Assessing the Effects of Prior History of Vertebral Osteomyelitis on Peri-Operative Factors and Post-Operative Recovery in Adult Spinal Deformity Patients

Background: Vertebral osteomyelitis (VOM) is a relatively rare infection of the vertebral body that requires aggressive antibiotics and may necessitate operative debridement, decompression, and/or fusion of affected segments. Post-treatment VOM can result in focal deformity, or can occur in conjunction with a global deformity. The influence of previous VOM on adult spinal deformity (ASD) surgery outcomes has not been examined previously. Purpose: To determine whether patients with a history of previous VOM treated for spinal deformities have different post-operative clinical trajectories or outcomes, including an increased risk of peri-operative complications and recurrence of infection. Study design/setting: Retrospective review. Patient sample: 836 ASD patients. Outcome measures: Complications; antibiotic course; HRQLs Methods: Patients (>18 y) with a history of resolved vertebral osteomyelitis (VOM) prior to primary deformity surgery, with complete data up to 2Y were included. A case–control analysis was performed, with cases of confirmed VOM (VOM+) matched to individuals without history of VOM (VOM−) in 1:1 fashion based on age, gender, and number of co-morbidities. Given the exploratory nature of this work, bivariate comparisons using chi-squared tests for categorical outcomes and t-test for continuous data were used. Results: 18 VOM+ patients were included (55.83 ± 10.42 years, 38% female, 29.48 ± 6.85 kg/m(2)). At baseline, VOM+ patients were significantly more likely to have a history of cancer (62.8 vs. 56.8, p = 0.011), and to be actively undergoing cancer treatment (p = 0.013) at the time of primary ASD surgery. HRQLs (p > 0.05) were similar between groups. In terms of baseline (BL) parameters, neither group demonstrated significantly different C-reactive protein (CRP), hemoglobin, or albumin (p > 0.05). Surgically, VOM+ patients did not have significantly higher mean levels fused (p = 0.002), mean blood loss (p < 0.001) or longer operative time (p = 0.003) compared to VOM− patients. Post-operatively, one VOM+ patient (5.6%) experienced recurrence of osteomyelitis in the thoracic spine after initially receiving treatment for lumbar VOM. VOM+ were found to have longer hospital length of stays (8.154 vs. 4.772 days, p = 0.003). At 2Y follow-up, there was no significant differences in terms of ODI, EQ5D/EQ5D-VAS, or NRS-Neck or NRS-Back (p > 0.05), rate of mechanical complications or surgical site infections (all p > 0.05). Conclusions: A history of previously treated VOM in adult spinal deformity patients appears to be associated with increased total hospital length of stay, blood loss, and operative time compared to case–control matched VOM− patients. Nonetheless, VOM+ pateints demonstrated iimprovement in terms of patient-reported outcomes without an increased risk of mechanical complications.