New anatomical profile of the nasal musculature: dilator naris vestibularis, dilator naris anterior, and alar part of the nasalis

Sonoanatomy of injecting botulinum neurotoxin into the facial muscles

INTRODUCTION

Ultrasonography (US) has become an essential tool for guiding botulinum neurotoxin (BoNT) injections in facial muscles, enhancing precision and safety. This narrative review explores the role of US in BoNT administration, particularly in complex anatomical regions, highlighting its impact on treatment customization, real-time visualization, and complication reduction.

MATERIALS AND METHODS

A comprehensive literature search was conducted using PubMed, MEDLINE, Embase, and Cochrane Library for articles published from January 2018 to December 2023. Search terms included "Botulinum neurotoxin," "facial anatomy," "ultrasonography guided injection," and "facial muscle sonoanatomy." Studies focusing on US-guided BoNT injections in facial muscles were included. Data extraction and synthesis were performed independently by two reviewers, focusing on study design, ultrasonography techniques, outcomes, and conclusions.

RESULTS

The review found that US guidance significantly enhances the precision of BoNT injections by providing real-time visualization of facial muscles and blood vessels, thereby reducing the risk of adverse events. US enables tailored injection strategies, ensuring symmetrical facial expressions and minimizing over-treatment. The technique also offers immediate feedback, allowing for on-the-spot adjustments to improve treatment efficacy and safety. However, the review identified limitations, including potential selection bias and variability in US techniques across different studies.

CONCLUSION

US guidance for BoNT injections into facial muscles offers substantial benefits in terms of precision, safety, and treatment customization. Despite the identified limitations, the integration of US into clinical practice is poised to enhance patient outcomes in aesthetic and therapeutic procedures. Further research is needed to standardize US techniques and broaden the inclusivity of studies to validate these findings comprehensively.

Use of LetibotulinumtoxinA for Aesthetic Treatment of Asians: A Consensus

Treatment of wrinkles and dynamic lines with botulinum toxin has been a routine practice for years in aesthetic clinical settings. The effective treatment of wrinkles requires a comprehensive understanding of facial expression muscles and their interactions, the mechanism of action of botulinum toxin, and individual patient preferences. The dose adjustment practice and injection technique of physicians are affected by cultural differences; most Asian patients prefer natural-looking results. This article aims to present an expert consensus on the injection sites, doses, and levels of botulinum toxin for various indications in Asians, with the hope of providing guidance to some clinicians. This consensus paper reviews LetibotulinumtoxinA for patient evaluation, dosage, and delivery techniques in Asians from the time LetibotulinumtoxinA was approved up to December 2022. Panelists proposed individualized treatment plans for botulinum toxin type A (BTxA) treatments in 3 areas-wrinkle removal, contour adjustment, and face lifting-for Asians based on their extensive experience and knowledge of facial anatomy. When using a different BTxA, clinicians should start with a conservative dose and carefully individualize the treatment for each patient, and adjust it according to feedback to obtain a higher satisfaction level.

LEVEL OF EVIDENCE: 5

Inverted-V Deformity: An Anatomic Study

BACKGROUND

The inverted-V deformity is an unwanted aesthetic consequence of dorsal hump resection. Despite their attachment to the nasal bones, the upper lateral cartilages (ULCs) can separate from the nasal bones, creating a step-off after cartilaginous dorsal hump removal.

OBJECTIVES

The mechanism of how the ULCs can separate from the nasal bones despite their attachment was studied to improve understanding of the inverted-V complication and its prevention.

METHODS

A dorsal hump resection (bony and cartilaginous) was performed on 12 fresh cadavers to observe the effect on the ULCs. As a secondary study, the effect of different preventative maneuvers was investigated.

RESULTS

Cartilaginous dorsal resection destroys the spreader mechanism of the T-frame and impacts the stabilization of the ULCs, resulting in them becoming free-floating. This causes them to migrate in a posterior, medial, and cranial direction relative to the nasal bones. The dynamic attachment of the ULCs to the nasal bones is key in this mechanism and allows actual separation of the ULCs from the nasal bones to result in the inverted-V deformity. Caudal traction to the ULCs re-tensions these attachments, pulling the ULCs against the nasal bones again.

CONCLUSIONS

This anatomic dissection study has established that the connection between the nasal dorsum and ULCs is not a static fusion but is dynamic. This attachment can be used in primary rhinoplasty to prevent inverted-V deformity by applying caudal traction to the ULCs when reconstructing the dorsum which will tension the ULCs toward the nasal bones.

