Blood flow velocities in basilar artery during rotation of the head

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.

Pre-manipulative cervical spine testing and sustained rotation do not influence intracranial hemodynamics: an observational study with transcranial Doppler ultrasound

INTRODUCTION

Manual joint mobilization and manipulation are recommended therapeutic interventions for people with neck pain. High-velocity thrust and sustained techniques have an uncertain association with serious arterial trauma. The validity of pre-manipulative tests of the cervical spine is often questioned, and the understanding of the effect of head/neck position on blood flow is still incomplete. Most of the evidence concerning hemodynamics in this area relates to extracranial flow (vertebral and carotid artery). Less is understood about the effects on intracranial flow while performing pre-manipulative tests and sustained positions like end of range cervical rotation mobilization. The aim of the study was to assess the influence of commonly used evaluation and treatment positions on intracranial hemodynamic parameters.

METHOD

A randomized, cross-over observational study using ultrasonography on healthy subjects (n = 19) was conducted to measure hemodynamic parameters (peak systolic velocity and end diastolic maximum) of intracranial arterial systems. Two test positions (sustained pre-manipulative thrust C0-1 and sustained cervical end of range rotation) were compared with a sham position for each test position.

RESULTS

:Neither the sequence of tests performed nor an independent variable (the two positions) had a significant effect (p < 0.05) on peak systolic velocity (PSV) or end diastolic maximum (EDM).

DISCUSSION

No effects from commonly used assessment and treatment of neck positions on hemodynamic parameters were found. This is consistent with previous studies. Further study is indicated on people with symptoms and known pathologies.

Effects of Head and Neck Positions on Blood Flow in the Vertebral, Internal Carotid, and Intracranial Arteries: A Systematic Review

BACKGROUND

Manual therapy interventions targeting the neck include various positions and movements of the craniocervical region. The hemodynamic changes in various spinal positions potentially have clinical relevance.

OBJECTIVES

To investigate the effects of craniocervical positions and movements on hemodynamic parameters (blood flow velocity and/or volume) of cervical and craniocervical arteries.

METHODS

A search of 4 databases (PubMed, Embase, CINAHL, and Index to Chiropractic Literature) and, subsequently, a hand search of reference lists were conducted. Full-text experimental and quasi-experimental studies on the influence of cervical positions on blood flow of the vertebral, internal carotid, and basilar arteries were eligible for this review. Two independent reviewers selected and extracted the data using the double-screening method.

RESULTS

Of the 1453 identified studies, 31 were included and comprised 2254 participants. Most studies mentioned no significant hemodynamic changes during maximal rotation (n = 16). A significant decrease in hemodynamics was identified for the vertebral artery, with a hemodynamic decrease in the position of maximum rotation (n = 8) and combined movement of maximum extension and maximum rotation (n = 4). A similar pattern of decreased hemodynamics was also identified for the internal carotid and intracranial arteries. Three studies focused on high-velocity thrust positioning and movement. None of the studies reported hemodynamic changes. The synthesized data suggest that in the majority of people, most positions and movements of the craniocervical region do not affect blood flow.

CONCLUSION

The findings of this systematic review suggest that craniocervical positioning may not alter blood flow as much as previously expected.

LEVEL OF EVIDENCE

Therapy, level 2a. J Orthop Sports Phys Ther 2019;49(10):688-697. Epub 5 Jul 2019. doi:10.2519/jospt.2019.8578.

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.

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.

Microvascular Decompression in Patient With Atypical Features of Hemifacial Spasm Secondary to Compression by a Tortuous Vertebrobasilar System

OBJECTIVE

We report a case of hemifacial spasm in a patient who had associated hearing loss, numbness throughout the face, tinnitus, and vertigo, all of which occurred when turning his head to the left. To our knowledge, these symptoms have not occurred in this pattern and with a single trigger.

