Failed back surgery syndrome (FBSS) management
Definition
Failed back surgery syndrome (FBSS) is a generalized term used to describe the condition of patients who have not had a successful result with back or spine surgery and experience continued pain after surgery.
Causes
Multiple factors can contribute to the development of FBSS, including:- Recurrent spinal disc herniation
- Persistent pressure on a spinal nerve after surgery
- Altered joint mobility and scar tissue (fibrosis)
- Pre-existing conditions, such as diabetes, autoimmune disease, psychiatric and vascular diseases
Exercise, Physical Therapy, Rehabilitation
Intensive physical therapy and exercise programs are commonly prescribed for FBSS patients. Although the authors agree that physical rehabilitation, in general, may help maintain or increase the patient's functioning, there are only moderate, limited levels of evidence for the long-term outcomes within the peer-reviewed literature. There is no Level evidence for exercise, physical therapy, and behavioral modification FBSS treatments, but there is strong Level evidence to support these treatments. On the basis of the demonstrated evidence, the proven, active exercise modalities may be utilized, along with interventional techniques with high levels of evidence, such as SCS, in order to maximize function, reduce medications, and improve the activities of daliy living and Quality of Life. Passive modalities may be avoided due to lack of demonstrated efficacy and associated costs.
Medications
There is no “gold standard” for medication treatment of FBSS. Although many FBSS patients are treated with medications, data supporting their long-term efficacy are lacking.
Anticonvulsants and antidepressants are frequently recommended for FBSS with a neuropathic pain component, despite inconclusive evidence for their efficacy. Gabapentin has shown promise in reducing pain and improving function in case reports; however, high-level follow-up evidence is lacking. Furthermore, pregabalin failed to demonstrate greater efficacy than placebo in neuropathic pain associated with radiculopathy. Evidence supporting use of antidepressants for neuropathic pain is mixed.
Beyond a case report with unclear clinical implications, opioids have not been studied in FBSS. Although fair-to-good evidence supports efficacy for pain relief, lasting functional improvement is uncertain. The risks also include addiction, overdose complications including death, and analgesic failure due to intolerable side effects.
Medication management for FBSS is part of an interdisciplinary care model with an emphasis not only on pain control but also on improved function and attention to psychosocial factors. Nonetheless, there is no Level I or II evidence in support of any such medication utilization for FBSS.
Interventional Procedures
FBSS has many sub-etiologies, often overlapping, so it is difficult to control for confounding factors. Many patients suffer adjacent level disease of either discogenic or facetogenic origin, recurrent or persistent neural compressive disease, neuritis, fibrosis, deafferentation, and hardware pain, not to mention centralization of pain syndromes layered on the bio-psychosocial nature of failed surgeries and disability.
Interventional pain physicians may observe optimal outcomes for individual patients paired with certain procedures. Those with epidural fibrosis of the lateral recess, for example, may respond dramatically to epidural adhesiolysis directed to that level; or those with painful, prognostically positive facet arthrosis at an adjacent level may be resoundingly treated with denervation of those facet joints. Interventions aimed at a specific and responsible sub-etiology of the syndrome often work similarly to the effects seen in non-postoperative patients. Although short-term positive impacts on visual analog scale helping mesuring the level of pain from 0 (no pain) to 10 (extreme pain) have been shown, many studies have limited follow-up and cannot establish long-term efficacy.
Improvements in imaging resolution and understanding the correlation with prognostic indicators will likely generate more robust studies. Sweeping claims about treatment efficacy are hard to make due to the heterogeneity of the FBSS pain etiology. Therefore, sound clinical evaluation with particular sensitivity to the nuances of patient histories will best guide treatment options. Some data exist supporting interventions such as epidural steroid injections, lysis of epidural fibrosis, and radiofrequency rhizotomy to treat the appropriate FBSS patient. Long-term therapeutic evidence for any and all such interventions continues to be limited.
Implantable Technologies
Neuromodulation, including spinal cord stimulator and intrathecal drug delivery systems, may offer more effective, safer long-term pain management for FBSS patients, especially in light of the recent call by The Centers for Disease Control and Prevention (CDC) to lessen dependence on chronic opioid therapy for chronic pain. As SCS has fewer complications and no medication-related side effects it is usually the preferred over IDDS; however, both may be more effective than systemic medications. A significant advantage of both SCS and IDDS is the option to trial the therapy for several days with a simple percutaneous needle delivery of electrodes (SCS) or a catheter (IDDS) before undertaking a permanent implant.
The strongest evidence for FBSS treatment with implantable technology exists for SCS. Recent Level I data demonstrated robust results for high-frequency SCS at 10 kHz. High-frequency SCS at 10 kHz resulted in superior pain relief compared with traditional SCS, and demonstrated long-term efficacy up to 24 months.
When SCS does not provide adequate relief and systemic medications lack efficacy or cause intolerable side effects, IDDS may be effective by placing low doses of medication directly at the spinal target of interest (Level II).
Of course, as with all therapies, not every patient diagnosed with FBSS and noncorrective lesion is a candidate for implantable technologies. The authors encourage the astute clinician to weigh all evidence available along with a comprehensive evaluation of the specific FBSS patient, in order to choose the best therapeutic modality.
Surgical Options and Reoperation
Ultimately, there is a lack of evidence for an obvious surgical reoperative technique that reliably treats FBSS patients. Reoperation is likely to be considered when there is an obvious concordant anatomical and clinical source for symptoms, and fusion is likely to be considered when there may be obvious signs of spinal instability and/or acute nerve root compromise unresponsive to more conservative interventions. Some patients will likely benefit from reoperation, but there is no sufficiently high-level evidence to identify such surgical candidates. As always, astute, educated clinical judgment must determine surgical versus nonsurgical treatment decisions, as well as consider evidence-based alternatives, such as neuromodulation.
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