Impact of Needle-Tip Depth on Cement Leakage in Percutaneous Vertebroplasty: A Clinical and Finite Element Analysis.

Abstract

The purpose of this study was to explore the optimal needle-tip depth through conventional percutaneous vertebroplasty (PVP) and further analyze the correlation between needle-tip depth and anterior cement leakage in osteoporotic vertebral compression fractures. A total of 560 patients with PVP were retrospectively analyzed, and they were stratified into a shallow (needle-tip at 2/3-3/4 depth, n = 291) and deep placement group (3/4-7/8 depth, n = 269). The clinical outcomes and anterior leakage rates were compared. Biomechanical parameters, including symmetric cement diffusion, flow velocity, anterior wall arrival time, and contact pressure, were derived from finite element analysis. Anterior leakage risk was significantly higher with deep placement (P = 0.005). Finite element analysis demonstrated increased distal diffusion asymmetry fraction, decreased anterior wall arrival time, increased cement flow velocity, and increased contact pressure for the deep insertion (all P < 0.0001). Risk of leakage was particularly elevated in the type 4 German Society for Orthopaedics and Trauma Surgery Osteoporotic Fracture Classification fracture group when placed deep (72.92% vs. 29.17%, P < 0.001). Greater amount of cement septum extension during PVP increases anterior cement leakage risk, especially in osteoporotic fracture type 4 fractures, suggestive that practitioners should be cautious about controlling needle-depth in order to effectively minimize complications.