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Retrospective analysis of reasons and revision strategy for failed thoracolumbar fracture surgery by posterior approach: a series of 31 cases.

OBJECTIVES
This study aimed to analyze the reasons for failed thoracolumbar fracture treated with posterior surgical approaches and to discuss the revision strategies for the surgical treatment.


METHODS
We retrospectively studied the patients that received failed thoracolumbar fracture (T11-L2) treatment with posterior approach and underwent revision surgery in our spine department from March 2010 to December 2020.


RESULTS
A total of 31 patients were included in this study. There were 4 (12.9%) cases of A3, 2 (6.5%) cases of B1, 5 (16.1%) cases of B2, 7 (22.6%) cases of B3, and 13 (41.9%) cases of C, according to the AO classification for thoracolumbar injuries. For load sharing classification, 26 (83.9%) cases ≥7, and 5 (16.1%) cases < 7. Regarding to the reasons for surgery failure, 26 cases (83.9%) were due to fracture of the internal fixation (pedicle screw or connecting rod) and kyphosis, 3 cases (9.7%) were due to misplacement of the posterior pedicle screw, 1 case (3.2%) was due to incomplete posterior decompression, and 1 case (3.2%) was due to scoliosis after the removal of the internal fixation. The revision surgery methods included: 2 cases (6.5%) with anterior approach, 17 cases (54.8%) with posterior approach, and 12 cases (38.7%) with posterior and anterior approach. All the patients were followed-up for 12-24 months after the revision surgery, and successful bony fusion with no internal fixation failure was observed. The kyphosis angle improved significantly after the revision surgery in 26 patients at the last follow-up, and the final correction rate was 91.8%. Frankel grading system, visual analog scale (VAS), Oswestry Disability Index (ODI) showed significant improvement at the last follow-up.


CONCLUSIONS
Types B and C of thoracolumbar fracture, load sharing classification ≥7, and the posterior approach could lead to a high failure rate. Fracture of the internal fixation was the main reason for surgery failure. Performing the posterior approach is inappropriate for every thoracolumbar fracture. Reasonable revision surgery can achieve good results for posterior surgery failure in most cases.