Effect of cervical spondylosis on vertebral arterial flow and its association with vertigo

Resolution of Sporadic Hemiplegic Migraine by Correcting a Cervical Spine Kyphosis Utilizing the Chiropractic BioPhysics® (CBP®) Technique: A Case Report With Long-Term Follow-Up

A 19-year-old male suffered from sporadic hemiplegic migraine (SHM) for several years and experienced significant pain and disability with sensory and motor disturbances during the migraine headaches. Weakness, abnormal vision, abnormal sensation, one-sided disabling motor weakness, and other signs of SHM were diagnosed. The patient had received previous physical therapy, chiropractic and over-the-counter medications, as well as migraine-specific prescriptions without lasting improvements. Chiropractic BioPhysics® (CBP®) spinal structural rehabilitation protocols were used to increase cervical lordosis and improve cervical muscular strength, mobility, and posture. These protocols include spine-specific prescriptions for Mirror Image® postural exercises, traction, and spinal manipulative therapy. After 24 treatments over eight weeks, all subjective and objective outcomes improved dramatically with a near resolution of all initial symptoms of SHM. There were a significant increase in cervical lordosis and a reduction in forward head posture. The neck disability index improved from 26% to 6%, and all pain scores for all regions improved following treatment. A 10-month follow-up exam showed the outcomes were maintained. SHM is rare and debilitating, is part of the global burden of disease, and is a major cause of disability in the world. Reports of successful conservative and non-conservative long-term treatments for SHM are rare, and there are no clinical trials showing successful treatments for SHM. This successful case demonstrates preliminary evidence that CBP spinal structural rehabilitation may serve as a treatment option for SHM. Future studies are needed to replicate the findings from this case.

Increased risk of sudden sensorineural hearing loss in patients with cervical spondylosis

Whether cervical spondylosis (CS) is a risk factor for sudden sensorineural hearing loss (SSNHL) remains unclear. This study used national population-based data to investigate the risk of SSNHL in patients with CS in Taiwan of different ages and sexes. This study used data covering 2 million people in Taiwan, which were obtained from the National Health Insurance Research Database. The data that support the findings of this study are available from National Health Insurance Research Database but restrictions apply to the availability of these data, which were used under license for the current study, and so are not publicly available. Data are however available from the corresponding authors upon reasonable request and with permission of National Health Insurance Research Database. This retrospective cohort study enrolled 91,587 patients with a newly diagnosed CS between January 2000 and December 2018. Case and control cohorts were matched 1:1 according to age, sex, and comorbidities. SSNHL incidence rate and risk were compared between the groups. Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). The mean follow-up period was 8.80 (SD = 4.12) and 8.24 (SD = 4.09) years in the CS and control cohorts, respectively. The incidence rate of SSNHL in the CS cohort (85.28 per 100 000 person-years) was 1.49-fold significantly higher than that in the non-CS cohort (57.13 per 100,000 person-years) (95% CI 1.32-1.68, P < .001). After age, sex, and selected comorbidities were adjusted for, CS exhibited an independent risk factor for SSNHL (adjusted HR = 1.52; 95% CI   1.34-1.71, P < .001). An age-stratified analysis in this study demonstrated a strong and highly significant association between CS and SSNHL in patients aged < 35 years (IRR = 2.28, 95% CI   1.18-4.39, P = .013). This large-scale Taiwanese-population-based retrospective study found that CS was associated with an increased risk of SSNHL. Acute hearing loss in patients with CS, particularly at a young age, should be carefully evaluated, and prompt treatment for SSNHL should be initiated.

Risk of Cervical Dizziness in Patients With Cervical Spondylosis

Importance

The dizziness associated with cervical spondylosis is a controversial topic given that many experts believe that cervical spondylosis is a common cause of dizziness, whereas others do not believe it exists.

Objective

To compare the risk of dizziness between patients with cervical spondylosis and matched controls (ie, patients with lumbar spondylosis after propensity score matching [PSM]).

Design, Setting, and Participants

This cohort study used medical claims data from the National Health Insurance Research Database of Taiwan for patients 60 years or older with cervical or lumbar spondylosis newly diagnosed in any outpatient department between January 1, 2010, and December 31, 2015. Patients diagnosed with cervical spondylosis were included as the study cohort, and those diagnosed with lumbar spondylosis who were matched to the study cohort via PSM were selected as the control cohort. Both cohorts were followed up for 1 year unless they were diagnosed with dizziness, censored by death, or withdrew from the health insurance program. Data analysis was performed from August 9 to September 20, 2022.