What is a superior labial frenulum? An anatomical and histological study

Anatomy of the superior labial frenulum (SLF), at first glance, seems to be well established. However, existing studies on the SLF lack description of the incisivus labii superioris (ILS), which cannot be ignored when discussing the SLF. We believe that thorough understanding of the SLF necessitates the anatomical knowledge of the ILS. This study aimed to elucidate the anatomical relationship between the orbicularis oris (OO), ILS, and SLF. A total of 20 formalin fixed human cadaveric specimens were used for gross anatomical and/or histological observation. For histological observation, all specimens were stained with Masson-trichrome. The SLF was a mucosal fold between the gingival mucosa and alveolar mucosa with connective tissue deep to it. The connective tissue attached to the alveolar bone in the junction between the right and left ILS. Skeletal muscle fibers other than orbicularis oris was found in one specimen, which were considered the ILS. During a frenulectomy, removal of the connective tissue bundle is required to prevent recurrence of the high SLF insertion.

Classification of Alar Dynamic Aesthetic in an Asian Female Population: Experts or Automatic Algorithms?

AIM

To provide referenced classifications of alar dynamic aesthetics from both subjective and objective perspectives for determining proper surgical strategies in alarplasty.

METHODS

A total of 150 healthy Asian female participants were instructed to perform two standardized facial movements including a resting pose and a maximum smile while taking care not to show their teeth. The participants were recorded using a dynamic three-dimensional surface imaging system. Frames depicting the resting position and the alar maximum enlargement during the smile were exported separately for anthropometric analysis and classification. The alar dynamic aesthetic was assessed through measurement of the anthropomorphic changes comparing the resting and maximum smile statuses and then transformed into quantitative analysis through the algorithm [Formula: see text]. Subjective classification and evaluation of the subject cosmetic deficiencies and proposals for therapeutic interventions to improve the subjects' alar dynamic aesthetic were performed by three senior plastic surgeons through visualization of the resting and smiling images. The surgeons were asked to divide and classify the subjects into three groups (Class I, Class II and Class III) according to the surgeons' perceptions of degree of the subjects' deficiencies in alar dynamic aesthetic. The more deficiency there was in the aesthetic, the higher the class that the subject was assigned into. The surgeons were presented with the full set of images of the patients on two separate occasions each three months apart, to assess interobserver reliability. Clustering analysis, which is based on machine learning, was applied for objective classification of the images.

RESULTS

According to the senior plastic surgeon experts' subjective classification, the subjects' alar flaring mobility was judged as follows: Class I (6.78 ± 3.84%), Class II (10.35 ± 4.18%), and Class III (18.68 ± 4.15%), while alar base mobility was judged as Class I (12.71 ± 7.57%), Class II (20.06 ± 10.06%), and Class III (30.86 ± 13.20%). By clustering analysis, alar flaring mobility was determined to be Class I (7.01 ± 3.51%), Class II (11.18 ± 4.76%), and Class III (12.72 ± 5.66%), while alar base mobility was Class I (9.07 ± 4.23%), Class II (21.88 ± 4.25%), and Class III (38.59 ± 7.08%). No statistical significance was found in the distribution and assignment of classes between the two methodologies.

CONCLUSION

Classifications of alar dynamic aesthetics could arouse attention to facial dynamic aesthetics and provide referenced quantitative parameters for plastic surgeons to determine appropriate treatments for alarplasty. For patients with Class I mobility, treatments are not recommended, while minimally invasive treatments can be deemed to be optional for patients with Class II alar mobility to potentially improve alar dynamic aesthetics. For patients with Class III alar mobility, surgical treatments are strongly recommended as options. Combing subjective classification with automated algorithms can provide a novel perspective and improve reliability for facial aesthetic classification analysis.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. 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 .

