An epidemiological study of elongation of styloid process in the saurashtra population: A retrospective radiographic digital orthopantomographic study

Reeta Jha; Mansi Khatri; Foziya Pathan; Mansi Solanki; Hiren Tandel

doi:10.4103/aihb.aihb_1_22

ORIGINAL ARTICLE

Year : 2022 | Volume : 12 | Issue : 2 | Page : 202-206

An epidemiological study of elongation of styloid process in the saurashtra population: A retrospective radiographic digital orthopantomographic study

Reeta Jha, Mansi Khatri, Foziya Pathan, Mansi Solanki, Hiren Tandel
Department of Oral Medicine and Radiology, Government Dental College and Hospital, Jamnagar, Gujarat, India

Date of Submission	01-Jan-2022
Date of Decision	31-Mar-2022
Date of Acceptance	14-Apr-2022
Date of Web Publication	13-May-2022

Correspondence Address:
Mansi Khatri
Department of Oral Medicine and Radiology, Government Dental College and Hospital, Jamnagar, Gujarat
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/aihb.aihb_1_22

Abstract

Introduction: The styloid process (SP) is a cylindrical bony structure emerging from the lower surface of the petrous temporal bone, its normal length is from 20 mm to 30 mm and those with more than 30 mm length are considered elongated. Calcification in stylohyoid ligament or calcification of SP is termed Eagle's syndrome. The aim of this study is to conduct an epidemiological survey of SP on digital orthopantomogram (OPG) in the Saurashtra population with an age range of 5–90 years. Materials and Methods: This is a retrospective study of 1088 OPG radiographs randomly selected from the database of 2019–2020 from the oral medicine and radiology department of our institute, which was taken on the OPG model CS 8100 Carestream digital panoramic system. Measurements of SP were done from the temporal bone to the tip. Those with more than 30 mm in length were considered to be elongated. The study sample was divided into four different age groups and was compared according to gender and sides. The Chi-square test and t-test were performed. Results: Elongated SP was noted in 354 (32.53%) out of 1088 subjects. Among age groups, subjects of more than 50 years showed a maximum number of elongated SPs. Conclusion: Subjects showing elongated SP and their mean length are increased with age, which indicates chronic development of calcification. No statistical significance was found in the elongation of SP in correlation with the cohort's gender and sides (bilateral or unilateral).

Keywords: Digital orthopantomography, elongated styloid process, epidemiological study

How to cite this article:
Jha R, Khatri M, Pathan F, Solanki M, Tandel H. An epidemiological study of elongation of styloid process in the saurashtra population: A retrospective radiographic digital orthopantomographic study. Adv Hum Biol 2022;12:202-6

How to cite this URL:
Jha R, Khatri M, Pathan F, Solanki M, Tandel H. An epidemiological study of elongation of styloid process in the saurashtra population: A retrospective radiographic digital orthopantomographic study. Adv Hum Biol [serial online] 2022 [cited 2023 Apr 1];12:202-6. Available from: https://www.aihbonline.com/text.asp?2022/12/2/202/345201

Introduction

In Greek, 'stylos' means a pillar from which the name styloid process (SP) is derived. The SP is a cylindrical bony projection that emerges from the temporal bone. It is located in front of the stylomastoid foramen. The styloid ligament connects SP with the hyoid bone. It is derived from the second branchial arch and the Reichert's cartilage.^[1] The normal length of this process ranges between 20 mm and 30 mm. Greater than 30 mm is defined as elongated SP.^[2],[3] This condition could be a common finding in the population, and it is usually without any other clinical manifestations.

In the case of elongated SP, clinical symptoms such as pain in the neck and cervicofacial region are termed Eagle's syndrome. These signs and symptoms occur when an elongated process exerts pressure on nerves and vessels situated in the vicinity of the SP, such as nervus facialis and internal or external carotid arteries. Pain in the ear, dysphagia and tinnitus are also a few of the occasional occurrences of Eagle's syndrome. Eagle's syndrome symptoms often mimic other orofacial diseases such as pulpal pain, impacted third molars and temporomandibular disorders (TMDs). Different methods are evaluated for a diagnosis such as a dry human skull, digital orthopantomography, cone-beam computed tomography (CBCT) and computed tomography (CT). Digital orthopantomogram (OPG) is a cost-effective, easy and more accurate interpretation technique than any other method. It is the preferred technique for epidemiological studies and the screening process.^[2]

Materials and Methods

Preliminarily, approval of the local ethical committee was taken. The radiographs were selected from the database of the Government Dental College and Hospital for 2019–2020 from the Oral Medicine and Radiology Department. All radiographs evaluated were taken by the identical operator. The radiographs were taken using the model CS 8100 Carestream digital panoramic system (tube potential: 60–90 kV, tube current: 2–15 mA, total filtration: >2.5 mm Al, time: 10.5 s). The other factors followed are as follows: (1) the Frankfort horizontal plane of the subject was parallel to the floor, (2) the midsagittal plane bisected the face of the subject into two equal halves and (3) the canine plane was aligned along the long axis of the canine in the subject.

