Expandable versus nonexpandable cages for thoracolumbar burst fracture

Burst fractures account for more than half of all thoracolumbar fractures and are frequently associated with spine instability and neurological deficit. The anterior approach is favored when decompression of the spinal canal is necessary. We compare two commonly available struts used for anterior approach after corpectomy: expandable versus nonexpandable titanium cages.

We retrospectively evaluated 32 patients with acute thoracolumbar burst fractures treated by a single surgeon with a mean follow-up of 13 months. Half of the patients had nonexpandable cages placed (group 1) and the other half had expandable cages placed (group 2). Anterolateral plate/screw supplementation was used in all patients. Radiographs were reviewed to assess kyphosis correction and bony fusion.

In group 1, the mean kyphotic angle before surgery was 20.5 degrees. Immediately after surgery, this angle improved to 6 degrees and was 8.5 degrees at final follow-up. In group 2, the mean kyphotic angle before surgery was 21.5 degrees. This angle improved to 4 degrees immediately after surgery and was 6.5 degrees at final follow-up. At the end of follow-up, 2 of 16 patients in group 1 demonstrated pseudoarthrosis, whereas no patients in group 2 showed any evidence of nonunion. No patient in either group experienced hardware failure or new neurological deficit.

Anterior decompression and instrumented stabilization with either an expandable or nonexpandable cage is a safe and reliable surgical treatment option for unstable thoracolumbar burst fractures. Expandable cage enables greater immediate correction of kyphosis with good fusion rate.