Abstract WMP46: Rotational Ischemic Vertebral Artery Compression (RIVAC) Syndrome Due to Cervical Facet Hypertrophy and Uncinate Process Osteophyte: Review of Seven Consecutive Cases

Abstract

Introduction: The authors propose a new terminology, Rotational Ischemic Vertebral Artery Compression (RIVAC) syndrome, to describe patients who present with TIA or stroke from compression of the cervical vertebral artery (VA) below C2 by facet hypertrophy or uncinate process osteophyte associated with rotation of the head. The authors review clinical presentation, radiological findings, and management of 7 consecutive cases. Methods: Prospective analysis of 7 consecutive cases of RIVAC syndrome was performed between 2004 and 2012. We reviewed peri-operative imaging, method of treatment, and clinical and angiographic outcome. Results: A total of 6 patients (mean 66+/- 4 years) presented with stroke (N=2) or TIA including reproducible dizziness, vertigo, or syncope (N=4) associated with rotation of the head. Pre-operative dynamic cerebral angiogram showed near complete occlusion of cervical VA (N=2) or severe stenosis (60 to 80%) (N=5) during rotation of the head. The location of cervical VA compression was as follows: right C3-4 (N=1), left C4-5 (N=3), left C5-6 (N=2) and left C6-7 (N=1). Treatment included endovascular stent placement of VA without open surgery (N=1), endovascular stent placement of VA followed by partial left C5-6 factectomy 2 years later (N=1), posterior surgical decompression of VA along with bilateral facet screw fixation (N=4), and anterior cervical discectomy and fusion (N=1). Follow up dynamic cerebral angiograms and CTA angiogram of neck (6 months to 3 years) showed resolution of VA compression on rotation of head in all patients except for one who had lost in follow up. Clinical evaluation (range of 1 to 48 months) showed no recurrent stroke or TIA in all patients (mRS score of 0, N=6 and mRS of 3, N=1). Conclusion: RIVAC syndrome should be recognized as an important cause of posterior circulation TIA or stroke associated with rotation of head. Pre-operative dynamic cerebral angiogram and CT angiogram of neck are essential in localization and characterization of the level and cause of VA compression. Open surgical decompression and fixation appears to be safe and effective treatment of patients with RIVAC syndrome.