Digital OPG images showing (1) positioning and magnification errors, (2) incomplete images or unilaterally visible SP and (3) radiographs that showed errors such as size and shape distortion were excluded from the study.

In this retrospective radiographic study, digital OPG images of 1088 (574 males and 514 females) patients were included in the study. Patients' age ranged from 5 to 90 years. The sample size was divided into four different age groups as follows:

Group 1: <18 years
Group 2: 18–35 years
Group 3: 36–50 years
Group 4: >50 years.

In Group 1, subjects younger than 5 years were not included as full ossification of the SP takes place between the 5^th and 8^th years of life. Among age groups, 48 subjects in Group 1 of <18 years (0.55%), 464 subjects in Group 2 of 18–35 years (13.69%), 314 subjects in Group 3 of 36–50 years (2886%) and 262 subjects in Group 4 of older than 50 years (24.08%) were studied.

OPG was observed in a quiet room with adequate illumination on the console of the system by a single observer. The specifications for the console were intel core i3-6100 CPU, 8 GB RAM. The specifications of the display monitor were size of 18 × 10 inches and resolution of 1600 × 900 × 60 hertz. The observer made measurements of both right and left sides with the help of the software of the machine (CS imaging version 8) and its measurement tools. The magnification factor used for the machine was 1.20. The length of SP was measured on the frontal side from the tip of SP to the point where it left the petrous temporal bone by the operator. Length above 30 mm was considered elongated. The measurements are shown in [Figure 1].

Figure 1: OPG image showing measurements of the right and left styloid processes. OPG: Orthopantomogram.

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Statistical analysis

All data were recorded in a Microsoft Excel sheet and converted to.csv (comma-separated values). Statistical analysis was carried out with SPSS version 26 IBM International Business Machines Corporation – Armonk new York United states and RStudio (R version: 4.0.5) that was used for estimating cross tabulation and also the p-value of Chi-square test. If P < 0.05, the test is considered statistically significant. The t-test was accustomed to checking the difference of the mean of two different samples if their variances were equal.

Results

In the study sample, 354 (32.53%) of 1088 subjects showed radiographic interpretation, indicating an elongated SP. One hundred and fifty-five (14.24%) out of 514 females and 199 (18.29%) out of 574 males showed an elongated SP. P was calculated to be 0.11, i.e., >0.05, which means no significant relationship between gender in elongation of SP [Table 1].

Table 1: Distribution of frequencies of elongated styloid process according to different gender

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According to [Table 2], among age groups, maximum subjects showing elongation of SP were observed in Group 4 (37.40%) and minimum in Group 1 (12.5%). Among age groups, a maximum number of subjects showing unilateral elongation of SP were in Group 1 (66.66%), and a maximum number of subjects showing elongation of SP on both sides were in Group 4.

Table 2: Distribution of frequencies of elongated styloid process according to different age groups

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[Table 3] shows that the maximum means of the length of the right and left SP was observed in Group 4, which was 27.78 (±8.07) and 27.38 (±8.07), respectively, whereas the minimum means of the length of the right and left SP was observed in Group 1, which was 24.26 (±4.76) and 23.98 (±4.45), respectively. Distribution as per the age group and according to the gender of bilateral SP elongation is represented using boxplots [Figure 2] and [Figure 3].

Table 3: Mean, median and standard deviation among different age groups for the right and left styloid process elongation

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Figure 2: Right and left styloid process elongation distribution per age group represented using boxplots.

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Figure 3: Right and left styloid process elongation distribution per gender represented using boxplots.

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[Table 4] shows that the maximum means of the length of the right and left SP was observed in male subjects, which was 27.5 (±6.61) and 27.46 (±7.69), respectively. The Welch's two-sample t-test showed a P of 0.3472 (>0.05); hence, we came to the conclusion that no significant difference was noted between the length of elongated SP for left and right sides across all genders and age groups.

Table 4: Mean, median and standard deviation among gender for the right and left styloid process elongation

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After performing Welch's two-sample t-test, the P is 0.06399 (>0.05); hence, we came to the conclusion that no significant difference was noted in the length of elongated SP among different genders.

After performing the product–moment correlation test, the P is 0.0009514 between the age of the subject and the mean length of the SP. Thus, we rejected the null hypothesis at a 5% level of significance, and the alternative hypothesis was accepted, that is, there is a significant positive correlation between age and length of the SP, and the true correlation coefficient is 0.094034 (≠ 0).

