|Year : 2020 | Volume
| Issue : 4 | Page : 330-334
Elongated styloid process evaluation on digital panoramic radiographs: A retrospective study
MunBhawni Bagga1, Deepankar Bhatnagar2, Nishant Kumar3
1 Department of Oral Medicine Diagnosis and Radiology, MN DAV Dental College and Hospital, Solan, Himachal Pradesh, India
2 Department of Orthodontics, Rayat Bahra Dental College and Hospital, Mohali, Punjab, India
3 Department of Pedodontics, MN DAV Dental College and Hospital, Solan, Himachal Pradesh, India
|Date of Submission||09-Jun-2020|
|Date of Decision||10-Oct-2020|
|Date of Acceptance||15-Oct-2020|
|Date of Web Publication||28-Dec-2020|
Dr. MunBhawni Bagga
Department of Oral Medicine Diagnosis and Radiology, MN DAV Dental College and Hospital, Oachghat, Solan, Himachal Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: The precise knowledge about anatomy of both normal and abnormal styloid process is important for clinicians, surgeons, and radiologists. Thus, the present study highlighted the prevalence of anatomic-radiological features of elongated Styloid process on panoramic radiography. Aim: The aim of the study was to evaluate and classify the radiographic appearance of the Styloid process (SP) along with morphologic characteristics and patterns of calcification according to the subject gender and site predilection. Materials and Method: A random sample of 1706 good quality digital panoramic radiographs were included in present study. Elongated SPs were classified with the radiographic appearance based on morphology and calcification pattern. The data were analyzed by using student t test and Chi-squared with significance set at P = 0.05. Results: Bilateral elongation having “Elongated” Type SP with “partially calcified” pattern was the most frequent SP. No correlation was found between SP type and calcification pattern and subject gender, although elongated Styloid was more prevalent among male population (P < 0.001). Conclusion: Dentists should recognize the existence of morphological variation in elongated Styloid process apparent on panoramic radiographs. According to our knowledge, this is the first study conducted in Solan region to evaluate Styloid process elongation (SPE) and also had recorded highest prevalence of SPE in comparison with other studies conducted in Indian population. We found calcification of the Styloid process is common in older age groups with no correlation to gender and site predilection. “Type I” with “partially calcified” of the Styloid process was observed most frequently in the population studied.
Keywords: Calcification, styloid process and panoramic radiography
|How to cite this article:|
Bagga M, Bhatnagar D, Kumar N. Elongated styloid process evaluation on digital panoramic radiographs: A retrospective study. J Indian Acad Oral Med Radiol 2020;32:330-4
|How to cite this URL:|
Bagga M, Bhatnagar D, Kumar N. Elongated styloid process evaluation on digital panoramic radiographs: A retrospective study. J Indian Acad Oral Med Radiol [serial online] 2020 [cited 2021 Jan 27];32:330-4. Available from: https://www.jiaomr.in/text.asp?2020/32/4/330/305264
| Introduction|| |
The styloid process (SP) is a cylindrical, slender, needle-like projection from the inferior part of petrous temporal bone. Many nerves and vessels such as carotid arteries and internal jugular vein are adjacent to the SP. The normal SP length is approximately 20-30 mm. The styloid process tapers toward its tip and offers attachment to the stylohyoid ligament, stylopharyngeus, and styloglossus muscles. Many important neurovascular structures like facial and hypoglossal nerves, occipital artery lie near the tip of the styloid process. Keur JJ suggested the SP length which is longer than 30 mm can be considered to be styloid process elongation (SPE).
Eagle an Otorhinolaryngologist first described a term, “Eagle syndrome” characterized by an elongated styloid process and pain in the cervicofacial region. The elongation can be frequently encountered by calcification of stylohyoid and stylomandibular ligaments which precipitates a series of signs and clinical symptoms of neck and cervicofacial pain. More uncommonly, symptoms such as dysphagia, foreign body sensation in the throat, vertigo, facial pain, tinnitus, and otalgia were present. The purpose of this study was to investigate the prevalence, morphology, and calcification pattern of the elongated SP in Solan population and its relation to subject gender and age.
| Materials and Method|| |
A total of 2000 digital panoramic radiographs were consecutively retrieved from the archival records of department of Oral Medicine and Radiology from January 2019 to December 2019. The regionality, age, and gender of patients were recorded from the case history. Only good quality radiographs showing the styloid process were included, while radiographs having positioning and magnification errors were excluded from the study. Out of total of 2000 panoramic radiographs only 1706 were considered as good quality and included in present study. The sample size was calculated taking power of the study to be 80%, DEFF as 1.1 and expected response rate as 90%. The inclusion criteria were digital panoramic radiograph showing both styloid processes, good quality radiograph, and those radiographs in which data regarding regionality, age, and gender of patients were available. However, the exclusion criteria were positioning and magnification errors in radiograph, superimposition of temporal bone, and obscured images of either of the styloid process.
