Vertebral artery stenting for the treatment of bow hunter's syndrome: report of 4 cases

Bow Hunter Phenomenon From Advanced Cerebrovascular Disease Treated With Subclavian Artery Stenting and Carotid Endarterectomy

Bow Hunter syndrome (BHS) is a rare disorder characterized by mechanical occlusion of the vertebral artery (VA) during neck rotation, resulting in symptomatic, transient, and positional vertebrobasilar insufficiency. We describe a case of a 76-year-old female who presented with dizziness and right ear tinnitus triggered by right head rotation. Her symptoms would immediately resolve upon returning her head to the neutral position. CT angiogram showed 80% stenosis of the left subclavian artery origin, 50%-70% stenosis of the proximal right internal carotid artery (ICA), and near occlusive stenoses of the origins of the bilateral VAs. After failing conservative management, the patient was treated with left subclavian artery stenting, followed by a right carotid endarterectomy (CEA) 6 weeks later. Follow-up at 1 month showed resolution of paroxysmal symptoms and no neurological sequelae. To our knowledge, there have not yet been reported cases of patients with concurrent BHS, subclavian artery stenosis, and carotid artery stenosis. We suggest that global revascularization via subclavian artery stenting and CEA may be considered as treatment for patients with BHS complicated by other cerebrovascular disease secondary to stenoses of the ICA and subclavian artery. This approach obviates the need for more complex surgery or endovascular intervention of the VA.

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.

A case report of Bow Hunter's syndrome with intravascular ultrasound showing changing significant severe stenosis of the left vertebral artery associated with turning left

Background

Bow Hunter's syndrome is vertebral basilar artery insufficiency caused by mechanical occlusion of the vertebral artery during head rotation. This is often due to the formation of osteophytes, herniated discs, cervical spondylosis, or tumours. However, whether the contralateral vessel is organically stenotic is not well known.

Case summary

A 79-year-old man was referred to our department for a close examination of syncope because the transient loss of consciousness occurring when he was made to turn his head to the left was reproducibly induced and recovered when his face was returned to the normal position. The carotid massage did not induce significant bradycardia or hypotension bilaterally, and Holter electrocardiography, echocardiography, head-up tilt test, coronary angiography, and an acetylcholine stress test showed no obvious abnormalities. A 3D CT angiography was performed to investigate the possibility of vertebrobasilar artery insufficiency, as C3/4 cervical spondylosis, and the left vertebral artery was compressed by the C4 superior process osteophyte, indicating hypoplasia of the contralateral vertebral artery. Vertebral artery angiography and intravascular ultrasound (IVUS) showed moderate stenosis of the left vertebral artery, and IVUS showed a half-circumferential calcified lesion. Compared to the midline position, the stenosis worsened at the site of compression and drainage when the patient turned left downward, and a diagnosis of Bow Hunter's syndrome was made.

Discussion

Bow Hunter's syndrome is characterized by vertebrobasilar insufficiency. Intravascular ultrasound clearly showed that the lesion was not only stenotic due to compression but also had plaque growth due to continuous mechanical stimulation.

Bow Hunter's syndrome with clicking sounds: A rare etiology of transient loss of consciousness with tonic-clonic seizure

We present the case of a young male patient experiencing a transient loss of consciousness and manifesting a seizure when he tilted his head backward. Transcranial Doppler ultrasound (TCD) and carotid artery ultrasound (CAU) examination were normal when the patient's neck was in the neutral position. However, the CAU revealed vertebral artery (VA) transient occlusion during neck rotation or backward movement. Electroencephalogram (EEG) monitoring was performed with multiple neck rotation-induced tests. The patient developed dizziness, which was the same as the prodromal symptoms of the first seizure, and the EEG showed a large number of spinal slow waves and sharp slow waves in the frontal-to-frontal midline area, with an occasional generalization trend. CT angiography revealed occipitalization of the atlas and the lack of contrast agent filling in the local area of the VA when the patient's head was turned contralaterally. Thus, the patient was diagnosed with Bow Hunter's syndrome (BHS) and treated conservatively with neck immobilization. No recurrence occurred at 3 and 6 months of follow-up. Therefore, this case alerts neurologists to suspect BHS on observing seizure manifestations during neck rotation, and CAU may be a recommended dynamic screening method for BHS. This report is accompanied by a discussion of the phenomenon and diagnosis in the context of the existing literature.

