Vertebral Artery Loop: A Rare Cause of Cervical Radiculopathy Lianne Wood, Marcin Czyz, Bronek M. Boszczyk; Nottingham University Hospitals NHS Trust Introduction: Although a vertebral artery loop (VAL) causing cervical radiculopathy is a rare condition, practitioners should be mindful of this as a differential diagnosis in order to ensure patients receive the most appropriate care timeously. The aim of this poster is to present two cases of a VAL compressing cervical nerve roots as a rare but important differential diagnosis to be considered in cervical radiculopathy.   Methods: A literature search of Medline, Cinahl, Pubmed and Web of Science over one month by both authors was conducted to find articles regarding VALs and vertebral artery anomalies. Two single retrospective case studies are reported with regard to the evidence. Results: Seven case reports are reported in the literature regarding VALs causing cervical radiculopathy, with one updated literature review. A variety of cervical levels are reported, with higher prevalence noted at C4/5, followed by C3/4 and C5/6. Salient identifying features include widening of the intervertebral foramen. This is not always reported radiographically and therefore an awareness of this condition is important to ensure it is not missed. Two cases of a VAL compressing cervical nerve roots were diagnosed based on clinical findings, neuroimaging and pain relief achieved after fluoroguided nerve root block. Both of them were listed for surgical decompression of the vertebral artery. Figure 1: (L) VAL demonstrated with widening of the left intervertebral foramen at the level of C3/4.; (R) VAL demonstrated at level of C3/4 and C4/5 on left. Case 1: History: A 48 year old lady presented with a ten year history of left shoulder pain radiating into her middle three fingers with occasional paraesthesia and weakness. Over time, she had at least two shoulder decompressions via arthroscopy, regular botox injections, suprascapular nerve blocks and intensive physiotherapy rehabilitation. Examination: She had significant elevation of her left shoulder in comparison to her right. Cervical range was maintained, however shoulder range was markedly reduced to 45 degrees of abduction and 90degrees of flexion limited by pain. Neurological examination normal upper limb reflexes, with intact sensation and no weakness apart from marked winging of the medial border of her scapula with abduction. Spurlings was positive. Investigations revealed a normal shoulder MRI, with left C5/6 and C6/7 foraminal narrowing on cervical MRI. Nerve conduction studies were normal. Plan: A diagnostic NRB provided 80% benefit. She successfully underwent a C3-5 left vertebral artery transposition on 3/5/16 at this level. Case 2: History: This 35 year old gentleman presented initially in June 2012 with symptoms in keeping with a left C7 radiculopathy due to an anomalous C7 vertebral artery loop causing radicular compression. A targeted nerve root block to this level provided 48 hours of relief, but a left sided C6/7 ACDF did not change his symptoms significantly. He represented in 2014 with similar symptoms and a C6 vertebral artery loop was confirmed. Examination: There was no loss of cervical range of movement. Neurological examination did not reveal any weakness, however sensation was decreased in C6,7, and C8 on the left to light touch. Reflexes were symmetrical and there were no signs of myelopathy. Nerve conduction studies were normal for the upper limbs and a recent cervical MRI confirmed a satisfactory decompression of the C7 foramen. Plan: He successfully underwent a C5/6 vertebral artery transposition for C6 radiculopathy on 8/2/16. Conclusion: Vertebral artery loops are a rare condition that may have implications for patients with persistent radicular pain in the absence of degeneration or disc prolapse. Many of the patients were successfully managed conservatively with physiotherapy, but surgical decompression should be considered should conservative measures be unsuccessful. This is an important differential diagnosis for those working in an extended scope role, especially in a spinal secondary care setting. Early recognition and management can ensure appropriate care for improved patient outcomes. References: 1.Detwiler et al. 1998. Vascular decompression of a vertebral artery loop producing cervical radiculopathy. J Neurosurg. 89:485-488; 2. Doweidar et al. 2014. Symptomatic vertebral artery loop: a case report and review of the literature. Radiology Case. May. 8(5):35-41; 3. Fink et al. 2010. Vertebral artery loop formation causing severe cervical nerve root compression. Neurology. 2-21-. 75; 192; 4. 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