History	History of presenting illness • Onset: any significant or mild trauma preceding onset or insidious onset (AS). • Duration: affects imaging and management decisions. • Alleviating/exacerbating factors: positions, timing, past treatments, exercise and/or rest. • Associated symptoms: sciatica, paresthesias, pseudoclaudication, hip/knee pain (inflammatory arthritis), bowel/bladder dysfunction. Review of Systems: • Visceral causes (Renal, GI, Pelvic). • Systemic symptoms of cancer or infection: (Fever, weight loss, night sweat or loss of appetite). Past medical and surgical history: • Previous cancer history. • Medications. • Osteoporosis/pathologic fractures. • Anxiety or depression. Social History: • Smoking, obesity, older age, intravenous (IV) drug use and work ergonomics.
Physical Exam	• Inspect back and posture for any anatomical abnormalities. • Palpate the back to assess vertebral or soft tissue tenderness (sensitive for spinal infection). • Straight leg raise test to confirm radiculopathy. • Neurologic assessment of L5 and S1 roots for patient suspected to have disc herniation. • Evaluation for malignancy if history compatible with systemic diseases. • Detect the baseline range of motion for the patient.
Diagnostic Studies	Red Flags appropriate for imaging: • Recent significant trauma, or milder trauma age >50. • Unexplained weight loss. • Unexplained fever. • Immunosuppression. • History of cancer. • IV drug use. • Osteoporosis, prolonged use of glucocorticoids. • Age >70. • Focal neurologic deficit progressive or disabling symptoms. • Duration greater than 6 weeks. • Prior surgery.
	Plain x-rays	• Can detect infection, fracture, malignancy, spondylolisthesis, degenerative changes, disc space narrowing, and prior surgery. • ESR can be used as a screening test if malignancy and infection are concerned, where are very unlikely in patients with an ESR <20 and no more than one risk factor for a systemic illness.
	CT	• Demonstrating bony abnormalities such as sacroiliac joint disease, fractures, spondylolisthesis, unstable fusions, abnormal facet joints, degenerative changes, and congenital abnormalities. • Abnormal radiographs of the spine or non-diagnostic following trauma.
	MRI	• Best for viewing soft tissues—indicated with neurologic signs/symptoms; most useful when there is concern for disk herniation, spinal stenosis, osteomyelitis, discitis, spinal epidural abscess, bone metastasis, arachnoiditis, neural tube defects. • Detect the sacroiliac changes of AS before these are apparent on plain radiographs.
	Electromyography (EMG)	• For patients with radiculopathy who may be surgical candidates and who have poor correlation between their radicular symptoms and neuroimaging. • For patients with multilevel disease evident on neuroimaging.
	Radionuclide bone scans	• Sensitive for detecting occult infection or a neoplasm than are plain radiographs. • Limited use in patients who have both normal plain films and a normal ESR.
AS, Ankylosing spondylitis; ESR, Erythrocyte sedimentation rate.