- Anesthetic management of a patient in prone position with a drill bit penetrating the spinal canal at C1-C2, using a laryngeal mask. Valero, R., Serrano, S., Adalia, R., Tercero, J., Blasi, A., Sánchez-Etayo, G., Martínez, G., Caral, L., Ibáñez, G. Anesth. Analg. (2004)