|Year : 2021 | Volume
| Issue : 1 | Page : 30-34
Characterization of Mexican pediatric nostril sill: Classification and topographic findings
Rodrigo Davila-Diaz1, Daniel De-Luna-Gallardo2, Tatiana Izchel Castillo-Torres3, Patricia Elizabeth Arguelles-Lopez4, Christian Morales-Orozco5
1 Pediatric Plastic and Reconstructive Surgeon. Hospital Central Sur de Alta Especialidad Pemex, Mexico City, , Mexico
2 Plastic and Reconstructive Surgery Resident. Hospital Central Sur de Alta Especialidad Pemex, Mexico City, Mexico
3 PhD in Medical Sciences. Orthodontist in Fernando Ortíz Monasterios Foundation, Mexico City, Mexico
4 Plastic and Reconstructive Surgeon, Mexico City, Mexico
5 Craniofacial Plastic and Reconstructive Surgeon. Hospital Angeles Lomas, Mexico City, Mexico
|Date of Submission||14-Oct-2020|
|Date of Acceptance||13-Nov-2020|
|Date of Web Publication||13-Jan-2021|
Source of Support: None, Conflict of Interest: None
Introduction: The nostril sill is defined as the “facial subunit composed of fibro-adipose soft tissue whose topographic delimitation is given by four anatomical limits: the medial crura of the columella on its medial limit, the nasal wing on its lateral limit, the nasal vestibule in its upper limit, and the upper lip on the lower limit.” It represents an essential element in the appearance, balance, and function of the nose. The study and classification of the nostril sill in the healthy Mexican pediatric population are the necessary tools for facial reconstruction since it is generally affected in patients with cleft lip and palate and craniofacial malformations. Objective: The objective of the study is to describe the nostril sill in the Mexican pediatric population using standardized photographs taken in frontal and basal projections and classifying according to Oh et al. and to study if there is a significant relationship between nostril sill with age and gender. Materials and Methods: An observational cross-sectional study was carried out in a sample size of 83 healthy children aged between 3 and 12 years, simple randomly chosen. The classification was performed with facial photographs in frontal and basal projections. The data analysis was performed with descriptive statistics, kappa concordance coefficient was used between observers, and bivariate analysis was used to evaluate the association of the nostril sill classification with age and gender. Results: Of the 83 volunteers, 51.8% (n = 43) were female and 48.2% (n = 40) male, with a mean age of 7.38 years. The 74.6% (n = 62) were classified as a nostril sill Type I, 14.4% (n = 12) as Type III, and 10.8% (n = 9) as Type II, with a Cohen's kappa coefficient between observers of 0.92 (almost perfect agreement). In the bivariate analysis with Chi-square test, no statistically significant association was found between age (P = 0.420) and sex (P = 0.524). Conclusion: The nostril sill of the nostril represents a fundamental nasal subunit that every reconstructive surgeon must recognize and locate. It is crucial to describe and classify the nostril sill according to ethnic and racial characteristics, in the Mexican pediatric population, the most frequent corresponds to Type I, followed by Type III and finally the least frequent Type II, and that gender and age are not associated with a specific type.
Keywords: Cleft, lip, Mexico, nostril, palate, sill
|How to cite this article:|
Davila-Diaz R, De-Luna-Gallardo D, Castillo-Torres TI, Arguelles-Lopez PE, Morales-Orozco C. Characterization of Mexican pediatric nostril sill: Classification and topographic findings. J Cleft Lip Palate Craniofac Anomal 2021;8:30-4
|How to cite this URL:|
Davila-Diaz R, De-Luna-Gallardo D, Castillo-Torres TI, Arguelles-Lopez PE, Morales-Orozco C. Characterization of Mexican pediatric nostril sill: Classification and topographic findings. J Cleft Lip Palate Craniofac Anomal [serial online] 2021 [cited 2021 Mar 1];8:30-4. Available from: https://www.jclpca.org/text.asp?2021/8/1/30/306776
| Introduction|| |
The nostril sill has been an anatomical structure poorly described in the literature compared to other mid-face structures and even forgotten in plastic and reconstructive surgery books.,,,, Although the term nostril sill is sometimes used erroneously or confusingly, it is defined grammatically as the “structure at the foot of an opening.” However, its use in medical terminology has been described in various contexts, such as: “the protrusion of the nasal floor,” “the floor of the entrance to the nasal vestibule,” “the prominent soft tissue between the upper lip and the nasal base,” and “anatomical structure of the perimeter of the nostril,” among others.,,,
These definitions provide a general idea; however, we agree with the one proposed by Irwin and Milling as the “facial subunit composed of fibro-adipose soft tissue whose topographic delimitation is given by four anatomical limits: the medial crura of the columella on its medial limit, the nasal wing on its lateral limit, the nasal vestibule in its upper limit, and the upper lip on the lower limit” [Figure 1]. For this reason, the nostril sill is a part of the base of the nose, and its presence and recognition represent a key point in the appearance and anatomical balance that any reconstruction must take into account.
