Surgical site infection after osteotomy of the adult spine: does type of osteotomy matter?

Background context: Surgical site infection after spinal surgery is frequently seen. It occurs between 0.7% and 12% of patients, leading to higher morbidity, mortality, and health-care costs. Osteotomy procedures are known to have increased blood losses and surgical times when compared with other spinal surgeries. Both of these factors have previously been identified as significant risk factors for SSI. We performed a cohort study of this high-risk population to identify risk factors and rates of SSI after spinal osteotomy surgery and identify difference in risk between different types of osteotomies. Purpose: The objective of the study was to assess the incidence and identify significant risk factors for surgical site infection (SSI) after spinal osteotomy. Study design: Retrospective review of all adult patients who underwent spinal osteotomy surgery for deformity by an orthopedic surgeon in our university. Methods: All electronic records of adult orthopedic patients whom underwent a spinal osteotomy procedure at our department between January 1998 and December 2005 (n=363) were abstracted. During surgery, a pedicle subtraction osteotomy (transpedicular wedge resection), anterior spine osteotomy (resection of anterior and middle columns), posterior Smith-Petersen osteotomy (resection of a portion of the superior and inferior lamina, ligamentum flavum, and the inferior and superior articular processed), or a combined anterior and posterior osteotomy (vertebral column resection [VCR]) (circumferential resection of the vertebrae via either a combined anterior/posterior or posterior-only approach) was performed. Primary outcome measurement was SSI. Subanalysis to deep and superficial SSI was performed. Results: Twenty patients (5.5%) were found to have an SSI, with nine (2.5%) having deep SSI. Analysis showed that patients undergoing VCR (p=.042) had a significant increased risk for deep SSI (11.1%). Obese patients had a significant increased risk (p=.045) for superficial SSI. Conclusions: Vertebral column resection has a significant increased risk for SSI (11.1%) compared with other types of osteotomies (4.1%). When possible, osteotomy techniques that involve less extensive exposures and soft-tissue dissection should be chosen to minimize deep SSI risk. Obese patients should be counseled on weight loss to try minimizing superficial SSI risk.