Deep surgical site infection (DSSI) is one of the most challenging complications for spinal surgeons and can lead to a poor clinical outcome. This ambispective study was designed to examine the effect of vancomycin powder mixed with autogenous bone graft and bone substitute on preventing deep surgical site infection (DSSI) in degenerative lumbar fusion surgeries as well as any interference with bony fusion.

Inclusion Criteria:

• Patients who have instrumented spine fusion surgery due to failed conservative treatment (bed rest, medication, rehabilitation programs) for 3 to 6 months
• Patients who are willing to sign the surgical permit after the surgeon explains all surgical procedures along with the surgical risks
• Patients who fully understand the surgical procedures as well as the surgical risks and are willing to sign the surgical permit and the inform consent
• Patients who agree one more blood withdrawal after operation

Exclusion Criteria:

• Patients who agree to accept the spine surgery but do not agree to sign the inform consent
• Patients who have allergic reaction to vancomycin