Caudal nasal deviation

Caudal nasal deviation, manifested by a "crooked tip," asymmetric nostrils, and a deviated columella, is one of the most challenging deformities encountered in rhinoplasty. This entity is often ignored by rhinoplasty surgeons, on the basis of the assumption that correction of other segments of the deviated nose will improve the caudal nose. Failure to correct this imperfection (or, occasionally, deformity) invariably produces suboptimal results. The nasal structures involved in caudal nasal deviation, namely, the septum, the lower lateral cartilages, and the anterior nasal spine, must be evaluated for identification of the anatomical blocks that have a causative role in caudal nasal deviation. The specific structures with abnormalities related to this deformity are discussed, as are techniques for the correction of the deformities. These techniques significantly augment the surgeon's repertoire of methods for addressing the subtleties of caudal nasal deviation correction and achieving predictable results.     

Atrophic rhinitis: a CFD study of air conditioning in the nasal cavity.

Atrophic rhinitis is a chronic disease of the nasal mucosa. The disease is characterized by abnormally wide nasal cavities, and its main symptoms are dryness, crusting, atrophy, fetor, and a paradoxical sensation of nasal congestion. The etiology of the disease remains unknown. Here, we propose that excessive evaporation of the mucous layer is the basis for the relentless nature of this disease. Airflow and water and heat transport were simulated using computational fluid dynamics (CFD) techniques. The nasal geometry of an atrophic rhinitis patient was acquired from computed tomography scans before and after a procedure to narrow the nasal cavity. Simulations of air conditioning in the atrophic nose were compared with similar computations performed within the nasal geometries of four healthy humans. The excessively wide cavity of the patient generated abnormal flow patterns, which led to abnormal patterns of water fluxes across the wall. Geometrically, the atrophic nose had a much lower surface area than the healthy nasal passages, which increased water fluxes per unit area. Nevertheless, the simulations indicated that the atrophic nose did not condition inspired air as effectively as the healthy geometries. These simulations of water transport in the nasal cavity are consistent with the hypothesis that excessive evaporation of mucus plays a key role in the pathophysiology of atrophic rhinitis. We conclude that the main goals of a surgery to treat atrophic rhinitis should be 1) to restore the original surface area of the nose, 2) to restore the physiological airflow distribution, and 3) to create symmetric cavities.     

Numerical modeling of turbulent and laminar airflow and odorant transport during sniffing in the human and rat nose

Human sniffing behavior usually involves bouts of short, high flow rate inhalation (>300 ml/s through each nostril) with mostly turbulent airflow. This has often been characterized as a factor enabling higher amounts of odorant to deposit onto olfactory mucosa than for laminar airflow and thereby aid in olfactory detection. Using computational fluid dynamics human nasal cavity models, however, we found essentially no difference in predicted olfactory odorant flux (g/cm2 s) for turbulent versus laminar flow for total nasal flow rates between 300 and 1000 ml/s and for odorants of quite different mucosal solubility. This lack of difference was shown to be due to the much higher resistance to lateral odorant mass transport in the mucosal nasal airway wall than in the air phase. The simulation also revealed that the increase in airflow rate during sniffing can increase odorant uptake flux to the nasal/olfactory mucosa but lower the cumulative total uptake in the olfactory region when the inspired air/odorant volume was held fixed, which is consistent with the observation that sniff duration may be more important than sniff strength for optimizing olfactory detection. In contrast, in rats, sniffing involves high-frequency bouts of both inhalation and exhalation with laminar airflow. In rat nose odorant uptake simulations, it was observed that odorant deposition was highly dependent on solubility and correlated with the locations of different types of receptors.     

Physical stresses at the air-wall interface of the human nasal cavity during breathing.

The nose is the front line defender of the respiratory system and is rich with mechanoreceptors, thermoreceptors, and nerve endings. A time-dependent computational model of transport through nasal models of a healthy human has been used to analyze the fields of physical stresses that may develop at the air-wall interface of the nasal mucosa. Simulations during quiet breathing revealed wall shear stresses as high as 0.3 Pa in the noselike model and 1.5 Pa in the anatomical model. These values are of the same order of those known to exist in uniform large arteries. The distribution of temperature near the nasal wall at peak inspiration is similar to that of wall shear stresses. The lowest temperatures occur in the vicinity of high stresses due to the narrow passageway in these locations. Time and spatial gradients of these stresses may have functional effects on nasal sensation of airflow and may play a role in the well-being of nasal breathing.     

