Journal of Brain and Spine Foundation Nepal Morphological evaluation of styloid processes and their correlation with gender and age using Multidetector Computed tomography. and

Morphological evaluation of styloid processes and their correlation with gender age using Multidetector Computed ABSTRACT: Introduction: The styloid process (SP) extends inferiorly from the temporal bone. Many neurovascular structures are closely related to its tip. Alteration in the length, angle and morphology of styloid process may lead to symptoms related to neurovascular compression. Hence it is necessary to know the normal variations before delineating the exact cause of symptoms related to head and neck region. This study was conducted to assess the variations in length, angle and morphology of styloid process and to correlate it with gender and age group. Methods: The Patients of trauma undergoing Paranasal Sinus Computed Tomography (CT) scan who were otherwise asymptomatic prior to the trauma were included in the study. Images were evaluated in dedicated work station. Length of bilateral styloid process were measured. Angulation of the SP was defined in the coronal and sagittal planes, respectively and morphology was identified as type I, II, III and IV. Findings were correlated with gender and age group. Results: A total of 192 patients were included in the study. The age of the patients ranged from 13 to 86 years. Mean length of right styloid process was 26.6±8.6 mm and mean length of left styloid process was 27.0±8.2 mm. There was no significant difference between the length of styloid process in males and females. Males had a significantly larger coronal angle as compared to females. There was a linear, weak, positive correlation between the length of styloid process and advancing age. Conclusion: There was a wide variation in length, angle and morphology of styloid process.

pathological styloid. Hence, the purpose of this study was to investigate the morphological characteristics of the mineralized styloid process with the help of CT scan.
It aims at measuring the length and angle of styloid process and to correlate the length and angle of styloid process with age and gender. This study adds important information about the diversity of the styloid process in the Nepalese population.

Methods:
This observational study was conducted in the determined. T test was used to see the association between angle of styloid process and gender, length of styloid process and gender. ANOVA test was used to see the association between the angle of styloid process and the age group, length of styloid process and the age group. The Pearson correlation test was used to assess the relationship between length of styloid process and age. Statistical significance was defined at a P value of less than 0.05.

Results:
There was a total of 192 patients in our study. Age of the patients ranged from 13 to 86 years and mean age was 44.99±18.9 years. There were 85 (43.3%) females and 107 (55.7%) males. The mean length of the left styloid process was greater than that of the right styloid process.
The angle of styloid in coronal plane was greater on the right side as compared to the left. But Angle of left styloid in sagittal plane was greater than of right side (Table 1). There was no significant difference in the mean length of bilateral styloid processes within gender. Angle of bilateral styloid process in coronal plane was significantly higher in males as compared to females.
There was no significant difference between the angle of bilateral styloid processes in sagittal plane ( Table 2).
The right styloid process length was significantly longer in 40 to 60 years' age group whereas left styloid length was significantly higher in >60 years' age group.
Bilateral styloid angle in coronal plane was greater in <40 years' age group but was not statistically significant.
Right styloid angle in Sagittal plane was greater in >60 years' age group whereas left styloid angle in sagittal plane was greater in 40 to 60 years' age group which was also not statistically significant ( Table 3). Most of the styloid process were type I in both male and female groups (Table 4).  There was a significant weak positive linear correlation between length of right styloid process and age (r=0.192, positive linear correlation between the length of left styloid process and age (r=0.222, p=0.002) (Fig 1 and 2).  Type 1  53  63  116  Type II  13  22  35  Type III  8  9  17  Type IV  11  13  24   Left Styloid   Type I  47  63  110  Type II  22  25  47  Type III  9  5 14 Type IV 7 12 19 Discussion: The symptoms related to elongation of SP were first described by Eagle. Thereafter, the array of symptoms due to the structural changes in SP was named as Eagle's syndrome. It has been reported that abnormal angulations are responsible for the symptoms. 5 Some of these symptoms include pain in the throat, ear, face, dysphasia or foreign body sensation in the pharynx. 6,7 These symptoms arise mainly due to compression on the neurovascular structures. In this study, we have attempted to show the normal variation in styloid process length, morphology and angulation. Its knowledge might be helpful in dealing patients with pain or other symptoms related to the head and neck region.
Knowledge of the anatomical diversity of SP is necessary before regarding it as pathological. Awareness about anatomical diversity in the populations is necessary before relating the symptoms to pathological changes in the styloid process.
Eagle stated the normal length of styloid to be 2.5 cm. 3 There are several studies done for the measurements of styloid process using different modalities which have shown that the average length of SP varies from 2.0 to 3.2 cm and the normal length of SP varies from 1.5 to 6.0 cm. [8][9][10][11][12][13][14][15] In our study, the average length was 2.7 cm.
Several studies have reported that the length of SP in different age and sex groups was not significantly different. [8][9][10][11][12][13][14][15][16] In our study we also did not observe a gender predilection in length of SP similar to their observation. Ramadoss T et al also did not find a gender predilection in their study. 17 However, we observed that the right styloid process was significantly longer in 40 to 60 years' age group whereas left styloid process was significantly higher in >60 years' age group. Bruno G et al observed that in the different age group there was a progressive increase of the prevalence of the elongation with advancing age. 18 Our study also shows a progressive increase in length of styloid process with advancing age. in the sagittal plane. 19 In our study the angulation varied between 55° to 89° on right side and 25° to 83° on left side in coronal plane. It varied between 70° to 291° on left side and 54° to 97° on right side in sagittal plane.
Regarding the calcification in SP, many studies have shown elongated being the most common type followed by pseudo articulated and segmented type, similar to our study. [20][21][22][23][24][25]