Vertebral Artery Origin Interarterial Kinking: A Distinct Anatomical–Pathophysiological Mechanism Mimicking High- Grade Stenosis

Background Multiple pathological mechanisms may lead to vertebral artery (VA) stenosis at its origin. Vertebrobasilar insufficiency, a major cause of neurogenic vertigo, may also present with ataxia and other posterior circulation symptoms. Classical vertebral artery kinking is defined as angulation within a single arterial segment; however, alternative mechanisms may exist that are not adequately captured by this definition. Methods Between 2016 and 2024, 115 patients with vertebrobasilar insufficiency due to V1 segment pathology underwent surgical treatment. Sixty-five patients exhibited kinking in the mid-V1 segment, while 50 demonstrated high-grade stenosis of the V1 segment. Among these, 32 patients showed ≥ 70% stenosis at the vertebral artery origin on preoperative cervical MR or CT angiography and underwent surgical exploration. Results Intraoperatively, 3 patients had external compression by fibrotic bands, and 2 had atherosclerotic plaques extending from the subclavian artery. In the remaining 27 patients (84%), the apparent stenosis was caused by an upward or lateral angulation between the subclavian artery and the vertebral artery at its origin, producing a functional high-grade stenosis without intrinsic luminal disease. Conclusion Vertebral artery origin interarterial kinking represents a distinct anatomical–pathophysiological configuration that may mimic true stenosis on angiographic imaging. Recognition of this mechanism is essential to avoid inappropriate endovascular interventions and to guide appropriate surgical management.