Novel Anatomical Guidelines on Botulinum Neurotoxin Injection for Wrinkles in the Nose Region

Botulinum neurotoxin injection surrounding the nose area is frequently used in aesthetic settings. However, there is a shortage of thorough anatomical understanding that makes it difficult to treat wrinkles in the nose area. In this study, the anatomical aspects concerning the injection of botulinum neurotoxin into the nasalis, procerus, and levator labii superioris alaeque muscles are assessed. In addition, the present knowledge on localizing the botulinum neurotoxin injection point from a newer anatomy study is assessed. It was observed that, for the line-associated muscles in the nose region, the injection point may be more precisely defined. The optimal injection sites are the nasalis, procerus, and levator labii superioris alaeque muscles, and the injection technique is advised. We advise the best possible injection sites in association with anatomical standards for commonly injected muscles to increase efficiency in the nose region by removing the wrinkles. Similarly, these suggestions support a more precise procedure.

A Single-Blinded Prospective Study on Using Botulinum Toxin Type A for Reducing Alar Mobility

BACKGROUND

With widespread utilization of instant social media, people desire a minimally invasive treatment to improve alar dynamic aesthetic, but few practical procedures on reducing alar mobility have been conducted.

OBJECTIVES

This study aimed to verify the effects of botulinum toxin on reducing nasal alar mobility and provide a supplemental treatment of rhinoplasty.

METHODS

This single-blind prospective study included a cohort of 20 participants with the desire to improve their alar dynamic aesthetic. The experimental group was injected with 3U botulinum toxin type A at dilator naris anterior, dilator naris vestibularis, levator labii superioris alaeque nasi, and dilator naris, and the control group received the equivalent of saline. Standardized facial movement (from rest to maximum smile without revealing teeth) was recorded with a 3-dimensional imaging system. The changes between rest and maximum smile statuses represented alar mobility and were generated by MOBILITY=WIDTHsmile-WIDTHrestWIDTHrest×100 % . Alar mobility and root mean square analysis were employed for postoperative evaluations.

RESULTS

In the experimental group, alar flaring mobility decreased from 10.05% ± 6.40% to 4.91% ± 3.48%(P < 0.05), and alar base mobility decreased from 16.83% ± 5.69% to 12.50% ± 4.89% (P < 0.05), whereas no significant changes in alar mobility were found in the control group. In root mean square analysis, changes in the experimental group were significantly higher than in the control group (P < 0.05).

CONCLUSIONS

Botulinum toxin type A can effectively restrain alar mobility without any significant adverse events and improve alar dynamic esthetic, which can serve as a minimally invasive method or supplemental treatment for rhinoplasty.

LEVEL OF EVIDENCE: 2

A Novel Study on Alar Mobility of HAN Female by 3dMD Dynamic Surface Imaging System

AIM

The aim of this study is to conduct a quantitative analysis on alar mobility of HAN females and provided referenced materials for alar dynamic aesthetic.

METHODS

One hundred and fifty healthy HAN females without rhinoplasty, nasal injury, nasal deformity and craniofacial deformity were included in this study. 3dMD surface imaging system was used for anthropometric analysis. All participants were instructed to perform the desired dynamic facial expression from rest to maximum smile without reveling teeth and recorded by 3dMD dynamic surface imaging system simultaneously. Two frames of rest status and alar maximum enlargement were selected for measuring alar width, alar base width and inner-canthal distance. The difference between two status represented alar mobility, which was generated through equation: [Formula: see text].

RESULTS

Alar mobility consisted of alar flaring mobility and alar base mobility. The alar flaring mobility was (9.49 ± 4.90)%, reference range was(1.45, 17.53)% and regression equation between rest and maximum smile was Y = 7.953 + 0.886X (R² = 0.641, p = 0.000); the alar base mobility was (17.94 ± 10.44)%, reference range was (0.88, 35.00)% and regression equation between rest and maximum smile was Y = 4.481 + 0.966X (R² = 0.528, p = 0.000.

CONCLUSION

Asian alar anatomy has great distinction from Caucasian, processing conspicuous alar movement and damaging alar aesthetic dynamically. This study novelly defined alar mobility by three-dimensional anthropometric analysis, providing objective references for alar dynamic aesthetic and arousing plastic surgeons' attention on keeping balance of static and dynamic aesthetic in rhinoplasty.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. 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 .

Intrasubunit V-Y Muscle Sling Myocutaneous Island Advancement Flap for Small Defects Isolated to the Nasal Ala

BACKGROUND

The V-Y island advancement flap is a useful reconstruction technique for nasal alar defects, but flap mobility is limited by the insertion of the muscles of facial expression into the dermis of the alae.

OBJECTIVE

To describe a V-Y muscle sling myocutaneous island advancement flap (SMIAF) for improved mobility and intrasubunit reconstruction of alar defects.

