The Impact of Epidural Steroid Analgesia on Functional MRI for Patients With Low Back Pain

Pain, as an ancient enemy to human kind, was one of the most mystical phenomena within our body. For centuries, people search the magic wand to solve this issue and reach the heaven destination. However, like our original sin commit by Adam and Eve, the shadow of pain always surround and even rebel our body and spirit. Even more, pain traps our soul and body not only for the acute stage induced by noxious stimulation but also change our mind and body whenever chronic period start even the stimulation disappears. Chronic pain so far has become one of the greatest health issues for modern people. Chronic pain affects millions of people and the treatment options are quite limited and not effective everyone[1]. On the other way, why and how people develop chronic pain, especially when there is no further painful stimulation, remain to be investigated.

Chronic low back pain (CLBP) is the most prevalent form of chronic pain, and the most common reason for disability in working-age population [2]. CLBP has also been reported associated with many abnormal brain anatomy and function which includes the reduction in cortical gray matter in the bilateral dorsolateral prefrontal cortex (DLPFC), thalamus, brain stem, primary somatosensory cortex, and posterior parietal cortex. [3-5] There are already many studies that demonstrated abnormal cortical function for people with CLBP [6-10]. Meanwhile, DLPFC was also reported to be influenced by many pain process which included pain modulation [11-13], placebo analgesia [14, 15], pain control [16, 17]or pain catastrophizing[18]. And recent report has showed that effective treatment of chronic back pain patients reverses abnormal DLPFC function[19]. Meanwhile, epidural steroid injection has been performed in clinical for routinely managed for low back pain patients. Patients refused or have no indication for surgery or have little response to rehabilitation may consider this management. There was good evidence for short- and long-term relief of chronic pain secondary to disc herniation with local anesthetic and steroids[20, 21]. However, the impact of this treatment on functionalMRI (fMRI) has never been investigated. The investigators research will try to solve this issue.

Patients who first visited in pain clinic for low back pain with root sign will be included in this study.

Inclusion Criteria: 1. Patients with disc herniation or radiculitis who are over 18 years of age. 2. Patients with a history of chronic function-limiting low back pain and lower extremity pain for at least one months' duration. 3. Patients who are competent to understand the study and provide written informed consent and participate in outcome measurements. Exclusion Criteria: Patients have previous lumbar surgery with metal instrument. Initial MRI shows spinal stenosis or without disc herniation. Patients have unstable opioid use, uncontrolled psychiatric disorders, uncontrolled acute medical illness, any condition that could interfere with the interpretation of outcome assessments, pregnant or lactating women or allergy to local anesthetics or steroid. Patients who are unable to perform MRI or fMRI will also be excluded.

Pre-enrollment evaluation included demographic data, medical and surgical history with coexisting disease, lumbar spine X-ray will also be performed.