Comparison of Long-Term Follow-Up Outcomes Between Minimally Invasive and Open Surgery for Single-Level Lumbar Fusion.

Aim: To evaluate, and to compare the clinical outcomes of minimally invasive surgery (MIS), and open surgery for single-level lumbar fusion over a minimum of 10-year follow-up.

Material and methods: We included 87 patients who underwent spinal fusion at the L4 - L5 level between January 2004 and December 2010. Based on the surgical method, the patients were divided into the open surgery (n=44) and MIS groups (n=43). We evaluated baseline characteristics, perioperative comparisons, postoperative complications, radiologic findings, and patientreported outcomes.

Results: The mean follow-up period was > 10 years in both groups (open surgery, 10.50 years; MIS, 10.16 years). The operative time was longer in the MIS group (4.37 h) than that in the open surgery group (3.34 h) (p=0.001). Estimated blood loss was lower in the MIS group (281.40 mL) than in the open surgery group (440.23 mL) (p < 0.001). Postoperative complications, including surgical site infection, adjacent segment disease, and pseudoarthrosis, did not differ between the groups. Plain radiographic findings of the lumbar spine did not differ between the two groups. Visual scores for back/leg pain and the Oswestry disability index did not differ between the two groups, preoperatively and at 6 months, 1, 5, and 10 years after surgery.

Conclusion: After a minimum of the 10-year follow-up, postoperative complications and clinical outcomes did not differ significantly between patients who underwent open fusion and MIS fusion at the L4 - L5 level.