Hybrid Surgery Combined with Dynamic Stabilization System and Fusion for the Multilevel Degenerative Disease of the Lumbosacral Spine

NFlex system. A 67-year-old female had multilevel spinal stenosis with severe disc space narrowing at L5-S1. She underwent hybrid surgery, NFlex dynamic stabilization surgery at L4-5 and TLIF with PSF at L5-S1. Polycarbonate urethane (PCU) spacer was surrounded by a central titanium ring (arrow). Preoperative anteroposterior (A) and lateral (B) radiographs and postoperative 6-year anterolateral (C) and lateral (D) radiographs are shown.

Preoperative disc degeneration on MRI. A: Each lumbar segment. The most common operated segment, L4-5 in the Hybrid group and L3-4 in the Fusion group, showed the most degenerated disc status. The disc degeneration had relatively high grade in the Fusion group, but each segment had no statistically significant difference from Hybrid group (all p>0.05). B: Adjacent segments. The operated segments have high grade of disc degeneration compared with adjacent segments. And there was no statistical difference between two groups (all p>0.05).

Global angles at T12-S1. In the Hybrid group, lumbar lordosis and ROM at T12-S1 was maintained between preoperation and the final follow-up without significant changes. In the Fusion group, global lordosis was significantly changed (p=0.04), but global ROM was restricted at the final evaluation (p=0.01).

Angle changes in the Hybrid group. A: Segmental lordosis at L1-2, L2-3, L3-4, L5-S1 was preserved (p=0.39, p=0.49, p=0.07, and p=0.58, respectively), but lordosis at L4-5 was significantly decreased (p=0.02). B: Segmental angle at dynamic stabilized segment was decreased but it had no statistical significance (p=0.09) and lordosis at fused segment and adjacent segments was maintained in Hybrid group. C: Segmental ROM was generally decreased at all segment without statistical significance (all p>0.05). D: Segmental ROM at fused segment was significantly deceased (p=0.02). Segmental ROM at dynamic stabilized segment was increased without significance (p=0.05).

Angle changes in the Fusion group. A: Segmental lordosis at L2-3 was increased with statistical significance (p=0.02), but other segments had no changes in segmental lordosis. B: Segmental lordosis at the second above and above segment was significantly changed to lordosis (p=0.04 and p=0.02), but angle at the operated segments had no changes (p=0.38 and p=0.79). C: Segmental ROM at each segment was generally decreased at the final follow-up, but the changes had no statistical significance (L1-2, p=0.59, L2-3, p =0.73, L3-4, p=0.89, L4-5, p =0.50, and L5-S1, p=0.1). D: Segmental ROM at the fused segments was significantly restricted (both p=0.04) and ROM at above segment was also restricted (p=0.01).