Fixation with posterior short-segment pedicle screws and a mono-segment translaminar facet screw to treat fractures of lumbar vertebra

Abstract

Objective To investigate the efficacy of fixation across the injured vertebra with posterior short-segment pedicle screws and a mono-segment translaminar facet screw to treat fractures of lumbar vertebra.Methods The study reviewed 52 patients (43 males and 9 females) who had undergone surgery from January 2011 to June 2012 for lumbar fractures.Fixation across the injured vertebra with posterior short-segment pedicle screws was adopted for 27 cases (group A) and fixation across the injured vertebra with posterior short-segment pedicle screws and a mono-segment translaminar facet screw for 25 cases (group B).The 2 groups were compatible with no significant differences in general clinical data (P ＞ 0.05).The spinal cord function was evaluated according to Frankel's scale; the local pain and work status of the patients at the last follow-up were evaluated using the Denis scale.Postoperative implant failure and fusion rate,as well as the pain and work status of the patients at the last follow-up,were compared between the 2 groups.The 2 groups were also compared at preoperation,postoperation and the last follow-up in terms of spinal cord function,anterior height loss of the injured vertebra,spinal canal stenosis and cobb angle.Results All patients were followed up for 12 to 36 months (average,22.5 months).No implant loosening or breakage occurred in all the patients except in one case in group A who had implant loosening 16 months postoperation.There was a significant difference in the fusion rate between group A (88.9％) and group B (100％) (P ＜0.05).All the patients gained an improvement of 1 to 2 grades in neural function of the spinal cord.There were no significant differences at the last follow-up between the 2 groups regarding the Frankel's evaluation or work status (P ＞ 0.05),but group B scored significantly better than group A in local pain evaluation (P ＜0.05).There were no significant differences at postoperation and the last follow-up between the 2 groups regarding anterior height loss of the injured vertebra,spinal canal stenosis or correction of cobb angle (P ＞ 0.05),but group A had significantly greater loss of cobb angle than group B (P ＜ 0.05).Conclusions Compared with conventional transpedicular fixation with posterior short-segment pedicle screws,supplemental fixation with a mono-segment translaminar facet screw can strengthen the spinal stability,increase fusion rate and better maintain the correction of cobb angle.Therefore,it is a good posterior treatment for fractures of lumbar vertebra to adopt fixation with posterior short-segment pedicle screws and a mono-segment translaminar facet screw. Key words: Spinal fractures; Bone, screws; Fracture fixation, internal; Spinal fusion