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.

Bow Hunter's Syndrome with Rotational Atlantoaxial Instability: A Rare Association.

Bow Hunter's syndrome (BHS) is a very rare condition in which there is rotational vertebral artery (VA) insufficiency. The association of BHS with rotational atlantoaxial instability is extremely rare. We are reporting a case of pediatric BHS who presented with features of VA insufficiency on neck rotation. Careful evaluation revealed rotational C1-C2 instability. Provocative digital subtraction angiography and dynamic neck computed tomography were the mainstay of our diagnostic armamentarium. Our case emphasizes the fact that VA abnormalities need special consideration in young patients with craniovertebral junction instability and a high degree of suspicion is necessary in most instances for accurate diagnosis.

Anatomical and surgical considerations for Bow Hunter's syndrome in an elderly patient.

Bow Hunter's syndrome (BHS) is an uncommon condition characterized by impingement of one of the two vertebral arteries induced by cervical rotation, causing symptomatic vertebrobasilar insufficiency of the posterior cerebral circulation. We report a case of BHS in an 84-year-old male. Two months following a motor vehicle accident, the patient presented to an urgent care facility with subsequent transfer to the emergency department with complaints of lightheadedness upon right-lateral head movement. A cerebral angiogram demonstrated mild focal stenosis in the dominant left vertebral artery at the C2 level when in neutral position with significant worsening of the stenosis in the right-lateral head position with absent anterograde flow, consistent with BHS. Resultantly, the patient was referred for neurosurgery and successfully underwent placement of right-sided C2-C4 postero-lateral instrumentation and left-sided C2-C3 laminar screws projected towards the right side. This case highlights the importance of imaging in BHS diagnosis and guidance for treatment, as well as the need for a surgical standard of care for BHS patients.

Bow hunter's syndrome due to an anomalous right vertebral artery origin and contralateral absence: a case report and literature review.

BACKGROUND: Bow Hunter's syndrome (BHS), also known as rotational vertebral artery occlusion (RVAO), is a rare condition characterized by dynamic vertebrobasilar insufficiency due to position-dependent occlusion of the vertebral artery (VA). In the existing literature, most cases of BHS are attributed to osteophytic compression originating from the occipital condyle or within the transverse foramen, often accompanied by anatomical abnormalities of the VA. However, cases presenting solely with VA anomalies in the absence of any cervical vertebral structural abnormality are rare. This case report presents a unique instance of BHS in a 56-year-old male, attributed to the anomalous origin of the right VA and the absence of the left VA, without cervical structural abnormalities. CASE PRESENTATION: The patient exhibited symptoms like episodic dizziness and vertigo, which were exacerbated by rightward head rotation and alleviated upon returning to a neutral position. Diagnostic evaluation, including digital subtraction angiography, revealed that the right VA originated from the right common carotid artery and compression-induced stenosis of the right VA during head rotation. Conservative management, including avoidance of certain head movements and anti-arteriosclerosis medication, led to symptom resolution over a two-year follow-up period. CONCLUSIONS: This report contributes to the understanding of BHS by highlighting a rare vascular anomaly presentation and incorporates a review of 14 similar case reports in the literature describing that an anatomical abnormality of the VA is mainly responsible for the pathology of BHS in the absence of cervical vertebral anomalies, thus emphasizing the need for careful diagnostic and management strategies.

Endoscopic decompression of a C1 osteophyte causing bow hunter's syndrome in a 22-year-old male.

The patient is a 22-year-old male with a history of C1 avulsion fracture causing vertebral artery compression with pseudoaneurysm and symptomatic stroke. Cerebral angiography demonstrated dynamic compression of the V3 segment of the vertebral artery due to a chronic C1 avulsion fracture. The authors utilized a full endoscopic approach with intraoperative angiography for proximal control and Doppler ultrasound to confirm adequate decompression. The surgery duration was 3 hours with blood loss < 5 ml. The patient was discharged on postoperative day 1 with no complication and has been asymptomatic since surgery. This is the first documented use of endoscopic decompression to treat this condition. The video can be found here: https://stream.cadmore.media/r10.3171/2024.1.FOCVID23234.

Vertebral artery stenosis from osteophyte: A systematic review and case series.

