Evolution of prophylaxis protocols for venous thromboembolism in neurosurgery: results from a prospective comparative study on low-molecular-weight heparin, elastic stockings, and... von Chibbaro, S, Cebula, H, Todeschi, J, Fricia, M, Vigouroux, D, Abid, H, Kourbanhoussen, H, Pop, R, Nannavecchia, B, Gubian, A, Prisco, L, Ligarotti, G, Proust, F, Ganau, M