The internal vertebral venous plexus (IVVP) is part of the vertebral venous system (VVS). This system is the main alternative venous pathway, which joins, parallels but at the same time bypasses the caval venous system. The clinical relevance of the VVS is underestimated. We report on a patient who presented with cauda equina compression syndrome that was caused by engorgement of the IVVP. IVVP engorgement resulted from bilateral iliac vein thrombosis for which congenital agenesis of the inferior vena cava (IVC) was diagnosed as the predisposing factor.

Case report

A 17-year-old female, with an unremarkable medical history, was referred to our hospital. She had suffered progressive lower back pain for 14 days and a cramp-like burning sensation in her left leg for 11 days. In addition, she had paroxysmal paresthesias in both feet. On the day of referral she was unable to walk because of diffuse non-radicular pain and weakness in both legs which developed within seconds after standing up. In this position, she also suffered from severe headache and vomiting. Physical examination revealed a body temperature of 37.6°C. Both inguinal fossae were tender to palpation. Neurological examination, including fundoscopy, was unremarkable. Laboratory tests revealed elevated C reactive protein (233 mg/ml (normal <4 mg/ml)), leucocytes (8.9×10⁹/l (normal 4.0–10.0 …