A postoperative infection involving the tissues deep to the fascia is defined as a deep wound infection (DWI). Management of such infections after lumbar spinal surgery remains a challenge. One strategy is the use of vacuum-assisted wound closure (VAC) which applies negative pressure to the wound to improve microcirculation and to promote the formation of granulation tissue. When combined with antibiotics, VAC has been shown to successfully treat DWIs and is now a common strategy for treating deep postoperative wound infections after spinal surgery. In this article, we review the technique of VAC, its mechanism of action, indications and contraindications, and clinical outcomes in the treatment of DWIs after lumbar spinal surgery.A ccording to the Centers for Disease Control and Prevention, a surgical site infection (SSI) is an infection that "occurs within 30 days after the operation if no implant is left in place or within 1 year if an implant is in place and the infection seems to be related to the operation." 1 Based on more than one hundred thousand procedures, the Scoliosis Research Society Morbidity and Mortality Committee reported the rate of deep SSI (otherwise known as a deep wound infection [DWI]) after lumbar decompression or diskectomy is 0.4% or 1.1%, respectively. More recently, a recent large cohort study reported a 0.49% DWI rate across all surgical pathologies and both decompression only and fusion procedures after implementation of protective measures. The authors recommended chlorohexidine gluconate showers and glucose management, as well as intraoperative and postoperative considerations, to minimize DWI risk. 2 SSIs are associated with both patient-related and procedure-related factors. Patient-related factors include age greater than 60 years, obesity, tobacco use, alcohol abuse, malnourishment, bacteremia, diabetes, chronic obstructive pulmonary disease, coronary heart disease, osteoporosis, neurologic injury, cognitive impairment, prolonged postoperative bed rest, and skin maceration. 3 Procedure-related factors include posterior surgical approach, wound depth greater than 4 cm, use of implants, large blood loss, dural tear, use of allograft, fusion greater than seven levels, revision procedures, fusion to the sacrum, and drainage tubes exiting deeply to the rectum. 3,4 The operating room environment provides additional important risk factors including greater than 10