Main Outcomes and Measures

The main outcome was the date of outpatient diagnosis of dizziness. The risks of dizziness were compared between groups. The relative risk and incidence rate difference were calculated.

Results

A total of 3638 patients with cervical spondylosis (mean [SD] age, 67.9 [7.1] years; 2024 [55.6%] male) and 3638 patients with lumbar spondylosis (mean [SD] age, 68.0 [7.1] years; 2024 [55.6%] male) after PSM were selected as the study and control cohorts, respectively. The patients with cervical spondylosis had higher risk of dizziness than matched controls, with a 1-year relative risk of 1.20 (95% CI, 1.03-1.39). The 1-year incidence of dizziness was 10.2% (95% CI, 9.2%-11.2%) in patients with cervical spondylosis and 8.6% (95% CI, 7.7%-9.5%) in the matched group of lumbar spondylosis. The incidence rate difference between the groups was 1.6% (95% CI, 0.3%-3.0%).

Conclusions and Relevance

These data support the association between dizziness and cervical spondylosis, but the small difference between groups reveals that dizziness associated with cervical spondylosis is uncommon. Clinicians should be wary of diagnosing a cervical cause for dizziness based on an actual history of cervical spondylosis.

Impact of craniocervical junction abnormality on vertebral artery hemodynamics: based on computational fluid dynamics analysis

Background and purpose

A three-dimensional reconstruction and data analysis of the vertebral artery (VA) with craniocervical junction abnormality (CJA) was performed by computational fluid dynamics (CFD) based on images to assess the impact of CJA on vertebral artery hemodynamics.

Methods

Retrospective analysis of combined head and neck computed tomography angiography (CTA) images of 60 patients with CJA and 60 normal patients admitted to our department from January 2018 to June 2022. The VA was reconstructed in three dimensions using CFD-related software, and the results were visualized to derive vertebral artery lumen diameter (D), peak systolic velocity (PSV), mean blood flow velocity (MV), wall pressure (P), wall shear stress (WSS), normalized WSS (NWSS), etc. Statistical analysis was used to analyze whether the data related to hemodynamics in the CJA group and the control group were statistically significant.

Results

The lumen diameter of the vertebral artery in the CJA group were less than the control group, and the difference was statistically significant (3.354 ± 0.562 vs. 3.744 ± 0.520, p < 0.05); the PSV, MV, P, WSS, and NWSS of the CJA group were increased compared with the control group, and the difference was statistically significant (1.235 ± 0.182 vs. 1.104 ± 0.145, 0.339 ± 0.063 vs. 0.307 ± 0.042, 24576.980 ± 7095.836 vs. 20824.281 ± 6718.438, 34.863 ± 6.816 vs. 31.080 ± 5.438, 0.272 ± 0.075 vs. 0.237 ± 0.067, p < 0.05).

Conclusion

In the complex CJA, the possibility of hemodynamic variation in the VAs is higher than in the normal population. The hemodynamic aspects of the vertebral artery in patients with CJA, such as diameter, flow velocity, flow, wall pressure and shear force, differ from those in the normal population and may lead to the occurrence of clinical symptoms, such as dizziness, so preoperative examinations such as combined head and neck CTA should be performed to clarify the vascular abnormalities.

Degenerative Cervical Spondylosis: A Cause of Vertigo?

STUDY DESIGN

Prospective observational study.

OBJECTIVES

Studying the effect of degenerative cervical spondylosis(CS) on blood flow velocity of vertebral artery (VA) during cervical spine rotation in different head positions and its association with vertigo.

INTRODUCTION

Vertigo is one of the most common complaints seen in an out-patient clinic. Its association with CS remains an enigma for a treating physician. This study planned to systematically analyze the association between vertigo and CS by evaluating VA blood flow dynamics in different head positions.

METHODS

100 patients with ages ranging from 20-80 years were recruited. First group of 50 patients with CS with vertigo were compared with second study group of 50 patients having CS without vertigo. Cervical radiographs were used to evaluate CS using cervical degenerative index (CDI). Color doppler was used to measure VA blood flow with head in neutral position and 60° lateral rotation with 30° extension. Same procedure was repeated on opposite side. Measurements performed included peak systolic blood flow velocity(PSV) and end diastolic blood flow velocity (EDV).

