Diagnosis and management of thoracic intradural extra-arachnoidal disc herniation

BACKGROUND: Intradural extra-arachnoidal disc herniations (IEDHs) are rare. Here, we reviewed the clinical features and magnetic resonance (MR) diagnostic features of IEDH. CASE DESCRIPTION: A 58-year-old male presented with mid-thoracic back pain radiating to the left leg associated with ipsilateral leg weakness. The thoracic MR documented T8-T9 focal spinal canal stenosis and a ventral disc herniation. Thoracic spine computed tomography scan confirmed the diseased level and did not show any calcification. The patient underwent a right-sided transpedicular extracavitary approach for disc excision. At surgery, IEDH was identified with soft cartilaginous consistency and was morcellated to remove in piece meal while preserving the integrity of the arachnoid layer. CONCLUSION: IEDH poses a significant challenge for its diagnosis and management. A careful preoperative MR imaging review with a high index of clinical suspicion may ensure a good clinical outcome.