The Long-term Clinical Effect of Minimal-Invasive TLIF Technique in 1-Segment Lumbar Disease.

STUDY DESIGN: A prospective cohort double-center study.

OBJECTIVE: To assess the clinical effect of minimally invasive transforaminal lumbar interbody fusion (miTLIF) using the tunnel technique.

SUMMARY OF BACKGROUND DATA: A series of short-term studies have indicated that miTLIF could reduce blood loss and improve clinical results. However, long-term clinical study and magnetic resonance imaging research are still scare.

METHODS: From January 2008 to January 2009, 187 patients with 1-segment lumbar disease requiring intervertebral fusion were enrolled in this study. Patients were divided into 2 groups according to the operative methods. Postoperative low back pain (LBP), postoperative lumbar function, the fusion rate, lower extremity pain relief, variation of lumbar lordosis, and implant failure were assessed. At 48 months postoperation, the cross-sectional area of the paraspinal muscle was measured using magnetic resonance imaging.

RESULTS: The mean duration of follow-up was 54.4±5.9 months. The intermuscular pressure generated by the tunnel in the miTLIF group was lower than that generated in the oTLIF group. Patients in the miTLIF group reported a lower degree of LBP at all timepoints. The ODI scores were similar to the VAS scores. No significant differences were found in fusion rate, lower extremity pain relief, lumbar lordosis, or implant failure rate. A significant difference was found between the 2 groups in postoperative cross-sectional area.

CONCLUSIONS: This study confirmed the advantages of miTLIF in reducing postoperative LBP, improving postoperative quality of life and preventing paraspinal muscle atrophy compared with oTLIF, while achieving a similar therapeutic outcome. The lower intermuscular pressure generated by minimally invasive tunnel and subsequent moderate muscle atrophy were presumed to be possible reasons for its superiority.