Epidural migration of extruded cervical disc and its surgical treatment.

Twenty-two patients with epidural migration of cervical disc fragments were reviewed. Disc sequestrations can migrate to the anterior, posterior, and lateral aspects of the spinal canal and are divided into four types according to their localizations. Those migrating to the anterior or posterior surface of the spinal canal, causing myelopathy, were removed through either an anterior or posterior route. Removal of lateral sequestration by uncoforaminotomy provided full recovery for all patients with radiculopathy and drop-attacks. The number of disc sequestrations was not always one: three fragments were present in three patients and two fragments in five patients. Various routes combined with other approaches were indicated to eliminate completely the freely migrating disc sequestra.