Failed Back Syndromes

Gregory Gebauer and D. Greg Anderson

Those with a poor outcome (persistent low back and extremity pain) following lumbosacral spinal surgery are often said to have failed back surgery syndrome (FBSS). Although lumped under this diagnosis, patients with FBSS make up a heterogeneous group with a variety of causes for their persistent symptoms. Treatment for this group is challenging. The workup must consider the possibility of undiagnosed spinal or medical pathology, continued or recurrent spinal pathology, iatrogenic problems related to the prior spinal surgery, psychosocial factors or disorders, and/or secondary gain. By performing a thorough history and physical examination and appropriate studies, it may be possible to identify a specific cause for the ongoing problem. In some cases, patients may be successfully treated with revision surgery. Unfortunately, a leading cause of FBSS is an inappropriate indication for the initial surgical procedure. In this subset, additional surgery is unlikely to resolve the patient’s symptoms.

Classification

Although there is no uniformly accepted classification system for FBSS patients, one way to think about this population is to identify the surgical failure in terms of the following:

1. Wrong patient. The patient was an inappropriate candidate for the initial surgical procedure. Examples of this type of problem include patients with underlying psychosocial issues contributing to their pain, active litigation, personality disorders, or pathology that is not likely to be helped by surgery. Additional surgery in this group is not indicated.

3. Wrong surgery. The pathologic condition was amenable to, but not treated by, an operative approach that was able to correct the problem. The poor outcome could be due to incomplete treatment of the problem (incomplete decompression) or it could be iatrogenic, such as flat back syndrome with the surgical procedure. Some of these patients can be helped by correcting the underlying problem.

4. Unavoidable complication. The patient is suffering symptoms from a known complication of the surgical intervention, such as infection, arachnoiditis, or pseudarthrosis.

Workup

History

A thorough history is mandatory when trying to identify the cause of the FBSS patient’s continued complaints of pain. The office notes, operative reports, and radiographs from the index procedure should be reviewed whenever possible. The surgeon should seek to understand the initial symptoms and how they responded to surgery. The presence of a pain-free interval after surgery is important and may indicate recurrent or new pathology or a delayed iatrogenic problem, such as iatrogenic instability or pseudarthrosis. Patients without a pain-free interval may have retained pathology, have had improper diagnosis, or simply represent a poor process of patient selection for the index procedure. It is important to thoroughly explore possible psychosocial barriers, pending litigation, and secondary gain from a workers’ compensation claim, as these factors would generally be expected to decrease the likelihood of a good outcome from further surgery, regardless of the underlying spinal pathology.

Physical Examination

The physical examination should be complete and focus in particular on identifying musculoskeletal or neurologic abnormalities that may present a clue as to the underlying condition. In addition, the surgeon should search for signs of an exaggeration of pain response or nonorganic symptoms as described by Waddell et al., including a nonanatomic pain distribution, symptoms out of proportion to stimulus, or exaggerated pain behavior.

Spinal Imaging

Treatment

After compiling the necessary information, the physician should reach a diagnosis when possible. For patients who have an objective that may be corrected with further surgery, it is also important to consider psychosocial factors before proceeding with an operation. Patients without a correctable cause for their pain should be managed nonsurgically, generally with the assistance of other specialists (e.g., pain management team, psychiatry, exercise specialists). The most difficult group of patients are those who have a potentially surgically correctable source of pain but who also have psychosocial barriers impeding an optimal outcome. Treatment in such cases must be highly individualized. When possible, it is beneficial to reduce the barrier through preoperative interventions (e.g., psychological evaluation and counseling) and with frank and open discussions with the patients regarding their problems, the odds of success, and realistic expectations following intervention.

Outcome

The outcome for FBSS patients is less favorable than for patients undergoing primary spinal surgery. The workup and educational process for these patients are demanding. However, there is a subset of patients with an objective and correctable condition who may benefit from additional surgical intervention. With careful patient selection, meticulous preoperative planning, thorough patient education, and good technical execution, some patients (a minority of those with FBSS) can benefit from surgical intervention.

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