Failed back syndrome is a general term that refers to chronic severe pain experienced after unsuccessful surgery for back pain. Surgery for back pain is conducted when there is an identifiable source of pain-usually to decompress a pinched nerve root or to stabilize a painful joint. However, back pain can have a number of causes and accurate identification of a source of pain is complicated; often symptoms do not correlate well with x-rays or magnetic resonance imaging (MRI) scans. As a result, diagnosis and patient selection for surgery are essential.
Failed back syndrome can have any number of causes. For example, the original cause of the pain can recur or there may be complications during surgery. The nerve root causing the pain may be inadequately decompressed, joints or nerves may become irritated during the surgical procedure, or scar tissue may compress or bind nerve roots. In addition, nerve damage, either prior to surgery or during the procedure, will not heal and can contribute to ongoing pain. In some cases, nerves may regenerate to some extent, but even this can cause pain if the regeneration is abnormal. Inadequate or incomplete rehabilitation and physical therapy, especially in patients whose back muscles are deconditioned (out of shape), can cause chronic pain as well.
Spinal fusion surgery, a procedure used to stabilize joints in the spine, usually is very successful, but also carries the risk of failed back syndrome. For this procedure, hooks, rods, and screws are used to fix the spine, and then bone taken from another part of the body or from a bone bank is implanted to encourage bone to grow across the joints. Following surgery, there is a chance that the metal implants will fail, or the bones may fail to fuse for unknown reasons. Also, the fixing of one or more spinal joints may increase the strain on nearby joints. Any of these conditions may lead to ongoing pain.
The pain associated with failed back syndrome varies depending on the surgical procedure and the original condition. The pain, which ranges from a dull ache to sharp stabbing pain, may be localized to one region of the back or may extend to the legs.
The diagnosis of failed back syndrome is the same as the diagnosis of other forms of back pain. X-rays, MRI scans, and computed tomography (CT) scans are used to visualize the structures of the back to identify the source of the pain. Minimally invasive spine procedures, such as epidural injections of steroids or pain medication, also may be used to isolate the source of the pain and provide some pain relief to facilitate rehabilitation.