Endovascular Coil Embolization for Recurrent Bow Hunter's Stroke

Bow hunter's stroke is a rare cause of vertebrobasilar infarction. There is no consensus regarding the optimal treatment. We herein report a case of bow hunter's stroke successfully treated by endovascular treatment. A 70-year-old man presented with central vertigo. Magnetic resonance imaging (MRI) showed posterior circulation infarcts. Dynamic angiography revealed thrombus formation and hypoperfusion of the right vertebral artery upon head rotation to the left. Endovascular parent artery occlusion of the right vertebral artery was performed, and there was no recurrence at follow-up MRI. Endovascular parent artery occlusion might be a useful treatment for bow hunter's stroke.

Bow hunter’s syndrome successfully treated with a posterior surgical decompression approach: A case report and review of literature

BACKGROUND

Bow hunter’s syndrome (BHS) is a rare but surgically treatable cause of vertebrobasilar insufficiency due to dynamic rotational occlusion of the vertebral artery. Typically, patients present with posterior circulation transient ischaemic symptoms such as presyncope, syncope, vertigo, diplopia, and horizontal nystagmus, but irreversible deficits, including medullary and cerebellar infarctions, have also been described.

CASE SUMMARY

A 70-year-old patient presented an acute onset of vertigo and gait instability triggered by right head rotation. His medical history included previous episodes of unilateral left neck and occipital pain followed by light-headedness, sweating, and blurred vision when turning his head, and these episodes were associated with severe degenerative changes in the atlanto-dens and left atlanto-axial facet joints and right rotation of the C2 cervical vertebrae. Brain magnetic resonance imaging revealed the presence of acute bilateral cerebellar ischaemic lesions, while static vascular imaging did not reveal any vertebral artery abnormalities. Dynamic ultrasonography and angiography were performed and confirmed the presence of a dynamic occlusion of the vertebral artery V3-V4 segment when the head was rotated to the right secondary to left C1-C2 bone spur compression. Surgical decompression led to complete resolution of paroxysmal symptoms without neurological sequelae.

CONCLUSION

BHS should be considered in cases of repeated posterior circulation transient ischaemic attack or ischaemic stroke, particularly when associated with high cervical spine abnormalities.

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

Bow hunter's syndrome is due to vertebrobasilar insufficiency caused by rotational compression of the vertebral artery. We report a case in which an osteophyte compressed the left vertebral artery causing cerebellar stroke. The patient underwent successful resection of the osteophyte via anterior surgical approach, and his symptoms of headache and dizziness dissipated postoperatively. This unique syndrome has been treated with multiple modalities and must remain in the clinician's differential as a treatable cause of stroke.

Vascular Ultrasound Measurements After Atlas Orthogonal Chiropractic Care in a Patient With Bow Hunter Syndrome

Objective

This case report describes chiropractic treatment for a patient diagnosed with bow hunter syndrome with transient vision loss (TVL).

Clinical Features

A 39-year-old woman presented to a chiropractic clinic with hand and arm numbness that began after she was injured in a motor vehicle collision 18 months earlier. The primary symptom was TVL that began 3 days after the motor vehicle collision. At that time, she had been diagnosed with bow hunter syndrome using dynamic angiography findings. She had previously declined surgery recommended by her attending neurosurgeon at a local hospital.

