Part of the body that plays the most important role in our ability to distinguish individuals is the face, and the nose is the most noticeable part of the face [7]. The nose is also the most protruding structure. Therefore, it is very susceptible to injury. In addition, even a small deformity in the nasal bone or cartilage is very noticeable as it affects the overall esthetics of the face. Furthermore, nasal bone fracture is the most common fracture of the face. Its incidence rate has increased due to changes in lifestyle and increases in traffic accidents, thus creating a need for an epidemiological study [8]. Regarding the frequency of nasal bone fractures by gender, the ratio of male to female has been analyzed by Marco et al. [9] to be 4.1:1. Turvey et al. [10] have reported a ratio of 3:1, and Nishioka et al. [11] have shown a ratio of 2.3:1. These studies all indicate a higher frequency in males. In the present study, there was a significantly higher frequency of nasal bone fracture in males with a ratio of 6.8:1. Regarding age groups, Hwang et al. [3] have observed that nasal bone fractures occur most commonly in patients in their 20s (31.8%), followed by patients in their teens, 30s and 40s (22.3%, 19.7%, and 16.1% respectively). Oh et al. [8] have also observed that nasal bone fractures occur most commonly in patients in their 20s (31.7%), followed by patients in their teens (22.6%), 30s (20.0%), and 40s (16.1%).
Most research studies on incident rates of nasal bone fractures according to age groups have shown that the highest rate of incidence occurs in males aged 15 to 40 years old. In the present study, 36 (20.1%) patients aged 20–29 years old, which had the highest rate of occurrence among age groups, followed by 35 (19.6%) patients aged 10–19 years old, 31 (17.3%) patients aged 40–49 years old, 26 (14.5%) patients aged 30–39 years old, 25 (14.0%) patients aged 50–59 years old, 24 (13.4%) patients aged 60 years old and above, and 2 (1.1%) patients aged under 10 years old. Similar to most researches, males aged 10 to 40 years old had the highest rate of nasal bone fracture in the present study. The reason for this can be attributed to the fact that most males in this age group take part in labor, physical activity, violence, and so on.
Causes of nasal bone fracture are known to differ by age and region. Hwang et al. [12] have reported that the most common causes of nasal bone fracture in adults are fights (36.3%), traffic accidents (20.8%), sports (15.3%), and falls (13.4%) while the most common causes in children are sports (59.3%), fights (10.8%), traffic accidents (8.3%), collisions (5.0%), and falls (3.3%). Causes of nasal bone fractures also vary by region. Fighting is the most common cause in Asia (36.7%), South America (46.5%), and Europe (40.8%) while traffic accident is the most common cause in North America (33.6%). In the current study, the most common cause of nasal fractures was traffic accident (66 cases, 36.9%), followed by violence (49 cases, 27.4%), falling down (44 cases, 24.6%), industrial accidents (8 cases, 4.5%), other incidences (7 cases, 3.9%), and sports-related trauma (5 cases, 2.8%).
Regarding fractures associated with nasal bone fractures, Yang et al. [13] have reported that maxillary fracture is the most common fracture (50%), followed by mandible fracture (20%) and zygomatic bone fracture (15%). In the present study, 17 (9.5%) patients incurred Le Fort I fracture, 6 (3.4%) patients incurred Le Fort II fracture, 2 (1.1%) patients incurred Le Fort III fracture, 4 (2.2%) patients incurred NOE fracture, 33 (18.4%) patients incurred ZMC fracture, 18 (10.1%) patients incurred maxillary fracture, 44 (24.6%) patients incurred orbital fracture, 10 (5.6%) patients incurred frontal bone fracture, and 10 (5.6%) patients incurred alveolar bone fracture. The reason for such results might be because causes of fractures such as traffic accidents, falling down, violence, and so on often lead to stress to the middle portion of the face because the nasal bone is the most protruding structure. Thus, bones closest to the nasal bone have higher rates of associated fractures.
Although most nasal bone fractures can be treated with closed reduction, there is a difference in opinion about what the appropriate time for reduction is depending on the doctor [14]. Rohrich et al. [14] have stated that reduction should be carried out within 7 days of the fracture while it should be carried out within 10 days for adults. However, Harrison [4] claims that 3–7 days for children and 5–10 days for adults would be the appropriate time for reduction. Goode and Spooner [15] have suggested that the appropriate time for reduction is 2–3 days after fracture when edema disappears. Han [16] claims that in the case of nasal bone fractures with multiple fracture segments, reduction after 2 weeks can result in the best outcome. In the present study, reduction was carried out in an average of 7.7 days (range, 0 to 33 days) after the fracture. Reduction was not carried out for minor fractures that had no effect on the appearance of the face. In these instances, precise evaluation of facial appearance is needed. Therefore, it is advantageous to decide whether or not to carry out surgical procedures after the edema has dissipated after injury.
Regarding complications after the reduction of nasal bone fractures, Hwang et al. [17] reported that nasal deformity occurred in 10.4% of patients. In addition, 10.0% suffered septal deviation, 10.5% suffered nasal obstruction, 3.1% suffered epiphora, 3.1% suffered diplopia, and 37.7% of patients suffered olfactory disturbances. In the present study, 11 (6.1%) patients suffered nasal obstruction, 20 (11.2%) patients suffered postoperative deformity, and 2 (1.1%) patients suffered olfactory disturbances. Anatomically, olfactory epithelial cells are scattered on the superior part of the nasal cavity and bilaterally between the septum and the medial portion of the superior nasal concha [18]. Also, olfactory epithelium might be present above the middle turbinate superiorly and below the cribriform plate inferiorly. The reason for high rates of olfactory disturbances after the reduction of nasal bone fractures is that olfactory epithelial cells located on superior nasal concha or supreme nasal turbinate can get damaged during a procedure [19]. In the present study, olfactory disturbance was observed in only 2 patients. Thus, it could be inferred that closed reduction was carried out delicately.
In the current study, fractures were classified into five categories as stated by Higuera et al. [6]. This method of categorization does not take displacement into consideration. Rather, it uses subjective judgment. Therefore, it has a clear limitation as an objective method of categorization.
