Risk factors and morbidity associated with surgical site infection subtypes following adult neurosurgical procedures

Objective Studies on surgical site infection (SSI) in adult neurosurgery have presented all subtypes of SSIs as the general 'SSI'. Given that SSIs constitute a broad range of infections, we hypothesized that clinical outcomes and management vary based on SSI subtype. Methods A retrospective analysis of all neurosurgical SSI from 2012-2019 was conducted at a tertiary care institution. SSI subtypes were categorized as deep and superficial incisional SSI, brain, dural or spinal abscesses, meningitis or ventriculitis, and osteomyelitis. Results 9620 craniotomy, shunt, and fusion procedures were studied. 147 procedures (1.5%) resulted in postoperative SSI. 87 (59.2%) of these were associated with craniotomy, 36 (24.5%) with spinal fusion, and 24 (16.3%) with ventricular shunting. Compared with superficial incisional primary SSI, rates of reoperation to treat SSI were highest for deep incisional primary SSI (91.2% vs 38.9% for superficial, p < 0.001) and second-highest for intracranial SSI (90.9% vs 38.9%, p = 0.0001). Postoperative meningitis was associated with the highest mortality rate (14.9%). Compared with superficial incisional SSI, the rate of readmission for intracranial SSI was highest (57.6% vs 16.7%, p = 0.022). Conclusion Deep incisional and organ space SSI demonstrate a greater association with morbidity relative to superficial incisional SSI. Future studies should assess subtypes of SSI given these differences.