[Anterior surgery for fourth lumbar burst fractures]

To evaluate the clinical outcomes of anterior decompression, bone graft and internal fixation in treating fourth lumbar burst fractures with iliac fenestration.

From February 2001 to May 2006, 8 cases of fourth lumbar burst fractures were treated by anterior decompression, correction, reduction, iliac autograft, Z-plate internal fixation with-iliac fenestration. Of them, there were 7 males and 1 female, aging 24-46 years with an average of 29.3 years, including 3 cases of Denis type A and 5 cases of Denis type B. The decompression, intervertebral height were compared between preoperation and postoperation by CT scanning. According to Frankel assessment for neurological status, 2 cases were at grade C, 5 at grade D and 1 at grade E before operation. Four cases had different degrees of disturbance of sphincter. Time from injury to operation was 8 hours to 11 days. The preoperative height of the anterior border of the L4 vertebral body was (13.8 +/- 2.3) mm, the Cobb angel of fractured vertebral body was (13.2 +/- 2.5) degrees, the vertebral canal sagittal diameter of L4 was (10.6 +/- 3.5) mm. The bone graft volume was (7.5 +/- 1.3) cm3 during operation.

Operations were performed successfully. The mean operative time was (142 +/- 25) minutes and the mean amount of blood loss was (436 +/- 39) mL. The incisions obtained healing by first intention after operation. Two cases suffered donor site pain and received no treatment. The follow-up time of 8 cases was from 21 months to 52 months (mean 24.5 months). At one week after operation, the height of the anterior border of the L4 vertebral body was (32.5 +/- 2.6) mm, the Cobb angel of fractured vertebral body was (6.8 +/- 3.7) degrees, and the vertebral canal sagittal diameter of L4 was (19.8 +/- 5.1) mm, showing significant difference when compared with those of preoperation (P < 0.01). At the final follow-up, the results showed that the pressure was reduced sufficiently, all autograft fused well, the neurological status improved at Frankel grade from C to D in 1 patient, from D to E in 3 patients, but the others had no improvement. In 4 patients who had disturbance of sphincter, 3 restored to normal and 1 was better off.

Clinical outcomes of anterior surgery for fourth lumbar burst fractures with iliac fenestration are satisfactory. It can facilitate operation, reduce the pressure sufficiently, maintenance intervertebral height and recover the neurological function.