Incidence and management of deep surgical site infection following spinal deformity surgery: 8 818 cases at a single institution

Abstract

Objective To investigate the incidence and management of deep surgical site infection(SSI) after the spinal deformity surgery. Methods This study retrospectively reviewed a consecutive cohort of 8818 patients with spinal deformity who received spinal deformity surgery between January1998 and December 2017 at our center. The diagnosis of deep SSI was based on the clinical symptoms, imaging data and laboratory findings. Early infection and late infection were defined as deep infections occurring 3 months after the initial procedure, respectively. All deep SSIs were first treated with irrigation and debridement, closed suction irrigation system and antibiotics. If the infection cannot be eradicated, dressing change is recommended within 2 years after the initial surgery. The instrumentation can be removed 2 years after the initial surgery with careful evaluation of the fusion mass. The posterior-anterior and lateral radiographs were used to measure the coronal parameters and sagittal alignment. Results Sixty patients were diagnosed as deep SSI after spinal deformity surgery, including 11 patients with early infection and 49 patients with late infection. No significant difference was observed in terms of age, gender ratio, surgical approach and fusion levels between the two groups. Deep SSI seemed to be more likely to occur between 2 and 5 years after surgery. Incidence of SSI was lowest in the patients with idiopathic scoliosis and ankylosing spondylitis, and highest in the patients with neuromuscular and syndromic scoliosis. There was a high rate of negative culture in the primary culture. Staphylococcus aureus and Escherichia coli were the most common organisms in the early infection, while patients with late infection had a high rate of low-virulent skin flora. In the early infection group, nine patients retained instrumentation while the implants were removed 2 years after the primary surgery in 2 patients. In patients with late infection, instrumentation was retained in 5 cases and removed in 10 cases until 2 years after the primary surgery. 34 cases were infected 2 years after the primary surgery and the implants were removed directly. One patient underwent reoperation with instrumentation 1 month after implant removal, another patient underwent reoperation 3 years after implant removal due to progression of deformity. Significant loss of coronal correction was noted at the latest follow-up. Conclusion The rate of deep SSI after spinal deformity surgery was 0.68%, of which the incidence of early infection and delayed infection was 0.12% and 0.56%, respectively. An increased risk of SSI in patients with neuromuscular and syndromic scoliosis was noted. If the infection cannot be eradicated after repeated debridement, we recommend instrumentation removal 2 years after the initial surgery, but there is still a high risk of loss of correction in these patients. Key words: Scoliosis; Kyphosis; Spinal fusion; Infection; Treatment outcome