Does sagittal alignment after spinal reconstruction following en bloc tumor resection impact revision rate? A preliminary long-term retrospective study

Objective: To investigate if postoperative sagittal alignment in long spinal fusions after lumbar enbloc resections can affect mechanical failure rates in a long-term follow-up study. Methods: Retrospective study. All patients with more than 2-years follow-up, with complete demographic and oncological data, and with a set of standing x-rays that allowed the measure of sagittal spinopelvic parameters, the difference between the ideal and actual postoperative lumbar lordosis (LLM) and the Pelvic Incidence - Lumbar Lordosis mismatch (PI-LL) were included. Data on complications, revision surgery and causes of revision were analyzed. Results: A total of 31 patients were included. Mechanical failure was observed in 10 patients (31%), and of these, 7 (22.6%) received revision surgery. Higher postoperative LLM (21.7° vs. 10.8°, p < 0.05) and higher PI-LL (15.3° vs. 2.8°, p < 0.05) values were found in the group that suffered for implant failure or adjacent disease. Moreover, patients who had undergone surgical revision showed higher LLM (23.7° vs. 11.6, p < 0.05), and PI-LL (19.9° vs. 3°, p < 0.05). Conclusions: The oncological effectiveness of en bloc resections should be combined with a long-term effectiveness and stability of spinal implants, in order to avoid reduction of quality of life due to implant failure and re-hospitalizations for revision surgery. Our study found that for all included patients mechanical failures were strictly correlated with a mismatch between PI and LL. This suggests that the sagittal balance of the spine affects the endurance of surgical implants also in en bloc resection cases.