MATERIALS AND METHODS

A retrospective review of patient records and preoperative and postoperative photographs was performed on all patients with alar defects repaired with the SMIAF between April 2008 and October 2017. Patients and physicians rated aesthetic outcomes with the Patient and Observer Scar Assessment Scale (POSAS).

RESULTS

A total of 18 nasal alar defects were repaired with the SMIAF after Mohs micrographic surgery. All defects were located on the anterior two-thirds of the alar lobule and had a mean surface area of 0.42 ± 0.19 cm. No patients experienced flap necrosis. Patients and 3 independent dermatologic surgeons rated favorable aesthetic outcomes.

CONCLUSION

The SMIAF is a reliable reconstruction option with good aesthetic outcomes for small defects on the anterior two-thirds of the nasal ala.

Managing Alar Flare in Rhinoplasty

Alar flare is a common feature that contributes to the width of the lower third of the nose. In the right patient, alar flare reduction can improve nasal harmony and facial aesthetic balance; however, it is also difficult to correct if conducted inappropriately or overzealously. The unique anatomy and diverse morphologies of the alar lobule, and the dynamic relationship between flare and changes in tip projection, must be considered. The authors provide guidelines for flare reduction: when it is appropriate and how to tailor the excision pattern to safely and effectively refine nasal width. Alar flare is classified into three types according to alar rim shape on basal view analysis. By designing the excision pattern based on specific flare type, the lower third of the nose is narrowed without creating an operated appearance.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

Quantitative anatomical analysis of facial expression using a 3D motion capture system: Application to cosmetic surgery and facial recognition technology

The topography of the facial muscles differs between males and females and among individuals of the same gender. To explain the unique expressions that people can make, it is important to define the shapes of the muscle, their associations with the skin, and their relative functions. Three-dimensional (3D) motion-capture analysis, often used to study facial expression, was used in this study to identify characteristic skin movements in males and females when they made six representative basic expressions. The movements of 44 reflective markers (RMs) positioned on anatomical landmarks were measured. Their mean displacement was large in males [ranging from 14.31 mm (fear) to 41.15 mm (anger)], and 3.35-4.76 mm smaller in females [ranging from 9.55 mm (fear) to 37.80 mm (anger)]. The percentages of RMs involved in the ten highest mean maximum displacement values in making at least one expression were 47.6% in males and 61.9% in females. The movements of the RMs were larger in males than females but were more limited. Expanding our understanding of facial expression requires morphological studies of facial muscles and studies of related complex functionality. Conducting these together with quantitative analyses, as in the present study, will yield data valuable for medicine, dentistry, and engineering, for example, for surgical operations on facial regions, software for predicting changes in facial features and expressions after corrective surgery, and the development of face-mimicking robots.

The facial motor system

Facial movements support a variety of functions in human behavior. They participate in automatic somatic and visceral motor programs, they are essential in producing communicative displays of affective states and they are also subject to voluntary control. The multiplicity of functions of facial muscles, compared to limb muscles, is reflected in the heterogeneity of their anatomical and histological characteristics that goes well beyond the conventional classification in single facial muscles. Such parcellation in different functional muscular units is maintained throughout the central representation of facial movements from the brainstem up to the neocortex. Facial movements peculiarly lack a conventional proprioceptive feedback system, which is only in part vicariated by cutaneous or auditory afferents. Facial motor activity is the main marker of endogenous affective states and of the affective valence of external stimuli. At the cortical level, a complex network of specialized motor areas supports voluntary facial movements and, differently from upper limb movements, in such network there does not seem to be a prime actor in the primary motor cortex.

The lower nasal base: an anatomical study

Currently, most rhinoplasty surgeons focus their analysis and operative techniques on the upper nasal base, with its alar cartilages. They tend to minimize the lower nasal base, composed of the columellar base, nostril sills, and alar lobules. The requisite operative techniques are often considered ancillary techniques. In this article, the authors describe anatomical composition of the columellar base, nostril sill, and alar lobule; discuss the presence of a distinct lower nasal base; and reevaluate the nasal musculature and the nasal superficial muscular aponeurotic system in an anatomical cadaver model. They also discuss the results of both a detailed literature review (for articles related to the levator labii superioris alaeque nasalis, orbicularis oris, depressor septi nasalis, myrtiformis, and dilator naris) and the results of their own dissection of 45 fresh cadavers.