Comparison between effects of various partial inferior turbinectomy options on nasal airflow: a computer simulation study

Partial inferior turbinectomy is typically performed on patients suffering from chronic nasal obstruction due to hypertrophy of inferior turbinates and is refractory to other more conservative treatments. The effects of the various options of incision performed on the inferior turbinate in terms of the resulting nasal airflow pattern are examined using computational fluid mechanics. The pressure drops across the severely blocked nose and healthy nose models were found to be 32.3 and 12.3 Pa, respectively, whereas the pressure drops across the nasal cavity following one-third turbinate resection, total turbinate resection and front-end resection were obtained as 5.8, 6.1 and 30.5 Pa correspondingly. Based on the total pressure drop results, the one-third resection option seems to be better than the front-end surgery and the total turbinate resection.     

The soft triangle revisited

Five cadaveric adult human noses were examined to further elucidate the region of the soft triangle of the nose. Three distinct zones were found. Zone 1, just caudad to the lower lateral cartilages, consists of the fibers of the dilator nares anterior as it inserts into the dermis. Zone 2 is the dermal layer. Zone 3 is at the nostril rim and consists of muscle fibers interdigitating within the dermis; laterally, these fibers are continuations of the nasalis muscle, whereas medially they are extensions of the depressor septii muscle. Perpendicular incisions through any of these zones may cause notching and tip deformity. Incisions in zone 1 may, in addition, alter external nasal valve function by interrupting the fibers of the dilator naris anterior.     

Numerical Simulation of Airflow Fields in Two Typical Nasal Structures of Empty Nose Syndrome: A Computational Fluid Dynamics Study

Background

The pathogenesis of empty nose syndrome (ENS) has not been elucidated so far. Though postulated, there remains a lack of experimental evidence about the roles of nasal aerodynamics on the development of ENS.

Objective

To investigate the nasal aerodynamic features of ENS andto explore the role of aerodynamic changes on the pathogenesis of ENS.

Methods

Seven sinonasal models were numerically constructed, based on the high resolution computed tomography images of seven healthy male adults. Bilateral radical inferior/middle turbinectomy were numerically performed to mimic the typical nasal structures of ENS-inferior turbinate (ENS-IT) and ENS-middle turbinate (ENS-MT). A steady laminar model was applied in calculation. Velocity, pressure, streamlines, air flux and wall shear stress were numerically investigated. Each parameter of normal structures was compared with those of the corresponding pathological models of ENS-IT and ENS-MT, respectively.

Results

ENS-MT: Streamlines, air flux distribution, and wall shear stress distribution were generally similar to those of the normal structures; nasal resistances decreased. Velocities decreased locally, while increased around the sphenopalatine ganglion by 0.20±0.17m/s and 0.22±0.10m/s during inspiration and expiration, respectively. ENS-IT: Streamlines were less organized with new vortexes shown near the bottom wall. The airflow rates passing through the nasal olfactory area decreased by 26.27%±8.68% and 13.18%±7.59% during inspiration and expiration, respectively. Wall shear stresses, nasal resistances and local velocities all decreased.

Conclusion

Our CFD simulation study suggests that the changes in nasal aerodynamics may play an essential role in the pathogenesis of ENS. An increased velocity around the sphenopalatine ganglion in the ENS-MT models could be responsible for headache in patients with ENS-MT. However, these results need to be validated in further studies with a larger sample size and more complicated calculating models.     

