Nasal Breathing Assessment Using Computational Fluid Dynamics: An Update from the Rhinologic Perspective.

An objective assessment of nasal breathing is currently insufficiently achievable. The application of computational fluid dynamics for this purpose is increasingly gaining attention. However, the suggested specific frameworks can differ considerably. To the best of our knowledge, there is not yet a widely accepted clinical usage of computational fluid dynamics. In this article, selected aspects are addressed that might be crucial for future development and possible implementation of computational fluid dynamics in rhinology.

[Fundamentals and practice of the application of nasal packing in sinonasal surgery]. / Grundlagen und Praxis der Anwendung von Nasentamponaden in der endonasalen Chirurgie.

BACKGROUND AND OBJECTIVES: This paper presents an overview on nasal packing materials which are available in Germany. The current literature is analyzed whether there are robust criteria regarding use nasal packing after sinonasal surgery, whether there are fundamental and proven advantages or disadvantages of products, and what this means in clinical practice. MATERIALS AND METHODS: Selective literature analysis using the PubMed database (key words "nasal packing", "nasal tamponade", "nasal surgery", "sinonasal surgery", or "sinus surgery"), corresponding text books and resulting secondary literature. RESULTS AND CONCLUSIONS: Because of systematic methodological shortcomings, the literature does not help in the decision-making about which nasal packing should be used after which kind of sinonasal surgery. In fact, individual approaches for the many different clinical scenarios are recommended. In principle, nasal packing aims in hemostasis, should promote wound healing, and should not result in secondary morbidity. Nasal packing materials should be smooth (non-absorbable materials), inert (absorbable materials), and should not exert excessive pressure. Using non-absorbable packing entails the risk of potentially lethal aspiration and ingestion. For safety reasons inpatient control is recommended as long as this packing is in situ. With other, uncritical packing materials and in patients with special conditions, outpatient control could be justified.

Partial Maxillectomy for the Improvement of Nasal Obstruction Can Be Combined with Septorhinoplasty.

We describe the (anteromedial) partial maxillectomy technique which can be used to address impaired nasal breathing in cases of significant protrusion of the frontal process of the maxilla into the nasal cavity, narrowing the nasal pathway. It fits to nasal physiology avoiding mucosal resection. It can be combined with surgery of the inferior turbinate. The described technique can be used in all forms of rhinoplasty.

Rhinosurgery during and after the COVID-19 Pandemic: International Consensus Conference Statement on Preliminary Perioperative Safety Measures.

BACKGROUND: The coronavirus disease of 2019 (COVID-19) pandemic has widely affected rhinosurgery, given the high risk of contagion and the elective nature of the aesthetic procedure, generating many questions on how to ensure safety. The Science and Research Committee of the Rhinoplasty Society of Europe aimed at preparing consensus recommendations on safe rhinosurgery in general during the COVID-19 pandemic by appointing an international panel of experts also including delegates of The Rhinoplasty Society. METHODS: A Zoom meeting was performed with a panel of 14 international leading experts in rhinosurgery. During 3.5 hours, four categories of questions on preoperative safety measures in private practice and outpatient clinics, patient assessment before and during surgery, and legal issues were presented by four chairs and discussed by the expert group. Afterward, the panelists were requested to express an online, electronic vote on each category and question. The panel's recommendations were based on current evidence and expert opinions. The resulting report was circulated in an iterative open e-mail process until consensus was obtained. RESULTS: Consensus was obtained in several important points on how to safely restart performing rhinosurgery in general. Preliminary recommendations with different levels of agreement were prepared and condensed in a bundle of safety measures. CONCLUSION: The implementation of the panel's recommendations may improve safety of rhinoplasty by avoiding operating on nondetected COVID-19 patients and minimizing severe acute respiratory syndrome coronavirus 2 virus spread in outpatient clinics and operating rooms.

Characterization of the Airflow within an Average Geometry of the Healthy Human Nasal Cavity.

