Spontaneous atraumatic vertebral artery occlusion due to physiological cervical extension: case report

Safety and efficacy of dynamic catheter-directed cerebral digital subtraction angiography for diagnosis of bowhunter syndrome spectrum disorders: A systematic review of the literature

INTRODUCTION

Dynamic catheter-directed cerebral digital subtraction angiography (dcDSA) is the gold standard for diagnosing dynamic vascular occlusion syndromes such as bowhunter syndrome (BHS). Nonetheless, concerns about its safety exist and no standardized protocols have been published to date.

METHODS

We describe our methodology and insights regarding the use of dcDSA in patients with BHS. We also perform a systematic literature review to identify cases of typical and atypical presentations of BHS wherein dcDSA was utilized and report on any procedural complications related to dcDSA.

RESULTS

Our study included 104 cases wherein dcDSA was used for the diagnosis of BHS. There were 0 reported complications of dcDSA. DcDSA successfully established diagnosis in 102 of these cases. Thirty-eight cases were deemed atypical presentations of BHS. Fourteen patients endorsed symptoms during neck flexion/extension. In eight cases, there was dynamic occlusion of bilateral vertebral arteries during a single maneuver. Three patients had multiple areas of occlusion along a single vertebral artery (VA). An anomalous entry of the VA above the C6 transverse foramen was observed in four patients. One patient had VA occlusion with neutral head position and recanalization upon contralateral lateral head tilt.

CONCLUSION

Our study highlights the safety and diagnostic benefits of dcDSA in characterizing the broad spectrum of BHS pathology encountered in clinical practice. This technique offers a powerful means to evaluate changes in cerebral blood flow and cervical arterial morphology in real time, overcoming the constraints of static imaging methods. Our findings pave the way for further studies on dcDSA to enhance cross-sectional imaging methods for the characterization of BHS and other dynamic vascular occlusion syndromes.

Suboccipital Muscles, Forward Head Posture, and Cervicogenic Dizziness

Dizziness or vertigo can be caused by dysfunction of the vestibular or non-vestibular systems. The diagnosis, treatment, and mechanism of dizziness or vertigo caused by vestibular dysfunction have been described in detail. However, dizziness by the non-vestibular system, especially cervicogenic dizziness, is not well known. This paper explained the cervicogenic dizziness caused by abnormal sensory input with references to several studies. Among head and neck muscles, suboccipital muscles act as stabilizers and controllers of the head. Structural and functional changes of the suboccipital muscles can induce dizziness. Especially, myodural bridges and activation of trigger point stimulated by abnormal head posture may be associated with cervicogenic dizziness.

A Surgical Case of Bow Hunter’s Syndrome Diagnosed by Cervical Rotational MRA

Bow hunter's syndrome is an ischemic manifestation of vertebrobasilar artery (VA) insufficiency due to stenosis or occlusion of the contralateral VA at the bony elements of the atlas and axis during neck rotation. In early reports, VA stenosis at the craniovertebral junction was the main cause, but later, symptoms due to VA occlusion at the middle and lower cervical vertebrae were also included in this pathology. Although the confirmed diagnosis is usually determined by dynamic digital subtraction angiography (DSA), we have experienced a method of minimally invasive MR angiogram (MRA) that provides the same diagnostic value as DSA and would like to present it here. The patient was a 61-year-old man who had been visiting the outpatient clinic for cervical spondylosis due to neck pain for 9 months. When he rotated his neck to the left side, dizziness and syncope appeared. Initial MRA in the neutral position did not show any steno-occlusive changes in the vertebrobasilar artery. In our hospital, repeated MRA with the neck rotated 45 degrees to the left demonstrated ipsilateral left VA severe stenosis. Subsequent DSA showed the same findings, with occlusion of the left VA. CT of the cervical spine revealed a ventral C3/4 osteophyte within the foramen. Based on these findings, instability at the C3-4 during head rotation was considered the cause of the vertebrobasilar insufficiency. The patient underwent anterior discectomy and fusion (ACDF) at the C3/4 level using a cylindrical titanium cage. Immediately after the surgery, the patient's symptoms improved dramatically and did not appear even when the neck were fully rotated to the left. More than 5 years have passed since the surgery, and the patient is still in good health.