The digital panoramic radiographs were taken by Planmeca (Promax version 4.1) under standard exposure factor as recommended by the manufacturer. Our study was exempted from the DAV Institution Review Board Ethics Committee (wide letter no DAV/DCH/IRBC no. 735 dated 27.12.18) as all included panoramic radiographs were retrieved from the records of the Oral and Maxillofacial Radiology department and were taken for reasons other than the purpose of this study. The procedure is in accord with the ethical standards as per Helsinki Declaration of 1975.
The subjects consisted of 1181 males and 525 females with mean age of elongated styloid as 37.64 ± 7.3 years and non-elongated styloid process as 32.35 ± 6.1 years. .
Independently, length and calcification pattern of right and left SPs were analyzed and if the styloid process extends below an imaginary line connecting the anterior nasal spine and the mastoid process it was considered elongated [Figure 1]a & [Figure 1]b. When SP elongation present it was recorded as unilateral or bilateral and classified according to the Langlais et al. [Figure a, b, c &d]. Four study groups were made as Non elongated (group 1), unilateral right side SPE (group 2), unilateral left side SPE (group 3) and bilateral SPE (group 4) [Table 1].
|Figure 1: (a) Anterior nasal spine and mastoid process landmark on panoramic radiograph. (b) Imaginary line connecting the anterior nasal spine and mastoid process|
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The relationship between elongated styloid process, age, and gender were investigated. Examination of the panoramic radiographs was carried by single investigator. The data were analyzed by using t–test and Chi-square tests. All analyses were executed using SPSS 20.0 (Statistical package for social science Inc., Chicago, Illinois, USA).
| Results|| |
Out of 1706 total study subjects, there were 768 (45%) with elongated styloid process and 938 (55%) non elongated styloid process calcification [Figure 3]a. Out of 768 elongated styloid processes, 598 (77.9%) were bilateral elongated while elongation on left side was seen in 82 (10.7%) and elongation on right side was seen in 88 (11.5%) [Figure 3]b Out of 1181 males, 529 (44.8%) were with elongated styloid process and 652 (55.2%) were with non-elongated styloid process and out of 525 females, 239 (45.5%) were with elongated styloid process and 286 (54.5%) were with non-elongated styloid process [Figure 4].
|Figure 3: (a) Pie chart showing group wise distribution. (b) Pie chart showing distribution of elongated styloid process|
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|Figure 4: Bar chart showing gender wise elongated and non-elongated styloid process|
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Calcified styloid was more prevalent among the older age group and male population. The mean age was significantly higher in the patients with SPE than the patients without SPE (P < 0.001). The mean age for male and female patients with SPE were 40.34 ± 7.6 and 34.94 ± 7.1 years, respectively [Table 2]. Highly significant differences were observed in between two categories i.e., elongated and non elongated styloid process among male population and total population (P < 0.001).
|Table 2: Comparison of difference in mean age between the study population|
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In Solan population among group 2, 3, and 4 the most frequent type of calcification was elongated (Type I) with pattern observed was Partially Calcified (Pattern B) as shown in [Figure 2] [Table 3]. There was no association found between the gender and the type of styloid process with Group 2 (P > 0.05), with Group 3 (P > 0.05) and with Group 4 (P > 0.05). Moreover, there was no association between the pattern and the Group 2 (P > 0.05), with Group 3 (P > 0.05) and with Group 4 (P > 0.05) [Table 4].
|Figure 2: (a) Classification of elongation of SP; Type I (elongated), Type II (pseudo articulated), and Type III (segmented). (b) Pattern of calcification [A: Calcified outline; B: Partially calcified; C: Nodular; D: Completely calcified]. (c) OPG with each type of calcification [Type I, Type II & Type III]. (d) OPG with each pattern of calcification [Pattern A, B, C & D]|
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|Table 3: Prevalence and correlation of gender for pattern and type of calcification among group 2, 3 & 4|
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|Table 4: Total styloid calcification comparison in between site (right and left) and gender (male and female)|
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| Discussion|| |
The elongation of the styloid process and structural changes in stylohyoid ligament with its clinical symptoms and signs were first described by Eagle. Hence, it is termed as the Eagle's syndrome. Eagle's syndrome is diagnosed by both physical and radiographic examination. The styloid process palpation in the tonsillar fossa is indicative of SPE which are not normally palpable. If highly suspicious for Eagle's syndrome, confirmation can be done by radiographic imaging., There are many vessels such as carotid arteries and nerves adjacent to the styloid process. The signs and symptoms with this syndrome are due to the anatomic relationship between the styloid process and its surrounding structures., The symptoms can be confused with some disorders including a wide variety of facial neuralgias, oral and temporomandibular diseases., Therefore, a detailed differential diagnosis for styloid process elongation should be done. The important radiographic views taken for evaluation of styloid process are Panoramic, Lateral oblique of ramus of mandible, Towne's view, AP view, Transpharyngeal view, and CT scan.