RESULTS

Among patients with CS, patients having vertigo showed significantly more evident degenerative changes (CDI ≥25) (P=<0.001). High grade CS patients (CDI ≥25) with vertigo had statistically significant lower blood flow parameters with head rotation in the left and right VAs as compared to CS patients without vertigo.

CONCLUSION

This study highlights important pathophysiological mechanism of vertigo observed in patients of CS. The magnitude of reduction in VA blood flow was significantly higher in patients with advanced CS presenting as vertigo.

Risk Factors for Recurrence of Benign Paroxysmal Positional Vertigo. A Clinical Review

Benign paroxysmal positional vertigo (BPPV) is one of the most common peripheral vestibular dysfunctions encountered in clinical practice. Although the treatment of BPPV is relatively successful, many patients develop recurrence after treatment. Our purpose is to evaluate the mean recurrence rate and risk factors of BPPV after treatment. A review of the literature on the risk factors of BPPV recurrence was performed. A thorough search was conducted using electronic databases, namely Pubmed, CINAHL, Academic Search Complete and Scopus for studies published from 2000 to 2020. Thirty studies were included in this review with 13,358 participants. The recurrence rate of BPPV ranged from 13.7% to 48% for studies with follow-up <1 year, and from 13.3% to 65% for studies with follow-up ≥2 years. Pathophysiologic mechanisms and implication of each of the following risk factors in the recurrence of BPPV were described: advanced age, female gender, Meniere’s disease, trauma, osteopenia or osteoporosis, vitamin D deficiency, diabetes mellitus, hypertension, hyperlipidemia, cardiovascular disease, migraine, bilateral/multicanal BPPV, cervical osteoarthrosis and sleep disorders. Patients with hyperlipidemia and hypertension had the highest recurrence rates of BPPV, 67.80% and 55.89%, respectively, indicating that vascular comorbidities increase the risk of BPPV recurrence. In addition, more than half of patients (53.48%) with diabetes mellitus and BPPV experienced recurrence of BPPV. Knowledge and awareness of risk factors for recurrence of BPPV are essential for the assessment and long-term prognosis of patients. Identification of these relapse risk factors may enhance the ability of clinicians to accurately counsel patients regarding BPPV and associated comorbidities.

Vertigo in Patients with Degenerative Cervical Myelopathy

(1) Background: Cervical vertigo (CV) represents a controversial entity, with a prevalence ranging from reported high frequency to negation of CV existence. (2) Objectives: To assess the prevalence and cause of vertigo in patients with a manifest form of severe cervical spondylosis-degenerative cervical myelopathy (DCM) with special focus on CV. (3) Methods: The study included 38 DCM patients. The presence and character of vertigo were explored with a dedicated questionnaire. The cervical torsion test was used to verify the role of neck proprioceptors, and ultrasound examinations of vertebral arteries to assess the role of arteriosclerotic stenotic changes as hypothetical mechanisms of CV. All patients with vertigo underwent a detailed diagnostic work-up to investigate the cause of vertigo. (4) Results: Symptoms of vertigo were described by 18 patients (47%). Causes of vertigo included: orthostatic dizziness in eight (22%), hypertension in five (14%), benign paroxysmal positional vertigo in four (11%) and psychogenic dizziness in one patient (3%). No patient responded positively to the cervical torsion test or showed significant stenosis of vertebral arteries. (5) Conclusions: Despite the high prevalence of vertigo in patients with DCM, the aetiology in all cases could be attributed to causes outside cervical spine and related nerve structures, thus confirming the assumption that CV is over-diagnosed.

Risk of posterior circulation stroke in patients with cervical spondylosis: A nationwide, population-based study

BACKGROUND AND AIMS

Cervical spondylosis (CS) is reported to be associated with vertebrobasilar insufficiency. However, few cohort studies have investigated the association between CS and posterior circulation ischemic stroke.

