually alter the function of facial muscles. To further assess this 3 - dimensional (3D) surface imaging and electromyography (EMG) based prospective study investigated the changes of facial muscle contraction after injection of strategically placed hyaluronic - acid based soft - tissue fillers to assess the actual validity of the term myomodulation. A total of 13 subjects with a mean age of 37.8 years (12 females, 1 male) were injected according to a predefined injection protocol. Surface electromyography and 3D surface imaging were performed prior to the injection and 5 days after the injection. The results showed no significant change in the strength of the muscles (measured in µV) after injection of hyaluronic - acid based soft - tissue fillers. However, horizontal and vertical skin displacement upon contraction of the zygomaticus major muscle changed significantly between baseline and follow - up , with a mean horizontal skin displacement increase from 3.2 mm to 4.1 mm. Upon contraction of the depressor anguli oris muscle, the horizontal skin displacement did not change significantly (2.15 mm vs. 2.05 mm), while vertical skin displacement increased significantly from 2.9 mm to 4.3 mm. The modification of the surrounding tissue caused an alteration of the vectorial skin displacement upon contraction of the muscle. A potential explanation could be the increased distance between origin and insertion of the muscle due to the material deposition in the proximity of the relevant facial muscles, leading to a change of contraction vector.

Understanding the Interplay Between Skin, Fascia, and Muscles of the Midface in Facial Aging.

BACKGROUND: Surgical, minimally-invasive, and non-invasive aesthetic procedures try to ameliorate the signs of facial aging, but also focus on enhancing various individual features of beauty in each patient. Herein, the midface plays a central role due to its location but also its importance for the aesthetic perception and facial expression. OBJECTIVE: To date, no study has investigated the interplay between facial muscles and its connecting subdermal architecture during facial aging to provide a more comprehensive understanding of the middle face. MATERIALS AND METHODS: A total of 76 subjects, consisting of 30 males (39.5%) and 46 females (60.5%) with a mean age of 42.2 (18.7) years [range 19-80] and a mean BMI of 24.6 (3.7) kg/m2 [range 18-35], were enrolled in this investigation. Cutometry (skin aging), 3D skin displacement analyses (subdermal connective tissue aging), and sEMG (muscle aging) analyses were utilized. RESULTS: The results revealed that overall skin firmness increased, and skin elasticity decreased (p < 0.001), sEMG signal of the investigated muscles decreased (p < 0.001), whereas midfacial mobility remained unaltered (p = 0.722). CONCLUSION: The results of this study indicate that midfacial aging is a measurable effect when utilizing individual measurement modalities for assessing skin, subdermal fascia, and midfacial muscles. The function of midfacial muscles revealed a potential threshold effect, which is not reached during midfacial aging due to the unchanged soft tissue mobility at older age. However, to understand its clinical presentation all midfacial soft tissues need to be factored in and a holistic picture needs to be created. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes review articles, book reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to authors www.springer.com/00266 .

[Injection anatomy-a new discipline in aesthetic medicine]. / Injektionsanatomie ­ eine neue Disziplin der ästhetischen Medizin.

The basic anatomical understanding of aesthetic medicine has changed fundamentally since the turn of the millennium. With the advent of modern minimally invasive injection procedures using botulinum toxin and hyaluronic acid fillers, anatomical structures that had previously received little attention and were not considered relevant have steadily gained in importance and moved into the scientific focus. Understanding the three-dimensional arrangement of the face with its defined anatomical layers and compartments serves the procedural dermatologist in the sense of a navigation system to optimize treatment success and patient safety when performing aesthetic injections in the facial region. The principles of the biomechanical interaction of the structures are of elementary importance in the creation of individual treatment plans for the implementation of natural and balanced therapeutic results. Modern injection anatomy as an interdisciplinary subject of the three fields of anatomy, dermatology and plastic surgery makes a decisive contribution here.

Vertigo Associated With Cochlear Implant Surgery: Correlation With Vertigo Diagnostic Result, Electrode Carrier, and Insertion Angle.

Objective: Vertigo is a common side effect of cochlear implant (CI) treatment. This prospective study examines the incidence of postoperative vertigo over time and aims to analyze influencing factors such as electrode design and insertion angle (IA). Study Design and Setting: This is a prospective study which has been conducted at a tertiary referral center (academic hospital). Patients: A total of 29 adults were enrolled and received a unilateral CI using one of six different electrode carriers, which were categorized into "structure-preserving" (I), "potentially structure-preserving" (II), and "not structure-preserving" (III). Intervention: Subjective vertigo was assessed by questionnaires at five different time-points before up to 6 months after surgery. The participants were divided into four groups depending on the time of the presence of vertigo before and after surgery. Preoperatively and at 6 months postoperatively, a comprehensive vertigo diagnosis consisting of Romberg test, Unterberger test, subjective visual vertical, optokinetic test, video head impulse test, and caloric irrigation test was performed. In addition, the IA was determined, and the patients were divided in two groups (<430°; ≥430°). Main Outcome Measures: The incidence of vertigo after CI surgery (group 1) was reported, as well as the correlation of subjective vertigo with electrode array categories (I-III) and IA. Results: Among the participants, 45.8% experienced new vertigo after implantation. Based on the questionnaire data, a vestibular origin was suspected in 72.7%. The results did not show a significant correlation with subjective vertigo for any of the performed tests. In group 1 with postoperative vertigo, 18% of patients showed conspicuous results in a quantitative analysis of caloric irrigation test despite the fact that the category I or II electrodes were implanted, which are suitable for structure preservation. Average IA was 404° for the overall group and 409° for group 1. There was no statistically significant correlation between IA and perceived vertigo. Conclusions: Though vertigo after CI surgery seems to be a common complication, the test battery used here could not objectify the symptoms. Further studies should clarify whether this is due to the multifactorial cause of vertigo or to the lack of sensitivity of the tests currently in use. The proof of reduced probability for vertigo when using atraumatic electrode carrier was not successful, nor was the proof of a negative influence of the insertion depth.