What you need to know about: arterial cerebrovascular syndromes caused by static or dynamic musculoskeletal compression

Compressive syndromes of the cervical arteries caused by musculoskeletal structures include bow hunter's syndrome, beauty parlour stroke syndrome, carotid compression by the hyoid bone, carotid compression by the digastric muscle and Eagle syndrome. They are a rare but increasingly recognised group of syndromes, so a high level of suspicion is needed so the diagnosis is not missed. The diagnosis is typically based on a combination of clinical history and advanced imaging investigations. Compression of the arteries may be static (only provoked by compression) or dynamic (exaggerated by movement), and this should be considered when selecting imaging studies. Symptoms resulting from vertebrobasilar insufficiency or ischaemia of areas supplied by the internal carotid artery are caused by compression of the vertebral artery and the internal carotid artery respectively. Surgical procedures are the preferred treatment for most of these syndromes.

Ischemic Stroke Secondary to Dynamic Vertebral Artery Stenosis: Case Report and Review of the Literature

Ischemic stroke secondary to dynamic vertebral artery stenosis or occlusion, also known as “bow hunter's syndrome,” is a rare stroke mechanism. We report a case of a 24-year-old man with multiple hereditary exostosis (MHE) diagnosed at childhood. His first presentation to a neurologist was due to neck pain and clinical syndrome suggestive of ischemia in the vertebrobasilar territory. A therapeutic occlusion was done successfully without complication. The patient was discharged two days later on aspirin alone. In follow up one year later he continued to be symptom free. Moreover, this stroke mechanism has been reported extensively in the literature in isolation or secondary to many underlying diseases. In total, there are 168 cases reported in the published English literature, in either case reports or small series. In this review, we found that by far, vertebral artery occlusion at the atlanto-axial (C1-2) level dominated most reported cases. The most frequent presentation that led to further investigation was syncope or pre-syncope provoked by head rotation to one side. To our knowledge, there is no previous report of any stroke syndrome related to MHE before our case. In this paper, we report the first case secondary to MHE and review the literature up to date since the first reported case in 1952.

Bow hunter's syndrome due to an embolic mechanism: illustrative case

BACKGROUND

Bow hunter's syndrome (BHS) is an uncommon cause of vertebrobasilar ischemic stroke, which results from occlusion or injury to the vertebral artery (VA) during neck rotation. Although hemodynamic insufficiency is the predominant underlying mechanism of this entity, BHS due to embolic mechanisms is rare. The authors report a case of BHS characterized by repeated posterior circulation embolism and present some considerations of BHS with an embolic mechanism.

OBSERVATIONS

A 57-year-old man suffered from repeated embolic stroke in the posterior circulation. Digital subtraction angiography revealed caliber irregularity of the V3 segment of the left nondominant-side VA, which occluded when the neck rotated to the right side. The patient was diagnosed with BHS with an embolic mechanism due to endothelial damage caused by osteophytes at the C1 foramen transversarium. After C1-C2 fusion surgery, the patient never experienced the recurrence of stroke. According to a literature review, BHS due to embolic mechanisms tends to occur in young male adults, manifesting as recurrent stroke in the posterior circulation. Involvement of the nondominant-side VA can cause BHS with an underlying embolic mechanism.

LESSONS

BHS due to an embolic mechanism should be considered as a differential diagnosis if patients have repeated embolic strokes in the posterior circulation.

New diagnostic algorithm for detection of covert Bow Hunter's Syndrome

Bow hunter's syndrome (BHS) should not be overlooked as a cause of cerebral infarction in the posterior circulation. However, covert BHS, which does not impair blood flow with simple rotation but only at certain angles, may make the diagnosis of BHS difficult. We propose a new algorithm to detect BHS or covert BHS. We recommend that BHS and covert BHS be detected by noninvasive duplex ultrasonography, which will allow for appropriate treatment.

Bow hunter syndrome: A rare yet important etiology of posterior circulation stroke

A6-year-oldgirl presented with acute-onset headache andfluctuating right-sided weakness.HerPedNIHSSwas13. Brain MRI/MRA showed acute pontine arterial ischemic stroke(AIS)and remote right cerebellar and thalamic infarcts.No antecedent trauma or other stroke risk factors were identified. Clinical suspicion of bow hunter syndromewas raised. CTshowed congenital C2-C3 fusion and dynamic angiogramconfirmed the diagnosis. The management challenges of this rare condition are discussed below.

