Minimally Invasive Lumbar Fusion Is Associated with Lower Reoperation for Adjacent Segment Disease and Improved Patient-Reported Outcomes Compared with Open Surgery.

OBJECTIVE: Adjacent segment disease (ASD) is characterized by symptomatic degenerative changes at the level above or below an index spinal fusion. As minimally invasive surgical (MIS) approaches might be less traumatic to adjacent facet joints, we hypothesized that MIS approaches would lower the rate of ASD. METHODS: The authors retrospectively identified patients who underwent 1 or 2 levels of lumbar fusion from November 2013 to April 2024 at a single academic institution. The primary outcome was reoperation for ASD. Secondary outcomes included complications, reoperations, and long-term patient-reported outcomes (EuroQol 5-Dimension (EQ-5D), Oswestry Disability Index (ODI)). RESULTS: A total of 419 patients met inclusion criteria, including ≥ 12 months of follow-up or earlier re-operation: 259 underwent open spinal fusion surgery and 160 underwent MIS lumbar fusion. The mean follow-up period was 34 ± 27 months in the open group and 32 ± 28 months in the MIS group. The overall rate of reoperation for ASD was significantly higher in the open group (19% vs. 9%, p=0.003). In a subset of 108 patients for whom preoperative and 2-year follow-up patient-reported outcomes (PROMs) were available (68 open, 40 MIS), MIS surgery had significantly improved outcomes at 2 years comparing EQ-5D (0.86 ± 0.2 vs. 0.75 ± 0.2, p = 0.01) and ODI (13 ± 10 vs. 25 ± 21, p = 0.002). CONCLUSIONS: MIS lumbar fusion is associated with a significantly lower rate of reoperation for ASD, and among patients with available 2-year PROMs, improved EQ-5D and ODI, when compared with open surgery.