Hardware failure of lumbosacral reconstruction after sacral tumor resection, causes analysis

English Keywords:Orthopaedic oncology  Sacral tumor  Lumbosacral reconstruction  Breakage  Revision surgery

English Abstract:

  【Abstract】 Objectives: To investigate the causes of failed lumbosacral reconstruction after sacral tumor resection and its intervention. Methods: 12 patients diagnosed with high sacrum tumor and complicated with hardware failure following tumor resection and lumbosacral reconstruction during January 2007 and Octorber 2013 were reviewed retrospectively. All 12 patients received revisional surgical intervention. There were 4 males and 8 females with an average age of 30.4 years(18~62 years). The data related to failure were recorded, which included sacral defect, location of breakage, the diameter of rod, the union of bony graft and BMI of patients. Results: There were 7 cases of S1-S5 involvement and S2-S5 involvement in 5 cases. The lumbar pedicle screws were inserted in L2 and L3 in 1 case, L3 and L4 in 4, L4 and L5 in seven cases. The breakage occurred at an average age of 17.1 months(range, 8-24 months) after primary surgery. The most common cause for the failure was the breakage of rod, which occurred in 10 patients with 2 bilateral sides and 8 unilateral. Iliac screw breakage and loosening were observed in 2 and 4 cases respectively. The 5.5mm-diameter rod was used in 4 cases, 2 of them were noted bilateral breakage. Non-union of allograft was observed in 6 patients, 3 of them received radiation therapy after reconstruction. 5 out of 12 patients had BMI above 25. The implant was removed in 5 patients. Revision and bone graft were performed in 7 patients. Free fibular graft was used in 2 patients. 2 patients were noted breakage again at 12 and 21 months respectively and all received revisional surgery. No further breakage was observed in these 2 patients after 10 and 8 months follow-up respectively. Conclusions: The reconstruction of lumbosacral after high level sacral tumor resection still remains challenging. Rod breakage is most common for hardware failure. The possible reasons are non-union of allo/autograft, compared small diameter of connection rod, Improper level of pedicle screw insertion and patients′ high BMI, all these can be treated by revisional surgery.