Intervention and Outcome

The patient was treated using atlas orthogonal chiropractic technique for 8 visits over a 6-week period. Examination before and the after the initial treatment included cervical radiographic analysis and vascular ultrasound measurement of the right and the left vertebral artery (VA). After the initial spinal manipulation, there was an improvement in blood flow volume of 8.2% in the left VA and 22.2% in the right VA. There was improvement of the symptom of TVL and a measured reduction of rotational misalignment of the first and second cervical vertebra on the radiographic views. After 6 weeks, the patient's perception of TVL was absent.

Conclusion

A patient with TVL improved under chiropractic care using atlas orthogonal technique.

Compression Syndromes of the Vertebral Artery at the Craniocervical Junction

Compression syndromes of the vertebral artery that occur at the craniocervical junction are extremely rare causes of haemodynamic insufficiency of the posterior cerebral circulation. The aetiology of the compression syndrome may be a malformation, trauma, tumour, infection or degenerative pathology. This may lead to dynamic vertebral artery occlusion where the vessel courses around the atlas and the axis-the so-called V3 segment. This in turn may result in insufficient collateral flow to the posterior fossa. The clinical picture is a vertebrobasilar insufficiency syndrome of variable expression ranging from vertigo to posterior fossa stroke. The typical clinical presentation is syncope occurring during rotation of the head, also known as 'bow hunter's syndrome'. The workup is based on dynamic angiography and computed tomography angiography. The treatment of choice is surgical vascular decompression, resulting in a good clinical outcome. However, in some instances, atlantoaxial fusion may be indicated. Alternatively, conservative and endovascular options have to be considered in inoperable patients.

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.

Congenital Bilateral C2 Transverse Foramina Stenosis Causing Adult-Onset Vertebrobasilar Insufficiency and Posterior Circulation Stroke

Vertebrobasilar insufficiency leading to posterior circulation infarcts caused by congenital hypoplasia of the bilateral transverse foramina at the C2 level, affecting the caliber and flow of the bilateral distal cervical vertebral arteries in an adult, has not been previously reported. A 41-year-old male presented with episodic dizziness for a period of 1 year prior to consultation. Computed tomography angiography of the head and neck demonstrated congenital hypoplasia of the bilateral C2 transverse foramina, with absence of the vertebral arteries in each of the foramina and collateral reconstitution of diminutive intracranial vertebral artery segments. Brain MRI showed postinfarction encephalomalacia in the bilateral cerebellar hemispheres. The patient was considered not a surgical or endovascular candidate and was managed conservatively with antiplatelet therapy. Congenital anomalies of the bilateral cervical transverse foramina may present with vertebrobasilar insufficiency and infarction in adulthood.

Rotational vertebrobasilar insufficiency due to compression of a persistent first intersegmental vertebral artery variant: case report

Rotational vertebrobasilar insufficiency, or bow hunter's syndrome, is a rare cause of posterior circulation ischemia, which, following rotation of the head, results in episodic vertigo, dizziness, nystagmus, or syncope. While typically caused by dynamic occlusion of the vertebral artery in its V2 and V3 segments, the authors here describe a patient with dynamic occlusion of the vertebral artery secondary to a persistent first intersegmental artery, a rare variant course of the vertebral artery. In this case the vertebral artery coursed under rather than over the posterior arch of the C-1. This patient was also found to have incomplete development of the posterior arch of C-1, as is often seen with this variant. The patient underwent dynamic digital subtraction angiography, which demonstrated occlusion at the variant vertebral artery with head turning. He was then taken for decompression of the vertebral artery through removal of the incomplete arch of C-1 that was causing the dynamic compression. After surgery the patient had a complete resolution of symptoms. In this report, the authors present the details of this case, describe the anatomical variants involved, and provide a discussion regarding the need for atlantoaxial fusion in these patients.

