The effects of different orientations of cage implantation on lumbar interbody fusion.

Abstract Background Transforaminal lumbar interbody fusion (TLIF) via a fusion cage is widely carried out to treat degenerative lumbar spinal disease, and cage implantation plays a pivotal role in buttressing the vertebrate and promoting fusion. Clinically, the cage implantation is commonly placed in two different orientations: oblique and traverse. Therefore, this study aimed to explore the effects of different orientations of cage implantation on lumbar interbody fusion. Methods From January 2016 to January 2018, a retrospective study of 98 patients with lumbar degenerative disease who were treated with lumbar interbody fusion with at least 2-year follow-up was performed. According to the different positions of cage implantation, the patients were divided into two groups: oblique group (OG) and traverse group (TG). The clinical and radiographic outcomes were compared preoperatively, postoperatively, and at the last follow-up evaluation. Radiographic measurements included the height of intervertebral (HOI), segment lordosis (SL), lumbar lordosis (LL), the distance between the posterior of cage and vertebrate postoperatively (D1), at the final follow-up (D2) and the distance of cage move (D3). Radiographic evaluation of fusion integrity was performed based on Bridwell interbody fusion grading system at the final follow-up. Results There was no significant difference between the two groups in terms of sex, age, surgical levels, operative time, intraoperative blood loss, time to ambulation, and length of hospital stay(P>0.05). The HOI, SL, and LL in the two groups were noticeably improved postoperatively compared with preoperatively (P>0.05), and there was no significant difference between the two groups (P>0.05). However, at the final follow-up, HOI, SL, and LL in the TG were larger than those in the OG (P Conclusion The traverse cage implantation in TLIF had the same clinical effect as oblique cage implantation, while that is superior in improving sagittal alignment. Therefore, we advise that the cage should be placed in traverse orientation in TLIF.