Computer-aided assessment of bony nasal pyramid dimensions

Computed Tomography Evaluation of Nasal Dimensions among Different Singaporean Ethnicities

Osteotomies in rhinoplasty are performed to correct deformities in nasal contour. The size of osteotome used is dictated by the thickness of the bony nasal pyramid along the osteotomy route. The aim of this study is to determine whether nasal bony dimensions differ between different ethnic groups in Singapore. Randomly selected patients' computed tomography (CT) scans of the face performed between the years 2010 to 2013 in our institution (Khoo Teck Puat Hospital) were evaluated. The setting was a tertiary government hospital. CT images of 309 patients (233 Chinese [147 males, 86 females], 32 Malays [16 males, 16 females], and 44 Indians [33 males, 11 females]) were evaluated. Anthropomorphic measurements of the nasal bone along the track of the lateral, medial, and intermediate osteotomies, as well as the nasal bone length and pyriform aperture width were measured on the CT images by two independent observers. Statistical analysis was performed using Student's t-test and two-way analysis of variance (ANOVA) test. There was no significant difference between the nasal pyramid bone thickness between different ethnicities along the osteotomy tracks (p > 0.05; degrees of freedom [df] = 2). However, there was a significant difference between males and females of the same ethnicity at the low level of the lateral osteotomy (p = 0.003) and the midlevel (p = 0.002) and high-level (p = 0.004) of the intermediate osteotomy. There was a statistically significant difference in nasal pyramid length (p < 0.05, df = 2) and pyriform aperture width (p < 0.05, df = 2) among the races and between the genders (p < 0.05). The mean difference in nasal pyramid length of 2.54 mm and pyriform aperture width of 1.89 mm was particularly significant between the Chinese and the Indians. Gender and ethnic differences in nasal bony dimensions should be considered in surgical planning for rhinoplasty.

Computed Tomography Evaluation of Nasal Bone and Nasal Pyramid in the Turkish Population

OBJECTIVE

To classify shapes of the nasal bones in the Turkish population and comparatively evaluate the sizes of nasal bone and piriform apertures.

METHODS

Two- and three-dimensional paranasal sinus computed tomography images of 363 patients were evaluated. Upper, intermediate, and inferior thickness of bilateral nasal bones and thickness of medial and lateral osteotomy line were measured. The shapes of the nasal bones were classified.

RESULTS

The mean thickness of nasal bone in the study participants was 1.99 ± 0.40 mm, the mean thickness at the level of medial osteotomy line was 1.99 ± 0.40 mm, the mean thickness at the level of lateral osteotomy line was 1.75 ± 0.30 mm, the mean length of nasal bone was 1.75 ± 0.30 mm, maximum width and height of piriform aperture were 23.41 ± 2.68 and 36.76 ± 7.06 mm, respectively. When the patients were classified according to the type of nasal bone, 26.7% had type A, 10.5% had type B, 19.6% had type D, and 15.4% had type E nasal bone.

CONCLUSION

The results of the current study provide information about morphological characteristics of nasal bone and piriform aperture in the Turkish population and would therefore reduce postoperative complications after reconstructive surgery and contribute otolaryngology and anthropology.

The evaluation of morphometry of nasal bone and pyriform aperture using multidetector computed tomography

INTRODUCTION

The aim of this study was to measure nasal bone (NB) and pyriform aperture (PA), morphometrically. Besides, the different types of NB and PA were classified and determined the sexual differences.

MATERIALS AND METHODS

Our study was performed on 120 (60 women, 60 men) multidetector computed tomography images obtained from patients who underwent radiologic examination in the Department of Radiology of Meram Faculty of Medicine, Necmettin Erbakan University. The right, left, and median heights of NB; the superior and inferior widths of NB; the width of PA; and the distance between rhinion and anterior nasal spine (as the height of PA) were measured. Frontonasal and internasal angles were also determined. All data were analyzed statistically using Student's t-test.

RESULTS

The other data of men were higher than of women except for the superior and inferior widths of NB and the frontonasal angle. We also determined the ratio of the height of PA to the height of NB on median plane and the ratio of the height of PA to the width of PA. They were found less than 2.0 in 64.2% and 100% of the cases, respectively. The NB and PA were classified into 8 and 7 different types, respectively.

CONCLUSIONS

The knowledge of the morphometric data and different types of the NB and PA is essential for sex determination, all surgical procedures related to this area, and nasal reconstructions.

CBCT Evaluation of Bony Nasal Pyramid Dimensions in Iranian Population: A Comparative Study with Ethnic Groups

Background. The aim of the present study was to have normative data of nasal bone thickness for use before reconstructive surgery and nasal augmentation through radiography analysis. Methods and Materials. In this descriptive-analytical study, 74 patients were selected from people referred to Radiology Department of Isfahan University for CBCT examination in 2012. Patients with a history of nasal surgery or facial trauma and known congenital anomaly were excluded from the study. Height of nasal bone and width of pyriform aperture and nasal bone thickness in lateral and medial osteotomy line were measured. All these measurements were repeated by two radiologists; finally one sample t-test was performed. Results. The mean thickness of nasal bone on the lateral osteotomy line was 1.92 ± 0.29 mm in females and 1.73 ± 0.32 mm in males (P value = 0.39). The mean thickness of medial osteotomy line was 1.63 ± 0.47 mm in females and 1.94 ± 0.19 mm in males (P value = 0.31). The mean length of nasal bone was 23.5 ± 3.34 mm in females and 25.7 ± 2.96 mm in males (P value = 0.11). The mean width of pyriform aperture was 23.77 ± 2.58 mm in females and 25.67 ± 1.79 mm in males (P value = 0.25). Conclusions. The dimensions of nasal pyramid are known to be significant in choosing suitable osteotome size for reducing surgery side effect. Our results can be used for preoperative estimation of nasal bone dimension of people undergoing reconstructive surgery and augmentation.

