11.5.7\ Surgical Site Infections

11.5.7.1\ Discussion

Infection related to spine surgery has an overall incidence of 1.9% and is defined as occurring within 30 days of surgery or within 12 months of placement of foreign bodies and can be categorized by the depth of surgical tissue involvement, including superficial, deep incisional, or organ and surrounding space. Staphylococcus aureus is the most common causative organism. MRI with contrast is generally the modality of choice for evaluating postoperative infections. Rim-­enhancing fluid collections, bony erosions and enhancing, and paraspinal inflammation are suggestive of infection (Figs. 11.101 and 11.102). Hardware removal is often necessary in

cases of postoperative spine infection (Fig. 11.103). Other than removing old hardware and washout, antibiotic-­impregnated methyl methacrylate beads are sometimes left in the surgical cavity for direct site treatment (Fig. 11.104).

a

b

Fig. 11.101  Discitis-osteomyelitis. Sagittal post-­ contrast T1-weighted MRI shows enhancement in the vertebral bone marrow and prevertebral soft tissues at L5–S1 surrounding the intervertebral disc prosthesis

Fig. 11.102  Wound infection. Sagittal (a) T2-weighted and post-contrast fat-suppressed T1-weighted (b) MR images show a fluid collection (arrows) with surrounding enhancement and a draining sinus to the overlying skin in the posterior paraspinal soft tissues along the surgical approach following minimally invasive microdiscectomy