Assessment of Central Pain in Patients Who Undergo Spinal Surgery and Influence in Surgery Outcome

* Pain is one of the most common concerns for which patients seek medical attention. * Pain is usually understood as symptom that reflects peripheral organic damage. Many patients experience pain, often chronically, independently of any underlying cause such as chronic regional pain syndromes (irritable bowel syndrome, temporo-mandibular pain syndrome, chronic headache or chronic low back pain)or diffuse like in fibromyalgia. In all those \"functional\" syndromes, accumulated evidence supports involvement of central pain processing systems, hypothalamic pituitary adrenal axes and autonomic nervous system, and are now referred as central pain conditions. * Other patients suffers from chronic pain caused by damage or inflammation in peripheral tissues, but also experienced more diffuse pain, not directly explained by peripheral damage, that further aggravates pain and function. This is illustrated by the high prevalence of fibromyalgia observed in patients with rheumatoid arthritis, osteoarthritis or ankylosing spondylitis for example. These pain conditions are now understood as combinations of peripheral, neuropathic and central pain. The investigators aimed to focus in this study in patients that are candidates to spinal surgery and suffer from low back pain and/or radiculopathy. Pain in these patients may arise from damage to nerves - neuropathic pain- , to musculoskeletal structures - peripheral pain-, and may also reflects alteration in central pain processes. In these patients, spine surgery is usually performed to improve quality of life, decrease pain and avoid neurological deficits. Evaluation of surgical outcome includes objective measures such as neurological findings and radiographic evaluation, and subjective measures including patient self-assessments for pain and quality of life and psychological changes. The aim of this study is to evaluate patients who undergo spinal surgery for presence of central pain and central sensitization symptoms and evaluate their influence on these surgical outcomes