Discussion

The purpose of the study was to provide an epidemiological evaluation of the elongated SP on digital OPG in our population. This OPG is simple to perform and easy to interpret, lowers exposure to radiation and is more cost-effective than CT and CBCT, which suggests its use for epidemiological evaluation.^[4] The incidence of elongated SP incorporates a significant variability in the population. During this study, the observed incidence rate was 32.53%, which was in accordance with other radiological studies reported in the literature, which shows the incidence rate to be 29.6% and 38.5%, respectively.^[5],[6]

The elongation of styloid process and structural changes in stylohyoid ligament with its clinical signs and symptoms were first described by Eagle, otorhinolaryngologist, hence it's termed as Eagle's syndrome. It majorly occurs due to mineralisation or calcification of the stylohyoid ligament complex. The common signs and symptoms of Eagle's syndrome are otologia, headache, dysphagia and pain in swallowing. Patients have even reported sensation and perception of foreign body in the throat, pain during the change in head position and pain in the cervicofacial region.^[7] It is difficult to clinically diagnose it as its symptoms resemble that of orofacial disorders such as atypical orofacial pain, TMD, glossopharyngeal neuralgia and odontalgia. Eagle's syndrome should be correctly diagnosed, and the patient should be referred to an ENT surgeon. Its management includes a medical or surgical approach. There is not enough evidence for any particular approach. Non-steroidal anti-inflammatory drugs, carbamazepine, diazepam, heat application and transpharyngeal or extraoral approach will be curative. The transpharyngeal route is less invasive but may lead to injury and infection of local structures post-surgical oedema due to the compact operating field area. There is evidence of 20% surgical procedure failure rates, but newer studies reported complete resolution of symptoms in the majority of cases and showed very few post-operative complications, such as transient weakness of the marginal mandibular nerve.^[8]

Elongation of the SP is also suspected to be related to other disorders such as temporomandibular joint disorders and bilateral ischemic stroke due to carotid artery compression. Jelodar et al.^[9] have reported one such case of bilateral ischemic stroke due to carotid artery compression by elongated SP bilaterally, which was treated by surgical resection of elongated SP on both sides. Krohn et al.^[10] have studied 192 digital X-rays of patients diagnosed with research diagnostic criteria (RDC)/TMD for the length of the SP to find any correlation between it. However, they reported that no significant correlations between RDC/TMD diagnoses and SP length were found. The correlation of elongated SP with serum calcium levels is also being investigated. Tyagi et al.^[11] evaluated OPG and serum calcium levels of 500 patients and concluded that serum calcium levels and length of the SP showed a very poor correlation.

In our study, 1088 patients in the age group of 5–90 years were evaluated using digital OPG from Government Dental College and Hospital database. 32.53% of subjects showed an elongated SP. No statistical difference was observed in occurrence between gender, which was in accordance with the studies published by Roopashri et al.^[12] and More and Asrani.^[13] In our study more male subjects showed elongation of styloid process than female subjects which was in accordance with the studies published by Tyagi et al.,^[11] Alzarea^[14] and More and Asrani.^[13] In contrast to the above findings, some studies showed a sizable amount of elongation in female subjects than in male subjects such as Aoun et al.,^[15] Roopashri et al.^[12] and Sridevi et al.^[16]

A progressive increase in the prevalence of the elongation of SP was found with advancing age in different age groups. The rate of occurrence was 12.5% among the patients belonging to Group 1, 31.4% patients within the Group 2, 33.12% patients within the Group 3 and 37.40% patients within the Group 4. The findings were in accordance with Tyagi et al.^[11] In contrast to this study, elongation of the calcification of process in young adults was found to be common with no correlation to gender in an exceedingly study published by Kursoglu et al.^[17] and Alpoz et al.^[18]

In our study, unilateral elongation of the SP was seen more in comparison to bilateral elongation among different age groups, but no significance was found, which was in contrast with the studies presented by AlZarea,^[14] Aoun et al.^[15] and Guimarães et al.^[19]

In our study, no statistically significant difference was noted between the length of right and left side elongated SP across all genders and age groups. SP elongation was finally considered a continuous variable with the increasing age of the subjects. These findings were in accordance with the study done by Bruno et al.^[4],[20] In contrast to the current study, elongation of the SP was found more on the left than right within the study published by Roopashri et al.,^[12] while the elongation of the right side process was found to be more than left within the studies published by Aoun et al.^[15] and Hettiarachchi et al.^[21]

According to the data from our study, with the advancing age of an individual, an increase in mean length of right and left SP was observed, which was due to the chronic calcification process.

Conclusion

The rate of incidence of elongated SP was 32.53% in our epidemiological study. The incidence of elongation, as well as the mean length of the SP, increases with age. It confirms the development of chronic calcification described in the literature. No statistically significant correlation is noted between the incidence of elongated SP between the gender and affected side (bilateral and unilateral). OPG is a convenient tool for screening of Eagle's syndrome, i.e., elongated SP, and as it is easily available, low radiation, cost-effective, and easy to explain to patients.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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