Changing the convexity and concavity of nasal cartilages and cartilage grafts with horizontal mattress sutures: part II. Clinical results

Horizontal mattress sutures have previously been shown to remove unwanted bulbosity and convexity of nasal tip cartilages. The purpose of this study was to extend that concept by investigating the universal applicability of the horizontal mattress suture to change and control the curvature (e.g., convexity or concavity) of a wide variety of nasal cartilages and warped cartilage grafts. The horizontal mattress suture was applied to a variety of clinical situations, including nasal tip bulbosity caused by convex lateral crura, collapsed external nasal valves, warped grafts and struts, crooked L-shaped septal struts, and collapsed internal nasal valves. Twenty-nine cases were studied over a period of 10 to 23 months. The horizontal mattress suture proved to be a simple, effective means of achieving satisfactory control of the curvature of various cartilages of the nose (including external valves, internal valves, and septum) and warped cartilage grafts. Curvature control was obtained in all cases where the cartilage was supple. Moreover, the resultant strength was increased above normal. Partial recurrence of the curvature was seen in only two cases. Clinical results indicated that the horizontal mattress suture is universally applicable to a variety of situations in which the curvature of nasal cartilage and cartilage grafts needs to be removed or modified. The mattress suture drastically reduces the need for scoring (with its inherent problems of weakness) and the need for cartilage grafting.     

Changes in nasal airflow and heat transfer correlate with symptom improvement after surgery for nasal obstruction

Surgeries to correct nasal airway obstruction (NAO) often have less than desirable outcomes, partly due to the absence of an objective tool to select the most appropriate surgical approach for each patient. Computational fluid dynamics (CFD) models can be used to investigate nasal airflow, but variables need to be identified that can detect surgical changes and correlate with patient symptoms. CFD models were constructed from pre- and post-surgery computed tomography scans for 10 NAO patients showing no evidence of nasal cycling. Steady-state inspiratory airflow, nasal resistance, wall shear stress, and heat flux were computed for the main nasal cavity from nostrils to posterior nasal septum both bilaterally and unilaterally. Paired t-tests indicated that all CFD variables were significantly changed by surgery when calculated on the most obstructed side, and that airflow, nasal resistance, and heat flux were significantly changed bilaterally as well. Moderate linear correlations with patient-reported symptoms were found for airflow, heat flux, unilateral allocation of airflow, and unilateral nasal resistance as a fraction of bilateral nasal resistance when calculated on the most obstructed nasal side, suggesting that these variables may be useful for evaluating the efficacy of nasal surgery objectively. Similarity in the strengths of these correlations suggests that patient-reported symptoms may represent a constellation of effects and that these variables should be tracked concurrently during future virtual surgery planning.     

Surgical correction of the severely deviated nose by extramucosal excision of the osseocartilaginous septum and replacement as a free graft

Twenty-five patients with severe internal and external deviation of the nose characterized by deviation of the septum in several planes and almost total obstruction of the airway on one or both sides were operated on. The entire bony and cartilaginous septum was removed in each of these patients, preserving the mucoperichondrial and mucoperiosteal flaps. The extramucosal technique of septal dissection was used. A support graft was fashioned from cartilaginous remnants of the septal cartilage and placed between the mucoperichondrial flaps as a free graft. All patients were followed for a minimum of 1 year. The longest follow-up is 15 years. Aesthetic improvement of the nose was obtained in all patients. All patients experienced varying degrees of improvement in nasal blockade.     

Effect of anatomy on human nasal air flow and odorant transport patterns: implications for olfaction

Recent studies that have compared CT or MRI images of an individual's nasal anatomy and measures of their olfactory sensitivity have found a correlation between specific anatomical areas and performance on olfactory assessments. Using computational fluid dynamics (CFD) techniques, we have developed a method to quickly (相似文献   

Valvular obstruction of the nasal airway.

Valvular nasal obstruction may occur in the postoperative rhinoplasty patient. One may anticipate a dropping of the tip, from residual redundant or inelastic skin, in some older patients with long noses. Measures to correct (or avoid) this may be undertaken at the time of the primary rhinoplasty. However, an overcorrection may be necessary if there is much redundant skin. Discretion may indicate the need for a secondary procedure. Lateral wall valving is unusual-but it may occur in the long, high, thin nose (where a suggestion of this action may be observed preoperatively). Maintenance of continuous cartilage along the alar rim, at the time of alar cartilage resection, appears to be important in prevention of postoperative valvular obstruction in these few patients.     

