General Session: Thoraco-Lumbar Degenerative

Presented by: D. Ou-Yang - View Audio/Video Presentation (Members Only)

Author(s):

J. Sembrano(1,2), D. Ou-yang(1), S. Yson(1)

(1) University of Minnesota, Minneapolis, MN, United States
(2) Minneapolis VA Health Care System, Orthopaedic Surgery, Minneapolis, MN, United States

Abstract

Introduction: Multiple techniques for TLIF have been described. No single method has consistently demonstrated superior clinical and radiographic outcomes. Our study evaluated three surgical approaches in an attempt to identify advantages and disadvantages of each.

Methods: Sixty-five consecutive patients underwent TLIF at ≤3 levels at a VA Medical Center from 2009-2013. Fifteen underwent open unilateral TLIF, 21 underwent open bilateral TLIF, and 29 underwent MIS TLIF. Primary outcomes included complications within 90 days of surgery and surgical process measures. Secondary outcomes included clinical outcome measures (ODI, ZCQ, VAS scores), radiographic outcomes (segmental lordosis, regional lordosis, pelvic tilt, and PI-LL), and fusion rates. Patients were followed for an average of 13 months.

Results: Complication rate was 55% for any complication, and 18.5% for severe complications. There was no difference in complication rates between surgical groups. The MIS TLIF group demonstrated significantly less blood loss and duration of surgery than the open groups (p=0.0008 and p=0.0046 respectively), but length of hospital stay was similar between all groups. Overall mean improvement in ODI was 13.1 points (pre-op vs post-op; p< 0.0001), but there was no difference between groups. Overall mean VAS back and leg pain scores improved by 2.2 and 1.4 points respectively (pre-op vs post-op; p=0.0002 and p=0.0353), but there were no differences noted between groups. Overall fusion rate at 1 year was 55% in by-level assessment and 43% in by-patient assessment. MIS group demonstrated significantly lower fusion rates than the bilateral group (79% vs. 29% p=0.0021). No other between group differences was identified in by-level analysis. No difference in fusion rates between groups was identified in by-patient analysis. Mean segmental lordosis increased by 3.6° immediately post-operatively (p=0.0005). This correction decreased to 1.8° by 1 year (p=0.0669). No differences between groups was identified. Regional lordosis, pelvic tilt, and PI-LL did not significantly change from preop values, and no differences were noted between groups.

Conclusion: The three techniques demonstrated comparable outcomes in most of the variables evaluated. MIS technique afforded decreased blood loss and operative time. Open TLIF approaches were superior in achieving fusion compared to the MIS approach. This may be related to surgeon learning curve for MIS procedures. Further studies with a larger sample size are necessary to identify differences between bilateral and unilateral (open or MIS) approaches. Finally, the veterans population presents unique challenges in regards to spinal fusion and are at higher risk for complications, pseudarthrosis, and poor outcomes.