Objective:To investigate the difference between simple posterior interbody fixation and fusion and posterior interbody fixation combined with focus debridement and bone graft fusion for the treatment of mono- and bi-segmental lumbar brucella spondylitis.Methods:A total of 63 patients (42 males and 21 females), aged 50.9±8.18 years (range from 38 to 69 years) with mono- and bi-segmental lumbar brucella spondylitis who received surgical treatment from June 2014 to Feb 2018 were retrospectively analyzed. There were 44 cases of mono-segmental and 19 cases of bi-segmental. Thirty-one cases were treated with single posterior interbody fixation and fusion (PIFF group), and 32 caseswere treated with posterior interbody fixation combined with focus debridement and bone graft fusion (debridement group). The main observation indicators include operation time, intraoperative blood loss, postoperative hospital stay, postoperative medication time, Visual Analogue Scale(VAS), Oswestry Disability Index (ODI), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), Frankel score and clinical efficacy.Results:All of 63 patients were followed up for 27.16±6.07 months (range 15 to 38 months). The operation time of mono-segmental patients of PIFF group was 105.86±16.66 min,the intraoperative blood loss was 295.00±55.11 ml, and the postoperative hospitalization was 4.45±1.53 days, which was significantly shorter than debridement group ( P<0.001), while the postoperative medication time was without significant difference between the two groups ( P>0.05). The opration time of bi-segmental patients of PIFF group was 150.33±26.29 min, the intraoperative blood loss was 242.05±50.56 ml, and the postoperative hospitalization was 4.56±1.50 days, which was significantly shorter than debridement group ( P<0.001), while the postoperative medication time was also without significant difference between the two groups. At the last follow-up time, the VAS scores and ODI values of mono- and bi-segments in PIFF group and debridement group were lower than those preoperation, but there was no significant difference between the two groups ( P>0.05). There was no significant difference in CRP between mono-segments of PIFF group and debridement group at the preoperation, 3 months after operation and the last follow-up time ( P>0.05). The CRP in mono-segments of PIFF group and debridement group decreased at 3 months after the operation compared with that preoperation, and the difference was statistically significant ( P<0.001). There was no significant difference in CRP between bi-segments of PIFF group and debridement group at 3 months after operation and the last follow-up time ( P>0.05). There was no significant difference in ESR between mono- and bi-segments of PIFF group and debridement group at 3 months after operation and the last follow-up time ( P>0.05). There was significant difference in ESR between mono- and bi-segments of PIFF group and debridement group at the preoperation, 3 months after operation and the last follow-up time. There was no statistical difference in the proportion of excellent postoperative clinical efficacy between the two groups. Complications were observed in two patients in PIFF group (6.5%, 2/31) compared with 8 patients in debridement group (25%, 8/32, χ2=4.057, P=0.044). Conclusion:On the basis of standardized anti-brucella drug therapy, simple posterior interbody fixation and fusion for the treatment of brucella spondylitis has a satisfactory surgical effect, and has the advantages of less surgical trauma, shorter time, earlier postoperative movement time and fewer complications.