The Comparison of Fluid Dynamics Parameters in an Andersen Cascade Impactor Equipped With and Without a Preseparator

The fluid dynamic data in Andersen cascade impactor (ACI) are still lacking. Airflows and those affected parameters can be predicted in a preseparator and Andersen cascade impactor (ACI) by computational modeling. This study developed a validated computational fluid dynamic (CFD) model of an ACI and investigated the effects of the preseparator on the CFD parameters. Validation of the computational nozzle velocity for each of the stage 0 to stage 5 of the ACI stages was found to be within a 3.56% error. The flow field indicated that the preseparator accelerated the airflow velocity at the induction tube from 1.13 to 3.71 ± 0.09 m/s and 2.40 to 8.68 ± 0.16 m/s (at 28.3 and 60 L/min of flow rate, respectively). The preseparator produced a nozzle''s wall shear stress ranged from 0.08 to 0.34 Pa on a collection plate, while the ex-preseparator spread wall shear from the plate''s center was in a range of 0.11 to 0.37 Pa (at 28.3 L/min of flow rate). Moreover, the nozzle velocities increased along the distance from the middle of the collection plate to the periphery. The CFD explained the airflow of the preseparator equipped model by accelerating the airflow along the inlet port to maximize the trapping of desirable particles and the generation of a smooth wall shear stress at the collection plate to reduce the particle re-entrainment. While, the ex-preseparator generated an airflow that resulted in a higher wall shear stress occurring on the lower stages.Key words: ACI, flow field, preseparator, wall shear stress     

Rhinoplasty: a CT-scan analysis

In order to assess the postoperative consequences of various rhinoplasty techniques, CT scans were done in 35 patients having a rhinoplasty operation. This series can be subdivided into those having preoperative and postoperative scans at both 2 days and 6 months (15 patients), a postoperative scan only at 48 hours (10), or a long-term postoperative scan at a mean of 12 months (10). Preoperative analysis indicates that a wide variation exists in lateral nasal wall anatomy and angulation. Surgically, the lateral nasal walls undergo limited medial movement, with tilt a significant component. Postoperatively, extensive remodeling can occur, and virtually all osteotomies are healed by osseous union at 6 months. Future application of CT scans in severely deviated noses may be justified.     

The temporal relationship between the neural and vascular actions of kallidin within the nose

The time course of effect of the B(2)-receptor agonist kallidin (K) on induced changes of nasal airflow, rhinorrhoea, nasal pain, sneezing and nasal microvascular leakage has been examined and compared with its B(2) metabolite agonist bradykinin (B) and the B(1)-agonist [des-arg(9)]-bradykinin (D). When administered as a single dose K and B induced an immediate sensation of pain, rhinorrhoea, elevations in lavage albumin and protein levels and a sustained increase in nasal airways resistance (NAR) for 5-40 min post-challenge. [des-arg(9)]-Bradykinin and vehicle placebo (V) were without effect on any of these indices. These studies identify the action of K and B within the nose and differentiate the neural and vascular effects of these kinins in addition to suggesting the potential that nasal blockage and nasal microvascular leakage represent alterations in differing vascular compartments. These findings have implications for the understanding and therapeutic manipulation of rhinitis.     

Laminar airflow and nanoparticle or vapor deposition in a human nasal cavity model

The transport and deposition of nanoparticles, i.e., dp = 1-2 nm, or equivalent vapors, in the human nasal cavities is of interest to engineers, scientists, air-pollution regulators, and healthcare officials alike. Tiny ultrafine particles, i.e., dp < or = 5 nm, are of special interest because they are most rapidly absorbed and hence have an elevated toxic or therapeutic impact when compared to larger particles. Assuming transient laminar 3-D incompressible flow in a representative human nasal cavity, the cyclic airflow pattern as well as local and overall nanoparticle depositions were computationally simulated and analyzed. The focus was on transient effects during inhalation/exhalation as compared to the steady-state assumption typically invoked. Then, an equation for a matching steady-state inhalation flow rate was developed that generates the same deposition results as cyclic inhalation. Of special interest is the olfactory region where the narrow channel surfaces receive only about one-half of a percent of the inhaled nanoparticles because the airflow bypasses these recesses located in the superior-most portions in the geometrically complex nasal cavities.     

