Impact of Single-Level Minimally Invasive Versus Open L4-L5 and L5-S1 Transforaminal Lumbar Interbody Fusion on Postoperative Distal and Lumbar Lordosis.

STUDY

DESIGN

Retrospective cohort study.

OBJECTIVE

To compare distal lordosis (DL) and lumbar lordosis (LL) generated by single-level minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) and open TLIF at L4-L5 and L5-S1.

SUMMARY OF BACKGROUND DATA: Restoring or maintaining L4-S1 DL and LL is an important component of TLIF surgery. However, the current literature is conflicting regarding the effect of surgical approach on these postoperative sagittal parameters.

METHODS

Preoperative DL and LL were compared to postoperative values among adult patients undergoing single-level MI- and open TLIF surgeries. Subgroup analyses were performed with patients stratified based on pre-operative DL (low<25°, normal ≥ 25°), pelvic incidence (PI) (low<45°, moderate 45-60°, high > 60°), and PI-LL (high ≥ 10°, normal <10°). Regression analyses were conducted determining factors associated with postoperative DL and LL.

RESULTS

Of the 285 patients included in the study, 211 underwent MI-TLIF (74.0%) and 74 (26.0%) underwent open TLIF. Patients with a high preoperative PI obtained a significant increase in LL at 6-month follow-up with an open TLIF (Δ4.2°, P=0.009) but not with an MI-TLIF (Δ-0.8°, P=0.151). Patients with a preoperative DL ≥ 25° experienced a decrease in DL at 6-month follow-up with both an open TLIF (Δ-2.0°, P=0.013) and MI-TLIF (Δ-1.4°, P=0.011). Patients with a preoperative DL ≥ 25° also experienced a decrease in LL at 6-month follow-up with an MI-TLIF (Δ-1.0°, P=0.002) but not with an open TLIF (Δ-0.3°, P=0.552). Patients with a preoperative DL<25° obtained an increase in both DL and LL with both MI-TLIF and open TLIF.

CONCLUSION

Both MI-TLIF and open TLIF are effective for improving DL and LL among patients with a low preoperative DL (<25°). However, patients with a high preoperative PI (>60°) may benefit from an open approach for a greater restoration and maintenance of LL.

LEVEL OF EVIDENCE: 3.