Rhinoplasty and septorhinoplasty outcome evaluation

Outcome measures are a crucial tool in the analysis and comparison of medical interventions. We review the subjective and objective methods of assessing outcomes of rhinoplasty and septorhinoplasty. Both form and function of the nose are considered.

The oscillating micro-saw: a safe and pliable instrument for transverse osteotomy in rhinoplasty

BACKGROUND

A low-to-low lateral osteotomy combined with a transverse osteotomy offers a reliable technique to mobilize the lateral walls in patients with broad bony vaults, but variable "brittling" characteristics of the nasal bones near the radix make it difficult to guarantee the result of manual transverse osteotomy.

OBJECTIVES

The author describes a split-thickness transverse osteotomy with the aid of an oscillating micro-saw under video/endoscopic control to eliminate the risk of probable pitfall fractures on the structure of the bony nasal vault near the radix during blind manual osteotomy.

METHODS

The author reviewed 1550 consecutive rhinoplasty and septorhinoplasty operations performed between April 2005 and October 2010. Among these the transverse osteotomy was used bilaterally in 1374 cases. Split-thickness transverse osteotomy was carried out with a powered micro-saw system from an endonasal approach under video/endoscopic control. CT-based 3D models of 16 patients with different functional indications were used to assess the mean depth of the transverse osteotomy line.

RESULTS

The mean depth of the nasal wall at the thickest point of the transverse osteotomy line near the radix was 2.5 ± 0.66 mm. It decreased toward the medial canthus in all 16 patients. The mean thickness of bone was 1.2 ± 0.21 mm in the medial canthal area.

CONCLUSIONS

The oscillating micro-saw is a safe and pliable instrument to aid in transverse osteotomy during rhinoplasty. Video endoscopy provides an excellent view of the osteotomy site, including direction and depth, in addition to providing documentation for and education about the procedure.

CT evaluation of the bony nasal pyramid dimensions in Anatolian people

OBJECTIVES

The aim of this study was to evaluate the nasal bone and bony nasal pyramid in adult Anatolian people.

METHOD

A total of 80 patients (48 males, 32 females, mean age of 40.03 years) were all evaluated using CT. Upper, intermediate and inferior thickness of the nasal bone on each side and on the lateral and medial osteotomy line were measured. In addition, nasal bone length and pyriform aperture width were determined.

RESULTS

The bone thickness was 2.23 mm ± 0.15 mm in males and 2.19 mm ± 0.14 mm in females at the level of upper border of the nasal bone; 1.82 mm ± 0.32 mm in males and 1.81 mm ± 0.25 mm in females at the intermediate level; and 1.73 mm ± 0.30 mm in males and 1.86 mm ± 0.69 mm in females at the lower border of the nasal bone. The mean thickness on the lateral osteotomy line was 1.85 mm ± 0.32 mm in males and 1.91 mm ± 0.46 mm in females. The mean thickness of the medial osteotomy line was 2.08 ± 0.17 mm in males and 2.04 mm ± 0.17 mm in females. The mean length of the nasal bone was 30.61 mm ± 1.26 mm in males and 29.01 mm ± 1.12 mm in females. The mean width of the pyriform aperture was 18.83 mm ± 2.17 mm in males and 18.19 mm ± 1.85 in females.

CONCLUSION

The dimensions of the nasal pyramid are known to be important in the selection of appropriate osteotome. Our results can be used for pre-operative evaluation of Anatolian people undergoing nasal surgery.

Analysis of the nasal bone and nasal pyramid by three-dimensional computed tomography

Evaluation of the nasal bone and nasal pyramid is essential for the correct osteotomy. The shape of the nasal bone and nasal pyramid of Korean subjects were analyzed using a three-dimensional computed tomography (CT). This study includes 75 patients who visited Inha University Hospital and got a three-dimensional CT from October 2005 to June 2006 (58 males, 17 females, mean age of 33.1 years). The thickness of the bone at the nasomaxillary suture as well as between the rhinion and nasomaxillary suture, on which a lateral osteotomy was performed, was measured. In addition, the length of the nasal bone and the width of pyriform aperture were measured. The morphology of the nasal bone was classified from A to E type, according to Hwang's method. The subjects included 58 males and 17 females with a mean age of 33.1 years. The mean thickness of the lateral osteotomy point is 2.03+/-0.35 mm and that of the medial osteotomy point is 1.75+/-0.37 mm. The mean length of the nasal bone is 20.95+/-5.99 mm. The number of patients with a long nasal bone (more than 25 mm) is 14.7% (11/75). The most common morphology of the nasal bone is A type and there is no D or E type. Since there is no significant difference in the thickness of the nasal bone at the lateral and intermediate osteotomy point, the same strength should be used to perform the correct lateral and intermediate osteotomy. However, the actual lateral osteotomy is performed at a more lateral position than the nasomaxillary suture, which is our standard of measurement. So, using more power in the lateral osteotomy should be considered. There were nine patients with a long nasal bone in this study. For these patients, better results with percutaneous transverse osteotomy could be expected.