Objective
The purpose of this study was to evaluate and compare the natural course of morphologic changes and clinical outcomes between large central extruded disc herniation and sequestration.

Method
The study population consisted of 22 patients with sequestration and large central extrusion by an magnetic resonance (MR) imaging study. Seventeen (11 patients with sequestration, 6 patients with large central extrusion) patients underwent a follow-up MR imaging study. The size of herniated disc was measured on serial MR imaging studies and the change in size was classified into four categories. Clinical evaluations were also done using visual analogue scale (VAS), Oswestry low back pain disability questionnaire scoring, straight leg raising test (SLRT) and so forth.

Results
Successful clinical improvement was achieved in both groups. The VAS and Oswestry disability scoring established a greater change in the group with sequestration than in the group with large central extrusion. Greater morphologic decrease in the herniated discs occurred more frequently in sequestered disc herniation than large central extruded disc herniation.

Conclusion
Both sequestered disc and large central extruded disc herniation could be treated successfully by conservative treatment.