Objective To investigate the cl inical outcomes of one stage debridement and closed-suction drainage for treatment of infection after lumbar instrumentation. Methods Between June 2002 and March 2008, 12 patients with infection after lumbar instrumentation were treated with one stage debridement and closed-suction drainage, including 9 males and 3females and aging 35-68 years (48.5 years on average). The disease duration varied from 7 days to 183 days (56 days on average). The segments of internal fixation included 7 cases single segment at levels of L4, 5, 4 cases of double segments at levels of L 4, 5, L5, S1 (2 cases), and L3, 4, L4, 5 (2 cases), and 1 case of three segments at levels of L3, 4, L4, 5, L5, S1. Two patients were treated with internal fixator removal. Results The bacterial culture results of intervertebral discs were positive in 8 cases for Staphylococcus aureus and in 3 cases for Enterobacter cloacae, negative in 1 case. Primary healing of incisions were achieved in all cases. Twelve patients were followed up 18-53 months (34.7 months on average). The white blood cell count, erythrocyte sedimentation rate, and C reactive protein significantly decreased after operation, showing significant differences at 15 days after operation when compared with those before operation (P lt; 0.05). No obvious low back pain was observed. Pathological-changed vertebra-space fused. No displacement and breakage of internal fixator occurred; in 2 patients who were given internal fixator removal, no removal of the instrumentation was performed again. The X-ray films showed that the average kyphosis decreased 0.8° at 18 months after operation. At last follow-up, the visual analogue scale score was 2 ± 1, showing significant difference (P lt; 0.05) when compared with that (10 ± 2) before operation. Conclusion One stage debridement and closed-suction drainage therapy is an effective method for treating infection after lumbar instrumentation. The operation is easy and can reduce hospitalization days.