To assess the etiologies, related factors and clinical outcomes of revision arthrodesis after lumbar fusion.

Eighteen patients who underwent revision arthrodesis after lumbar fusion for degenerative lumbar disease were analyzed retrospectively. The authors analyzed the radiologic and clinical findings and compared these with outcome.

The causes of revision arthrodesis were adjacent segment degeneration in 14 cases (77.8%), pseudarthrosis in 4 cases (22.2%). A finding of adjacent segment degeneration was attributed to stenosis in 72.2% and instability in 44.4%. Of the 14 patients with adjacent segment degeneration: 12 patients (85.7%) underwent index fusion of more than two segments; 10 patients (71.4%) had lordosis of less than 20 ° within index fusion segment; 12 patients (85.7%) had preexisting degeneration at the segment; and the lesion was found just above the affected segment in 11 patients (78.5%). The surgical treatments involved decompression, extension of instrumentation and anterior or posterior fusion. The clinical success rate was 72.2% after 2.9 years follow up.

The multilevel arthrodesis, insufficient lordosis of the fused segment and underlying degenerative changes are related to adjacent segment degeneration. Immediately above the segment was the most common site of adjacent segment degeneration. These factors should be considered when deciding the fusion level.