The effects of patient related factors on hidden and total blood loss in single-level open transforaminal lumbar interbody fusion surgery - Gökhan Kürşat Kara; Hüseyin Kavak; Bahadır Gökçen; Kaya Turan; Çağatay Öztürk; Ufuk Aydınlı (Acta Orthopaedica et Traumatologica Turcica)