This retrospective investigation attempts to define the incidence effu
sion success after postoperative infection after a posterior lumbar fu
sion, as well as which risk factors may adversely affect arthrodesis a
fter successful debridement. At an average follow-up of 37 months, 18
of 29 patients (62.1%) had a successful arthrodesis. Eighty-seven perc
ent of patients whose fusion excluded the sacrum had a solid arthrodes
is, compared with only 36% of those fusions including the sacrum. The
fusion rate in female patients was 33.3%, compared with 82.4% in male
patients. The rate of fusion with allograft bone was 17.2 versus 83.3%
with autograft bone. Female sex, the use of allograft bone, and exten
sion of the fusion mass to the sacrum significantly increase the incid
ence of nonunion after a postoperative deep spinal wound infection.