Pyogenic spondylitis in adults is usually treated by antibiotics according to bacteria evidenced in a diagnostic intervertebral disc puncture. Brace treatment is associated in patients presenting back pain and a risk for vertebral body collapse due to infection with subsequent kyphotic deformity of the thoracolumbar spine. Percutaneous minimally invasive posterior spinal instrumentation has evolved over the last decade and indications in infections arouse over the last years. This procedure is interesting as it is performed through small skin incisions only. It avoids paravertebral muscle dissection and thus limits intraoperative bleeding and access morbidity. Recent retrospective data suggests that this internal fixation represents a theoretical advantage over brace treatment by lowering back pain and increasing patient's quality of life in the short run, up to 3 months, but no randomized study was published. The patient's autonomy, including walking ability and daily activities, might improve more rapidly after a percutaneous procedure. Additionally, the sagittal alignment of the thoracolumbar spine could be better maintained by internal fixation, which might prevent progression into kyphosis and improve long-term outcome. The hypothesis is the superiority of percutaneous minimally invasive instrumentation on brace treatment in term of quality of life, back pain and quality of osseous healing.

Safety and efficacy of percutaneous for the indication of pyogenic spondylitis has been demonstrated retrospectively on small cohort studies, which is in line with our clinical experience. Although this therapeutic concept seems applicable to patients with spondylitis, the theoretical clinical benefit of minimally invasive surgery remains hypothetic and unclear compared to brace treatment, which might still be regarded as the gold standard.

Inclusion criteria:

• adult patients presenting acute pyogenic spondylitis of the thoracolumbar spine
• back pain at a minimum of 4 out of 10 on VAS
• Diagnostic MRI and disc puncture + microbiological analysis required for antibiotic treatment and/or blood culture
• Vertebral body involvement (osteolysis) < 50% of VB height documented on CT

Exclusion criteria:

• postoperative pyogenic spondylitis or infection after spinal instrumentation spinal tuberculosis and mycosis
• contra-indications for surgery or general anaesthesia
• general septic conditions acute endocarditis documented by sonography
• patients presenting another major abcess or an epidural abscess
• Absence of vertebral body involvement (osteolysis) on CT or minor VB involvement less than 10% of VB height (surgery not indicated)
• Major destruction of vertebral body (>50%) on CT (surgery mandatory) Patients with concomitant bacterial endocarditis