Clinical Outcomes And Cost Analysis For Unilateral Versus Bilateral Pedicle Screw Fixation In Two Levels During Minimally Invasive Transforaminal Lumbar Interbody Fusion (Mis-Tlif): A Comparative Analysis

Study Design: Retrospective clinical study of 116 patients who underwent either a bilateral or unilateral TLIF procedure for the treatment of degenerative lumbar diseases. Objectives: We design this retrospective clinical study to compare the clinical, radiological outcomes and complication of unilateral pedicle screw (UPS) versus bilateral pedicle screw (BPS) in degenerative lumbar diseases after MIS-TLIF. Summary of Background Data. Studies have shown that minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) was used in a large number of lumbar degenerative disorders. However, unilateral or bilateral pedicle screw fixation after MITLIF remains controversial, especially in two-level surgery. Methods: We retrospectively analyzed 116 consecutive patients who had two-level MIS-TLIF at L4/L5 and L5/S1 from January 2010 to January 2014 and the clinical and radiological outcome and the complication were compared. Of the 116 patients for analysis, 52 patients underwent unilateral fixation, and 64 patients underwent bilateral fixation. Results: There was no statistically significant difference in baseline demographic characteristics and in hospital-stay period between the two groups (P>0.05). There was a significantly longer operating time, more blood loss and X-ray exposure times in BPS comparing with UPS (P<0.05). Clinical outcomes in two groups such as the pain (VAS) and Oswestry Disability Index (ODI) improved significantly after surgery and no difference was found between them (P<0.05). The number of patients who have good or excellent outcomes in UPS was 84.6% which in BPS was 82.3%. No significant difference was found in fusion rate and total complication rate between the two groups (P>0.05). Conclusion: There was no significant difference between the two fixation methods of MIS-TLIF in clinical outcomes and complications. However, unilateral pedicle screw has some superiorities such as shorter operating time, lower cost, less blood loss and X-ray exposure. Unilateral pedicle screw might be more suitable in performing two-level pedicle screw fixation after MIS-TLIF.