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.
Causes
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.
Symptoms
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.
Diagnosis
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.
