To investigate the relationship between the greenstick laminar fractures and the dural tear in low lumbar burst fractures and their optimal treatment.

We enrolled 51 patients (52 cases) who had been diagnosed with low lumbar burst fracture from June 2003 to May 2007. The average age was 39 years (range, 22 to 58), 30 male patients (58.8%), and 21 female patients (41.2%). Average follow-up periods was 19 months (range, 11 to 45). Lumbar CT scan were taken 1 mm slices in precision for all patients. We judged it incomplete fracture if lumbar CT scans show loss of cortical continuity over 3 slices if there is an aggrement of two among one radiologist and two orthopaedic surgeons reached a consensus. Dural tear and entrapment of nerve root were confirmed intraoperatively by the senior surgeon.

In 52 burst fractures, complete lamina fractures occurred in 21 cases and there were green stick laminar fractures in 14 cases. Neurologic defect has been found in 12 cases, 5 (63%) from complete laminar fractures and 3 (37%) from green stick laminar fractures. Dural tears has been detected in 9 cases (26%), 4 (19%) from complete laminar fractures and 5 (36%) from green stick laminar fractures.

Dural tear and nerve root entrapment can be accompanied in patients with green stick fracture. There is necessary to consider the possibility of dural tear and nerve root entrapment before operation and to indentify carefully to the presence of nerve root entrapment during operation.