In 1956, the facial esthetic units were described by Gonzalez–Ulloa, and later, in 1985, the nasal esthetic subunits were described by Burget and Menick. Since then, multiple anthropometric studies have been carried out to define the anatomical characteristics of the nose and its subunits, in which the nostril sill plays a minor role.,, A watershed in recognition of this structure was published by Oh et al., where they classified the nostril sill for the first time into three categories: Type I or full nostril sill (protruding soft tissue between the columella and the wing with protruding muscle fibers below the sill), Type II or point nostril sill (the base of the columella and the wing converge at an apex), and Type III or flat nostril sill (the upper lip slides into the nasal vestibule). Histologically, in Types II and III, no thickening of soft tissue or muscle below the nostril sill was found.
Descriptive demographic studies of the sill represent a fundamental element for reconstructive surgery, especially for specialized areas of the cleft lip and palate and craniofacial malformations. However, regarding nostril sill, there are no studies in the Mexican pediatric population that establish the bases, objectives, and parameters that reconstruction should pursue.
The objective of the present study is to describe the nostril sill in the Mexican pediatric population using standardized photographs taken in frontal and basal projections and classifying according to Oh et al. and to study if there is a significant relationship between nostril sill with age and gender.
| Materials and Methods|| |
An observational, cross-sectional study was carried out in 83 healthy Mexican pediatric volunteers, randomly chosen from three schools in Mexico City. The parents of the volunteers signed informed consent to participate in the study.
To document and standardize the anthropometry, facial photographs (166 nostrils) were taken in frontal and basal projections [Figure 2]. For the frontal view, the interpupillary line was kept in a horizontal plane with alignment of the head with the Frankfort horizontal plane. For the basal view, the submental vertical projection was used, where the nasal tip was aligned with the glabella. All photographs were taken in standard fashion with a Nikon d7100 18–140 mm AF lens camera. The lighting was done through two electronic lights with softboxes. The nostril sill was delimited according to the recommendations of Irwin and Milling.
|Figure 2: Frontal (above) and basal (below) projections. (a) Type I (full nostril sill), (b) Type II (point nostril sill), (c) Type III (flat nostril sill)|
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The inclusion criteria were Mexican children, aged between 3 and 12 years, with no hereditary family history of congenital craniofacial malformations associated with nasal deformity and no history of centrofacial surgery or trauma.
To improve the concordance of the study, the valuation of each nostril sill was performed comparatively and blinded by two plastic surgeons, with a subspecialty in pediatric plastic surgery (Dávila MD) and craniofacial surgery (Morales MD). Using Oh et al. classification, a characterization was first made between interindividual nostril sill, and finally, a categorization by types was made. The observers were standardized by blindly classifying the photographic projection, with no further training than a review of publications by Irwin and Milling and Oh et al.
| Results|| |
The frontal and basal projection photographs of 83 volunteers were analyzed, of which 51.8% (n = 43) were female and 48.2% (n = 40) were male. The mean age was 7.38 years, with a variance of 5.45 years. The age distribution of ours was according to the Kolmogorov–Smirnov and Shapiro–Wilk normality tests [Table 1].
All the volunteers (n = 83 [100%]) showed symmetry in both nostrils regarding the type of nostril sill. Cohen's kappa coefficient between observers was 0.92 (almost perfect agreement).
From our study population, 74.6% (n = 62) were classified as a nostril sill Type I, 14.4% (n = 12) as Type III, and 10.8% (n = 9) as Type II. The relation between nostril sill with the age and gender is presented in [Table 2].
|Table 2: In a total of 83 subjects, the conformation of the nostril sill was analyzed|
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To assess whether the type of nostril sill is associated with age, a bivariate analysis was performed using a contingency table (cross-tabulation or crosstab). Our population was stratified by age groups (according to growth peaks) into three groups: Category A: 3–5 years; Category B: 6–8 years; and Category C: 9–12 years. A Chi-square test was performed to determine if there is an association between age groups (independent variable) and the type of nostril sill (dependent variable). No significant association was found (P = 0.420) [Table 3].