This study's objective was the generation of a standardized geometry of the healthy nasal cavity. An average geometry of the healthy nasal cavity was generated using a statistical shape model based on 25 symptom-free subjects. Airflow within the average geometry and these geometries was calculated using fluid simulations. Integral measures of the nasal resistance, wall shear stresses (WSS) and velocities were calculated as well as cross-sectional areas (CSA). Furthermore, individual WSS and static pressure distributions were mapped onto the average geometry. The average geometry featured an overall more regular shape that resulted in less resistance, reduced WSS and velocities compared to the median of the 25 geometries. Spatial distributions of WSS and pressure of the average geometry agreed well compared to the average distributions of all individual geometries. The minimal CSA of the average geometry was larger than the median of all individual geometries (83.4 vs. 74.7 mm²). The airflow observed within the average geometry of the healthy nasal cavity did not equal the average airflow of the individual geometries. While differences observed for integral measures were notable, the calculated values for the average geometry lay within the distributions of the individual parameters. Spatially resolved parameters differed less prominently.

Digital Analysis of Nasal Airflow Facilitating Decision Support in Rhinosurgery.

Successful functional surgery on the nasal framework requires reliable and comprehensive diagnosis. In this regard, the authors introduce a new methodology: Digital Analysis of Nasal Airflow (diANA). It is based on computational fluid dynamics, a statistical shape model of the healthy nasal cavity and rhinologic expertise. diANA necessitates an anonymized tomographic dataset of the paranasal sinuses including the complete nasal cavity and, when available, clinical information. The principle of diANA is to compare the morphology and the respective airflow of an individual nose with those of a reference. This enables morphometric aberrations and consecutive flow field anomalies to localize and quantify within a patient's nasal cavity. Finally, an elaborated expert opinion with instructive visualizations is provided. Using diANA might support surgeons in decision-making, avoiding unnecessary surgery, gaining more precision, and target-orientation for indicated operations.

The Healthy Nasal Cavity-Characteristics of Morphology and Related Airflow Based on a Statistical Shape Model Viewed from a Surgeon's Perspective.

Functional surgery on the nasal framework requires referential criteria to objectively assess nasal breathing for indication and follow-up. This motivated us to generate a mean geometry of the nasal cavity based on a statistical shape model. In this study, the authors could demonstrate that the introduced nasal cavity's mean geometry features characteristics of the inner shape and airflow, which are commonly observed in symptom-free subjects. Therefore, the mean geometry might serve as a reference-like model when one considers qualitative aspects. However, to facilitate quantitative considerations and statistical inference, further research is necessary. Additionally, the authors were able to obtain details about the importance of the isthmus nasi and the inferior turbinate for the intranasal airstream.

Nasal Valve Lift in Nasal Valve Stenosis-A 2 Years Clinical Trial.

A clinical study was conducted to determine the effect of nasal valve lift treatment using absorbable, polylactic acid, self-retaining cone threads (Silhouette Soft) in patients with nasal valve stenosis. Sixty patients (n = 60) were included in this prospective study which was performed from January 2015 until December 2018, 19 patients dropped out due to noncompliance. Initially, participants were divided into two equal groups. One was treated by nasal valve lift only, the other additionally received turbinoplasty. A visual analog scale (VAS) was used to rate the sense of nasal ventilation. Patients' satisfaction was examined by a categorical scale, preoperatively, after 1 week, and after 1, 6, 12, 18, and 24 months. For statistical analysis, an univariant variance analysis was conducted to test the significance of differences in nasal breathing within one group at different points of postoperative controls, with the statistical significance set at p < 0.05. Moreover, the two groups were compared with each other regarding results of the categorical scale. After surgical treatment, an improvement is reported by all participants. Average VAS scores were significantly lower between preoperative and every postoperative rating. Although a decline in the effect of breathing improvement is recognizable as threads are dissolved, patients' satisfaction in improvement of nasal breathing is persistent in most cases, even at long-term observation. Overall, these results demonstrate that valve lift is an effective method to treat patients with nasal valve stenosis.

General Precautions and Safety Aspects of Facial Laser Treatment.

