Risk factors of instrumentation failure after multilevel total en bloc spondylectomy

Multilevel total en bloc spondylectomy (TES) is required to secure oncologically adequate resection margins. However, no useful information has been reported for spinal reconstruction after multilevel TES. Therefore, this study set out to assess the clinical and radiological outcomes of spinal reconstruction after multilevel TES.

Forty-eight patients treated with multilevel TES at our institute were included in the analysis. Reconstruction was achieved with posterior pedicle screw fixation and an anterior titanium mesh cage filled with iliac autograft in all cases. Spinal shortening was performed to increase spinal stability from the reconstruction. Instrumentation failure and radiological findings were evaluated with radiography and computerized tomography (CT).

After excluding one patient whose general condition was deteriorating, radiological evaluations of 47 patients were performed over a period of more than a year. The follow-up time was 17 to 120 months (mean: 70.2 months). Instrumentation failure occurred in one patient (5.9%) after thoracic multilevel TES, in 4 patients (25.0%) after thoracolumbar multilevel TES, and in 3 patients (42.9%) after lumbar multilevel TES. No instrumentation failure was observed in cervicothoracic cases. Cage subsidence (>2 mm) occurred in 30 patients (63.8%). In 22 of them, subsidence appeared on the CT one month after surgery. The risk factors of instrumentation failure included a multilevel TES below the thoracolumbar level and a long span of vertebral resection. There was no instrumentation failure in any of the 11 "disc-to-disc cutting" cases.

This study identified the risk factors of instrumentation failure after multilevel TES. There is a high risk of instrumentation failure in cases of long vertebral resection below the thoracolumbar level. On the other hand, our reconstruction method can be successful for multilevel TES above the thoracic level.