A bivariate analysis was performed with a Chi-square test, to analyze the association of gender with the type of nostril sill. There was no statistically significant evidence (P = 0.524) [Table 4].
| Discussion|| |
The nose is a key element in facial esthetics. Multiple studies of nasal anthropometry and its study by subunits have been carried out. Nevertheless, the nostril sill has represented a poorly studied and even underestimated nasal subunit.,,,,
The nostril sill represents a topographically well-defined nasal subunit. Histologically, it is made up of fibro-adipose tissue and underlying muscles (nasal muscle, depressor septi nasi muscle and the superficial portion of the orbicularis oculi muscle) with a circular arrangement that allows it's support, movement, and projection. Both the anatomical portion of soft tissue and the muscular component play a fundamental role for the macroscopic appearance.,,,,,,
There are multiple classifications of the nostril sill; however, most of them lack clinical and therapeutic value. The objectivity, high reproducibility, and verifiability of Oh et al. classification make it ideal for visual and photographic categorization of the nostril sill. We found that in healthy Mexican children, Type I is the most frequent (n = 62 [74.6%]), followed by Type III (n = 12 [14.4%]) and Type II being the least frequent (n = 9 [10.8%]). with Type II (31.9% vs. 10.8%) and III (12.3% vs. 14.4%).
Farkas et al., classified the nostril sill into seven types according to the inclination of the longitudinal axes in the basal view of the nose. Ducut et al. classified into horizontal and vertical types, as well as its relationship with muscle trophism in its anterior and posterior portion. The horizontal type presented more hypertrophic muscle than the vertical ones. Zhukhovitskaya et al. categorize the nostril sill with the implementation of a parametric model in six subtypes.
Another fundamental step is the categorization of the nostril sill according to ethnic and racial characteristic since these tend to vary according to the geographical place where they are studied. Ohki et al. showed that the most frequent nasal form in the European ethnic is the leptorhine type, while in the African and Asian ones, the mesorhine and platyrrhine types predominate, respectively. Similarly, within each ethnic group, subtypes should be established, as reported by Mori et al. that showed in its publication that in the Japanese ethnic, where found four subtypes. However, in our Mexican pediatric population, the entirety of our study sample could be perfectly classified according to Oh et al.
Sazgar et al. and Irwin and Milling reported a statistically significant association of the nostril sill with gender, where Type II was more prevalent in males and Type III in females in the Caucasian population. However, in our study, it was shown that Type I has a very similar proportion in both genders, while Type II is more prevalent in females and Type III in males; however, this difference was not statistically significant.
Pigott and Millard described that type of the nostril sill has an association with age and gender, contrasting with the results of the present study, that has shown no association between age and gender with the nostril sill. This is based on the structures that make up this anatomical subunit since they do not have growth centers that alter their configuration, compared to the upper and lower lateral cartilages, as well as the nasal septum, where we can find growth centers, while the angulation of the nostril was not a measurement parameter in our study.
Another important finding was the high prevalence of bilateral symmetry of nostril sill, which supports the need to reconstruct the nostril sill, based on the contralateral side type, in cases of unilateral fissures. On the other hand, in the reconstruction of bilateral fissures, we could suggest their reconstruction according to the most prevalent type according to the specific population characteristics, which in our case was Type I.
One of the limitations of this study is that cadaveric specimens were not studied to histologically document the composition of the nostril sill in our population. Another limitation that the population sample is centered on Mexico City, so extrapolating the result to the entire country would be questionable.
More studies are needed to characterize the nostril sill in the Mexican population since the ethnic variability in our country is wide, finding Mestizo, Caucasian, and indigenous noses in our population.
| Conclusion|| |
The nostril sill represents nasal subunit that every reconstructive surgeon must recognize and locate. It is relevant to describe and classify the nostril sill according to ethnic and racial characteristics.
We conclude that the most frequent nostril sill in the Mexican pediatric population corresponds to Type I, followed by Type III and finally the least frequent Type II. The type of nostril sill did not vary with age and gender.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4]