The current overview of laser radiation therapy options and the legal aspects of the head and neck region provides insight into the available laser hardware, discusses the indications and treatment options and risks, as well as the necessary precautions to be taken when operating a laser device. Further handling recommendations and requirements for the laser devices are drawn and the question of transferring tasks to nonmedical personnel is discussed. The reader should get an idea about the benefits and risks of using lasers in treating patients and be able to set the precise indication on the background of possibilities, adverse effects, and legal aspects.

Indications and Use of Isotretinoin in Facial Plastic Surgery.

Isotretinoin is a first generation retinoid with pleiotropic effects on keratinocyte differentiation, proliferation, and activity of sebaceous glands. For years, there has been intense debate on whether the use of isotretinoin combined with cosmetic or surgical procedures is safe and potentially more efficient than either therapy alone. Due to delays in wound healing and keloid formation, conservative recommendations were not to combine isotretinoin with any plastic surgery or local treatment at 6 to 12 months after discontinuation of the drug. However, there is increasing evidence that a combination approach is not only safe, but may also provide excellent cosmetic outcomes in acne scars, sebaceous gland hyperplasia, and thick-skinned patients undergoing facial plastic surgery. In particular, low-dose regimens of isotretinoin may offer advantages over standard dosage treatments because of better tolerability and safety in long-term use adjunct with surgical interventions. In this article, the authors aim to summarize the current evidence on the use of isotretinoin in facial plastic surgery and to share their experience from selected patients.

The Facial Profile in the Context of Facial Aesthetics.

Beauty has been an intriguing issue since the evolving of a culture in mankind. Even the Neanderthals are believed to have applied makeover to enhance facial structures and thus underline beauty. The determinants of beauty and aesthetics have been defined by artists and scientists alike. This article will give an overview of the evolvement of a beauty concept and the significance of the facial profile. It aims at sharpening the senses of the facial plastic surgeon for analyzing the patient's face, consulting the patient on feasible options, planning, and conducting surgery in the most individualized way.

The concept of rhinorespiratory homeostasis--a new approach to nasal breathing.

The suggested concept of rhinorespiratory homeostasis is a new theoretical model for the discussion of physiologic and physical principles of nasal breathing. This model is based on a comprehensive view of nasal functions that takes comparative animal physiology into account. Consequently, it has a universal cross-species character and emphasizes the central role of nasal secretion. In contrast to the established view, the focus is transferred from the inspired air to the nasal wall. This concept considers the parietal effect of airflow represented by wall shear stress with special regard to the epithelial lining fluid. It delivers one possible mechanism of an inherent triggering of the nasal cycle. Furthermore, the issue of biological fluid-structure interaction is introduced. This article presents a rethinking of nasal breathing that was inspired by clinical experience and results of flow field investigations through computational fluid dynamics.

Evaluation of the intranasal flow field through computational fluid dynamics.

A reliable and comprehensive assessment of nasal breathing is problematic and still a common issue in rhinosurgery. Impairments of nasal breathing need an objective approach. In this regard, currently rhinomanometry is the only standard diagnostic tool available but has various limitations. However, in the last decade, computational fluid dynamics (CFD) has become a promising method in facing the challenge of qualifying nasal breathing. This article presents use of CFD with a symptom-free subject and a symptomatic patient. Thereby, certain flow field features and changes before and after surgery were investigated. Moreover, the study outlines suggestions for concrete rhinologic CFD applications.

An interactive three-dimensional nose model for rhinosurgery.

The motivation behind the development of a new interactive three-dimensional (3D) model of the cartilaginous and bony framework of the nose originated from the significant demand for sophisticated patient communication and for accurate documentation of the surgical steps in rhinoplasty. Basically, the model consists of three features--the viewer function, the freehand function, and default applications--enabling the surgeon to replicate fundamental compilations of findings and to graphically document operative measures easily. The user is able to save all graphics in two-dimensional format and allocate them to patient files. Because the application was designed to be sufficiently universal without being too complex, the 3D model provides a well-balanced mix between freehand and default functions, representing the consistent development of currently available tools.