The pathophysiology behind the pain due to elongated styloid process was compression of the neural elements, the glossopharyngeal nerve, lower branch of the trigeminal nerve, and/or the chorda tympani by the elongated styloid process. The compression further leads to proliferation of granulation tissue that causes continuous pressure on surrounding structures and results in pain.
Several theories are proposed to explain the variance in ossification and elongation of styloid process namely theory of reactive metaplasia, reactive hyperplasia, anatomic variance, aging, developmental anomaly, and trauma leading to loss of elasticity in ligament simulating tendinosis. The calcification of Styloid is now considered as a part of heterotopic bone formation or ossification because microstructurally osteoid matrix is also present with the calcification. The regional factors too play significant role like dietary factors for different pattern and types of styloid process elongation. Despite all these theories, still the etiology remains unclear. Since the styloid process may exhibit anatomical variations that differ from person to person and population to population.
Panoramic radiographic techniques usually distort the dimension of the styloid process and produce magnification of the radiographic image which depends on the angulations of the process itself., Therefore, a simple millimeter measurement is not a suitable criterion because of the radiologic factors involved. Taking this factor into consideration, to determine the length of styloid process, ruler measurement was not chosen. The elongated styloid process in the radiographs were determined according to the method proposed by Ferrario et al.
According to our knowledge, the present study is the first report investigating the styloid process elongation prevalence, morphology, and calcification pattern and its relation to subject gender and age on digital panoramic radiographs in Solan population.
In our study the prevalence of elongated SP among the Solan population, combining both unilateral and bilateral instances, was 45%. This compares to values ranging from 2% to greater than 30% reported in literature.,,, The higher prevalence of elongated styloid could be attributed to the combination of factors including race, lifestyle and dietary habits. In Solan population majority of them are farmers, so weight loading and strenuous work promotes ossification in the ligament. Racial predisposition also favors ossification of ligament as center of ossification varies in a race.
We also observed that calcified styloid was more prevalent among the older age group and male population which are in accordance with previous findings., The reason could be ageing and reactive hyperplasia, respectively.
Bozkir et al. reported the bilateral elongation in 75% and unilateral in 25% of cases on panoramic radiography. Our study also showed that in elongated styloid process 77.9% of cases were bilateral and 22.2% cases were unilateral. More CB et al. reported the prevalence of Type I and partially calcified styloid process in >85% of Gujarat population which was in accordance with our study i.e., >55%. Our data is in accordance with to previous literature findings of SPE in the south Indian population. The bilateral SPE could be attributed to the fact that strenuous exercise and chewing habits result in clenching of jaw muscles that increases weight loading of Styloid process bilaterally and promotes ossification.
There was no statistically significant difference observed between genders for Styloid process elongation. This is in agreement with the reports of previous literature.,
When the elongated SP does not extend to the angle of the mandible, it is difficult to determine the related ligament. However, in theory of reactive metaplasia it was stated that the stylohyoid ligament is the structure responsible for abnormal ossification as it undergoes metaplasia and partial ossification. We recommend the term ''mineralized stylohyoid-stylomandibular ligament complex'' in view of the ambiguity of these structures when viewed on panoramic radiographs which is in accordance with the previous literature findings of Correll et al. and Zaki et al.
Limitations and Future prospects
Since panoramic radiography is a 2D imaging technique, further advanced imaging studies are required to correlate the symptoms, dietary patterns, lifestyles and styloid process elongation.
| Conclusion|| |
Panoramic radiography plays an important role in patients with symptoms of styloid process elongation and can thus help to avoid misinterpretation of the symptoms as tonsillar pain or pain of dental, muscular, or pharyngeal origin. Elongation or calcification of SP in older adults was common without gender predilection in the present study. “Type I” with “partially calcified” SP was observed most frequently in the population studied. Awareness could be created among people who are prone for SPE specially in farmers.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4]