INTRADURAL THORACIC DISC HERNIATION

Study Design. Patients with intradural herniation of an intervertebral disc were identified and managed surgically. Objectives. Illustrative cases of patients with intradural herniated discs at the mid-thoracic level are presented, the literature is reviewed, and the management o f these patients is discussed. Summary of Background Data. Intradural herniation of an intervertebral disc is rare and most common at the lu mbar level, but isolated cases have been reported at other levels. Cas es reports of this entity have been published, but the surgical detail s have not been adequately addressed. Methods. In this report, two pat ients with calcified intradural herniated discs at the mid-thoracic le vel are presented. Results. Both patients had progressive paraparesis and had calcified disc material in the mid-thoracic canal. Both Were t reated successfully with a posterolateral extracavitary costotransvers ectomy and hemilaminotomy using intraoperative ultrasound and somatose nsory-evoked potential monitoring. Conclusions. This entity should be suspected when a calcified disc within the spinal canal is being treat ed. The optimal exposure is a posterolateral extracavitary costotransv ersectomy with a hemilaminotomy. Alternative approaches to a typical t horacic disc would be problematic in managing these patients.