Changes in Vertebral Artery Hemodynamics Associated With McKenzie Therapeutic Cervical Movements: An Exploration Using Duplex Ultrasound Imaging

OBJECTIVE

The purpose of this study was to explore vertebral artery hemodynamic changes associated with McKenzie therapeutic cervical movements in healthy individuals.

METHODS

A single-group repeated-measure design was used to examine 20 healthy participants aged 22.05 (1.69) years, mean (standard deviation). Vertebral artery volume flow, diameter, resistive index, time-averaged maximum velocity, and pulsatility index were measured using Duplex ultrasound. Vertebral artery hemodynamics were measured at cervical neutral positions then compared against vertebral artery hemodynamics measured during end-range loading and after repeated McKenzie therapeutic movements. Wilcoxon signed rank tests were used for comparisons, and standardized mean differences (SMDs) were calculated to quantify the changes in size.

RESULTS

Repeated retraction with extension in a sitting position and end-range retraction with extension in supine position were significantly associated with an increase in vertebral artery volume flow, P ≤ .01, and the SMD suggests small-medium changes in size. Statistical significant vertebral artery dilation was observed in the sitting position with protraction, combined retraction with extension, and flexion, P ≤ .01, yet the SMD suggested small changes in size. End-range flexion was significantly associated with a reduction in vertebral artery pulsatility index, and the SMD suggested large changes in size. Repeated retraction with extension in supine position was significantly associated with an increase in vertebral artery time-averaged maximum velocity, yet the SMD revealed no clinically important difference.

CONCLUSION

For the healthy participants in this study, McKenzie cervical movements were mostly associated with an increase in vertebral artery hemodynamics.

A young woman with traumatic vertebral artery occlusion: a case report

Vertebral artery occlusion (VAO) may result from closed head or neck trauma and can be lifethreatening due to brain-stem and cerebellar infarction. CT angiography is recommended as a screening diagnostic tool in selected patients after blunt cervical trauma. A 24-year-old woman was admitted to our emergency department with left hemiplegia two days after motor vehicle collision. Final diagnosis of occlusion of the right vertebral artery was made in CT angiography. She was treated with anticoagulant for 4 days then discharged with 5/5 muscle forces. She was advised to continue warfarin and atorvastatin for her after discharge.

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.

Bow Hunter's Syndrome by Nondominant Vertebral Artery Compression: A Case Report, Literature Review, and Significance of Downbeat Nystagmus as the Diagnostic Clue

BACKGROUND

Bow hunter's syndrome (BHS) is rare and typically induced by mechanical compression of the dominant vertebral artery (VA) during head rotation. We report a case of BHS induced by nondominant VA compression in which contralateral VA patency was preserved. Definite diagnosis of BHS is not often feasible because of transient symptoms and nonspecific clinical features, such as vertigo or dizziness, especially in nondominant VA compression. We discuss the diagnostic clues of BHS and clinical features of BHS caused by nondominant VA compression through a literature review.

CASE DESCRIPTION

A 65-year-old man suffered repeated bouts of dizziness whenever his head was rotated to the left. This dizziness was consistently accompanied by downbeat nystagmus (DBN). Radiography revealed left VA compression by a lateral osteophyte at the C3-C4 level only during left head rotation. In contrast, patency of the right VA, which was almost equivalent in size to the left VA, was preserved during head rotation. The distinctive clinical finding of head rotation-induced DBN, which is usually associated with lesions involving the caudal midline cerebellum, was observed. Symptoms disappeared immediately after left VA decompression with osteophytectomy and C3-C4 fusion.

CONCLUSIONS

Despite excellent flow through the contralateral VA, occlusion of the nondominant VA occasionally induces BHS. According to a review of the literature, BHS cases do not always depend on the VA on one side for blood supply. Head rotation-induced DBN can be useful for diagnosis of BHS, even in cases of nondominant VA compression.

Acute massive cerebellar infarction associated with craniocervical junction complex malformation: a case report and literature review

We report a case of acute massive cerebellar infarction associated with craniocervical junction (CVJ) complex malformation in a 21-year-old male. Timely surgical intervention prevented the deterioration of his neurological status.