Numerical Simulation of Airway Dimension Effects on Airflow Patterns and Odorant Deposition Patterns in the Rat Nasal Cavity

The sense of smell is largely dependent on the airflow and odorant transport in the nasal cavity, which in turn depends on the anatomical structure of the nose. In order to evaluate the effect of airway dimension on rat nasal airflow patterns and odorant deposition patterns, we constructed two 3-dimensional, anatomically accurate models of the left nasal cavity of a Sprague-Dawley rat: one was based on high-resolution MRI images with relatively narrow airways and the other was based on artificially-widening airways of the MRI images by referencing the section images with relatively wide airways. Airflow and odorant transport, in the two models, were determined using the method of computational fluid dynamics with finite volume method. The results demonstrated that an increase of 34 µm in nasal airway dimension significantly decreased the average velocity in the whole nasal cavity by about 10% and in the olfactory region by about 12% and increased the volumetric flow into the olfactory region by about 3%. Odorant deposition was affected to a larger extent, especially in the olfactory region, where the maximum odorant deposition difference reached one order of magnitude. The results suggest that a more accurate nasal cavity model is necessary in order to more precisely study the olfactory function of the nose when using the rat.     

鼻的活体测量与观察

本文对九江地区汉族成年男女,共计950例(男467例,女483例),进行鼻的活体测量与活体观察。结果表明:男、女不仅在鼻的形态上有明显差异,而且外鼻各径亦存在显著差异。本文还对这些差异进行了初步讨论,分析了该地区鼻型特点,并且与国外一些民族鼻型资料进行分析比较,初步确定本地区鼻型属于狭鼻型。     

Reciprocity Versus Rhythmicity in Spontaneous Alternations of Nasal Airflow

Active anterior rhinomanometry was used to observe nasal airflow in five men and four women (ages 18-30). Measurements were obtained for each nasal passage every 5 min throughout an uninterrupted 8-hr session. Facial skin temperature from the left and right side of the face was recorded simultaneously from thermocouples. Observations were made during the months of May and June; subjects were allowed to maintain their routine diurnally active schedules prior to observation. Airflow in the two passages showed a significant negative correlation (i.e. Was reciprocal) in 44% of subjects (N= 9). Autocorrelation and spectral analysis of the airflow data found evidence of periodicity in 39% of individual nostrils and 56% of subjects. Mean estimated period was 4.5 ± 1.0 hr (range 3.5-6.0 hr). Only 22% of subjects showed statistical evidence of periodicity in both nostrils (i.e. a “nasal cycle”). Left- and right-side facial skin temperatures changed in parallel rather than reciprocally, but showed evidence of periodicity in 50% of hemifacial time series (56% of subjects), with an estimated period of 3.8 ± 1.0 hr (range 2.3-5.0).     

Segmental analysis of nasal cavity compliance by acoustic rhinometry.

To explore the determinants of possible collapse of the nasal valve region, a common cause of nasal obstruction, we evaluated the mechanical properties of the nasal wall. In this study, we determined the nasal cross-sectional area-to-negative pressure ratio (nasal wall compliance) in the anterior part of the nose in six healthy subjects by measuring nasal area by acoustic rhinometry at pressures ranging from atmospheric pressure to a negative pressure of -10 cmH(2)O. Measurements were performed at baseline and after nasal mucosal decongestion (oxymetazoline). At baseline, nasal wall compliance increased progressively from the nasal valve (0.031 +/- 0.016 cm2/cmH(2)O, mean +/- SD) to the anterior and medial part of the inferior turbinate (0.045 +/- 0.024 cm2/cmH(2)O) and to the middle meatus region (0.056 +/- 0.029 cm2/cmH(2)O). After decongestant, compliances decreased and became similar in the three regions. On the basis of these results, we hypothesize that compliance of the nasal wall is partly related to mucosal blood volume and quantity of vascular tissue, which differ in the three regions, increasing from the nasal valve to the middle meatus.