CLINICAL PRESENTATION

A 45-year-old man presented with a 3-year history of right-sided hemifacial spasm initially treated with botulinum toxin. One month before presentation, he had an episode of acute hearing loss in the right ear when turning his head to the left, followed by multiple episodes of transient hearing loss in his right ear, numbness in his right face in all distributions of the trigeminal nerve, tinnitus, and vertigo. He was found to have decreased sensation in nerves V1 to V3 and House-Brackmann grade 3/6 weakness in his right face, despite not having botulinum toxin injections in more than a year. Magnetic resonance imaging/angiography showed an ectatic vertebrobasilar system causing compression of the fifth, seventh, and eighth cranial nerves.

INTERVENTION

The patient underwent a retromastoid craniotomy and microvascular decompression. Postoperatively, he had complete resolution of his symptoms except for his facial weakness. The benefit has been long-lasting.

CONCLUSION

Multiple, simultaneous cranial neuropathies from vascular compression are rare, but this case is an example of safe and effective treatment with microvascular decompression with durable results.

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.

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

The aim in this study was to evaluate the effect of cervical spondylosis on vertebral arterial flow. The flow changes on Doppler measurements in patients with vertigo were also assessed. Ninety-one patients with different grades of degeneration on disks and apophysis were evaluated. The severity of degeneration was determined by two observers, and the effect of cervical degeneration on vertebral arterial flow was assessed. The relation between vertigo and changes in Doppler measurements of vertebral artery in neck and cranium was analyzed. As total degeneration increases, the flow volume decreases in the right vertebral artery but increases in the left. No other correlation between degeneration scores, cervical curve measurements, and Doppler measurements was noted. According to the total degeneration scores, no differences were noted between the patients with and without vertigo. In patients with vertigo, the resistive index was higher in the neck before the vertebral foramina. In correlations of the ratios of the intra/extracranial vertebral artery with Doppler measurements, the only change was observed in the left flow volume. The severity of degeneration in disks and apophysis does not cause a considerable change in vertebral arterial flow, and also no significant finding on Doppler measurements were noted in patients with vertigo.

The association between positional vertebral and basilar artery flow lesion and prevalence of vertigo in patients with cervical spondylosis

OBJECTIVE

The aim of our investigations was to characterize the relationship between basilar artery (BA) flow velocity in patients with cervical spondylosis and age, grade of radiological changes, prevalence of vertigo, and decreased blood flow velocity through vertebral arteries (VA) after head rotation.

STUDY DESIGN AND SETTING

A prospective, controlled study in academic neurotology was conducted. We examined 80 patients with radiological evidence of cervical spondylosis. Forty patients complained of positional vertigo lasting more than 6 months. Patients were examined by transcranial Doppler ultrasound with head rotations.

RESULTS

We showed significant association between velocity flow in basilar artery after neck rotation and age, prevalence of vertigo, grade of radiological changes, and positional vertebral artery flow lesion.

CONCLUSION

Spondylotic-induced VA compression may be the reason for decreased blood flow velocity in the basilar artery during head rotation, which may be of particular importance for older patients, especially complaining of vertigo.

SIGNIFICANCE

Every patient with high-grade cervical spondylosis, especially complaining of vertigo, should be examined by using TCD (transcranial Doppler) with head rotations. In case of positional blood flow reduction during head rotation, further angiographic examination should be undertaken so as to plan suitable treatment.

EBM RATING

C-4.

Causes of complications from cervical spine manipulation

Cervical manipulation occasionally causes serious vertebrobasilar complications. The usual cause is vertebral artery dissection, however in some cases there has been no obvious arterial injury. The present paper reviews the mechanisms by which complications occur, particularly when the applied force is trivial or there is no injury to the vertebral arteries, and the factors that increase risk of complications. In addition, implications are drawn for use of the recently revised Australian Physiotherapy Association (APA) guidelines. In the absence of vertebral artery rupture, complications are proposed to arise from vasospasm, haemostasis, endothelial injury or turbulent flow. These mechanisms have a sound scientific basis but have yet to be demonstrated as specifically causing vertebrobasilar complications. The most important risk factors for vertebrobasilar complications appear to be prior trauma to the vertebral arteries and symptoms of vertebrobasilar ischaemia from previous manipulation. There is weak evidence that hypoplasia of the vertebral arteries also increases the risk of complications. Neither general vascular factors nor pre-existing degenerative conditions of the cervical spine increase risk of vertebrobasilar complications. The procedures described in the APA guidelines test adequacy of total cerebral perfusion during cervical movements rather than patency of the vertebral arteries or their susceptibility to injury. The guidelines may therefore indicate potential for surviving a complication from manipulation. They may also identify patients at risk of complications from minor trauma. It is recommended that the procedures described in the APA guidelines be applied prior to every manipulation, and that manipulation be avoided in the presence of any signs of vertebrobasilar insufficiency.

