30. A 45 year-old man with Ankylosing Spondylitis presents with progressive back pain without neurological deficit. Plain radiographs show a discovertebral lesion T10-T11. The diagnostic and treatment policy includes:
1. Spinal instrumentation and fusion, biopsy and culture
2. Spinal instrumentation and fusion, no biopsy, no culture
3. Biopsy, culture and antibiotic treatment
4. Biopsy, culture and plaster immobilisation
5. Plaster immobilisation