METHODS

The study cohort comprised 27,990 patients aged ≥18 years with a first diagnosis of CS. The controls consisted of patients with propensity score matched for age, sex, and comorbidities at a ratio of 1:1. We investigated the relationships of CS with ischemic stroke and all-cause mortality. Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). The average follow-up duration was 6.13 (SD = 3.18) and 6.07 (SD = 3.19) years in the CS and non-CS cohorts, respectively.

RESULTS

The mean age of CS patients and non-CS patients was 54.9 ± 13.4 and 55.1 ± 14.9 years. Fifty-eight point five percent of CS patients and 59.2% of non-CS patients were women. CS patients were 1.46 folds more likely to develop a posterior circulation ischemic stroke (95% CI, 1.23-1.72) than non-CS patients. CS patients with myelopathy exhibited a 1.50-fold risk (95% CI, 1.21-1.86) of posterior circulation ischemic stroke compared with non-CS patients; CS patients without myelopathy were at a 1.43-fold risk (95% CI, 1.18-1.73) of posterior ischemic stroke compared with non-CS patients. The risk of posterior ischemic stroke was non-significant between non-CS patients and CS patients who had received spinal anterior decompression (adjusted HR, 1.66; 95% CI, 0.78-3.52), while receiving posterior decompression was associated with a 4.23-fold risk of posterior ischemic stroke (95% CI, 1.05-17.0).

CONCLUSIONS

This population-based study showed that CS is associated with an increased risk of posterior circulation ischemic stroke. Surgical posterior decompression was associated with the highest risk of posterior ischemic stroke.

Approach to cervicogenic dizziness: a comprehensive review of its aetiopathology and management

PURPOSE

Though there is abundant literature on cervicogenic dizziness with at least half a dozen of review articles, the condition remains to be enigmatic for clinicians dealing with the dizzy patients. However, most of these studies have studied the cervicogenic dizziness in general without separating the constitute conditions. Since the aetiopathological mechanism of dizziness varies between these cervicogenic causes, one cannot rely on the universal conclusions of these studies unless the constitute conditions of cervicogenic dizziness are separated and contrasted against each other.

METHODS

This narrative review of recent literature revisits the pathophysiology and the management guidelines of various conditions causing the cervicogenic dizziness, with an objective to formulate a practical algorithm that could be of clinical utility. The structured discussion on each of the causes of the cervicogenic dizziness not only enhances the readers' understanding of the topic in depth but also enables further research by identifying the potential areas of interest and the missing links.

RESULTS

Certain peculiar features of each condition have been discussed with an emphasis on the recent experimental and clinical studies. A simple aetiopathological classification and a sensible management algorithm have been proposed by the author, to enable the identification of the most appropriate underlying cause for the cervicogenic dizziness in any given case. However, further clinical studies are required to validate this algorithm.

CONCLUSIONS

So far, no single clinical study, either epidemiological or interventional, has incorporated and isolated all the constitute conditions of cervicogenic dizziness. There is a need for such studies in the future to validate either the reliability of a clinical test or the efficacy of an intervention in cervicogenic dizziness.

Decreased Vertebral Artery Hemodynamics in Patients with Loss of Cervical Lordosis

Background

Because loss of cervical lordosis leads to disrupted biomechanics, the natural lordotic curvature is considered to be an ideal posture for the cervical spine. The vertebral arteries proceed in the transverse foramen of each cervical vertebra. Considering that the vertebral arteries travel in close anatomical relationship to the cervical spine, we speculated that the loss of cervical lordosis may affect vertebral artery hemodynamics. The aim of this study was to compare the vertebral artery values between subjects with and without loss of cervical lordosis.

Material/Methods

Thirty patients with loss of cervical lordosis and 30 controls matched for age, sex, and body mass index were included in the study. Sixty vertebral arteries in patients with loss of cervical lordosis and 60 in controls without loss of cervical lordosis were evaluated by Doppler ultrasonography. Vertebral artery hemodynamics, including lumen diameter, flow volume, peak systolic velocity, end-diastolic velocity, and resistive index, were measured, and determined values were statistically compared between the patient and the control groups.

Results

The means of diameter (p=0.003), flow volume (p=0.002), and peak systolic velocity (p=0.014) in patients were significantly lower as compared to controls. However, there was no significant difference between the 2 groups in terms of the end-diastolic velocity (p=0.276) and resistive index (p=0.536) parameters.