Basilar artery blood flow during head rotation in vertebrobasilar ischemia

PATIENTS AND METHODS

Forty-six patients with vertebrobasilar ischemia and 40 control subjects were examined during head rotation using transcranial Doppler ultrasonography.

RESULTS

In the control group, no difference in blood flow velocity through the BA was found between the neutral and rotated positions. Based on these data, a blood flow reduction in the BA of more than 20% was considered to be significantly abnormal (p < 0.01). In three of 46 patients no signal was detectable in the BA using TCD. The reduction in blood flow velocity through the BA during head rotation was strongly dependent on the condition of the VA; none of 23 patients without atherosclerotic lesions or hypoplasia of the VA developed a significant reduction in blood flow through the BA. Two of 11 patients with unilateral VA lesions had significantly reduced blood flow in the BA (27% and 31%), although both were asymptomatic. Five of nine patients with bilateral VA lesions showed a significant reduction in blood flow through the BA (mean = 52%, minimum = 30%), and four of these developed clinical symptoms such as vertigo or diplopia during the rotation maneuver.

CONCLUSION

These data suggest that patients with uni- or bilateral lesions of the VA are at risk for developing clinically relevant reductions in blood flow through the BA during head rotation. Because not all patients with VA lesions developed reduced blood flow velocity, we conclude that individual vascular mechanisms must play an important compensatory role.

Influence of extreme head rotations on brainstem auditory evoked potentials (BAEP)

The influence of extreme head rotations on BAEP was studied in 47 patients who had vertebral artery angiogram. Patients with and without unilateral hypoplasia of the vertebral artery (VA) lumen were identified and all patients were further divided into two groups: with and without hypertension. The subjects underwent a BAEP examination in three head positions: neutral position, extreme right and extreme left rotation. In the subgroup of patients with hypertension and unilateral VA hypoplasia, and following the rotation away from the non-hypoplastic vessel a statistically significant decrease in the PV wave amplitude and prolonged PV wave latency was found. Head maneuvers in subjects with normal blood pressure or in hypertensive patients with symmetrical VA did not cause significant changes in BAEP. These results document the effect of head rotation in subjects with potentially impaired collateral flow. An increase in the PV wave latency and decrease in its amplitude may reflect subtle changes in the brainstem perfusion in hypertensive patients. These changes maybe due to a reduced capacity to compensate for dynamic obstruction of VA following the head rotations.

Changes of blood flow velocity indicating mechanical compression of the vertebral arteries during rotation of the head in the normal human measured with transcranial Doppler sonography

The dynamical changes of blood flow velocity of the intracranial vertebral arteries (VA's) and proximal basilar artery (BA) provoked by rotation of the head in normal volunteers were measured using pulsed-wave transcranial Doppler sonography (TCD). In another group both VA's were examined simultaneously with 2-channel TCD. Blood flow velocities diminished compared to the neutral position in all vessels, independently of the side. Total obstruction of the flow was not observed. Our findings reveal a definitive decrease of blood flow velocity at the vertebrobasilar artery system provoked by rotation of the head in normal humans. This physiological phenomenon is suggested to have an impact on the cerebral blood flow in patients with impaired autoregulation of the cerebral vessels, low volume flow reserve in the contralateral VA or insufficient collateral channels because of normal anatomical variation, especially those patients under general anesthesia or comatose.