“…The majority of studies used the more common Tsukayama et al [172] classification system, in which acute (early) infections occur within one month of the index procedure and chronic (late) infections occur more than one month after the index procedure. The pooled average early SSI rate among 14,517 patients was 2.1% (median, 2.6%; range, 0.5%–16.7%) [11,13,20,22,25,32,78,82–84,86,142,147,156,164,167,170,171] compared with 0.8% (median, 0.9%; range, 0.1%–4.7%) for pooled average late SSI rate among 12,238 patients [11,13,54,83,167,171]. In terms of specific types of spine operations, 52 studies evaluated SSI rates among patients who underwent spinal fusion [9,10,14,15,21,24,27,30,33,42,43,46,52,56,58,62,63,68–70,72,75,76,92,103,105,107–109,111,113–115,119,120,123,125,128,133,139,141–144,146,150,151,157,161,162,164,173].…”