Spondylectomy for extripation of spinal tumors would be performed through piecemeal excision or by total en blocspondylectomy with cutting at the neural arch by the threadwire saw (T-saw) that is sometimes inevitably intralesional.The purposeof this study was to compare the potential for tumor growth after rubbing of the cut surface of tumors cut by either T-saw or blunt instrument againstthe subcutaneous tissues of nude mice. Tumorswereprepared by subcutaneous injection of human HT 1080fibrosarcoma cells innude mice. The animals were sacrificed,and tumors were harvested en blocand cut with either a T-saw or artery forceps. A 3-cm wound was created on the backs of other (plain)nude mice. The tumor’scut surface was rubbed for 10 seconds against the subcutaneous tissue of one of these nude mice. The wounds were then sutured. Tumor blockswere inoculated into other nude mice.Nude mice were followed for occurrence of tumor growth.Tumor growth occurred in all nude mice after block inoculation.The incidence of tumor growth after rubbing with the tumor surfacescutwith T-saw and artery forceps were 16.7% and58.3%, respectively (P=0.035). Onset of tumor growth after tumor rubbing and inoculation of tumor blocks were 30.1 ±25 and 12.2 ±5 days respectively (P=0.015). Rubbing of T-saw-cut tumor surface has less possibility of causing tumor growth than rubbing of surfaceof bluntly-cut tumors.