Bow Hunter’s Syndrome
Bow Hunter’s Syndrome is a rare disorder resulting from a physical factor that blocks the vertebral artery (VA) and leads to a reduction in blood flow in the back of the brain during head and neck rotation or extension. It is also known as rotational Vertebral Artery Occusion (blockage) syndrome.
Meaning, the underlying pathophysiology is dynamic stenosis (primary) or compression of the VA by abnormal bony structures (secondary) with neck rotation or extension. In secondary BHS, stenosis or compression of the VA is caused by abnormal structures such as osteophytes, idiopathic skeletal hyperostosis, disc herniation, muscle hypertrophy, cervical spondylosis, tendinous bands, or tumors. Compression in BHS has been most commonly observed at or above the C2 level. There are still no diagnostic guidelines for BHS.
Provocative Digital Subtraction Angiography showing that the arteries are unobstructed in the neutral position and abnormally constricted with head rotation is the gold standard diagnostic method. CT and MR can detect abnormal bony structures, infarction lesions, or stenotic arteries and are useful for individual management. (Taiwan) Reference
Advances in the Pathogenesis, Diagnosis and Treatment of Bow Hunter’s Syndrome: A Comprehensive Review of the Literature. (China) Reference
“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 (dizziness when turning head) 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.”