Study design:

Retrospective Cohort Study OBJECTIVE: To determine if intraoperative on-table lumbar lordosis and segmental lordosis correlate with postoperative lordosis following single-level posterolateral decompression and fusion (PLDF) or transforaminal lumbar interbody fusion (TLIF).

Methods:

Electronic medical records were reviewed for patients ≥18 years old who underwent PLDF or TLIF between 2012 and 2020. Lumbar lordosis and segmental lordosis were compared between pre-, intra-, and post-operative radiographs using paired t-tests. Significance was set at p<0.05.

Results:

A total of 200 patients met inclusion criteria. No significant differences in preoperative, intraoperative, or postoperative measurements were found between groups. Patients who underwent PLDF experienced less disc height loss over one year postoperatively (PLDF: 0.45 + 0.9 mm vs TLIF: 1.2 + 1.4 mm, p<0.001). Lumbar lordosis significantly decreased between intraoperative to postoperative radiographs at 2-6 weeks for PLDF (Δ: -4.0°, p<0.001) and TLIF (Δ: -5.6°, p<0.001), but no change was identified between the intraoperative and >6 month postoperative radiographs for PLDF (Δ: -0.3°, p=0.634) or TLIF (Δ: -1.6°, p=0.087). Segmental lordosis significantly increased from the preoperative to post-instrumentation intraoperative radiographs for PLDF (Δ: 2.7°, p<0.001) and TLIF (Δ: 1.8°, p<0.001), but it subsequently decreased at the final follow up for PLDF (Δ: -1.9°, p<0.001) and TLIF (Δ: -2.3°, p<0.001).

Conclusion:

Subtle decreases in lumbar lordosis may be noticed in the early postoperative radiographs compared to intraoperative images on Jackson operative tables. However, these changes are not present at one-year follow-up as lumbar lordosis increases to a similar level as intraoperative fixation.