Causes for failed posterior pedicle screw instrumentation for thoracolumbar fractures / 中华创伤骨科杂志

ABSTRACT

Objective To analyze the causes for the failures after posterior pedicle screw instrumentation for thoracolumbar fractures.Methods From June 2003 to December 2014,182 patients with thoracolumbar fracture were treated by fixation through the posterior approach using pedicle screws and fully followed up in our institute.We analyzed the cases of postoperative infection,recovery of neural symptoms,breakage and loosening of pedicle screws and connecting rod,non-union of the fractured vertebra,and correction loss of kyphosis in associations with the AO classification and Loading Sharing Classification of Spine Fracture (LSCSF) system,osteoporosis,intervertebral disc injury and methods of internal fixation.Results In this series,altogether 27 cases failed(14.8％).The rate of postoperative infection was 1.1％ (2/182).The rate of breakage of pedicle screw or connecting rod was 7.7％ (14/182).The implant breakage rates for fractures of AO types A1,A2 and A3.1 were significantly lower than for other types (P ＜ 0.05).The implant breakage rate for the patients with ≤6 LSCSF points was significantly lower than for those with ≥7 LSCSF points (P ＜ 0.05).The implant breakage occurred in 3 cases of those who underwent fixation of one normal vertebra respectively below and above the two contiguous segments but not in those who underwent additional fixation of the injured vertebrae.The rate of screw loosening was 2.2％ (4/182).The non-union rate of the injured vertebra was 2.7％ (5/182).The rate of kyphosis recurrence was 1.1％ (2/182).Conclusions To prevent the failure of posterior pedicle screw fixation,surgeons should pay more attention to the following key points before operationthe type and evaluation of spinal fractures,a proper approach and method of internal fixation,and the weight bearing capability of the anterior column.