Pedicle Screw Loosening After Lumbar Spinal Stenosis Surgery and an Analytical Review of Recurrent Loosening: Based on Revision Surgery Experience.

BACKGROUND Although pedicle screw fixation is widely used in lumbar spinal fusion, screw loosening, which is well described in patients with osteoporosis, remains a clinically relevant yet insufficiently investigated problem in individuals without osteoporosis, particularly regarding revision strategies and risk factors for recurrence. This study aimed to identify risk factors for recurrent pedicle screw loosening after revision surgery for lumbar spinal stenosis using bone grafting, cement augmentation, and longer and larger-diameter screws. MATERIAL AND METHODS A retrospective review included 1063 patients who underwent lumbar instrumentation between January 2021 and January 2025. Screw loosening was defined on computed tomography (CT) as a radiolucent zone greater than 1 mm or a "double-halo" sign. Seventeen patients without osteoporosis developed loosening. In these cases, the original screw tract was preserved, reinforced with allograft and semi-cured cement, and revised using screws 5 mm longer and 1 mm wider. At 3-month follow-up, patients were classified into no recurrent loosening (group A) or recurrent loosening (group B) based on CT findings. RESULTS Screw loosening occurred in 17 multilevel cases. Mean patient age was 60.9 ± 11.1 years; 41.2% were male. Recurrent loosening occurred in 52.9% (9/17). Group A had a significantly higher T-score than did group B (-0.70 ± 0.93 vs -1.18 ± 0.77; P = 0.021). CONCLUSIONS The combined revision approach provided acceptable short-term stability. Lower T-scores were associated with recurrent loosening despite the absence of osteoporosis. Multilevel instrumentation increased the risk of primary loosening. Larger multicenter studies are warranted to confirm these findings.