Bow Hunter's Syndrome: Surgical Management (Video) and Review of the Literature

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.

Compressive lesions of the head and neck: Common and uncommon must-know entities

There are many lesions that cause compression of nerves and vessels in the head and neck, and they can often be overlooked in the absence of adequate history or if not suspected by the radiologist. Many of these lesions require a high index of suspicion and optimal positioning for imaging. While a multimodality approach is critical in the evaluation of compressive lesions, an MRI utilizing high-resolution (heavily weighted) T2-weighted sequence is extremely useful as a starting point. In this review, we aim to discuss the radiological features of the common and uncommon compressive lesions of the head and neck which are broadly categorized into vascular, osseous, and miscellaneous etiologies.

Rotational Vertebral Artery Syndrome (Bow Hunter's Syndrome): A Rare Differential Diagnosis in Patients With Syncope

Syncope is a common symptom in clinical practice. Rotational vertebral artery occlusion syndrome, also referred to as Bow Hunter's syndrome (BHS), is a rare condition associated with syncope and is caused by mechanical occlusion or stenosis secondary to mechanical compression of the vertebral artery during head rotation. BHS is associated with a multifactorial etiology; however, in most cases, this condition is attributed to degenerative changes. A 53-year-old man visited our hospital for the evaluation of fainting and dizziness episodes that occurred when he turned his head. Evaluation as an outpatient in the Department of Neurology showed a positive result on the Frenzel goggle test. Transfemoral cerebral angiography performed at the Department of Neurosurgery revealed stenosis of the proximal right vertebral artery. Complete occlusion of the vertebral artery was observed, and the head was turned to the right. Decompression and fusion were performed, and the contributory lesion was completely removed. Postoperative imaging confirmed complete removal of the spur and sufficient vertebral artery decompression; the patient's symptoms resolved postoperatively.

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.

Bow hunter’s syndrome treated by anterior decompression with fusion: A case report

Background:

Bow hunter’s syndrome (BHS) is a rare condition induced by occlusion or compression of the vertebral artery (VA) during head movement or rotation. Here, we report a patient with BHS effectively treated with an anterior cervical discectomy and fusion (ACDF).

Case Description:

A 75-year-old male experienced recurrent embolic strokes to the posterior circulation. This was attributed angiographically to transient stenosis of the right VA due to a right-sided C5-C6 osteophyte when the head was rotated to the right; the stenosis was improved when the patient rotated his head to the left. The patient successfully underwent a C5-C6 ACDF for removal of the right-sided lateral osteophyte which resulted in no further transient right-sided VA occlusion.

Conclusion:

Following a C5-C6 ACDF for removal of a right lateral osteophyte, a 75-year-old male’s intermittent right-sided VA occlusion responsible for multiple posterior circulation emboli was relieved.

The Outpatient Approach to Dizziness

The evaluation of the dizzy patient is complicated by many common pitfalls. The patient's description of symptoms and the standard neurologic examination are often nonspecific or unrevealing, and neuroimaging is most often normal. Over the past several years, research has demonstrated that a refocusing of history taking results in more reliable and diagnostically helpful information. This can guide a targeted expansion of the exam, often with an emphasis on eye movements.

Yes, we should abandon pre-treatment positional testing of the cervical spine

Although there seems to be no causality between cervical spine (CS) manipulation and major adverse events (MAE), it remains important that manual therapists try to prevent every potential MAE. Although the validity of positional testing for vertebrobasilar insufficiency (VBI) has been questioned, recently, the use of these tests was recommended. However, based on the low sensitivity of the VBI tests, which may result in too many false-negative results, the VBI tests seem to be less valuable in pre-manipulative screening. Moreover, because the VBI tests are unable to consistently produce a decreased blood flow in the contralateral vertebral artery in (healthy people), the underlying mechanism of the test may not be a valid construct. There are numerous cases reporting MAE after a negative VBI test, indicating that the VBI tests do not have a role in assessing the risk of serious neurovascular pathology, such as cervical arterial dissection, the most frequently described MAE after CS manipulation. Symptoms of VBI can be identified in the patient interview and should be considered as red flags or warning signs and require further medical investigation. VBI tests are not able to predict MAE and seem not to have any added value to the patient interview with regard to detecting VBI or another vascular pathology. Furthermore, a negative VBI test can be wrongly interpreted as 'safe to manipulate'. Therefore, the use of VBI tests cannot be recommended and should be abandoned.

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.