Advances in the Pathogenesis, Diagnosis and Treatment of Bow Hunter's Syndrome: A Comprehensive Review of the Literature

Bow hunter's syndrome (BHS), also known as rotational vertebral artery (VA) occlusion syndrome, is a rare yet treatable type of symptomatic vertebrobasilar insufficiency resulting from mechanical occlusion or stenosis of the VA during head and neck rotation or extension. The symptoms of BHS range from transient vertigo to posterior circulation stroke. The underlying pathology is dynamic stenosis or compression of the VA by abnormal bony structures with neck rotation or extension in many cases, such as osteophyte, disc herniation, cervical spondylosis, tendinous bands or tumors. Imaging approaches, such as Doppler sonography, computed tomography and angiography, as well as magnetic resonance imaging and angiography, are widely used in the diagnosis and evaluation of this syndrome. Digital subtraction angiography with head rotation remains the gold standard diagnostic method. Conservative management, surgery and endovascular procedures are the three major treatment methods for BHS, whereas some symptomatic patients may need operative treatment including surgery and endovascular procedures when conservative management is not adequate.

Surgical decompression coupled with diagnostic dynamic intraoperative angiography for bow hunter's syndrome

Background:

Bow hunter's syndrome, also known as rotational vertebrobasilar insufficiency, arises from mechanical compression of the vertebral artery during the neck rotation. Surgical options have been the mainstay treatment of choice. Postoperative imaging is typically used to assess adequate decompression. On the other hand, intraoperative assessment of decompression has been rarely reported.

Case Description:

A 52-year-old male began to see “black spots,” and experienced presyncope whenever he rotated his head toward the right. The patient ultimately underwent a dynamic diagnostic cerebral angiogram, which revealed a dominant right vertebral artery and complete proximal occlusion of the right vertebral artery with the head rotated toward the right. Subsequently, the patient underwent an anterior transcervical approach to the right C6/C7 transverse process. The bone removal occurred along with the anterior wall of the C6 foramen transversarium, followed by the upper portion of the anterior C6 body medially, and the transverse process of C6 laterally. An oblique osseofibrous band was noted to extend across the vertebral artery; it was dissected and severed. An intraoperative cerebral angiogram confirmed no existing compression of the vertebral artery with the head rotated toward the right. The patient recovered from surgery without issues; he denied recurrence of preoperative symptoms at follow-up.

Conclusions:

The authors report the third instance where intraoperative dynamic angiography was employed with good outcomes. Although intraoperative cerebral angiography is an invasive procedure, which prompts additional risks, the authors believe the modality affords better, real-time visualization of the vertebral artery, allowing for assessment of the adequacy of the decompression. This advantage may reduce the probability for a second procedure, which has its own set of risks, and may counteract the risks involved with intraoperative dynamic angiography.

Cervicogenic vertigo treated by c1 transverse foramen decompression : a case report

Cervicogenic vertigo was known as Bow hunter's syndrome. Occlusion of vertebral artery causes vertebrobasilar insufficiency and we reported cervicogenic vertigo case which was treated by simple decompression of transverse foramen of C1. The patient was 48 years old female who had left side dominant vertebral artery and vertigo was provoked when she rotated her head to right side. Angiography showed complete obliteration of blood flow of left vertebral artery when her head was rotated to right side. The operation was decompression of left vertebral artery at C1 level. Posterior wall of transverse foramen was resected and vertebral artery was exposed and decompressed. After surgery, vertigo of the patient was disappeared, and angiography showed patent left vertebral artery when her head was rotated to right side. Vertigo caused by compression of cervical vertebral artery could be treated by decompression without fusion or instrumentation, especially in C1 transverse foramen.

Simultaneous bilateral stenosis of the vertebral arteries treated by unilateral decompression: a case report

A 56-year-old man presented with a 3-month history of progressive dizziness. His dizziness was aggravated when his head was rotated to the right side. Diagnostic angiography showed that a normal right-sided vertebral artery in the neutral position became an abnormal vertebral artery with two stenotic lesions at the C3-4 and C5-6 levels when the patient's head was turned to the right. A normal left-sided vertebral artery also showed a stenotic lesion at the C2 level when the patient's head was turned right. The axial dimensions of the bilateral vertebral arteries were similar. The patient was successfully treated with decompression of only one level (C5-6). We conclude that if a bilateral stenosis is found upon one directional head rotation and the bilateral vertebral arteries are similarly sized, a one-sided treatment may suffice.

