Symptomatic Vertebral Artery Stenosis Secondary to Cervical Spondylolisthesis

Study Design. Case report. Objective. To present a rare case of vertebrobasilar insufficiency (VBI) syndrome secondary to the C6 level isthmic spondylolisthesis. Summary of Background Data. VBI associated with voluntary head movements is known as the bow hunter syndrome. It may manifest in temporary symptoms of dizziness, syncope, nausea, or motor and sensory deficits in certain head positions. The present syndrome is rare and difficult to diagnose. The authors describe a VBI case caused by vertebral artery compression due to the C6 level isthmic spondylolisthesis (to date, the authors have not found any other similar case described in the literature). Methods. The patient was a 27-year-old male with a 12-month history of vertigo and dizziness in relation to head movements. These problems interfered with his day-to-day activities. With other causes of neurological and cardiac origin dismissed, the patient was sent for an orthopedic evaluation. Radiological imaging showed spondylolisys, spondylolisthesis, and spina bifida between the facets of the C6 and C7. Dynamic radiographies evidenced C6 and C7 cervical instability. Angio-MRI indicated an anomalous trajectory of the right vertebral artery at the C6 level upon entering the foramen transversarium. However, there were no signs of stenosis. Dynamic angiography confirmed partial stenosis of the right vertebral artery upon rightward head rotation. The substantial suspicion of positional VBI after rejecting other diagnoses and the significant disability of the patient led to treating the patient with anterior cervical arthrodesis at the C6-C7 level. Results. The patient was symptom free for more than 15 months' monitoring and returned to all his daily work and life activities. Conclusion. Isthmic spondylolisthesis must be considered as a cause within VBI. Surgery presents good results.