BACKGROUND: Rotational vertebral artery syndrome, also referred to as Bow Hunter's syndrome (BHS), manifests when the vertebral artery (VA) is compressed following head rotation. This compression is often caused by an osteophyte and may lead to symptoms of a posterior stroke. This systematic review aims to shed light on the current management strategies for BHS resulting from osteophytes. Additionally, we present two illustrative cases where the VA compression by an osteophyte was effectively resolved by complete resection of the problematic bone spur. METHODS: A literature search was conducted across Embase, PubMed and Medline in September 2023. Keywords related to vertebral artery [MESH], vertebrobasilar insufficiency [MESH] and osteophyte [MESH] were the focus of this review. Risk of bias in retained studies was assessed using the Joanna Briggs Institute Critical Appraisal tools for Qualitative Research. A narrative synthesis of our findings is presented. RESULTS: A total of 30 studies were included in this review. Vertigo was the most reported symptom by patients (n = 16). On imaging, the VA was often compressed at C4-5 (n = 10) and C5-6 (n = 10) with no evident side predominance observed. Anterior cervical discectomy and fusion (ACDF, n = 13) followed by anterior decompression without fusion (n = 8) were the most performed surgical procedures to manage BHS. CONCLUSION: Surgical decompression of the VA is a safe and effective intervention for patients experiencing symptomatic osteophytic compression during head rotation. This procedure restores normal vascular function and reduces the risk of ischemic events. This review highlights the importance of timely diagnosis and intervention in such cases.

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.

Vertebrobasilar Insufficiency Syndrome in Extension: Insights into Surgical Treatment.

BACKGROUND: Rotational vertebrobasilar artery syndrome, or bow hunter syndrome, is a rare yet well-documented pathology. This study presents a surgical approach to a latent manifestation of dynamic, extension-only, bilateral codominant vertebral artery compression in the V3 segment, associated with craniocervical instability and central canal stenosis. METHODS: The clinical presentation involves the treatment of positional vertigo resulting from left and high-grade right vertebral artery stenosis during neck extension only. Diagnosis was confirmed through a formal angiogram under provocative maneuvers. Surgical intervention, detailed in this section, employed a multidisciplinary approach, including intraoperative angiograms to ensure patent vertebral arteries precraniocervical fusion. RESULTS: The surgical treatment demonstrated success in addressing extension-only vertebrobasilar syndrome and associated complications of C1-2 pannus and craniocervical instability. Intraoperative angiograms confirmed vertebral artery patency pre- and postsurgical positioning, ensuring the effectiveness of the multidisciplinary approach. CONCLUSIONS: This study concludes by highlighting the successful multidisciplinary surgical treatment of a patient with nonunion of a C1 Jefferson fracture, leading to extension-only vertebrobasilar syndrome complicated by C1-2 pannus and craniocervical instability. The importance of considering vertebral artery dynamic stenosis in cases of positional vertigo or transient neurological symptoms following an injury is emphasized. Surgical stabilization, particularly when conservative measures prove ineffective, is recommended, with careful attention to pre- and postsurgical positioning to verify vertebral artery patency and posterior vasculature integrity.

Bow Hunter Syndrome: An Illustrative Case and Operative Management.

The differential for vertebrobasilar insufficiency is wide and can be caused by posterior circulation infarcts, steal-type phenomena, or other systemic causes. In the absence of imaging findings explaining symptomology, the utility of appropriate history gathering and dynamic angiography cannot be understated in identifying Bow Hunter's syndrome, a rare cause of dynamic vertebrobasilar insufficiency. We present a case of a 69-year-old man who complained of presyncope and severe dizziness when turning his head towards the right. On examination he had no radiculopathy but did have objective evidence of myelopathy. Computed tomography imaging and dynamic angiography demonstrated C3-C4 right uncovertebral joint hypertrophy and near complete stenosis of the right vertebral artery with dynamic head position towards the right. Given vertebrobasilar insufficiency and myelopathy, he was taken to the operating room for C3-C4 anterior cervical discectomy and fusion with vertebral artery decompression (Video 1). The patient provided consent for the procedure. Standard anterior cervical neck dissection was undertaken with additional platysmal undermining to facilitate exposure of the right uncovertebral joint and transverse processes. The vertebral artery was first decompressed above and below the area of most significant stenosis at the respective transverse foramina before the hypertrophied uncovertebral joint was removed. Next, discectomy and posterior osteophyte removal were completed in typical fashion followed by graft, plate, and screw placement. Postoperatively the patient had immediate resolution of symptoms and continued so at eight month follow-up. Imaging demonstrated return to normal caliber of the right vertebral artery and successful decompression.

Hidden Bow Hunter's Syndrome Diagnosed Using Dynamic Cerebral Angiography and Successfully Treated with Spinal Surgery: A Case Report and Review of the Literature.

Hidden bow hunter's syndrome (HBHS) is a rare disease in which the vertebral artery (VA) occludes in a neutral position but recanalizes in a particular neck position. We herein report an HBHS case and assess its characteristics through a literature review. A 69-year-old man had repeated posterior-circulation infarcts with right VA occlusion. Cerebral angiography showed that the right VA was recanalized only with neck tilt. Decompression of the VA successfully prevented stroke recurrence. HBHS should be considered in patients with posterior circulation infarction with an occluded VA at its lower vertebral level. Diagnosing this syndrome correctly is important for preventing stroke recurrence.