Unilateral versus bilateral Pedicle Screw Fixation associated with interbody fusion in degenerative Lumbar spine diseases

Background Lumbar interbody fusion is a recognized surgical technique in treatment of degenerative lumbar instability. Interbody fusion supplemented with pedicle screw fixation has several advantages over posterolateral fusion and has been advocated to improve fusion rates and clinical outcomes. Interbody fusion places the bone graft in the loadbearing position of the anterior and middle spinal columns thereby enhancing the potential for fusion. In addition, the interbody space has more vascularity than the posterolateral space, also increasing the potential for a solid fusion mass to form. Aim of the Work to assess safety and efficacy of unilateral pedicle screw fixation associated with interbody fusion in Lumbar spine degenerative diseases and to evaluate and compare outcomes of unilateral versus bilateral pedicle screw fixation associated with interbody fusion in lumbar spine degenerative diseases, as regard the operation time, bleeding, postoperative stay, cost, and the clinical and biomechanical results. Material & Methods This observational prospective comparative study of the 2 groups who were operated either unilateral (Group A /25 patients) or bilateral (Group B/25 patients) pedicle screw fixation with interbody fusion was done. Patients were followed up for 1, 6, 12 months. This study occurred at Ain Shams University hospitals. Results No differences were observed between the two groups with respect to demographic data. The patients of the two groups had significant improvement in functional outcome compared to preoperatively, except in early postoperative VAS back and ODI in unilateral group which is better than bilateral group. However, no significant difference noticed in the further follow up. There was no significant difference comparing fusion rate, complication rate and duration of hospital stay between the two groups at postoperative follow-up. There was significantly less blood loss, shorter postoperative pain killer use and significantly shorter operation time in the unilateral PS fixation group as compared with the bilateral PS fixation group in our study. Conclusion Our study suggested TLIF with unilateral PS fixation was as safe and effective as that with bilateral PS fixation. Unilateral PS fixation may significantly reduce the intraoperative blood loss and shorten the operation time, somewhat improve the clinical outcome scores of ODI and VAS Back without significant difference comparing fusion rate, complication rate and duration of hospital stay between the two groups at postoperative follow-up. BPSF with TLIF likely causes more degeneration at the cranial adjacent segment compared with UPSF techniques. However, the long-term follow up is required to demonstrate the impact of these findings.