Conclusions

The present study revealed a significant association between loss of cervical lordosis and decreased vertebral artery hemodynamics, including diameter, flow volume, and peak systolic velocity. Further studies are required to confirm these findings and to investigate their possible clinical implications.

Medical and Psychiatric Causes of Episodic Vestibular Symptoms

Dizziness and vertigo are among the most common presenting patient complaints in ambulatory settings. Specific vestibular causes are often not immediately identifiable. The first task of the clinician is to attempt to rule in specific vestibular disorders, such as benign paroxysmal positional vertigo through physical examination, diagnostic testing, and history taking. A large proportion of patients with dizziness and vertigo will not be easily classified or confirmed as having a specific vestibular cause. As with any undifferentiated patient, the focus in this setting is to attempt to exclude serious or threatening causes.

Cervical spondylosis and hypertension: a clinical study of 2 cases

Cervical spondylosis and hypertension are all common diseases, but the relationship between them has never been studied. Patients with cervical spondylosis are often accompanied with vertigo. Anterior cervical discectomy and fusion is an effective method of treatment for cervical spondylosis with cervical vertigo that is unresponsive to conservative therapy. We report 2 patients of cervical spondylosis with concomitant cervical vertigo and hypertension who were treated successfully with anterior cervical discectomy and fusion. Stimulation of sympathetic nerve fibers in pathologically degenerative disc could produce sympathetic excitation, and induce a sympathetic reflex to cause cervical vertigo and hypertension. In addition, chronic neck pain could contribute to hypertension development through sympathetic arousal and failure of normal homeostatic pain regulatory mechanisms. Cervical spondylosis may be one of the causes of secondary hypertension. Early treatment for resolution of symptoms of cervical spondylosis may have a beneficial impact on cardiovascular disease risk in patients with cervical spondylosis.

Vertigo-related cerebral blood flow changes on magnetic resonance imaging

STUDY DESIGN

A prospective study using magnetic resonance imaging on a consecutive cohort of patients with cervical vertigo.

OBJECTIVE

To quantitatively investigate the cerebral blood flow (CBF) changes associated with cervical vertigo by using 3-dimensional pseudocontinuous arterial spin labeling.

SUMMARY OF BACKGROUND DATA

Previous studies reported blood flow velocity reduction in posterior circulation during vertigo. However, the detailed information of CBF related to cervical vertigo has not been provided.

METHODS

A total of 33 patients with cervical vertigo and 14 healthy volunteers were recruited in this study. Three-dimensional pseudocontinuous arterial spin labeling was performed on each subject to evaluate the CBF before and after the cervical hyperextension-hyperflexion movement tests, which was used to induce cervical vertigo. Repeated-measures analysis of variance was conducted to assess the effect of subjects and tests.

RESULTS

There were time effects of CBF in the territory of bilateral superior cerebellar artery, bilateral posterior cerebral artery, bilateral middle cerebral artery, and right anterior cerebral artery, but no group effect was observed. The analysis of CBF revealed a significant main effect of tests (P=0.024) and participants (P=0.038) in the dorsal pons.

CONCLUSION

Cervical vertigo onset may be related to CBF reduction in the dorsal pons, which sequentially evokes the vestibular nuclei.

LEVEL OF EVIDENCE

2.

Application of vertebral artery ultrasonography in enlistment-age male student pilots

The aim of this study was to investigate the vertebral artery (VA) morphology of enlistment-age male student pilots with ultrasound to provide a basis for early diagnosis of potentially asymptomatic cervical vertigo. Ultrasound results of the origin position, diameter and hemodynamics of the VA in 935 cases of student pilots with a mean age of 18.0 y were analyzed. The inner diameters of both sides of the VA differ: the left is larger than the right statistically (p < 0.001). Moreover, the peak systolic velocity of the left VA is significantly greater than that of the right (p < 0.001). Congenital VA anomalies in age-appropriate male student pilots included inner diameter variation, course variation and origin position variation. The incidence of course variation or origin position proportion was low (3.46%, 32/925), and origin position variation was often accompanied by inner diameter variation or course variation. This study confirms that there are a variety of congenital abnormalities in the vertebral arteries of enlistment-age male student pilots, and a VA diameter <2.5 mm may be a reasonable criterion for diagnosis of VA hypoplasia.

