Symptomatic Vertebral Artery Loop Formations: A Scoping Review of Epidemiology, Pathogenesis, and Treatment

BACKGROUND AND OBJECTIVES: Vertebral artery loop formations (VALFs) are under-reported yet treatable causes of cervical radiculopathy. Incidence varies between 2% and 7.5%. Exact pathogenesis is unclear. Literature is sparse, and optimal treatment remains controversial. This review aims to collect all available literature describing symptomatic VALFs. METHODS: We performed a scoping review in PubMed, Ovid Medline, Cochrane Library, British Medical Journal, and Google Scholar. Full-text original, descriptive, and analytical studies were collated. Data from retrieved articles were collaboratively reviewed, tabulated, and synthesized. Clinical features, diagnosis, and treatment outcomes were discussed. RESULTS: A total of 31 articles and 33 patients found to have symptomatic VALFs were included. The mean age of patients was 52 years, 17 (53%) of whom were females. Tortuosity was more apparent on the left, with C4-C5 and C5-C6 (28%) being the most common levels affected. Neck (13%) and shoulder pain (26%) were the most common left- and right-sided presenting symptoms. In the 31 treated patients, 71% (n = 22) underwent surgery, whereas the remaining 29% (n = 9) were treated conservatively. There was complete resolution of symptoms in 54% of patients who underwent surgery and in 75% of patients who were treated conservatively. CONCLUSION: Vertebral artery loops are understudied yet clinically significant causes of radiculopathy. Believed to arise from various etiologies, it can be tricky to diagnose and manage, necessitating a high index of suspicion and prompt clinical recognition. When conservative management fails, a patient-tailored surgical approach may provide the most direct decompression with the least associated surgical risks.