Bow hunter's syndrome: the use of dynamic magnetic resonance angiography and intraoperative fluorescent angiography

Bow hunter's syndrome is a diagnosis typically made using dynamic digital subtraction angiography. The authors present the case of a 68-year-old woman who presented with symptoms consistent with bow hunter's syndrome that was accurately diagnosed utilizing noninvasive dynamic MR angiography. The dynamic MR angiogram clearly illustrated unilateral vertebral artery compression upon turning of the head. A subsequent CT of the cervical spine showed a ventral C-1 osteophyte within the foramen. The patient underwent posterior surgical decompression of the left vertebral artery. Sufficient decompression was confirmed using intraoperative fluorescent angiography with the patient's head turned. This case report is the first to illustrate that dynamic MR angiography can be a reliable and less invasive diagnostic tool. It can also be used to confirm sufficient postoperative decompression and monitor for recurrence. Intraoperative fluorescent angiography has been previously used in the evaluation of intracranial and extracranial vascular patency. This report is the first to show that fluorescent angiography can offer rapid and reliable intraoperative evaluation of vertebral artery decompression in bow hunter's syndrome.

An unusual case of pediatric bow hunter's stroke

Background:

Bow Hunter's syndrome/stroke is defined as symptomatic, vertebrobasilar insufficiency provoked by physiologic head rotation. It is a diagnostically challenging cause of posterior circulation stroke in children. While there have been prior reports of this rare disorder, we describe an exceptional case of pediatric Bow Hunter's stroke resulting from a near complete occlusion the right vertebral artery (VA) secondary to an anomalous spur emanating from the right occipital condyle. Surgical and endovascular options and approaches are also detailed herein.

Case Description:

A 16-year-old male presented with multiple posterior circulation ischemic strokes. A dynamic computerized tomography angiogram performed with the patient's head in a rotated position revealed a near complete occlusion of the V3 segment of the right VA from a bone spur arising from his occipital condyle. The spur caused a focal dissection of the distal right VA with associated thrombus. He was initially managed with a cervical collar, antiplatelet therapy with aspirin 81 mg and anticoagulation with coumadin (INR goal 2-3) for 3 months. Despite the management plan, he had a subsequent thromboembolic event and a right VA sacrifice with coil embolization was then performed. At the 3-month follow-up, the patient was doing well with no reports of any subsequent strokes.

Conclusion:

We report the first reported pediatric case of Bow Hunter's stroke due to dynamic right VA occlusion from an occipital condylar bone spur. The vascular compression from this spur led to a right VA dissection and thrombus formation and ultimately caused multiple posterior circulation thromboembolic strokes. Endovascular treatment options including vessel sacrifice should be considered in cases that have failed maximal medical management.

Bow hunter's syndrome causing vertebrobasilar insufficiency in a young man with neck muscle hypertrophy

Vertebrobasilar insufficiency is characterized by impaired blood flow within the posterior circulation, producing symptoms of vertigo, nausea, vomiting, visual disturbances, and syncope. Given these nonspecific symptoms, the diagnosis of vertebrobasilar ischemia may be difficult to distinguish from more benign conditions. A healthy 37-year-old man presented to our clinic with near syncope upon turning his head to the left. Dynamic angiography revealed occlusion of the left vertebral artery at C7 with 90° head rotation to the left, consistent with bow hunter's syndrome. No obvious bony abnormalities were identified on computed tomography or magnetic resonance imaging scans. Transient rotational vertebral artery syndrome, a rare cause of vertebrobasilar insufficiency, has most often been reported at the C1-2 level, and the majority of cases occur in patients >50 years of age because of degenerative osteophytes and contralateral atherosclerosis. We present the unusual case of a young man with symptoms of vertebrobasilar insufficiency and discuss the potential effects of weightlifting and neck muscle hypertrophy on vertebral artery flow dynamics.