The comparative analyses of the auditory evoked potentials and color Doppler sonography findings in patients diagnosed with vertebrobasilar insufficiency

Auditory evoked potentials (AEP) represent an electrophysiological method used in the diagnostics of pathological changes of the brainstem. Patients with vertebrobasilar insufficiency (VBI) show changes in the AEP-caused ischemia of the brain structures that generate their responses. The aim of the study was to determine the diagnostic significance and correlation among the findings of AEP in patients with VBI established by color Doppler sonography. The cross-sectional and prospective research included 48 inpatients and outpatients treated at the Clinic of Neurology, Clinical Center Nis. Ultrasound Doppler of blood vessels in the neck included an examination of the carotid blood vessels, the outcome and all sonographically available parts of the vertebral artery (VA) with particular emphasis on the intravertebral segment (V2). The morphological and hemodynamic characteristics of VA in this segment were monitored, and it was important to test the systolic velocity in two adjacent intervertebral spaces. Auditory evoked potentials were used to monitor the amplitudes, absolute latencies of waves I, II, III, IV, and V, as well as interwave latencies (IWLs) I-III, III-V, and I-V. There is statistically significant difference in the more frequent pathological finding of AEP in patients with higher degree of the reduced flow of VA established by color Doppler (P < 0.05) compared to patients with less reduction in the flow. Pathological findings of AEP are well correlated with pathological findings of VBI in color Doppler, and it may be applied as an additional and useful marker in diagnosis of VBI.

Vertigo is associated with advanced degenerative changes in patients with cervical spondylosis

Since vascular risk factors that predispose to vertebrobasilar ischemia are common findings in elderly, cervical spondylosis-which is also common in such age group-as a cause of vertigo is sometimes considered as a myth. The purpose of this study is to investigate the effect of cervical spondylosis on blood flow velocity of VAs during cervical rotation and to identify the possible association of vertigo with the decreased blood flow velocity through VAs during head rotation in these patients. The incidence of cervical spondylosis was estimated in patients with and without vertigo. Patients with vertigo proved to have spondylosis are further compared with patients having spondylosis but not complaining of vertigo and patients who neither have spondylosis nor complain of vertigo who served as controls. Plain cervical radiography was used to evaluate cervical degenerative changes using cervical degenerative index. Color duplex sonography was used to measure vertebral artery blood flow with the cervical spine in the neutral position then with 60° rotation and 30° extension to measure the opposite vertebral artery. A significantly higher prevalence of cervical spondylosis was found among patients complaining of vertigo than those in non-vertigo group (71.4% vs. 32.9%, respectively). Furthermore, among patients with cervical spondylosis, patients having vertigo showed significantly more evident degenerative changes (P = 0.003). Despite Doppler ultrasound examination with head in neutral position was similar in all groups; cervical spondylosis patients with vertigo had statistically significant lower blood flow parameters with contralateral head rotation in the left and right vertebral arteries than cervical spondylosis patients without vertigo and controls. The decreased vertebral artery blood flow that occurs with cervical rotation can be observed in patients with cervical spondylosis. In patients with high-grade cervical spondylosis with more extensive osteophyte formation, the decreased blood flow becomes prominent and symptomatic presenting as vertigo.

Non-invasive evaluation of vertebral artery blood flow in cervical spondylosis with and without vertigo and association with degenerative changes

Cervical spondylosis is a common disease that results from degenerative changes of the cervical spine and vertigo may occur in this process. The aim of the present study was to assess the blood flow measurements of the vertebral artery (VA) using color Doppler ultrasonography (CDUS) in patients who have cervical spondylosis with and without vertigo. The study population included 101 patients with vertigo and spondylosis, 66 patients with spondylosis without vertigo, and 62 healthy controls. A bilateral decrease in the VA blood flow velocities were measured in patients with cervical spondylosis. A negative correlation was found between the stage of cervical degenerative changes and the flow velocities in patients with vertigo, while this relationship was not found in patients without vertigo. The CDUS evaluation of the pretransverse and transverse segments of VAs demonstrated significantly reduced flow velocities in patients with spondylosis. The degenerative changes in the cervical spine seem to be related to these velocity changes in the subgroup of patients who are also affected with vertigo. The pretransverse segment of the VA provides valuable measurements as well as transverse segment of the VA, and it can be used as an appropriate segment for CDUS examination in cervical spondylosis and associated vertigo.